Merge pull request #1742 from tgstation/TheGreatNullening

Add support for nullable reference types in `Tgstation.Server.Host`. Use the RobustToolbox watchdog API to shutdown OpenDream

.github/workflows/ci-pipeline.yml

@@ -203,7 +203,7 @@ jobs:
     - name: Create TGS Deployment
       run: |
         cd $HOME/OpenDream
-        dotnet run -c Release --project OpenDreamPackageTool -- --tgs -o tgs_deploy
+        dotnet run -c Release --project OpenDreamPackageTool --property WarningLevel=0 -- --tgs -o tgs_deploy
 
     - name: Build DMAPI
       run: |

src/Tgstation.Server.Api/Models/EngineVersion.cs

@@ -38,7 +38,7 @@ namespace Tgstation.Server.Api.Models
 		public int? CustomIteration { get; set; }
 
 		/// <summary>
-		/// Parses a stringified <see cref="EngineVersion"/>.
+		/// Attempts to parse a stringified <see cref="EngineVersion"/>.
 		/// </summary>
 		/// <param name="input">The input <see cref="string"/>.</param>
 		/// <param name="engineVersion">The output <see cref="EngineVersion"/>.</param>
@@ -110,6 +110,23 @@ namespace Tgstation.Server.Api.Models
 			return true;
 		}
 
+		/// <summary>
+		/// Parses a stringified <see cref="EngineVersion"/>.
+		/// </summary>
+		/// <param name="input">The input <see cref="string"/>.</param>
+		/// <returns>The output <see cref="EngineVersion"/>.</returns>
+		/// <exception cref="InvalidOperationException">If the <paramref name="input"/> is not a valid stringified <see cref="EngineVersion"/>.</exception>
+		public static EngineVersion Parse(string input)
+		{
+			if (input == null)
+				throw new ArgumentNullException(nameof(input));
+
+			if (TryParse(input, out var engineVersion))
+				return engineVersion!;
+
+			throw new InvalidOperationException($"Invalid engine version: {input}");
+		}
+
 		/// <summary>
 		/// Initializes a new instance of the <see cref="EngineVersion"/> class.
 		/// </summary>

src/Tgstation.Server.Api/Models/ErrorCode.cs

@@ -150,10 +150,10 @@ namespace Tgstation.Server.Api.Models
 		InstanceLimitReached,
 
 		/// <summary>
-		/// Attempted to create an <see cref="Instance"/> with a whitespace <see cref="NamedEntity.Name"/>.
+		/// Attempted to create an <see cref="Instance"/> with a whitespace <see cref="NamedEntity.Name"/> or <see cref="Instance.Path"/>.
 		/// </summary>
-		[Description("Instance names cannot be whitespace!")]
-		InstanceWhitespaceName,
+		[Description("Instance names and paths cannot be whitespace!")]
+		InstanceWhitespaceNameOrPath,
 
 		/// <summary>
 		/// The <see cref="ApiHeaders.InstanceIdHeader"/> header was required but not set.

src/Tgstation.Server.Api/Models/JobCode.cs

@@ -16,7 +16,7 @@ namespace Tgstation.Server.Api.Models
 		/// <summary>
 		/// When the instance is being moved.
 		/// </summary>
-		[Description("Instance move")]
+		[Description("Move instance")]
 		Move,
 
 		/// <summary>

src/Tgstation.Server.Api/Models/Response/ServerUpdateResponse.cs

@@ -20,7 +20,7 @@ namespace Tgstation.Server.Api.Models.Response
 		/// <param name="newVersion">The value of <see cref="NewVersion"/>.</param>
 		/// <param name="fileTicket">The optional value of <see cref="FileTicketResponse.FileTicket"/>.</param>
 		[JsonConstructor]
-		public ServerUpdateResponse(Version newVersion, string fileTicket)
+		public ServerUpdateResponse(Version newVersion, string? fileTicket)
 		{
 			NewVersion = newVersion ?? throw new ArgumentNullException(nameof(newVersion));
 			FileTicket = fileTicket;

src/Tgstation.Server.Host/Components/Chat/ChannelMapping.cs

@@ -1,4 +1,6 @@
-namespace Tgstation.Server.Host.Components.Chat
+using System;
+
+namespace Tgstation.Server.Host.Components.Chat
 {
 	/// <summary>
 	/// Represents a mapping of a <see cref="ChannelRepresentation.RealId"/>.
@@ -38,6 +40,15 @@
 		/// <summary>
 		/// The <see cref="ChannelRepresentation"/> with the mapped Id.
 		/// </summary>
-		public ChannelRepresentation Channel { get; set; }
+		public ChannelRepresentation Channel { get; }
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="ChannelMapping"/> class.
+		/// </summary>
+		/// <param name="channel">The value of <see cref="Channel"/>.</param>
+		public ChannelMapping(ChannelRepresentation channel)
+		{
+			Channel = channel ?? throw new ArgumentNullException(nameof(channel));
+		}
 	}
 }

src/Tgstation.Server.Host/Components/Chat/ChannelRepresentation.cs

@@ -14,7 +14,7 @@ namespace Tgstation.Server.Host.Components.Chat
 		/// <summary>
 		/// Backing field for <see cref="RealId"/>. Represented as a <see cref="string"/> to avoid BYOND percision loss.
 		/// </summary>
-		public string Id { get; set; }
+		public string Id { get; private set; }
 
 		/// <summary>
 		/// The <see cref="Providers.IProvider"/> channel Id.
@@ -30,12 +30,12 @@ namespace Tgstation.Server.Host.Components.Chat
 		/// <summary>
 		/// The user friendly name of the <see cref="ChannelRepresentation"/>.
 		/// </summary>
-		public string FriendlyName { get; set; }
+		public string FriendlyName { get; }
 
 		/// <summary>
 		/// The name of the connection the <see cref="ChannelRepresentation"/> belongs to.
 		/// </summary>
-		public string ConnectionName { get; set; }
+		public string ConnectionName { get; }
 
 		/// <summary>
 		/// If this is considered a channel for admin commands.
@@ -45,16 +45,30 @@ namespace Tgstation.Server.Host.Components.Chat
 		/// <summary>
 		/// If this is a 1-to-1 chat channel.
 		/// </summary>
-		public bool IsPrivateChannel { get; set; }
+		public bool IsPrivateChannel { get; init; }
 
 		/// <summary>
 		/// For user use.
 		/// </summary>
-		public string Tag { get; set; }
+		public string? Tag { get; set; }
 
 		/// <summary>
 		/// If this channel supports embeds.
 		/// </summary>
-		public bool EmbedsSupported { get; set; }
+		public bool EmbedsSupported { get; init; }
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="ChannelRepresentation"/> class.
+		/// </summary>
+		/// <param name="connectionName">The value of <see cref="ConnectionName"/>.</param>
+		/// <param name="friendlyName">The value of <see cref="FriendlyName"/>.</param>
+		/// <param name="id">The value of <see cref="RealId"/>/<see cref="Id"/>.</param>
+		public ChannelRepresentation(string connectionName, string friendlyName, ulong id)
+		{
+			ConnectionName = connectionName ?? throw new ArgumentNullException(nameof(connectionName));
+			FriendlyName = friendlyName ?? throw new ArgumentNullException(nameof(friendlyName));
+			Id = null!;
+			RealId = id;
+		}
 	}
 }

src/Tgstation.Server.Host/Components/Chat/ChatManager.cs

@@ -24,8 +24,7 @@ using Tgstation.Server.Host.Utils;
 namespace Tgstation.Server.Host.Components.Chat
 {
 	/// <inheritdoc cref="IChatManager" />
-	// TODO: Decomplexify
-#pragma warning disable CA1506
+#pragma warning disable CA1506 // TODO: Decomplexify
 	sealed class ChatManager : IChatManager, IRestartHandler
 	{
 		/// <summary>
@@ -69,7 +68,7 @@ namespace Tgstation.Server.Host.Components.Chat
 		readonly Dictionary<long, IProvider> providers;
 
 		/// <summary>
-		/// Map of <see cref="SemaphoreSlim"/>s used to guard concurrent access to <see cref="ChangeChannels(long, IEnumerable{Models.ChatChannel}, CancellationToken)"/>, keyed by <see cref="ChatBotSettings"/> <see cref="Api.Models.EntityId.Id"/>.
+		/// Map of <see cref="SemaphoreSlim"/>s used to guard concurrent access to <see cref="ChangeChannels(long, IEnumerable{Models.ChatChannel}, CancellationToken)"/>, keyed by <see cref="ChatBotSettings"/> <see cref="EntityId.Id"/>.
 		/// </summary>
 		readonly ConcurrentDictionary<long, SemaphoreSlim> changeChannelSemaphores;
 
@@ -101,17 +100,17 @@ namespace Tgstation.Server.Host.Components.Chat
 		/// <summary>
 		/// The <see cref="ICustomCommandHandler"/> for the <see cref="ChangeChannels(long, IEnumerable{Models.ChatChannel}, CancellationToken)"/>.
 		/// </summary>
-		ICustomCommandHandler customCommandHandler;
+		ICustomCommandHandler? customCommandHandler;
 
 		/// <summary>
 		/// The <see cref="Task"/> that monitors incoming chat messages.
 		/// </summary>
-		Task chatHandler;
+		Task? chatHandler;
 
 		/// <summary>
 		/// A <see cref="Task"/> that represents the <see cref="IProvider"/>s initial connection.
 		/// </summary>
-		Task initialProviderConnectionsTask;
+		Task? initialProviderConnectionsTask;
 
 		/// <summary>
 		/// A <see cref="Task"/> that represents all sent messages.
@@ -234,7 +233,7 @@ namespace Tgstation.Server.Host.Components.Chat
 
 					var newMappings = results.SelectMany(
 						kvp => kvp.Value.Select(
-							channelRepresentation => new ChannelMapping
+							channelRepresentation => new ChannelMapping(channelRepresentation)
 							{
 								IsWatchdogChannel = kvp.Key.IsWatchdogChannel == true,
 								IsUpdatesChannel = kvp.Key.IsUpdatesChannel == true,
@@ -242,7 +241,6 @@ namespace Tgstation.Server.Host.Components.Chat
 								IsSystemChannel = kvp.Key.IsSystemChannel == true,
 								ProviderChannelId = channelRepresentation.RealId,
 								ProviderId = connectionId,
-								Channel = channelRepresentation,
 							}));
 
 					ulong baseId;
@@ -255,7 +253,7 @@ namespace Tgstation.Server.Host.Components.Chat
 					lock (mappedChannels)
 					{
 						lock (providers)
-							if (!providers.TryGetValue(connectionId, out IProvider verify) || verify != provider) // aborted again
+							if (!providers.TryGetValue(connectionId, out var verify) || verify != provider) // aborted again
 								return;
 						foreach (var newMapping in newMappings)
 						{
@@ -269,7 +267,7 @@ namespace Tgstation.Server.Host.Components.Chat
 					// we only want to update contexts if everything at startup has connected once already
 					// otherwise we could send an incomplete channel set to the DMAPI, which will then spout all its queued messages into it instead of all relevant chatbots
 					// The watchdog can call this if it needs to after starting up
-					if (initialProviderConnectionsTask.IsCompleted)
+					if (initialProviderConnectionsTask!.IsCompleted)
 						await UpdateTrackingContexts(cancellationToken);
 				}
 				finally
@@ -287,23 +285,25 @@ namespace Tgstation.Server.Host.Components.Chat
 			logger.LogTrace("ChangeSettings...");
 
 			Task disconnectTask;
-			IProvider provider = null;
+			IProvider? provider = null;
+			var newSettingsId = Models.ModelExtensions.Require(newSettings, x => x.Id);
+			var newSettingsEnabled = Models.ModelExtensions.Require(newSettings, x => x.Enabled);
 			lock (providers)
 			{
 				// raw settings changes forces a rebuild of the provider
-				if (providers.ContainsKey(newSettings.Id.Value))
-					disconnectTask = DeleteConnection(newSettings.Id.Value, cancellationToken);
+				if (providers.ContainsKey(newSettingsId))
+					disconnectTask = DeleteConnection(newSettingsId, cancellationToken);
 				else
 					disconnectTask = Task.CompletedTask;
-				if (newSettings.Enabled.Value)
+				if (newSettingsEnabled)
 				{
 					provider = providerFactory.CreateProvider(newSettings);
-					providers.Add(newSettings.Id.Value, provider);
+					providers.Add(newSettingsId, provider);
 				}
 			}
 
 			lock (mappedChannels)
-				foreach (var oldMappedChannelId in mappedChannels.Where(x => x.Value.ProviderId == newSettings.Id).Select(x => x.Key).ToList())
+				foreach (var oldMappedChannelId in mappedChannels.Where(x => x.Value.ProviderId == newSettingsId).Select(x => x.Key).ToList())
 					mappedChannels.Remove(oldMappedChannelId);
 
 			await disconnectTask;
@@ -317,8 +317,8 @@ namespace Tgstation.Server.Host.Components.Chat
 			}
 
 			var reconnectionUpdateTask = provider?.SetReconnectInterval(
-				newSettings.ReconnectionInterval.Value,
-				newSettings.Enabled.Value)
+				Models.ModelExtensions.Require(newSettings, x => x.ReconnectionInterval),
+				newSettingsEnabled)
 				?? Task.CompletedTask;
 			lock (activeChatBots)
 			{
@@ -326,7 +326,7 @@ namespace Tgstation.Server.Host.Components.Chat
 				if (originalChatBot != null)
 					activeChatBots.Remove(originalChatBot);
 
-				activeChatBots.Add(new Models.ChatBot
+				activeChatBots.Add(new Models.ChatBot(newSettings.Channels)
 				{
 					Id = newSettings.Id,
 					ConnectionString = newSettings.ConnectionString,
@@ -334,7 +334,6 @@ namespace Tgstation.Server.Host.Components.Chat
 					Name = newSettings.Name,
 					ReconnectionInterval = newSettings.ReconnectionInterval,
 					Provider = newSettings.Provider,
-					Channels = newSettings.Channels,
 				});
 			}
 
@@ -357,7 +356,7 @@ namespace Tgstation.Server.Host.Components.Chat
 
 			message = String.Format(CultureInfo.InvariantCulture, "WD: {0}", message);
 
-			if (!initialProviderConnectionsTask.IsCompleted)
+			if (!initialProviderConnectionsTask!.IsCompleted)
 				logger.LogTrace("Waiting for initial provider connections before sending watchdog message...");
 
 			// Reimplementing QueueMessage
@@ -376,12 +375,12 @@ namespace Tgstation.Server.Host.Components.Chat
 		}
 
 		/// <inheritdoc />
-		public Func<string, string, Action<bool>> QueueDeploymentMessage(
+		public Func<string?, string, Action<bool>> QueueDeploymentMessage(
 			Models.RevisionInformation revisionInformation,
 			EngineVersion engineVersion,
 			DateTimeOffset? estimatedCompletionTime,
-			string gitHubOwner,
-			string gitHubRepo,
+			string? gitHubOwner,
+			string? gitHubRepo,
 			bool localCommitPushed)
 		{
 			List<ulong> wdChannels;
@@ -390,17 +389,17 @@ namespace Tgstation.Server.Host.Components.Chat
 
 			logger.LogTrace("Sending deployment message for RevisionInformation: {revisionInfoId}", revisionInformation.Id);
 
-			var callbacks = new List<Func<string, string, ValueTask<Func<bool, ValueTask>>>>();
+			var callbacks = new List<Func<string?, string, ValueTask<Func<bool, ValueTask>>>>();
 
 			var task = Task.WhenAll(
 				wdChannels.Select(
 					async x =>
 					{
-						ChannelMapping channelMapping;
+						ChannelMapping? channelMapping;
 						lock (mappedChannels)
 							if (!mappedChannels.TryGetValue(x, out channelMapping))
 								return;
-						IProvider provider;
+						IProvider? provider;
 						lock (providers)
 							if (!providers.TryGetValue(channelMapping.ProviderId, out provider))
 								return;
@@ -431,8 +430,8 @@ namespace Tgstation.Server.Host.Components.Chat
 			AddMessageTask(task);
 
 			Task callbackTask;
-			Func<bool, Task> finalUpdateAction = null;
-			async Task CallbackTask(string errorMessage, string dreamMakerOutput)
+			Func<bool, Task>? finalUpdateAction = null;
+			async Task CallbackTask(string? errorMessage, string dreamMakerOutput)
 			{
 				await task;
 				var callbackResults = await ValueTaskExtensions.WhenAll(
@@ -457,7 +456,7 @@ namespace Tgstation.Server.Host.Components.Chat
 					return;
 				}
 
-				AddMessageTask(finalUpdateAction(active));
+				AddMessageTask(finalUpdateAction!(active));
 			}
 
 			return (errorMessage, dreamMakerOutput) =>
@@ -495,7 +494,7 @@ namespace Tgstation.Server.Host.Components.Chat
 			if (customCommandHandler == null)
 				throw new InvalidOperationException("RegisterCommandHandler() hasn't been called!");
 
-			IChatTrackingContext context = null;
+			IChatTrackingContext context = null!;
 			lock (mappedChannels)
 				context = new ChatTrackingContext(
 					customCommandHandler,
@@ -524,7 +523,7 @@ namespace Tgstation.Server.Host.Components.Chat
 				await channelSink.UpdateChannels(channels, cancellationToken);
 			}
 
-			var waitingForInitialConnection = !initialProviderConnectionsTask.IsCompleted;
+			var waitingForInitialConnection = !initialProviderConnectionsTask!.IsCompleted;
 			if (waitingForInitialConnection)
 			{
 				logger.LogTrace("Waiting for initial chat bot connections before updating tracking contexts...");
@@ -562,7 +561,7 @@ namespace Tgstation.Server.Host.Components.Chat
 				? semaphore
 				: null)
 			using (hasSemaphore
-				? await SemaphoreSlimContext.Lock(semaphore, cancellationToken)
+				? await SemaphoreSlimContext.Lock(semaphore!, cancellationToken)
 				: null)
 			{
 				var provider = await RemoveProviderChannels(connectionId, true, cancellationToken);
@@ -589,7 +588,7 @@ namespace Tgstation.Server.Host.Components.Chat
 		}
 
 		/// <inheritdoc />
-		public ValueTask HandleRestart(Version updateVersion, bool handlerMayDelayShutdownWithExtremelyLongRunningTasks, CancellationToken cancellationToken)
+		public ValueTask HandleRestart(Version? updateVersion, bool handlerMayDelayShutdownWithExtremelyLongRunningTasks, CancellationToken cancellationToken)
 		{
 			var message = updateVersion == null
 				? $"TGS: {(handlerMayDelayShutdownWithExtremelyLongRunningTasks ? "Graceful shutdown" : "Going down")}..."
@@ -618,10 +617,10 @@ namespace Tgstation.Server.Host.Components.Chat
 		/// <param name="removeProvider">If the provider should be removed from <see cref="providers"/> and <see cref="trackingContexts"/> should be update.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in the <see cref="IProvider"/> being removed if it exists, <see langword="null"/> otherwise.</returns>
-		async ValueTask<IProvider> RemoveProviderChannels(long connectionId, bool removeProvider, CancellationToken cancellationToken)
+		async ValueTask<IProvider?> RemoveProviderChannels(long connectionId, bool removeProvider, CancellationToken cancellationToken)
 		{
 			logger.LogTrace("RemoveProviderChannels {connectionId}...", connectionId);
-			IProvider provider;
+			IProvider? provider;
 			lock (providers)
 			{
 				if (!providers.TryGetValue(connectionId, out provider))
@@ -663,7 +662,7 @@ namespace Tgstation.Server.Host.Components.Chat
 		async ValueTask RemapProvider(IProvider provider, CancellationToken cancellationToken)
 		{
 			logger.LogTrace("Remapping channels for provider reconnection...");
-			IEnumerable<Models.ChatChannel> channelsToMap;
+			IEnumerable<Models.ChatChannel>? channelsToMap;
 			long providerId;
 			lock (providers)
 				providerId = providers.Where(x => x.Value == provider).Select(x => x.Key).First();
@@ -684,7 +683,7 @@ namespace Tgstation.Server.Host.Components.Chat
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask"/> representing the running operation.</returns>
 #pragma warning disable CA1502
-		async ValueTask ProcessMessage(IProvider provider, Message message, bool recursed, CancellationToken cancellationToken)
+		async ValueTask ProcessMessage(IProvider provider, Message? message, bool recursed, CancellationToken cancellationToken)
 #pragma warning restore CA1502
 		{
 			if (!provider.Connected)
@@ -765,11 +764,10 @@ namespace Tgstation.Server.Host.Components.Chat
 							message.User.Channel.ConnectionName,
 							message.User.FriendlyName,
 							newId);
-						mappedChannels.Add(newId, new ChannelMapping
+						mappedChannels.Add(newId, new ChannelMapping(message.User.Channel)
 						{
 							ProviderChannelId = message.User.Channel.RealId,
 							ProviderId = providerId,
-							Channel = message.User.Channel,
 						});
 
 						logger.LogTrace(
@@ -799,7 +797,7 @@ namespace Tgstation.Server.Host.Components.Chat
 
 				var mappingChannelRepresentation = mappedChannel.Value.Value.Channel;
 
-				message.User.Channel.Id = mappingChannelRepresentation.Id;
+				message.User.Channel.RealId = mappingChannelRepresentation.RealId;
 				message.User.Channel.Tag = mappingChannelRepresentation.Tag;
 				message.User.Channel.IsAdminChannel = mappingChannelRepresentation.IsAdminChannel;
 			}
@@ -813,11 +811,9 @@ namespace Tgstation.Server.Host.Components.Chat
 			if (address.Length > 1 && (address.Last() == ':' || address.Last() == ','))
 				address = address[0..^1];
 
-			address = address.ToUpperInvariant();
-
 			var addressed =
-				address == CommonMention.ToUpperInvariant()
-				|| address == provider.BotMention.ToUpperInvariant();
+				address.Equals(CommonMention, StringComparison.OrdinalIgnoreCase)
+				|| address.Equals(provider.BotMention, StringComparison.OrdinalIgnoreCase);
 
 			// no mention
 			if (!addressed && !message.User.Channel.IsPrivateChannel)
@@ -843,16 +839,16 @@ namespace Tgstation.Server.Host.Components.Chat
 				splits.RemoveAt(0);
 				var arguments = String.Join(" ", splits);
 
-				Tuple<ICommand, IChatTrackingContext> GetCommand()
+				Tuple<ICommand, IChatTrackingContext?>? GetCommand()
 				{
 					if (!builtinCommands.TryGetValue(command, out var handler))
 						return trackingContexts
 							.Where(trackingContext => trackingContext.Active)
-							.SelectMany(trackingContext => trackingContext.CustomCommands.Select(customCommand => Tuple.Create<ICommand, IChatTrackingContext>(customCommand, trackingContext)))
+							.SelectMany(trackingContext => trackingContext.CustomCommands.Select(customCommand => Tuple.Create<ICommand, IChatTrackingContext?>(customCommand, trackingContext)))
 							.Where(tuple => tuple.Item1.Name.Equals(command, StringComparison.OrdinalIgnoreCase))
 							.FirstOrDefault();
 
-					return Tuple.Create<ICommand, IChatTrackingContext>(handler, null);
+					return Tuple.Create<ICommand, IChatTrackingContext?>(handler, null);
 				}
 
 				const string UnknownCommandMessage = "TGS: Unknown command! Type '?' or 'help' for available commands.";
@@ -935,11 +931,11 @@ namespace Tgstation.Server.Host.Components.Chat
 		async Task MonitorMessages(CancellationToken cancellationToken)
 		{
 			logger.LogTrace("Starting processing loop...");
-			var messageTasks = new Dictionary<IProvider, Task<Message>>();
+			var messageTasks = new Dictionary<IProvider, Task<Message?>>();
 			ValueTask activeProcessingTask = ValueTask.CompletedTask;
 			try
 			{
-				Task updatedTask = null;
+				Task? updatedTask = null;
 				while (!cancellationToken.IsCancellationRequested)
 				{
 					if (updatedTask?.IsCompleted != false)
@@ -1025,7 +1021,7 @@ namespace Tgstation.Server.Host.Components.Chat
 		/// <param name="message">The <see cref="MessageContent"/> to send.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="Task"/> representing the running operation.</returns>
-		ValueTask SendMessage(IEnumerable<ulong> channelIds, Message replyTo, MessageContent message, CancellationToken cancellationToken)
+		ValueTask SendMessage(IEnumerable<ulong> channelIds, Message? replyTo, MessageContent message, CancellationToken cancellationToken)
 		{
 			var channelIdsList = channelIds.ToList();
 
@@ -1035,17 +1031,17 @@ namespace Tgstation.Server.Host.Components.Chat
 				message.Embed != null ? " (with embed)" : String.Empty,
 				String.Join(", ", channelIdsList));
 
-			if (!channelIdsList.Any())
+			if (channelIdsList.Count == 0)
 				return ValueTask.CompletedTask;
 
 			return ValueTaskExtensions.WhenAll(
 				channelIdsList.Select(x =>
 				{
-					ChannelMapping channelMapping;
+					ChannelMapping? channelMapping;
 					lock (mappedChannels)
 						if (!mappedChannels.TryGetValue(x, out channelMapping))
 							return ValueTask.CompletedTask;
-					IProvider provider;
+					IProvider? provider;
 					lock (providers)
 						if (!providers.TryGetValue(channelMapping.ProviderId, out provider))
 							return ValueTask.CompletedTask;
@@ -1102,7 +1098,7 @@ namespace Tgstation.Server.Host.Components.Chat
 			{
 				var cancellationToken = handlerCts.Token;
 				if (waitForConnections)
-					await initialProviderConnectionsTask.WaitAsync(cancellationToken);
+					await initialProviderConnectionsTask!.WaitAsync(cancellationToken);
 
 				await SendMessage(
 					channelIdsFactory(),

src/Tgstation.Server.Host/Components/Chat/ChatManagerFactory.cs

@@ -7,6 +7,7 @@ using Microsoft.Extensions.Logging;
 using Tgstation.Server.Host.Components.Chat.Commands;
 using Tgstation.Server.Host.Components.Chat.Providers;
 using Tgstation.Server.Host.Core;
+using Tgstation.Server.Host.Models;
 
 namespace Tgstation.Server.Host.Components.Chat
 {
@@ -54,6 +55,6 @@ namespace Tgstation.Server.Host.Components.Chat
 				serverControl,
 				loggerFactory,
 				loggerFactory.CreateLogger<ChatManager>(),
-				initialChatBots.Where(x => x.Enabled.Value));
+				initialChatBots.Where(x => x.Require(y => y.Enabled)));
 	}
 }

src/Tgstation.Server.Host/Components/Chat/ChatTrackingContext.cs

@@ -7,16 +7,17 @@ using System.Threading.Tasks;
 using Microsoft.Extensions.Logging;
 
 using Tgstation.Server.Host.Components.Chat.Commands;
+using Tgstation.Server.Host.Utils;
 
 namespace Tgstation.Server.Host.Components.Chat
 {
 	/// <inheritdoc />
-	sealed class ChatTrackingContext : IChatTrackingContext
+	sealed class ChatTrackingContext : DisposeInvoker, IChatTrackingContext
 	{
 		/// <inheritdoc />
 		public bool Active
 		{
-			get => active && onDispose != null;
+			get => active && !IsDisposed;
 			set
 			{
 				if (active == value)
@@ -61,25 +62,20 @@ namespace Tgstation.Server.Host.Components.Chat
 		readonly ILogger<ChatTrackingContext> logger;
 
 		/// <summary>
-		/// <see langword="lock"/> <see cref="object"/> for modifying <see cref="onDispose"/>, <see cref="channelSink"/>, and <see cref="Channels"/>.
+		/// <see langword="lock"/> <see cref="object"/> for modifying <see cref="Channels"/> and calling <see cref="IChannelSink.UpdateChannels(IEnumerable{ChannelRepresentation}, CancellationToken)"/>.
 		/// </summary>
 		readonly object synchronizationLock;
 
+		/// <summary>
+		/// The <see cref="IChannelSink"/> if any.
+		/// </summary>
+		volatile IChannelSink? channelSink;
+
 		/// <summary>
 		/// Backing field for <see cref="CustomCommands"/>.
 		/// </summary>
 		IReadOnlyCollection<CustomCommand> customCommands;
 
-		/// <summary>
-		/// The <see cref="IChannelSink"/> if any.
-		/// </summary>
-		IChannelSink channelSink;
-
-		/// <summary>
-		/// The <see cref="Action"/> to run when <see cref="Dispose"/>d.
-		/// </summary>
-		Action onDispose;
-
 		/// <summary>
 		/// Backing field for <see cref="Active"/>.
 		/// </summary>
@@ -91,45 +87,31 @@ namespace Tgstation.Server.Host.Components.Chat
 		/// <param name="customCommandHandler">The value of <see cref="customCommandHandler"/>.</param>
 		/// <param name="initialChannels">The initial value of <see cref="Channels"/>.</param>
 		/// <param name="logger">The value of <see cref="logger"/>.</param>
-		/// <param name="onDispose">The value of <see cref="onDispose"/>.</param>
+		/// <param name="disposeAction">The <see cref="IDisposable.Dispose"/> action for the <see cref="DisposeInvoker"/>.</param>
 		public ChatTrackingContext(
 			ICustomCommandHandler customCommandHandler,
 			IEnumerable<ChannelRepresentation> initialChannels,
 			ILogger<ChatTrackingContext> logger,
-			Action onDispose)
+			Action disposeAction)
+			: base(disposeAction)
 		{
 			this.customCommandHandler = customCommandHandler ?? throw new ArgumentNullException(nameof(customCommandHandler));
 			Channels = initialChannels?.ToList() ?? throw new ArgumentNullException(nameof(initialChannels));
 			this.logger = logger ?? throw new ArgumentNullException(nameof(logger));
-			this.onDispose = onDispose ?? throw new ArgumentNullException(nameof(onDispose));
 
 			synchronizationLock = new object();
 			Active = true;
 			customCommands = Array.Empty<CustomCommand>();
 		}
 
-		/// <inheritdoc />
-		public void Dispose()
-		{
-			lock (synchronizationLock)
-			{
-				onDispose?.Invoke();
-				onDispose = null;
-			}
-		}
-
 		/// <inheritdoc />
 		public void SetChannelSink(IChannelSink channelSink)
 		{
 			ArgumentNullException.ThrowIfNull(channelSink);
 
-			lock (synchronizationLock)
-			{
-				if (this.channelSink != null)
-					throw new InvalidOperationException("channelSink already set!");
-
-				this.channelSink = channelSink;
-			}
+			var originalValue = Interlocked.CompareExchange(ref this.channelSink, channelSink, null);
+			if (originalValue != null)
+				throw new InvalidOperationException("channelSink already set!");
 		}
 
 		/// <inheritdoc />

src/Tgstation.Server.Host/Components/Chat/ChatUser.cs

@@ -13,7 +13,7 @@ namespace Tgstation.Server.Host.Components.Chat
 		/// <summary>
 		/// Backing field for <see cref="RealId"/>. Represented as a <see cref="string"/> to avoid BYOND percision loss.
 		/// </summary>
-		public string Id { get; set; }
+		public string Id { get; private set; }
 
 		/// <summary>
 		/// The internal user id.
@@ -21,23 +21,40 @@ namespace Tgstation.Server.Host.Components.Chat
 		[JsonIgnore]
 		public ulong RealId
 		{
-			get => UInt64.Parse(Id, CultureInfo.InvariantCulture);
-			set => Id = value.ToString(CultureInfo.InvariantCulture);
+			get => UInt64.Parse(Id!, CultureInfo.InvariantCulture);
+			private set => Id = value.ToString(CultureInfo.InvariantCulture);
 		}
 
 		/// <summary>
 		/// The friendly name of the user.
 		/// </summary>
-		public string FriendlyName { get; set; }
+		public string FriendlyName { get; }
 
 		/// <summary>
 		/// The text to mention the user.
 		/// </summary>
-		public string Mention { get; set; }
+		public string Mention { get; }
 
 		/// <summary>
 		/// The <see cref="ChannelRepresentation"/> the user spoke from.
 		/// </summary>
-		public ChannelRepresentation Channel { get; set; }
+		public ChannelRepresentation Channel { get; }
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="ChatUser"/> class.
+		/// </summary>
+		/// <param name="channel">The value of <see cref="Channel"/>.</param>
+		/// <param name="friendlyName">The value of <see cref="FriendlyName"/>.</param>
+		/// <param name="mention">The value of <see cref="Mention"/>.</param>
+		/// <param name="realId">The value of <see cref="RealId"/>.</param>
+		public ChatUser(ChannelRepresentation channel, string friendlyName, string mention, ulong realId)
+		{
+			Channel = channel ?? throw new ArgumentNullException(nameof(channel));
+			FriendlyName = friendlyName ?? throw new ArgumentNullException(nameof(friendlyName));
+			Mention = mention ?? throw new ArgumentNullException(nameof(mention));
+
+			Id = null!;
+			RealId = realId;
+		}
 	}
 }

src/Tgstation.Server.Host/Components/Chat/Commands/CommandFactory.cs

@@ -46,7 +46,7 @@ namespace Tgstation.Server.Host.Components.Chat.Commands
 		/// <summary>
 		/// The <see cref="IWatchdog"/> for the <see cref="CommandFactory"/>.
 		/// </summary>
-		IWatchdog watchdog;
+		IWatchdog? watchdog;
 
 		/// <summary>
 		/// Initializes a new instance of the <see cref="CommandFactory"/> class.

src/Tgstation.Server.Host/Components/Chat/Commands/CustomCommand.cs

@@ -12,18 +12,31 @@ namespace Tgstation.Server.Host.Components.Chat.Commands
 	public sealed class CustomCommand : ICommand
 	{
 		/// <inheritdoc />
-		public string Name { get; set; }
+		public string Name { get; }
 
 		/// <inheritdoc />
-		public string HelpText { get; set; }
+		public string HelpText { get; }
 
 		/// <inheritdoc />
-		public bool AdminOnly { get; set; }
+		public bool AdminOnly { get; }
 
 		/// <summary>
 		/// The <see cref="ICustomCommandHandler"/> for the <see cref="CustomCommand"/>.
 		/// </summary>
-		ICustomCommandHandler handler;
+		ICustomCommandHandler? handler;
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="CustomCommand"/> class.
+		/// </summary>
+		/// <param name="name">The value of <see cref="Name"/>.</param>
+		/// <param name="helpText">The value of <see cref="HelpText"/>.</param>
+		/// <param name="adminOnly">The value of <see cref="AdminOnly"/>.</param>
+		public CustomCommand(string name, string helpText, bool adminOnly)
+		{
+			Name = name ?? throw new ArgumentNullException(nameof(name));
+			HelpText = helpText ?? throw new ArgumentNullException(nameof(helpText));
+			AdminOnly = adminOnly;
+		}
 
 		/// <summary>
 		/// Set a new <paramref name="handler"/>.

src/Tgstation.Server.Host/Components/Chat/Commands/EngineCommand.cs

@@ -48,7 +48,7 @@ namespace Tgstation.Server.Host.Components.Chat.Commands
 		/// <inheritdoc />
 		public ValueTask<MessageContent> Invoke(string arguments, ChatUser user, CancellationToken cancellationToken)
 		{
-			EngineVersion engineVersion;
+			EngineVersion? engineVersion;
 			if (arguments.Split(' ').Any(x => x.Equals("--active", StringComparison.OrdinalIgnoreCase)))
 				engineVersion = engineManager.ActiveVersion;
 			else
@@ -67,8 +67,7 @@ namespace Tgstation.Server.Host.Components.Chat.Commands
 							Text = "None!",
 						});
 
-				if (!EngineVersion.TryParse(watchdog.ActiveCompileJob.EngineVersion, out engineVersion))
-					throw new InvalidOperationException($"Invalid engine version: {watchdog.ActiveCompileJob.EngineVersion}");
+				engineVersion = EngineVersion.Parse(watchdog.ActiveCompileJob.EngineVersion);
 			}
 
 			string text;
@@ -76,10 +75,10 @@ namespace Tgstation.Server.Host.Components.Chat.Commands
 				text = "None!";
 			else
 			{
-				text = engineVersion.Engine.Value switch
+				text = engineVersion.Engine!.Value switch
 				{
 					EngineType.OpenDream => $"OpenDream: {engineVersion.SourceSHA}",
-					EngineType.Byond => $"BYOND {engineVersion.Version.Major}.{engineVersion.Version.Minor}",
+					EngineType.Byond => $"BYOND {engineVersion.Version!.Major}.{engineVersion.Version.Minor}",
 					_ => throw new InvalidOperationException($"Invalid EngineType: {engineVersion.Engine.Value}"),
 				};
 

src/Tgstation.Server.Host/Components/Chat/Commands/PullRequestsCommand.cs

@@ -81,7 +81,7 @@ namespace Tgstation.Server.Host.Components.Chat.Commands
 #pragma warning disable CA1506
 		public async ValueTask<MessageContent> Invoke(string arguments, ChatUser user, CancellationToken cancellationToken)
 		{
-			IEnumerable<Models.TestMerge> results = null;
+			IEnumerable<Models.TestMerge> results;
 			var splits = arguments.Split(' ');
 			var hasRepo = splits.Any(x => x.Equals("--repo", StringComparison.OrdinalIgnoreCase));
 			var hasStaged = splits.Any(x => x.Equals("--staged", StringComparison.OrdinalIgnoreCase));
@@ -112,12 +112,13 @@ namespace Tgstation.Server.Host.Components.Chat.Commands
 					head = repo.Head;
 				}
 
+				results = null!;
 				await databaseContextFactory.UseContext(
 					async db => results = await db
 						.RevisionInformations
 						.AsQueryable()
-						.Where(x => x.Instance.Id == instance.Id && x.CommitSha == head)
-						.SelectMany(x => x.ActiveTestMerges)
+						.Where(x => x.Instance!.Id == instance.Id && x.CommitSha == head)
+						.SelectMany(x => x.ActiveTestMerges!)
 						.Select(x => x.TestMerge)
 						.Select(x => new Models.TestMerge
 						{
@@ -143,7 +144,7 @@ namespace Tgstation.Server.Host.Components.Chat.Commands
 						compileJobToUse = null;
 				}
 
-				results = compileJobToUse?.RevisionInformation.ActiveTestMerges.Select(x => x.TestMerge).ToList() ?? Enumerable.Empty<Models.TestMerge>();
+				results = compileJobToUse?.RevisionInformation.ActiveTestMerges?.Select(x => x.TestMerge).ToList() ?? Enumerable.Empty<Models.TestMerge>();
 			}
 
 			return new MessageContent
@@ -153,7 +154,7 @@ namespace Tgstation.Server.Host.Components.Chat.Commands
 					: String.Join(
 						", ",
 						results.Select(
-							x => $"#{x.Number} at {x.TargetCommitSha[..7]}")),
+							x => $"#{x.Number} at {x.TargetCommitSha![..7]}")),
 			};
 		}
 #pragma warning restore CA1506

src/Tgstation.Server.Host/Components/Chat/Commands/RevisionCommand.cs

@@ -75,7 +75,7 @@ namespace Tgstation.Server.Host.Components.Chat.Commands
 					{
 						Text = "Server offline!",
 					};
-				result = watchdog.ActiveCompileJob?.RevisionInformation.OriginCommitSha;
+				result = watchdog.ActiveCompileJob?.RevisionInformation.OriginCommitSha!;
 			}
 
 			return new MessageContent

src/Tgstation.Server.Host/Components/Chat/IChatManager.cs

@@ -67,12 +67,12 @@ namespace Tgstation.Server.Host.Components.Chat
 		/// <param name="gitHubRepo">The repository GitHub name, if any.</param>
 		/// <param name="localCommitPushed"><see langword="true"/> if the local deployment commit was pushed to the remote repository.</param>
 		/// <returns>A <see cref="Func{T1, T2, TResult}"/> to call to update the message at the deployment's conclusion. Parameters: Error message if any, DreamMaker output if any. Returns an <see cref="Action"/> to call to mark the deployment as active/inactive. Parameter: If the deployment is being activated or inactivated.</returns>
-		Func<string, string, Action<bool>> QueueDeploymentMessage(
+		Func<string?, string, Action<bool>> QueueDeploymentMessage(
 			Models.RevisionInformation revisionInformation,
 			Api.Models.EngineVersion engineVersion,
 			DateTimeOffset? estimatedCompletionTime,
-			string gitHubOwner,
-			string gitHubRepo,
+			string? gitHubOwner,
+			string? gitHubRepo,
 			bool localCommitPushed);
 
 		/// <summary>

src/Tgstation.Server.Host/Components/Chat/Providers/DiscordMessage.cs

@@ -12,5 +12,19 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		/// The <see cref="IMessageReference"/> of the source <see cref="Message"/>.
 		/// </summary>
 		public Optional<IMessageReference> MessageReference { get; set; }
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="DiscordMessage"/> class.
+		/// </summary>
+		/// <param name="user">The value of <see cref="Message.User"/>.</param>
+		/// <param name="content">The value of <see cref="Message.Content"/>.</param>
+		/// <param name="messageReference">The value of <see cref="MessageReference"/>.</param>
+		public DiscordMessage(ChatUser user, string content, Optional<IMessageReference> messageReference)
+			: base(
+				  user,
+				  content)
+		{
+			MessageReference = messageReference;
+		}
 	}
 }

src/Tgstation.Server.Host/Components/Chat/Providers/DiscordProvider.cs

@@ -58,13 +58,13 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		/// <summary>
 		/// The <see cref="ChannelType"/>s supported by the <see cref="DiscordProvider"/> for mapping.
 		/// </summary>
-		static readonly ChannelType[] SupportedGuildChannelTypes = new[]
-		{
+		static readonly ChannelType[] SupportedGuildChannelTypes =
+		[
 			ChannelType.GuildText,
 			ChannelType.GuildAnnouncement,
 			ChannelType.PrivateThread,
 			ChannelType.PublicThread,
-		};
+		];
 
 		/// <summary>
 		/// The <see cref="IAssemblyInformationProvider"/> for the <see cref="DiscordProvider"/>.
@@ -104,17 +104,17 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		/// <summary>
 		/// The <see cref="CancellationTokenSource"/> for the <see cref="gatewayTask"/>.
 		/// </summary>
-		CancellationTokenSource gatewayCts;
+		CancellationTokenSource? gatewayCts;
 
 		/// <summary>
 		/// The <see cref="TaskCompletionSource"/> for the initial gateway connection event.
 		/// </summary>
-		TaskCompletionSource gatewayReadyTcs;
+		TaskCompletionSource? gatewayReadyTcs;
 
 		/// <summary>
 		/// The <see cref="Task"/> representing the lifetime of the client.
 		/// </summary>
-		Task<Result> gatewayTask;
+		Task<Result>? gatewayTask;
 
 		/// <summary>
 		/// The bot's <see cref="Snowflake"/>.
@@ -157,8 +157,8 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 			mappedChannels = new List<ulong>();
 			connectDisconnectLock = new object();
 
-			var csb = new DiscordConnectionStringBuilder(chatBot.ConnectionString);
-			var botToken = csb.BotToken;
+			var csb = new DiscordConnectionStringBuilder(chatBot.ConnectionString!);
+			var botToken = csb.BotToken!;
 			outputDisplayType = csb.DMOutputDisplay;
 			deploymentBranding = csb.DeploymentBranding;
 
@@ -194,7 +194,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		}
 
 		/// <inheritdoc />
-		public override async ValueTask SendMessage(Message replyTo, MessageContent message, ulong channelId, CancellationToken cancellationToken)
+		public override async ValueTask SendMessage(Message? replyTo, MessageContent message, ulong channelId, CancellationToken cancellationToken)
 		{
 			ArgumentNullException.ThrowIfNull(message);
 
@@ -218,6 +218,22 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 			var channelsClient = serviceProvider.GetRequiredService<IDiscordRestChannelAPI>();
 			async ValueTask SendToChannel(Snowflake channelId)
 			{
+				if (message.Text == null)
+				{
+					Logger.LogWarning(
+						"Failed to send to channel {channelId}: Message was null!",
+						channelId);
+
+					await channelsClient.CreateMessageAsync(
+						channelId,
+						"TGS: Could not send message to Discord. Message was `null`!",
+						messageReference: replyToReference,
+						allowedMentions: allowedMentions,
+						ct: cancellationToken);
+
+					return;
+				}
+
 				var result = await channelsClient.CreateMessageAsync(
 					channelId,
 					message.Text,
@@ -285,25 +301,23 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		}
 
 		/// <inheritdoc />
-		public override async ValueTask<Func<string, string, ValueTask<Func<bool, ValueTask>>>> SendUpdateMessage(
+		public override async ValueTask<Func<string?, string, ValueTask<Func<bool, ValueTask>>>> SendUpdateMessage(
 			Models.RevisionInformation revisionInformation,
 			EngineVersion engineVersion,
 			DateTimeOffset? estimatedCompletionTime,
-			string gitHubOwner,
-			string gitHubRepo,
+			string? gitHubOwner,
+			string? gitHubRepo,
 			ulong channelId,
 			bool localCommitPushed,
 			CancellationToken cancellationToken)
 		{
 			ArgumentNullException.ThrowIfNull(revisionInformation);
 			ArgumentNullException.ThrowIfNull(engineVersion);
-			ArgumentNullException.ThrowIfNull(gitHubOwner);
-			ArgumentNullException.ThrowIfNull(gitHubRepo);
 
 			localCommitPushed |= revisionInformation.CommitSha == revisionInformation.OriginCommitSha;
 
 			var fields = BuildUpdateEmbedFields(revisionInformation, engineVersion, gitHubOwner, gitHubRepo, localCommitPushed);
-			var author = new EmbedAuthor(assemblyInformationProvider.VersionPrefix)
+			Optional<IEmbedAuthor> author = new EmbedAuthor(assemblyInformationProvider.VersionPrefix)
 			{
 				Url = "https://github.com/tgstation/tgstation-server",
 				IconUrl = "https://cdn.discordapp.com/attachments/1114451486374637629/1151650846019432448/tgs.png",
@@ -323,7 +337,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 			Logger.LogTrace("Attempting to post deploy embed to channel {channelId}...", channelId);
 			var channelsClient = serviceProvider.GetRequiredService<IDiscordRestChannelAPI>();
 
-			var prefix = GetEngineCompilerPrefix(engineVersion.Engine.Value);
+			var prefix = GetEngineCompilerPrefix(engineVersion.Engine!.Value);
 			var messageResponse = await channelsClient.CreateMessageAsync(
 				new Snowflake(channelId),
 				$"{prefix}: Deployment in progress...",
@@ -386,7 +400,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 
 				var updatedMessageText = errorMessage == null ? $"{prefix}: Deployment pending reboot..." : $"{prefix}: Deployment failed!";
 
-				IMessage updatedMessage = null;
+				IMessage? updatedMessage = null;
 				async ValueTask CreateUpdatedMessage()
 				{
 					var createUpdatedMessageResponse = await channelsClient.CreateMessageAsync(
@@ -532,27 +546,23 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 						messageGuildResponse.LogFormat());
 			}
 
-			var result = new DiscordMessage
-			{
-				MessageReference = messageReference,
-				Content = content,
-				User = new ChatUser
-				{
-					RealId = messageCreateEvent.Author.ID.Value,
-					Channel = new ChannelRepresentation
+			var result = new DiscordMessage(
+				new ChatUser(
+					new ChannelRepresentation(
+						pm ? messageCreateEvent.Author.Username : guildName,
+						channelResponse.Entity.Name.Value!,
+						messageCreateEvent.ChannelID.Value)
 					{
-						RealId = messageCreateEvent.ChannelID.Value,
 						IsPrivateChannel = pm,
-						ConnectionName = pm ? messageCreateEvent.Author.Username : guildName,
-						FriendlyName = channelResponse.Entity.Name.Value,
 						EmbedsSupported = true,
 
 						// isAdmin and Tag populated by manager
 					},
-					FriendlyName = messageCreateEvent.Author.Username,
-					Mention = NormalizeMentions($"<@{messageCreateEvent.Author.ID}>"),
-				},
-			};
+					messageCreateEvent.Author.Username,
+					NormalizeMentions($"<@{messageCreateEvent.Author.ID}>"),
+					messageCreateEvent.Author.ID.Value),
+				content,
+				messageReference);
 
 			EnqueueMessage(result);
 			return Result.FromSuccess();
@@ -635,8 +645,8 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 			CancellationTokenSource localGatewayCts;
 			lock (connectDisconnectLock)
 			{
-				localGatewayTask = gatewayTask;
-				localGatewayCts = gatewayCts;
+				localGatewayTask = gatewayTask!;
+				localGatewayCts = gatewayCts!;
 				gatewayTask = null;
 				gatewayCts = null;
 				if (localGatewayTask == null)
@@ -662,7 +672,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 			var guildsClient = serviceProvider.GetRequiredService<IDiscordRestGuildAPI>();
 			var guildTasks = new ConcurrentDictionary<Snowflake, Task<Result<IGuild>>>();
 
-			async ValueTask<Tuple<Models.ChatChannel, IEnumerable<ChannelRepresentation>>> GetModelChannelFromDBChannel(Models.ChatChannel channelFromDB)
+			async ValueTask<Tuple<Models.ChatChannel, IEnumerable<ChannelRepresentation>>?> GetModelChannelFromDBChannel(Models.ChatChannel channelFromDB)
 			{
 				if (!channelFromDB.DiscordChannelId.HasValue)
 					throw new InvalidOperationException("ChatChannel missing DiscordChannelId!");
@@ -719,12 +729,12 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 
 				var connectionName = guildsResponse.Entity.Name;
 
-				var channelModel = new ChannelRepresentation
+				var channelModel = new ChannelRepresentation(
+					guildsResponse.Entity.Name,
+					discordChannelResponse.Entity.Name.Value!,
+					channelId)
 				{
-					RealId = channelId,
 					IsAdminChannel = channelFromDB.IsAdminChannel == true,
-					ConnectionName = guildsResponse.Entity.Name,
-					FriendlyName = discordChannelResponse.Entity.Name.Value,
 					IsPrivateChannel = false,
 					Tag = channelFromDB.Tag,
 					EmbedsSupported = true,
@@ -742,8 +752,9 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 
 			var channelTuples = await ValueTaskExtensions.WhenAll(tasks.ToList());
 
-			var enumerator = channelTuples
+			var list = channelTuples
 				.Where(x => x != null)
+				.Cast<Tuple<Models.ChatChannel, IEnumerable<ChannelRepresentation>>>() // NRT my beloathed
 				.ToList();
 
 			var channelIdZeroModel = channels.FirstOrDefault(x => x.DiscordChannelId == 0);
@@ -752,7 +763,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 				Logger.LogInformation("Mapping ALL additional accessible text channels");
 				var allAccessibleChannels = await GetAllAccessibleTextChannels(cancellationToken);
 				var unmappedTextChannels = allAccessibleChannels
-					.Where(x => !tasks.Any(task => task.Result != null && new Snowflake(task.Result.Item1.DiscordChannelId.Value) == x.ID));
+					.Where(x => !tasks.Any(task => task.Result != null && new Snowflake(task.Result.Item1.DiscordChannelId!.Value) == x.ID));
 
 				async ValueTask<Tuple<Models.ChatChannel, IEnumerable<ChannelRepresentation>>> CreateMappingsForUnmappedChannels()
 				{
@@ -773,32 +784,36 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 						.ToList();
 
 					// Add catch-all channel
-					unmappedTasks.Add(Task.FromResult(
-						new ChannelRepresentation
+					unmappedTasks.Add(Task.FromResult<ChannelRepresentation?>(
+						new ChannelRepresentation(
+							"(Unknown Discord Guilds)",
+							"(Unknown Discord Channels)",
+							0)
 						{
-							IsAdminChannel = channelIdZeroModel.IsAdminChannel.Value,
-							ConnectionName = "(Unknown Discord Guilds)",
+							IsAdminChannel = channelIdZeroModel.IsAdminChannel!.Value,
 							EmbedsSupported = true,
-							FriendlyName = "(Unknown Discord Channels)",
-							RealId = 0,
 							Tag = channelIdZeroModel.Tag,
 						}));
 
 					await Task.WhenAll(unmappedTasks);
 					return Tuple.Create<Models.ChatChannel, IEnumerable<ChannelRepresentation>>(
 						channelIdZeroModel,
-						unmappedTasks.Select(x => x.Result).Where(x => x != null).ToList());
+						unmappedTasks
+							.Select(x => x.Result)
+							.Where(x => x != null)
+							.Cast<ChannelRepresentation>() // NRT my beloathed
+							.ToList());
 				}
 
 				var task = CreateMappingsForUnmappedChannels();
 				var tuple = await task;
-				enumerator.Add(tuple);
+				list.Add(tuple);
 			}
 
 			lock (mappedChannels)
 			{
 				mappedChannels.Clear();
-				mappedChannels.AddRange(enumerator.SelectMany(x => x.Item2).Select(x => x.RealId));
+				mappedChannels.AddRange(list.SelectMany(x => x.Item2).Select(x => x.RealId));
 			}
 
 			if (remapRequired)
@@ -807,7 +822,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 				EnqueueMessage(null);
 			}
 
-			return new Dictionary<Models.ChatChannel, IEnumerable<ChannelRepresentation>>(enumerator.Select(x => new KeyValuePair<Models.ChatChannel, IEnumerable<ChannelRepresentation>>(x.Item1, x.Item2)));
+			return new Dictionary<Models.ChatChannel, IEnumerable<ChannelRepresentation>>(list.Select(x => new KeyValuePair<Models.ChatChannel, IEnumerable<ChannelRepresentation>>(x.Item1, x.Item2)));
 		}
 
 		/// <summary>
@@ -881,46 +896,55 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		List<IEmbedField> BuildUpdateEmbedFields(
 			Models.RevisionInformation revisionInformation,
 			EngineVersion engineVersion,
-			string gitHubOwner,
-			string gitHubRepo,
+			string? gitHubOwner,
+			string? gitHubRepo,
 			bool localCommitPushed)
 		{
 			bool gitHub = gitHubOwner != null && gitHubRepo != null;
-			var engineField = engineVersion.Engine.Value switch
+			var engineField = engineVersion.Engine!.Value switch
 			{
 				EngineType.Byond => new EmbedField(
 					"BYOND Version",
-					$"{engineVersion.Version.Major}.{engineVersion.Version.Minor}{(engineVersion.CustomIteration.HasValue ? $".{engineVersion.CustomIteration.Value}" : String.Empty)}",
+					$"{engineVersion.Version!.Major}.{engineVersion.Version.Minor}{(engineVersion.CustomIteration.HasValue ? $".{engineVersion.CustomIteration.Value}" : String.Empty)}",
 					true),
 				EngineType.OpenDream => new EmbedField(
 					"OpenDream Version",
-					$"[{engineVersion.SourceSHA[..7]}]({generalConfiguration.OpenDreamGitUrl}/commit/{engineVersion.SourceSHA})",
+					$"[{engineVersion.SourceSHA![..7]}]({generalConfiguration.OpenDreamGitUrl}/commit/{engineVersion.SourceSHA})",
 					true),
 				_ => throw new InvalidOperationException($"Invaild EngineType: {engineVersion.Engine.Value}"),
 			};
 
+			var revisionSha = revisionInformation.CommitSha!;
+			var revisionOriginSha = revisionInformation.OriginCommitSha!;
 			var fields = new List<IEmbedField>
 			{
 				engineField,
+			};
+
+			if (gitHubOwner == null || gitHubRepo == null)
+				return fields;
+
+			fields.Add(
 				new EmbedField(
 					"Local Commit",
 					localCommitPushed && gitHub
-						? $"[{revisionInformation.CommitSha[..7]}](https://github.com/{gitHubOwner}/{gitHubRepo}/commit/{revisionInformation.CommitSha})"
-						: revisionInformation.CommitSha[..7],
-					true),
+						? $"[{revisionSha[..7]}](https://github.com/{gitHubOwner}/{gitHubRepo}/commit/{revisionSha})"
+						: revisionSha[..7],
+					true));
+
+			fields.Add(
 				new EmbedField(
 					"Branch Commit",
 					gitHub
-						? $"[{revisionInformation.OriginCommitSha[..7]}](https://github.com/{gitHubOwner}/{gitHubRepo}/commit/{revisionInformation.OriginCommitSha})"
-						: revisionInformation.OriginCommitSha[..7],
-					true),
-			};
+						? $"[{revisionOriginSha[..7]}](https://github.com/{gitHubOwner}/{gitHubRepo}/commit/{revisionOriginSha})"
+						: revisionOriginSha[..7],
+					true));
 
 			fields.AddRange((revisionInformation.ActiveTestMerges ?? Enumerable.Empty<RevInfoTestMerge>())
 				.Select(x => x.TestMerge)
 				.Select(x => new EmbedField(
 					$"#{x.Number}",
-					$"[{x.TitleAtMerge}]({x.Url}) by _[@{x.Author}](https://github.com/{x.Author})_{Environment.NewLine}Commit: [{x.TargetCommitSha[..7]}](https://github.com/{gitHubOwner}/{gitHubRepo}/commit/{x.TargetCommitSha}){(String.IsNullOrWhiteSpace(x.Comment) ? String.Empty : $"{Environment.NewLine}_**{x.Comment}**_")}",
+					$"[{x.TitleAtMerge}]({x.Url}) by _[@{x.Author}](https://github.com/{x.Author})_{Environment.NewLine}Commit: [{x.TargetCommitSha![..7]}](https://github.com/{gitHubOwner}/{gitHubRepo}/commit/{x.TargetCommitSha}){(String.IsNullOrWhiteSpace(x.Comment) ? String.Empty : $"{Environment.NewLine}_**{x.Comment}**_")}",
 					false)));
 
 			return fields;
@@ -932,7 +956,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		/// <param name="embed">The <see cref="ChatEmbed"/> to convert.</param>
 		/// <returns>The parameter for sending a single <see cref="IEmbed"/>.</returns>
 #pragma warning disable CA1502
-		Optional<IReadOnlyList<IEmbed>> ConvertEmbed(ChatEmbed embed)
+		Optional<IReadOnlyList<IEmbed>> ConvertEmbed(ChatEmbed? embed)
 		{
 			if (embed == null)
 				return default;
@@ -955,7 +979,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 				embed.Author = null;
 			}
 
-			List<IEmbedField> fields = null;
+			List<IEmbedField>? fields = null;
 			if (embed.Fields != null)
 			{
 				fields = new List<IEmbedField>();
@@ -987,7 +1011,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 					if (invalid)
 						continue;
 
-					fields.Add(new EmbedField(field.Name, field.Value)
+					fields.Add(new EmbedField(field.Name!, field.Value!)
 					{
 						IsInline = field.IsInline ?? default(Optional<bool>),
 					});
@@ -1026,7 +1050,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 			var discordEmbed = new Embed
 			{
 				Author = embed.Author != null
-					? new EmbedAuthor(embed.Author.Name)
+					? new EmbedAuthor(embed.Author.Name!)
 					{
 						IconUrl = embed.Author.IconUrl ?? default(Optional<string>),
 						ProxyIconUrl = embed.Author.ProxyIconUrl ?? default(Optional<string>),
@@ -1037,14 +1061,14 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 				Description = embed.Description ?? default(Optional<string>),
 				Fields = fields ?? default(Optional<IReadOnlyList<IEmbedField>>),
 				Footer = embed.Footer != null
-					? new EmbedFooter(embed.Footer.Text)
+					? (Optional<IEmbedFooter>)new EmbedFooter(embed.Footer.Text!)
 					{
 						IconUrl = embed.Footer.IconUrl ?? default(Optional<string>),
 						ProxyIconUrl = embed.Footer.ProxyIconUrl ?? default(Optional<string>),
 					}
 					: default,
 				Image = embed.Image != null
-					? new EmbedImage(embed.Image.Url)
+					? new EmbedImage(embed.Image.Url!)
 					{
 						Width = embed.Image.Width ?? default(Optional<int>),
 						Height = embed.Image.Height ?? default(Optional<int>),
@@ -1059,7 +1083,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 					}
 					: default(Optional<IEmbedProvider>),
 				Thumbnail = embed.Thumbnail != null
-					? new EmbedThumbnail(embed.Thumbnail.Url)
+					? new EmbedThumbnail(embed.Thumbnail.Url!)
 					{
 						Width = embed.Thumbnail.Width ?? default(Optional<int>),
 						Height = embed.Thumbnail.Height ?? default(Optional<int>),

src/Tgstation.Server.Host/Components/Chat/Providers/IProvider.cs

@@ -45,7 +45,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="Task{TResult}"/> resulting in the next available <see cref="Message"/> or <see langword="null"/> if the <see cref="IProvider"/> needed to reconnect.</returns>
 		/// <remarks>Note that private messages will come in the form of <see cref="ChannelRepresentation"/>s not returned in <see cref="MapChannels(IEnumerable{ChatChannel}, CancellationToken)"/>.</remarks>
-		Task<Message> NextMessage(CancellationToken cancellationToken);
+		Task<Message?> NextMessage(CancellationToken cancellationToken);
 
 		/// <summary>
 		/// Gracefully disconnects the provider. Permanently stops the reconnection timer.
@@ -65,12 +65,12 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		/// <summary>
 		/// Send a message to the <see cref="IProvider"/>.
 		/// </summary>
-		/// <param name="replyTo">The <see cref="Message"/> to reply to.</param>
+		/// <param name="replyTo">The optional <see cref="Message"/> to reply to.</param>
 		/// <param name="message">The <see cref="MessageContent"/>.</param>
 		/// <param name="channelId">The <see cref="ChannelRepresentation.RealId"/> to send to.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask"/> representing the running operation.</returns>
-		ValueTask SendMessage(Message replyTo, MessageContent message, ulong channelId, CancellationToken cancellationToken);
+		ValueTask SendMessage(Message? replyTo, MessageContent message, ulong channelId, CancellationToken cancellationToken);
 
 		/// <summary>
 		/// Set the interval at which the provider starts jobs to try to reconnect.
@@ -92,12 +92,12 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		/// <param name="localCommitPushed"><see langword="true"/> if the local deployment commit was pushed to the remote repository.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in a <see cref="Func{T1, T2, TResult}"/> to call to update the message at the deployment's conclusion. Parameters: Error message if any, DreamMaker output if any. Returns another callback which should be called to mark the deployment as active.</returns>
-		ValueTask<Func<string, string, ValueTask<Func<bool, ValueTask>>>> SendUpdateMessage(
+		ValueTask<Func<string?, string, ValueTask<Func<bool, ValueTask>>>> SendUpdateMessage(
 			Models.RevisionInformation revisionInformation,
 			Api.Models.EngineVersion engineVersion,
 			DateTimeOffset? estimatedCompletionTime,
-			string gitHubOwner,
-			string gitHubRepo,
+			string? gitHubOwner,
+			string? gitHubRepo,
 			ulong channelId,
 			bool localCommitPushed,
 			CancellationToken cancellationToken);

src/Tgstation.Server.Host/Components/Chat/Providers/IrcProvider.cs

@@ -75,23 +75,23 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		/// <summary>
 		/// Map of <see cref="ChannelRepresentation.RealId"/>s to channel names.
 		/// </summary>
-		readonly Dictionary<ulong, string> channelIdMap;
+		readonly Dictionary<ulong, string?> channelIdMap;
 
 		/// <summary>
 		/// Map of <see cref="ChannelRepresentation.RealId"/>s to query users.
 		/// </summary>
 		readonly Dictionary<ulong, string> queryChannelIdMap;
 
+		/// <summary>
+		/// The <see cref="ValueTask"/> used for <see cref="IrcConnection.Listen(bool)"/>.
+		/// </summary>
+		Task? listenTask;
+
 		/// <summary>
 		/// Id counter for <see cref="channelIdMap"/>.
 		/// </summary>
 		ulong channelIdCounter;
 
-		/// <summary>
-		/// The <see cref="ValueTask"/> used for <see cref="IrcConnection.Listen(bool)"/>.
-		/// </summary>
-		Task listenTask;
-
 		/// <summary>
 		/// If we are disconnecting.
 		/// </summary>
@@ -119,11 +119,11 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 			if (builder == null || !builder.Valid || builder is not IrcConnectionStringBuilder ircBuilder)
 				throw new InvalidOperationException("Invalid ChatConnectionStringBuilder!");
 
-			address = ircBuilder.Address;
-			port = ircBuilder.Port.Value;
-			nickname = ircBuilder.Nickname;
+			address = ircBuilder.Address!;
+			port = ircBuilder.Port!.Value;
+			nickname = ircBuilder.Nickname!;
 
-			password = ircBuilder.Password;
+			password = ircBuilder.Password!;
 			passwordType = ircBuilder.PasswordType;
 
 			client = new IrcFeatures
@@ -138,7 +138,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 				ActiveChannelSyncing = true,
 				AutoNickHandling = true,
 				CtcpVersion = assemblyInformationProvider.VersionString,
-				UseSsl = ircBuilder.UseSsl.Value,
+				UseSsl = ircBuilder.UseSsl!.Value,
 			};
 			if (ircBuilder.UseSsl.Value)
 				client.ValidateServerCertificate = true; // dunno if it defaults to that or what
@@ -149,7 +149,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 			/*client.OnReadLine += (sender, e) => Logger.LogTrace("READ: {line}", e.Line);
 			client.OnWriteLine += (sender, e) => Logger.LogTrace("WRITE: {line}", e.Line);*/
 
-			channelIdMap = new Dictionary<ulong, string>();
+			channelIdMap = new Dictionary<ulong, string?>();
 			queryChannelIdMap = new Dictionary<ulong, string>();
 			channelIdCounter = 1;
 		}
@@ -164,7 +164,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		}
 
 		/// <inheritdoc />
-		public override async ValueTask SendMessage(Message replyTo, MessageContent message, ulong channelId, CancellationToken cancellationToken)
+		public override async ValueTask SendMessage(Message? replyTo, MessageContent message, ulong channelId, CancellationToken cancellationToken)
 		{
 			ArgumentNullException.ThrowIfNull(message);
 
@@ -218,12 +218,12 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		}
 
 		/// <inheritdoc />
-		public override async ValueTask<Func<string, string, ValueTask<Func<bool, ValueTask>>>> SendUpdateMessage(
+		public override async ValueTask<Func<string?, string, ValueTask<Func<bool, ValueTask>>>> SendUpdateMessage(
 			Models.RevisionInformation revisionInformation,
 			EngineVersion engineVersion,
 			DateTimeOffset? estimatedCompletionTime,
-			string gitHubOwner,
-			string gitHubRepo,
+			string? gitHubOwner,
+			string? gitHubRepo,
 			ulong channelId,
 			bool localCommitPushed,
 			CancellationToken cancellationToken)
@@ -233,7 +233,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 			ArgumentNullException.ThrowIfNull(gitHubOwner);
 			ArgumentNullException.ThrowIfNull(gitHubRepo);
 
-			var commitInsert = revisionInformation.CommitSha[..7];
+			var commitInsert = revisionInformation.CommitSha![..7];
 			string remoteCommitInsert;
 			if (revisionInformation.CommitSha == revisionInformation.OriginCommitSha)
 			{
@@ -241,7 +241,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 				remoteCommitInsert = String.Empty;
 			}
 			else
-				remoteCommitInsert = String.Format(CultureInfo.InvariantCulture, ". Remote commit: ^{0}", revisionInformation.OriginCommitSha[..7]);
+				remoteCommitInsert = String.Format(CultureInfo.InvariantCulture, ". Remote commit: ^{0}", revisionInformation.OriginCommitSha![..7]);
 
 			var testmergeInsert = (revisionInformation.ActiveTestMerges?.Count ?? 0) == 0
 				? String.Empty
@@ -251,17 +251,17 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 					String.Join(
 						", ",
 						revisionInformation
-							.ActiveTestMerges
+							.ActiveTestMerges!
 							.Select(x => x.TestMerge)
 							.Select(x =>
 							{
-								var result = String.Format(CultureInfo.InvariantCulture, "#{0} at {1}", x.Number, x.TargetCommitSha[..7]);
+								var result = String.Format(CultureInfo.InvariantCulture, "#{0} at {1}", x.Number, x.TargetCommitSha![..7]);
 								if (x.Comment != null)
 									result += String.Format(CultureInfo.InvariantCulture, " ({0})", x.Comment);
 								return result;
 							})));
 
-			var prefix = GetEngineCompilerPrefix(engineVersion.Engine.Value);
+			var prefix = GetEngineCompilerPrefix(engineVersion.Engine!.Value);
 			await SendMessage(
 				null,
 				new MessageContent
@@ -351,14 +351,11 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 										dbChannel,
 										new List<ChannelRepresentation>
 										{
-											new()
+											new(address, channelName, id!.Value)
 											{
-												RealId = id.Value,
-												IsAdminChannel = dbChannel.IsAdminChannel == true,
-												ConnectionName = address,
-												FriendlyName = channelIdMap[id.Value],
-												IsPrivateChannel = false,
 												Tag = dbChannel.Tag,
+												IsAdminChannel = dbChannel.IsAdminChannel == true,
+												IsPrivateChannel = false,
 												EmbedsSupported = false,
 											},
 										});
@@ -503,7 +500,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 			var username = e.Data.Nick;
 			var channelName = isPrivate ? username : e.Data.Channel;
 
-			ulong MapAndGetChannelId(Dictionary<ulong, string> dicToCheck)
+			ulong MapAndGetChannelId(Dictionary<ulong, string?> dicToCheck)
 			{
 				ulong? resultId = null;
 				if (!dicToCheck.Any(x =>
@@ -520,36 +517,31 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 						channelIdMap.Add(resultId.Value, null);
 				}
 
-				return resultId.Value;
+				return resultId!.Value;
 			}
 
 			ulong userId, channelId;
 			lock (client)
 			{
-				userId = MapAndGetChannelId(queryChannelIdMap);
+				userId = MapAndGetChannelId(new Dictionary<ulong, string?>(queryChannelIdMap
+					.Cast<KeyValuePair<ulong, string?>>())); // NRT my beloathed
 				channelId = isPrivate ? userId : MapAndGetChannelId(channelIdMap);
 			}
 
-			var message = new Message
-			{
-				Content = e.Data.Message,
-				User = new ChatUser
-				{
-					Channel = new ChannelRepresentation
+			var channelFriendlyName = isPrivate ? String.Format(CultureInfo.InvariantCulture, "PM: {0}", channelName) : channelName;
+			var message = new Message(
+				new ChatUser(
+					new ChannelRepresentation(address, channelFriendlyName, channelId)
 					{
-						ConnectionName = address,
-						FriendlyName = isPrivate ? String.Format(CultureInfo.InvariantCulture, "PM: {0}", channelName) : channelName,
-						RealId = channelId,
 						IsPrivateChannel = isPrivate,
 						EmbedsSupported = false,
 
 						// isAdmin and Tag populated by manager
 					},
-					FriendlyName = username,
-					RealId = userId,
-					Mention = username,
-				},
-			};
+					username,
+					username,
+					userId),
+				e.Data.Message);
 
 			EnqueueMessage(message);
 		}

src/Tgstation.Server.Host/Components/Chat/Providers/Message.cs

@@ -1,4 +1,6 @@
-namespace Tgstation.Server.Host.Components.Chat.Providers
+using System;
+
+namespace Tgstation.Server.Host.Components.Chat.Providers
 {
 	/// <summary>
 	/// Represents a message received by a <see cref="IProvider"/>.
@@ -8,11 +10,22 @@
 		/// <summary>
 		/// The text of the message.
 		/// </summary>
-		public string Content { get; set; }
+		public string Content { get; }
 
 		/// <summary>
 		/// The <see cref="ChatUser"/> who sent the <see cref="Message"/>.
 		/// </summary>
-		public ChatUser User { get; set; }
+		public ChatUser User { get; }
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="Message"/> class.
+		/// </summary>
+		/// <param name="user">The value of <see cref="User"/>.</param>
+		/// <param name="content">The value of <see cref="Content"/>.</param>
+		public Message(ChatUser user, string content)
+		{
+			User = user ?? throw new ArgumentNullException(nameof(user));
+			Content = content ?? throw new ArgumentNullException(nameof(content));
+		}
 	}
 }

src/Tgstation.Server.Host/Components/Chat/Providers/Provider.cs

@@ -42,7 +42,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		/// <summary>
 		/// <see cref="Queue{T}"/> of received <see cref="Message"/>s.
 		/// </summary>
-		readonly Queue<Message> messageQueue;
+		readonly Queue<Message?> messageQueue;
 
 		/// <summary>
 		/// The backing <see cref="TaskCompletionSource"/> for <see cref="InitialConnectionJob"/>.
@@ -62,12 +62,12 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		/// <summary>
 		/// The auto reconnect <see cref="Task"/>.
 		/// </summary>
-		Task reconnectTask;
+		Task? reconnectTask;
 
 		/// <summary>
 		/// <see cref="CancellationTokenSource"/> for <see cref="reconnectTask"/>.
 		/// </summary>
-		CancellationTokenSource reconnectCts;
+		CancellationTokenSource? reconnectCts;
 
 		/// <summary>
 		/// Get the prefix for messages about deployments.
@@ -96,7 +96,10 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 			Logger = logger ?? throw new ArgumentNullException(nameof(logger));
 			ChatBot = chatBot ?? throw new ArgumentNullException(nameof(chatBot));
 
-			messageQueue = new Queue<Message>();
+			if (chatBot.Instance == null)
+				throw new ArgumentException("chatBot must have Instance!", nameof(chatBot));
+
+			messageQueue = new Queue<Message?>();
 			nextMessage = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
 			initialConnectionTcs = new TaskCompletionSource();
 			reconnectTaskLock = new object();
@@ -157,7 +160,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		}
 
 		/// <inheritdoc />
-		public async Task<Message> NextMessage(CancellationToken cancellationToken)
+		public async Task<Message?> NextMessage(CancellationToken cancellationToken)
 		{
 			while (true)
 			{
@@ -191,15 +194,15 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		}
 
 		/// <inheritdoc />
-		public abstract ValueTask SendMessage(Message replyTo, MessageContent message, ulong channelId, CancellationToken cancellationToken);
+		public abstract ValueTask SendMessage(Message? replyTo, MessageContent message, ulong channelId, CancellationToken cancellationToken);
 
 		/// <inheritdoc />
-		public abstract ValueTask<Func<string, string, ValueTask<Func<bool, ValueTask>>>> SendUpdateMessage(
+		public abstract ValueTask<Func<string?, string, ValueTask<Func<bool, ValueTask>>>> SendUpdateMessage(
 			RevisionInformation revisionInformation,
 			Api.Models.EngineVersion engineVersion,
 			DateTimeOffset? estimatedCompletionTime,
-			string gitHubOwner,
-			string gitHubRepo,
+			string? gitHubOwner,
+			string? gitHubRepo,
 			ulong channelId,
 			bool localCommitPushed,
 			CancellationToken cancellationToken);
@@ -232,7 +235,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		/// Queues a <paramref name="message"/> for <see cref="NextMessage(CancellationToken)"/>.
 		/// </summary>
 		/// <param name="message">The <see cref="Message"/> to queue. A value of <see langword="null"/> indicates the channel mappings are out of date.</param>
-		protected void EnqueueMessage(Message message)
+		protected void EnqueueMessage(Message? message)
 		{
 			if (message == null)
 				Logger.LogTrace("Requesting channel remap...");
@@ -257,7 +260,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 					reconnectCts.Cancel();
 					reconnectCts.Dispose();
 					reconnectCts = null;
-					var reconnectTask = this.reconnectTask;
+					var reconnectTask = this.reconnectTask!;
 					this.reconnectTask = null;
 					return reconnectTask;
 				}
@@ -286,7 +289,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 						connectNow = false;
 					if (!Connected)
 					{
-						var job = Job.Create(Api.Models.JobCode.ReconnectChatBot, null, ChatBot.Instance, ChatBotRights.WriteEnabled);
+						var job = Job.Create(Api.Models.JobCode.ReconnectChatBot, null, ChatBot.Instance!, ChatBotRights.WriteEnabled);
 						job.Description += $": {ChatBot.Name}";
 
 						await jobManager.RegisterOperation(

src/Tgstation.Server.Host/Components/Deployment/DmbFactory.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Linq;
 using System.Threading;
@@ -15,6 +16,7 @@ using Tgstation.Server.Host.Components.Events;
 using Tgstation.Server.Host.Database;
 using Tgstation.Server.Host.IO;
 using Tgstation.Server.Host.Models;
+using Tgstation.Server.Host.Utils;
 
 namespace Tgstation.Server.Host.Components.Deployment
 {
@@ -34,6 +36,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 		}
 
 		/// <inheritdoc />
+		[MemberNotNullWhen(true, nameof(nextDmbProvider))]
 		public bool DmbAvailable => nextDmbProvider != null;
 
 		/// <summary>
@@ -74,7 +77,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 		/// <summary>
 		/// Map of <see cref="CompileJob.JobId"/>s to locks on them.
 		/// </summary>
-		readonly IDictionary<long, int> jobLockCounts;
+		readonly Dictionary<long, int> jobLockCounts;
 
 		/// <summary>
 		/// <see cref="TaskCompletionSource"/> resulting in the latest <see cref="DmbProvider"/> yet to exist.
@@ -89,7 +92,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 		/// <summary>
 		/// The latest <see cref="DmbProvider"/>.
 		/// </summary>
-		IDmbProvider nextDmbProvider;
+		IDmbProvider? nextDmbProvider;
 
 		/// <summary>
 		/// If the <see cref="DmbFactory"/> is "started" via <see cref="IComponentService"/>.
@@ -130,7 +133,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 		public void Dispose() => cleanupCts.Dispose(); // we don't dispose nextDmbProvider here, since it might be the only thing we have
 
 		/// <inheritdoc />
-		public async ValueTask LoadCompileJob(CompileJob job, Action<bool> activationAction, CancellationToken cancellationToken)
+		public async ValueTask LoadCompileJob(CompileJob job, Action<bool>? activationAction, CancellationToken cancellationToken)
 		{
 			ArgumentNullException.ThrowIfNull(job);
 
@@ -173,8 +176,8 @@ namespace Tgstation.Server.Host.Components.Deployment
 				throw new ArgumentOutOfRangeException(nameof(lockCount), lockCount, "lockCount must be greater than or equal to 0!");
 			lock (jobLockCounts)
 			{
-				var jobId = nextDmbProvider.CompileJob.Id;
-				var incremented = jobLockCounts[jobId.Value] += lockCount;
+				var jobId = nextDmbProvider.CompileJob.Require(x => x.Id);
+				var incremented = jobLockCounts[jobId] += lockCount;
 				logger.LogTrace("Compile job {jobId} lock count now: {lockCount}", jobId, incremented);
 				return nextDmbProvider;
 			}
@@ -183,16 +186,15 @@ namespace Tgstation.Server.Host.Components.Deployment
 		/// <inheritdoc />
 		public async Task StartAsync(CancellationToken cancellationToken)
 		{
-			CompileJob cj = null;
-			await databaseContextFactory.UseContext(async (db) =>
-			{
-				cj = await db
-					.CompileJobs
-					.AsQueryable()
-					.Where(x => x.Job.Instance.Id == metadata.Id)
-					.OrderByDescending(x => x.Job.StoppedAt)
-					.FirstOrDefaultAsync(cancellationToken);
-			});
+			CompileJob? cj = null;
+			await databaseContextFactory.UseContext(
+				async (db) =>
+					cj = await db
+						.CompileJobs
+						.AsQueryable()
+						.Where(x => x.Job.Instance!.Id == metadata.Id)
+						.OrderByDescending(x => x.Job.StoppedAt)
+						.FirstOrDefaultAsync(cancellationToken));
 
 			try
 			{
@@ -227,35 +229,39 @@ namespace Tgstation.Server.Host.Components.Deployment
 
 		/// <inheritdoc />
 #pragma warning disable CA1506 // TODO: Decomplexify
-		public async ValueTask<IDmbProvider> FromCompileJob(CompileJob compileJob, CancellationToken cancellationToken)
+		public async ValueTask<IDmbProvider?> FromCompileJob(CompileJob compileJob, CancellationToken cancellationToken)
 		{
 			ArgumentNullException.ThrowIfNull(compileJob);
 
 			// ensure we have the entire metadata tree
-			logger.LogTrace("Loading compile job {id}...", compileJob.Id);
+			var compileJobId = compileJob.Require(x => x.Id);
+			logger.LogTrace("Loading compile job {id}...", compileJobId);
 			await databaseContextFactory.UseContext(
 				async db => compileJob = await db
 					.CompileJobs
 					.AsQueryable()
-					.Where(x => x.Id == compileJob.Id)
-					.Include(x => x.Job)
+					.Where(x => x!.Id == compileJobId)
+					.Include(x => x.Job!)
 						.ThenInclude(x => x.StartedBy)
-					.Include(x => x.Job)
+					.Include(x => x.Job!)
 						.ThenInclude(x => x.Instance)
-					.Include(x => x.RevisionInformation)
-						.ThenInclude(x => x.PrimaryTestMerge)
-						.ThenInclude(x => x.MergedBy)
-					.Include(x => x.RevisionInformation)
-						.ThenInclude(x => x.ActiveTestMerges)
-						.ThenInclude(x => x.TestMerge)
-						.ThenInclude(x => x.MergedBy)
+					.Include(x => x.RevisionInformation!)
+						.ThenInclude(x => x.PrimaryTestMerge!)
+							.ThenInclude(x => x.MergedBy)
+					.Include(x => x.RevisionInformation!)
+						.ThenInclude(x => x.ActiveTestMerges!)
+							.ThenInclude(x => x.TestMerge!)
+								.ThenInclude(x => x.MergedBy)
 					.FirstAsync(cancellationToken)); // can't wait to see that query
 
-			if (!EngineVersion.TryParse(compileJob.EngineVersion, out var engineVersion))
+			EngineVersion engineVersion;
+			if (!EngineVersion.TryParse(compileJob.EngineVersion, out var engineVersionNullable))
 			{
-				logger.LogWarning("Error loading compile job, bad engine version: {0}", compileJob.EngineVersion);
+				logger.LogWarning("Error loading compile job, bad engine version: {engineVersion}", compileJob.EngineVersion);
 				return null; // omae wa mou shinderu
 			}
+			else
+				engineVersion = engineVersionNullable!;
 
 			if (!compileJob.Job.StoppedAt.HasValue)
 			{
@@ -274,7 +280,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 					CleanRegisteredCompileJob(compileJob);
 			}
 
-			var newProvider = new DmbProvider(compileJob, engineVersion, ioManager, CleanupAction);
+			var newProvider = new DmbProvider(compileJob, engineVersion, ioManager, new DisposeInvoker(CleanupAction));
 			try
 			{
 				const string LegacyADirectoryName = "A";
@@ -311,22 +317,22 @@ namespace Tgstation.Server.Host.Components.Deployment
 					// rebuild the provider because it's using the legacy style directories
 					// Don't dispose it
 					logger.LogDebug("Creating legacy two folder .dmb provider targeting {aDirName} directory...", LegacyADirectoryName);
-					newProvider = new DmbProvider(compileJob, engineVersion, ioManager, CleanupAction, Path.DirectorySeparatorChar + LegacyADirectoryName);
+					newProvider = new DmbProvider(compileJob, engineVersion, ioManager, new DisposeInvoker(CleanupAction), Path.DirectorySeparatorChar + LegacyADirectoryName);
 				}
 
 				lock (jobLockCounts)
 				{
-					if (!jobLockCounts.TryGetValue(compileJob.Id.Value, out int value))
+					if (!jobLockCounts.TryGetValue(compileJobId, out int value))
 					{
 						value = 1;
-						jobLockCounts.Add(compileJob.Id.Value, 1);
+						jobLockCounts.Add(compileJobId, 1);
 					}
 					else
-						jobLockCounts[compileJob.Id.Value] = ++value;
+						jobLockCounts[compileJobId] = ++value;
 
 					providerSubmitted = true;
 
-					logger.LogTrace("Compile job {id} lock count now: {lockCount}", compileJob.Id, value);
+					logger.LogTrace("Compile job {id} lock count now: {lockCount}", compileJobId, value);
 					return newProvider;
 				}
 			}
@@ -348,10 +354,10 @@ namespace Tgstation.Server.Host.Components.Deployment
 			lock (jobLockCounts)
 				jobIdsToSkip = jobLockCounts.Keys.ToList();
 
-			List<string> jobUidsToNotErase = null;
+			List<string>? jobUidsToNotErase = null;
 
 			// find the uids of locked directories
-			if (jobIdsToSkip.Any())
+			if (jobIdsToSkip.Count > 0)
 			{
 				await databaseContextFactory.UseContext(async db =>
 				{
@@ -359,9 +365,9 @@ namespace Tgstation.Server.Host.Components.Deployment
 							.CompileJobs
 							.AsQueryable()
 							.Where(
-								x => x.Job.Instance.Id == metadata.Id
-								&& jobIdsToSkip.Contains(x.Id.Value))
-							.Select(x => x.DirectoryName.Value)
+								x => x.Job.Instance!.Id == metadata.Id
+								&& jobIdsToSkip.Contains(x.Id!.Value))
+							.Select(x => x.DirectoryName!.Value)
 							.ToListAsync(cancellationToken))
 						.Select(x => x.ToString())
 						.ToList();
@@ -370,7 +376,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 			else
 				jobUidsToNotErase = new List<string>();
 
-			jobUidsToNotErase.Add(SwappableDmbProvider.LiveGameDirectory);
+			jobUidsToNotErase!.Add(SwappableDmbProvider.LiveGameDirectory);
 
 			logger.LogTrace("We will not clean the following directories: {directoriesToNotClean}", String.Join(", ", jobUidsToNotErase));
 
@@ -405,7 +411,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 #pragma warning restore CA1506
 
 		/// <inheritdoc />
-		public CompileJob LatestCompileJob()
+		public CompileJob? LatestCompileJob()
 		{
 			if (!DmbAvailable)
 				return null;
@@ -426,7 +432,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 				// DCT: None available
 				var deploymentJob = remoteDeploymentManager.MarkInactive(job, CancellationToken.None);
 
-				var deleteTask = DeleteCompileJobContent(job.DirectoryName.ToString(), cleanupCts.Token);
+				var deleteTask = DeleteCompileJobContent(job.DirectoryName!.Value.ToString(), cleanupCts.Token);
 				var otherTask = cleanupTask;
 
 				async Task WrapThrowableTasks()
@@ -445,20 +451,23 @@ namespace Tgstation.Server.Host.Components.Deployment
 			}
 
 			lock (jobLockCounts)
-				if (jobLockCounts.TryGetValue(job.Id.Value, out var currentVal))
+			{
+				var jobId = job.Require(x => x.Id);
+				if (jobLockCounts.TryGetValue(jobId, out var currentVal))
 					if (currentVal == 1)
 					{
-						jobLockCounts.Remove(job.Id.Value);
-						logger.LogDebug("Cleaning lock-free compile job {id} => {dirName}", job.Id, job.DirectoryName);
+						jobLockCounts.Remove(jobId);
+						logger.LogDebug("Cleaning lock-free compile job {id} => {dirName}", jobId, job.DirectoryName);
 						cleanupTask = HandleCleanup();
 					}
 					else
 					{
-						var decremented = --jobLockCounts[job.Id.Value];
-						logger.LogTrace("Compile job {id} lock count now: {lockCount}", job.Id, decremented);
+						var decremented = --jobLockCounts[jobId];
+						logger.LogTrace("Compile job {id} lock count now: {lockCount}", jobId, decremented);
 					}
 				else
-					logger.LogError("Extra Dispose of DmbProvider for CompileJob {compileJobId}!", job.Id);
+					logger.LogError("Extra Dispose of DmbProvider for CompileJob {compileJobId}!", jobId);
+			}
 		}
 
 		/// <summary>

src/Tgstation.Server.Host/Components/Deployment/DmbProvider.cs

@@ -4,6 +4,7 @@ using System.Threading.Tasks;
 using Tgstation.Server.Api.Models;
 using Tgstation.Server.Api.Models.Internal;
 using Tgstation.Server.Host.IO;
+using Tgstation.Server.Host.Utils;
 
 namespace Tgstation.Server.Host.Components.Deployment
 {
@@ -11,7 +12,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 	sealed class DmbProvider : DmbProviderBase, IDmbProvider
 	{
 		/// <inheritdoc />
-		public override string Directory => ioManager.ResolvePath(CompileJob.DirectoryName.ToString() + directoryAppend);
+		public override string Directory => ioManager.ResolvePath(CompileJob.DirectoryName!.Value.ToString() + directoryAppend);
 
 		/// <inheritdoc />
 		public override Models.CompileJob CompileJob { get; }
@@ -32,7 +33,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 		/// <summary>
 		/// The <see cref="Action"/> to run when <see cref="DisposeAsync"/> is called.
 		/// </summary>
-		Action onDispose;
+		DisposeInvoker? onDispose;
 
 		/// <summary>
 		/// Initializes a new instance of the <see cref="DmbProvider"/> class.
@@ -42,7 +43,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 		/// <param name="ioManager">The value of <see cref="ioManager"/>.</param>
 		/// <param name="onDispose">The value of <see cref="onDispose"/>.</param>
 		/// <param name="directoryAppend">The optional value of <see cref="directoryAppend"/>.</param>
-		public DmbProvider(Models.CompileJob compileJob, EngineVersion engineVersion, IIOManager ioManager, Action onDispose, string directoryAppend = null)
+		public DmbProvider(Models.CompileJob compileJob, EngineVersion engineVersion, IIOManager ioManager, DisposeInvoker onDispose, string? directoryAppend = null)
 		{
 			CompileJob = compileJob ?? throw new ArgumentNullException(nameof(compileJob));
 			EngineVersion = engineVersion ?? throw new ArgumentNullException(nameof(engineVersion));
@@ -54,7 +55,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 		/// <inheritdoc />
 		public override ValueTask DisposeAsync()
 		{
-			onDispose?.Invoke();
+			onDispose?.Dispose();
 			return ValueTask.CompletedTask;
 		}
 

src/Tgstation.Server.Host/Components/Deployment/DmbProviderBase.cs

@@ -13,11 +13,11 @@ namespace Tgstation.Server.Host.Components.Deployment
 		/// <inheritdoc />
 		public string DmbName => String.Concat(
 			CompileJob.DmeName,
-			EngineVersion.Engine.Value switch
+			EngineVersion.Engine switch
 			{
 				EngineType.Byond => ".dmb",
 				EngineType.OpenDream => ".json",
-				_ => throw new InvalidOperationException($"Invalid EngineType: {EngineVersion.Engine.Value}"),
+				_ => throw new InvalidOperationException($"Invalid EngineType: {EngineVersion.Engine}"),
 			});
 
 		/// <inheritdoc />

src/Tgstation.Server.Host/Components/Deployment/DreamMaker.cs

@@ -113,12 +113,12 @@ namespace Tgstation.Server.Host.Components.Deployment
 		/// <summary>
 		/// The active callback from <see cref="IChatManager.QueueDeploymentMessage"/>.
 		/// </summary>
-		Func<string, string, Action<bool>> currentChatCallback;
+		Func<string?, string, Action<bool>>? currentChatCallback;
 
 		/// <summary>
 		/// Cached for <see cref="currentChatCallback"/>.
 		/// </summary>
-		string currentDreamMakerOutput;
+		string? currentDreamMakerOutput;
 
 		/// <summary>
 		/// If a compile job is running.
@@ -207,18 +207,18 @@ namespace Tgstation.Server.Host.Components.Deployment
 
 			currentChatCallback = null;
 			currentDreamMakerOutput = null;
-			Models.CompileJob compileJob = null;
+			Models.CompileJob? compileJob = null;
 			try
 			{
-				string repoOwner = null;
-				string repoName = null;
+				string? repoOwner = null;
+				string? repoName = null;
 				TimeSpan? averageSpan = null;
-				Models.RepositorySettings repositorySettings = null;
-				Models.DreamDaemonSettings ddSettings = null;
-				Models.DreamMakerSettings dreamMakerSettings = null;
-				IRepository repo = null;
-				IRemoteDeploymentManager remoteDeploymentManager = null;
-				Models.RevisionInformation revInfo = null;
+				Models.RepositorySettings? repositorySettings = null;
+				Models.DreamDaemonSettings? ddSettings = null;
+				Models.DreamMakerSettings? dreamMakerSettings = null;
+				IRepository? repo = null;
+				IRemoteDeploymentManager? remoteDeploymentManager = null;
+				Models.RevisionInformation? revInfo = null;
 				await databaseContextFactory.UseContext(
 					async databaseContext =>
 					{
@@ -268,7 +268,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 								throw new JobException(ErrorCode.RepoMissing);
 
 							remoteDeploymentManager = remoteDeploymentManagerFactory
-								.CreateRemoteDeploymentManager(metadata, repo.RemoteGitProvider.Value);
+								.CreateRemoteDeploymentManager(metadata, repo.RemoteGitProvider!.Value);
 
 							var repoSha = repo.Head;
 							repoOwner = repo.RemoteRepositoryOwner;
@@ -276,13 +276,13 @@ namespace Tgstation.Server.Host.Components.Deployment
 							revInfo = await databaseContext
 								.RevisionInformations
 								.AsQueryable()
-								.Where(x => x.CommitSha == repoSha && x.Instance.Id == metadata.Id)
-								.Include(x => x.ActiveTestMerges)
-									.ThenInclude(x => x.TestMerge)
-									.ThenInclude(x => x.MergedBy)
+								.Where(x => x.CommitSha == repoSha && x.InstanceId == metadata.Id)
+								.Include(x => x.ActiveTestMerges!)
+									.ThenInclude(x => x.TestMerge!)
+										.ThenInclude(x => x.MergedBy)
 								.FirstOrDefaultAsync(cancellationToken);
 
-							if (revInfo == default)
+							if (revInfo == null)
 							{
 								revInfo = new Models.RevisionInformation
 								{
@@ -310,16 +310,17 @@ namespace Tgstation.Server.Host.Components.Deployment
 					});
 
 				var likelyPushedTestMergeCommit =
-					repositorySettings.PushTestMergeCommits.Value
+					repositorySettings!.PushTestMergeCommits!.Value
 					&& repositorySettings.AccessToken != null
 					&& repositorySettings.AccessUser != null;
 				using (repo)
 					compileJob = await Compile(
-						revInfo,
-						dreamMakerSettings,
-						ddSettings,
-						repo,
-						remoteDeploymentManager,
+						job,
+						revInfo!,
+						dreamMakerSettings!,
+						ddSettings!,
+						repo!,
+						remoteDeploymentManager!,
 						progressReporter,
 						averageSpan,
 						likelyPushedTestMergeCommit,
@@ -332,11 +333,11 @@ namespace Tgstation.Server.Host.Components.Deployment
 						async databaseContext =>
 						{
 							var fullJob = compileJob.Job;
-							compileJob.Job = new Models.Job(job.Id.Value);
+							compileJob.Job = new Models.Job(job.Require(x => x.Id));
 							var fullRevInfo = compileJob.RevisionInformation;
 							compileJob.RevisionInformation = new Models.RevisionInformation
 							{
-								Id = revInfo.Id,
+								Id = revInfo!.Id,
 							};
 
 							databaseContext.Jobs.Attach(compileJob.Job);
@@ -348,7 +349,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 							logger.LogTrace("Created CompileJob {compileJobId}", compileJob.Id);
 							try
 							{
-								var chatNotificationAction = currentChatCallback(null, compileJob.Output);
+								var chatNotificationAction = currentChatCallback!(null, compileJob.Output!);
 								await compileJobConsumer.LoadCompileJob(compileJob, chatNotificationAction, cancellationToken);
 							}
 							catch
@@ -367,11 +368,11 @@ namespace Tgstation.Server.Host.Components.Deployment
 				}
 				catch (Exception ex)
 				{
-					await CleanupFailedCompile(compileJob, remoteDeploymentManager, ex);
+					await CleanupFailedCompile(compileJob, remoteDeploymentManager!, ex);
 					throw;
 				}
 
-				var commentsTask = remoteDeploymentManager.PostDeploymentComments(
+				var commentsTask = remoteDeploymentManager!.PostDeploymentComments(
 					compileJob,
 					activeCompileJob?.RevisionInformation,
 					repositorySettings,
@@ -398,7 +399,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 			{
 				currentChatCallback?.Invoke(
 					FormatExceptionForUsers(ex),
-					currentDreamMakerOutput);
+					currentDreamMakerOutput!);
 
 				throw;
 			}
@@ -420,13 +421,13 @@ namespace Tgstation.Server.Host.Components.Deployment
 			var previousCompileJobs = await databaseContext
 				.CompileJobs
 				.AsQueryable()
-				.Where(x => x.Job.Instance.Id == metadata.Id)
+				.Where(x => x.Job.Instance!.Id == metadata.Id)
 				.OrderByDescending(x => x.Job.StoppedAt)
 				.Take(10)
 				.Select(x => new
 				{
-					x.Job.StoppedAt,
-					x.Job.StartedAt,
+					StoppedAt = x.Job.StoppedAt!.Value,
+					StartedAt = x.Job.StartedAt!.Value,
 				})
 				.ToListAsync(cancellationToken);
 
@@ -435,7 +436,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 			{
 				var totalSpan = TimeSpan.Zero;
 				foreach (var previousCompileJob in previousCompileJobs)
-					totalSpan += previousCompileJob.StoppedAt.Value - previousCompileJob.StartedAt.Value;
+					totalSpan += previousCompileJob.StoppedAt - previousCompileJob.StartedAt;
 				averageSpan = totalSpan / previousCompileJobs.Count;
 			}
 
@@ -445,6 +446,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 		/// <summary>
 		/// Run the compile implementation.
 		/// </summary>
+		/// <param name="job">The currently running <see cref="Job"/>.</param>
 		/// <param name="revisionInformation">The <see cref="RevisionInformation"/>.</param>
 		/// <param name="dreamMakerSettings">The <see cref="Api.Models.Internal.DreamMakerSettings"/>.</param>
 		/// <param name="launchParameters">The <see cref="DreamDaemonLaunchParameters"/>.</param>
@@ -456,6 +458,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in the completed <see cref="CompileJob"/>.</returns>
 		async ValueTask<Models.CompileJob> Compile(
+			Models.Job job,
 			Models.RevisionInformation revisionInformation,
 			Api.Models.Internal.DreamMakerSettings dreamMakerSettings,
 			DreamDaemonLaunchParameters launchParameters,
@@ -483,22 +486,20 @@ namespace Tgstation.Server.Host.Components.Deployment
 					repository.RemoteRepositoryName,
 					localCommitExistsOnRemote);
 
-				var job = new Models.CompileJob
+				var compileJob = new Models.CompileJob(job, revisionInformation, engineLock.Version.ToString())
 				{
 					DirectoryName = Guid.NewGuid(),
 					DmeName = dreamMakerSettings.ProjectName,
-					RevisionInformation = revisionInformation,
-					EngineVersion = engineLock.Version.ToString(),
 					RepositoryOrigin = repository.Origin.ToString(),
 				};
 
 				progressReporter.StageName = "Creating remote deployment notification";
 				await remoteDeploymentManager.StartDeployment(
 					repository,
-					job,
+					compileJob,
 					cancellationToken);
 
-				logger.LogTrace("Deployment will timeout at {timeoutTime}", DateTimeOffset.UtcNow + dreamMakerSettings.Timeout.Value);
+				logger.LogTrace("Deployment will timeout at {timeoutTime}", DateTimeOffset.UtcNow + dreamMakerSettings.Timeout!.Value);
 				using var timeoutTokenSource = new CancellationTokenSource(dreamMakerSettings.Timeout.Value);
 				var timeoutToken = timeoutTokenSource.Token;
 				using (timeoutToken.Register(() => logger.LogWarning("Deployment timed out!")))
@@ -508,7 +509,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 					{
 						await RunCompileJob(
 							progressReporter,
-							job,
+							compileJob,
 							dreamMakerSettings,
 							launchParameters,
 							engineLock,
@@ -522,7 +523,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 					}
 				}
 
-				return job;
+				return compileJob;
 			}
 			catch (OperationCanceledException)
 			{
@@ -560,7 +561,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 			IRemoteDeploymentManager remoteDeploymentManager,
 			CancellationToken cancellationToken)
 		{
-			var outputDirectory = job.DirectoryName.ToString();
+			var outputDirectory = job.DirectoryName!.Value.ToString();
 			logger.LogTrace("Compile output GUID: {dirGuid}", outputDirectory);
 
 			try
@@ -644,13 +645,13 @@ namespace Tgstation.Server.Host.Components.Deployment
 
 					progressReporter.StageName = "Validating DMAPI";
 					await VerifyApi(
-						launchParameters.StartupTimeout.Value,
-						dreamMakerSettings.ApiValidationSecurityLevel.Value,
+						launchParameters.StartupTimeout!.Value,
+						dreamMakerSettings.ApiValidationSecurityLevel!.Value,
 						job,
 						engineLock,
-						dreamMakerSettings.ApiValidationPort.Value,
-						dreamMakerSettings.RequireDMApiValidation.Value,
-						launchParameters.LogOutput.Value,
+						dreamMakerSettings.ApiValidationPort!.Value,
+						dreamMakerSettings.RequireDMApiValidation!.Value,
+						launchParameters.LogOutput!.Value,
 						cancellationToken);
 				}
 				catch (JobException)
@@ -796,7 +797,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 
 			ApiValidationStatus validationStatus;
 			await using (var provider = new TemporaryDmbProvider(
-				ioManager.ResolvePath(job.DirectoryName.ToString()),
+				ioManager.ResolvePath(job.DirectoryName!.Value.ToString()),
 				job,
 				engineLock.Version))
 			await using (var controller = await sessionControllerFactory.LaunchNew(provider, engineLock, launchParameters, true, cancellationToken))
@@ -856,7 +857,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 			await using var dm = processExecutor.LaunchProcess(
 				engineLock.CompilerExePath,
 				ioManager.ResolvePath(
-					job.DirectoryName.ToString()),
+					job.DirectoryName!.Value.ToString()),
 				arguments,
 				readStandardHandles: true,
 				noShellExecute: true);
@@ -886,14 +887,15 @@ namespace Tgstation.Server.Host.Components.Deployment
 		async ValueTask ModifyDme(Models.CompileJob job, CancellationToken cancellationToken)
 		{
 			var dmeFileName = String.Join('.', job.DmeName, DmeExtension);
-			var dmePath = ioManager.ConcatPath(job.DirectoryName.ToString(), dmeFileName);
+			var stringDirectoryName = job.DirectoryName!.Value.ToString();
+			var dmePath = ioManager.ConcatPath(stringDirectoryName, dmeFileName);
 			var dmeReadTask = ioManager.ReadAllBytes(dmePath, cancellationToken);
 
 			var dmeModificationsTask = configuration.CopyDMFilesTo(
 				dmeFileName,
 				ioManager.ResolvePath(
 					ioManager.ConcatPath(
-						job.DirectoryName.ToString(),
+						stringDirectoryName,
 						ioManager.GetDirectoryName(dmeFileName))),
 				cancellationToken);
 
@@ -952,7 +954,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 			async ValueTask CleanDir()
 			{
 				logger.LogTrace("Cleaning compile directory...");
-				var jobPath = job.DirectoryName.ToString();
+				var jobPath = job.DirectoryName!.Value.ToString();
 				try
 				{
 					// DCT: None available
@@ -965,13 +967,16 @@ namespace Tgstation.Server.Host.Components.Deployment
 				}
 			}
 
-			// DCT: None available
+			var dirCleanTask = CleanDir();
+
+			var failRemoteDeployTask = remoteDeploymentManager.FailDeployment(
+				job,
+				FormatExceptionForUsers(exception),
+				CancellationToken.None); // DCT: None available
+
 			return ValueTaskExtensions.WhenAll(
-				CleanDir(),
-				remoteDeploymentManager.FailDeployment(
-					job,
-					FormatExceptionForUsers(exception),
-					CancellationToken.None));
+				dirCleanTask,
+				failRemoteDeployTask);
 		}
 	}
 }

src/Tgstation.Server.Host/Components/Deployment/HardLinkDmbProvider.cs

@@ -153,7 +153,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 			if (taskThrottle.HasValue && taskThrottle < 1)
 				throw new ArgumentOutOfRangeException(nameof(taskThrottle), taskThrottle, "taskThrottle must be at least 1!");
 
-			var src = IOManager.ResolvePath(CompileJob.DirectoryName.ToString());
+			var src = IOManager.ResolvePath(CompileJob.DirectoryName!.Value.ToString());
 			var dest = IOManager.ResolvePath(mirrorGuid.ToString());
 
 			using var semaphore = taskThrottle.HasValue ? new SemaphoreSlim(taskThrottle.Value) : null;
@@ -178,10 +178,10 @@ namespace Tgstation.Server.Host.Components.Deployment
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="IEnumerable{T}"/> of <see cref="Task"/>s representing the running operations. The first <see cref="Task"/> returned is always the necessary call to <see cref="IIOManager.CreateDirectory(string, CancellationToken)"/>.</returns>
 		/// <remarks>I genuinely don't know how this will work with symlinked files. Waiting for the issue report I guess.</remarks>
-		IEnumerable<Task> MirrorDirectoryImpl(string src, string dest, SemaphoreSlim semaphore, CancellationToken cancellationToken)
+		IEnumerable<Task> MirrorDirectoryImpl(string src, string dest, SemaphoreSlim? semaphore, CancellationToken cancellationToken)
 		{
 			var dir = new DirectoryInfo(src);
-			Task subdirCreationTask = null;
+			Task? subdirCreationTask = null;
 			var dreamDaemonWillAcceptOutOfDirectorySymlinks = CompileJob.MinimumSecurityLevel == DreamDaemonSecurity.Trusted;
 			foreach (var subDirectory in dir.EnumerateDirectories())
 			{
@@ -191,7 +191,8 @@ namespace Tgstation.Server.Host.Components.Deployment
 				if (subDirectory.Attributes.HasFlag(FileAttributes.ReparsePoint))
 					if (dreamDaemonWillAcceptOutOfDirectorySymlinks)
 					{
-						var target = subDirectory.ResolveLinkTarget(false);
+						var target = subDirectory.ResolveLinkTarget(false)
+							?? throw new InvalidOperationException($"\"{subDirectory.FullName}\" was incorrectly identified as a symlinked directory!");
 						logger.LogDebug("Recreating directory {name} as symlink to {target}", subDirectory.Name, target);
 						if (subdirCreationTask == null)
 						{
@@ -250,7 +251,9 @@ namespace Tgstation.Server.Host.Components.Deployment
 					if (fileInfo.Attributes.HasFlag(FileAttributes.ReparsePoint))
 					{
 						// AHHHHHHHHHHHHH
-						var target = fileInfo.ResolveLinkTarget(!dreamDaemonWillAcceptOutOfDirectorySymlinks);
+						var target = fileInfo.ResolveLinkTarget(!dreamDaemonWillAcceptOutOfDirectorySymlinks)
+							?? throw new InvalidOperationException($"\"{fileInfo.FullName}\" was incorrectly identified as a symlinked file!");
+
 						if (dreamDaemonWillAcceptOutOfDirectorySymlinks)
 						{
 							logger.LogDebug("Recreating symlinked file {name} as symlink to {target}", fileInfo.Name, target.FullName);

src/Tgstation.Server.Host/Components/Deployment/ICompileJobSink.cs

@@ -15,9 +15,9 @@ namespace Tgstation.Server.Host.Components.Deployment
 		/// Load a new <paramref name="job"/> into the <see cref="ICompileJobSink"/>.
 		/// </summary>
 		/// <param name="job">The <see cref="CompileJob"/> to load.</param>
-		/// <param name="activationAction">An <see cref="Action{T1}"/> to be called when the <see cref="CompileJob"/> becomes active or is discarded with <see langword="true"/> or <see langword="false"/> respectively.</param>
+		/// <param name="activationAction">An optional <see cref="Action{T1}"/> to be called when the <see cref="CompileJob"/> becomes active or is discarded with <see langword="true"/> or <see langword="false"/> respectively.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask"/> representing the running operation.</returns>
-		ValueTask LoadCompileJob(CompileJob job, Action<bool> activationAction, CancellationToken cancellationToken);
+		ValueTask LoadCompileJob(CompileJob job, Action<bool>? activationAction, CancellationToken cancellationToken);
 	}
 }

src/Tgstation.Server.Host/Components/Deployment/IDmbFactory.cs

@@ -23,7 +23,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 		bool DmbAvailable { get; }
 
 		/// <summary>
-		/// Gets the next <see cref="IDmbProvider"/>.
+		/// Gets the next <see cref="IDmbProvider"/>. <see cref="DmbAvailable"/> is a precondition.
 		/// </summary>
 		/// <param name="lockCount">The amount of locks to give the resulting <see cref="IDmbProvider"/>. It's <see cref="IDisposable.Dispose"/> must be called this many times to properly clean the job.</param>
 		/// <returns>A new <see cref="IDmbProvider"/>.</returns>
@@ -35,7 +35,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 		/// <param name="compileJob">The <see cref="CompileJob"/> to make the <see cref="IDmbProvider"/> for.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in a new <see cref="IDmbProvider"/> representing the <see cref="CompileJob"/> on success, <see langword="null"/> on failure.</returns>
-		ValueTask<IDmbProvider> FromCompileJob(CompileJob compileJob, CancellationToken cancellationToken);
+		ValueTask<IDmbProvider?> FromCompileJob(CompileJob compileJob, CancellationToken cancellationToken);
 
 		/// <summary>
 		/// Deletes all compile jobs that are inactive in the Game folder.

src/Tgstation.Server.Host/Components/Deployment/ILatestCompileJobProvider.cs

@@ -10,7 +10,7 @@ namespace Tgstation.Server.Host.Components.Deployment
 		/// <summary>
 		/// Gets the latest <see cref="CompileJob"/>.
 		/// </summary>
-		/// <returns>The latest <see cref="CompileJob"/>.</returns>
-		CompileJob LatestCompileJob();
+		/// <returns>The latest <see cref="CompileJob"/> or <see langword="null"/> if none are available.</returns>
+		CompileJob? LatestCompileJob();
 	}
 }

src/Tgstation.Server.Host/Components/Deployment/Remote/BaseRemoteDeploymentManager.cs

@@ -52,18 +52,23 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 		/// <inheritdoc />
 		public async ValueTask PostDeploymentComments(
 			CompileJob compileJob,
-			RevisionInformation previousRevisionInformation,
+			RevisionInformation? previousRevisionInformation,
 			RepositorySettings repositorySettings,
-			string repoOwner,
-			string repoName,
+			string? repoOwner,
+			string? repoName,
 			CancellationToken cancellationToken)
 		{
-			if (repositorySettings?.AccessToken == null)
+			ArgumentNullException.ThrowIfNull(compileJob);
+			ArgumentNullException.ThrowIfNull(repositorySettings);
+			ArgumentNullException.ThrowIfNull(repoOwner);
+			ArgumentNullException.ThrowIfNull(repoName);
+
+			if (repositorySettings.AccessToken == null)
 				return;
 
 			var deployedRevisionInformation = compileJob.RevisionInformation;
 			if ((previousRevisionInformation != null && previousRevisionInformation.CommitSha == deployedRevisionInformation.CommitSha)
-				|| !repositorySettings.PostTestMergeComment.Value)
+				|| !repositorySettings.PostTestMergeComment!.Value)
 				return;
 
 			previousRevisionInformation ??= new RevisionInformation();
@@ -94,7 +99,7 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 					.Any(y => y.TestMerge.Number == x.Number))
 				.ToList();
 
-			if (!addedTestMerges.Any() && !removedTestMerges.Any() && !updatedTestMerges.Any())
+			if (addedTestMerges.Count == 0 && removedTestMerges.Count == 0 && updatedTestMerges.Count == 0)
 				return;
 
 			Logger.LogTrace(
@@ -105,48 +110,54 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 
 			var tasks = new List<ValueTask>(addedTestMerges.Count + updatedTestMerges.Count + removedTestMerges.Count);
 			foreach (var addedTestMerge in addedTestMerges)
-				tasks.Add(
-					CommentOnTestMergeSource(
+			{
+				var addCommentTask = CommentOnTestMergeSource(
+					repositorySettings,
+					repoOwner,
+					repoName,
+					FormatTestMerge(
 						repositorySettings,
+						compileJob,
+						addedTestMerge,
 						repoOwner,
 						repoName,
-						FormatTestMerge(
-							repositorySettings,
-							compileJob,
-							addedTestMerge,
-							repoOwner,
-							repoName,
-							false),
-						addedTestMerge.Number,
-						cancellationToken));
+						false),
+					addedTestMerge.Number,
+					cancellationToken);
+				tasks.Add(addCommentTask);
+			}
 
 			foreach (var removedTestMerge in removedTestMerges)
-				tasks.Add(
-					CommentOnTestMergeSource(
-						repositorySettings,
-						repoOwner,
-						repoName,
-						"#### Test Merge Removed",
-						removedTestMerge.Number,
-						cancellationToken));
+			{
+				var removeCommentTask = CommentOnTestMergeSource(
+					repositorySettings,
+					repoOwner,
+					repoName,
+					"#### Test Merge Removed",
+					removedTestMerge.Number,
+					cancellationToken);
+				tasks.Add(removeCommentTask);
+			}
 
 			foreach (var updatedTestMerge in updatedTestMerges)
-				tasks.Add(
-					CommentOnTestMergeSource(
+			{
+				var updateCommentTask = CommentOnTestMergeSource(
+					repositorySettings,
+					repoOwner,
+					repoName,
+					FormatTestMerge(
 						repositorySettings,
+						compileJob,
+						updatedTestMerge,
 						repoOwner,
 						repoName,
-						FormatTestMerge(
-							repositorySettings,
-							compileJob,
-							updatedTestMerge,
-							repoOwner,
-							repoName,
-							true),
-						updatedTestMerge.Number,
-						cancellationToken));
+						true),
+					updatedTestMerge.Number,
+					cancellationToken);
+				tasks.Add(updateCommentTask);
+			}
 
-			if (tasks.Any())
+			if (tasks.Count > 0)
 				await ValueTaskExtensions.WhenAll(tasks);
 		}
 
@@ -155,7 +166,7 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 		{
 			ArgumentNullException.ThrowIfNull(compileJob);
 
-			if (activationCallbacks.TryGetValue(compileJob.Id.Value, out var activationCallback))
+			if (activationCallbacks.TryGetValue(compileJob.Require(x => x.Id), out var activationCallback))
 				activationCallback(true);
 
 			return ApplyDeploymentImpl(compileJob, cancellationToken);
@@ -169,7 +180,7 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 		{
 			ArgumentNullException.ThrowIfNull(compileJob);
 
-			if (activationCallbacks.TryRemove(compileJob.Id.Value, out var activationCallback))
+			if (activationCallbacks.TryRemove(compileJob.Require(x => x.Id), out var activationCallback))
 				activationCallback(false);
 
 			return MarkInactiveImpl(compileJob, cancellationToken);
@@ -183,12 +194,13 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 			CancellationToken cancellationToken);
 
 		/// <inheritdoc />
-		public ValueTask StageDeployment(CompileJob compileJob, Action<bool> activationCallback, CancellationToken cancellationToken)
+		public ValueTask StageDeployment(CompileJob compileJob, Action<bool>? activationCallback, CancellationToken cancellationToken)
 		{
 			ArgumentNullException.ThrowIfNull(compileJob);
 
-			if (activationCallback != null && !activationCallbacks.TryAdd(compileJob.Id.Value, activationCallback))
-				Logger.LogError("activationCallbacks conflicted on CompileJob #{id}!", compileJob.Id.Value);
+			var compileJobId = compileJob.Require(x => x.Id);
+			if (activationCallback != null && !activationCallbacks.TryAdd(compileJobId, activationCallback))
+				Logger.LogError("activationCallbacks conflicted on CompileJob #{id}!", compileJobId);
 
 			return StageDeploymentImpl(compileJob, cancellationToken);
 		}

src/Tgstation.Server.Host/Components/Deployment/Remote/GitHubRemoteDeploymentManager.cs

@@ -65,7 +65,7 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 
 			Logger.LogTrace("Starting deployment...");
 
-			RepositorySettings repositorySettings = null;
+			RepositorySettings? repositorySettings = null;
 			await databaseContextFactory.UseContext(
 				async databaseContext =>
 					repositorySettings = await databaseContext
@@ -74,12 +74,12 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 						.Where(x => x.InstanceId == Metadata.Id)
 						.FirstAsync(cancellationToken));
 
-			var instanceAuthenticated = repositorySettings.AccessToken != null;
-			IAuthenticatedGitHubService authenticatedGitHubService;
+			var instanceAuthenticated = repositorySettings!.AccessToken != null;
+			IAuthenticatedGitHubService? authenticatedGitHubService;
 			IGitHubService gitHubService;
 			if (instanceAuthenticated)
 			{
-				authenticatedGitHubService = gitHubServiceFactory.CreateService(repositorySettings.AccessToken);
+				authenticatedGitHubService = gitHubServiceFactory.CreateService(repositorySettings.AccessToken!);
 				gitHubService = authenticatedGitHubService;
 			}
 			else
@@ -88,12 +88,14 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 				gitHubService = gitHubServiceFactory.CreateService();
 			}
 
+			var repoOwner = remoteInformation.RemoteRepositoryOwner!;
+			var repoName = remoteInformation.RemoteRepositoryName!;
 			var repositoryIdTask = gitHubService.GetRepositoryId(
-				remoteInformation.RemoteRepositoryOwner,
-				remoteInformation.RemoteRepositoryName,
+				repoOwner,
+				repoName,
 				cancellationToken);
 
-			if (!repositorySettings.CreateGitHubDeployments.Value)
+			if (!repositorySettings.CreateGitHubDeployments!.Value)
 				Logger.LogTrace("Not creating deployment");
 			else if (!instanceAuthenticated)
 				Logger.LogWarning("Can't create GitHub deployment as no access token is set for repository!");
@@ -102,7 +104,7 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 				Logger.LogTrace("Creating deployment...");
 				try
 				{
-					compileJob.GitHubDeploymentId = await authenticatedGitHubService.CreateDeployment(
+					compileJob.GitHubDeploymentId = await authenticatedGitHubService!.CreateDeployment(
 						new NewDeployment(compileJob.RevisionInformation.CommitSha)
 						{
 							AutoMerge = false,
@@ -111,8 +113,8 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 							ProductionEnvironment = true,
 							RequiredContexts = new Collection<string>(),
 						},
-						remoteInformation.RemoteRepositoryOwner,
-						remoteInformation.RemoteRepositoryName,
+						repoOwner,
+						repoName,
 						cancellationToken);
 
 					Logger.LogDebug("Created deployment ID {deploymentId}", compileJob.GitHubDeploymentId);
@@ -123,8 +125,8 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 							Description = "The project is being deployed",
 							AutoInactive = false,
 						},
-						remoteInformation.RemoteRepositoryOwner,
-						remoteInformation.RemoteRepositoryName,
+						repoOwner,
+						repoName,
 						compileJob.GitHubDeploymentId.Value,
 						cancellationToken);
 
@@ -166,7 +168,7 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 			ArgumentNullException.ThrowIfNull(repositorySettings);
 			ArgumentNullException.ThrowIfNull(revisionInformation);
 
-			if (revisionInformation.ActiveTestMerges?.Any() != true)
+			if ((revisionInformation.ActiveTestMerges?.Count > 0) != true)
 			{
 				Logger.LogTrace("No test merges to remove.");
 				return Array.Empty<TestMerge>();
@@ -178,7 +180,11 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 
 			var tasks = revisionInformation
 				.ActiveTestMerges
-				.Select(x => gitHubService.GetPullRequest(repository.RemoteRepositoryOwner, repository.RemoteRepositoryName, x.TestMerge.Number, cancellationToken));
+				.Select(x => gitHubService.GetPullRequest(
+					repository.RemoteRepositoryOwner!,
+					repository.RemoteRepositoryName!,
+					x.TestMerge.Number,
+					cancellationToken));
 			try
 			{
 				await Task.WhenAll(tasks);
@@ -190,7 +196,7 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 
 			var newList = revisionInformation.ActiveTestMerges.Select(x => x.TestMerge).ToList();
 
-			PullRequest lastMerged = null;
+			PullRequest? lastMerged = null;
 			async ValueTask CheckRemovePR(Task<PullRequest> task)
 			{
 				var pr = await task;
@@ -249,7 +255,7 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 			int testMergeNumber,
 			CancellationToken cancellationToken)
 		{
-			var gitHubService = gitHubServiceFactory.CreateService(repositorySettings.AccessToken);
+			var gitHubService = gitHubServiceFactory.CreateService(repositorySettings.AccessToken!);
 
 			try
 			{
@@ -272,12 +278,12 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 			CultureInfo.InvariantCulture,
 			"#### Test Merge {4}{0}{0}<details><summary>Details</summary>{0}{0}##### Server Instance{0}{5}{1}{0}{0}##### Revision{0}Origin: {6}{0}Pull Request: {2}{0}Server: {7}{3}{8}{0}</details>",
 			Environment.NewLine,
-			repositorySettings.ShowTestMergeCommitters.Value
+			repositorySettings.ShowTestMergeCommitters!.Value
 				? String.Format(
 					CultureInfo.InvariantCulture,
 					"{0}{0}##### Merged By{0}{1}",
 					Environment.NewLine,
-					testMerge.MergedBy.Name)
+					testMerge.MergedBy!.Name)
 				: String.Empty,
 			testMerge.TargetCommitSha,
 			testMerge.Comment != null
@@ -292,7 +298,7 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 			compileJob.RevisionInformation.OriginCommitSha,
 			compileJob.RevisionInformation.CommitSha,
 			compileJob.GitHubDeploymentId.HasValue
-				? $"{Environment.NewLine}[GitHub Deployments](https://github.com/{remoteRepositoryOwner}/{remoteRepositoryName}/deployments/activity_log?environment=TGS%3A+{Metadata.Name.Replace(" ", "+", StringComparison.Ordinal)})"
+				? $"{Environment.NewLine}[GitHub Deployments](https://github.com/{remoteRepositoryOwner}/{remoteRepositoryName}/deployments/activity_log?environment=TGS%3A+{Metadata.Name!.Replace(" ", "+", StringComparison.Ordinal)})"
 				: String.Empty);
 
 		/// <summary>
@@ -319,7 +325,7 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 
 			Logger.LogTrace("Updating deployment {gitHubDeploymentId} to {deploymentState}...", compileJob.GitHubDeploymentId.Value, deploymentState);
 
-			string gitHubAccessToken = null;
+			string? gitHubAccessToken = null;
 			await databaseContextFactory.UseContext(
 				async databaseContext =>
 					gitHubAccessToken = await databaseContext

src/Tgstation.Server.Host/Components/Deployment/Remote/GitLabRemoteDeploymentManager.cs

@@ -46,7 +46,7 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 			ArgumentNullException.ThrowIfNull(repositorySettings);
 			ArgumentNullException.ThrowIfNull(revisionInformation);
 
-			if (revisionInformation.ActiveTestMerges?.Any() != true)
+			if ((revisionInformation.ActiveTestMerges?.Count > 0) != true)
 			{
 				Logger.LogTrace("No test merges to remove.");
 				return Array.Empty<TestMerge>();
@@ -75,7 +75,7 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 
 			var newList = revisionInformation.ActiveTestMerges.Select(x => x.TestMerge).ToList();
 
-			MergeRequest lastMerged = null;
+			MergeRequest? lastMerged = null;
 			async ValueTask CheckRemoveMR(Task<MergeRequest> task)
 			{
 				var mergeRequest = await task;
@@ -162,12 +162,12 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 			CultureInfo.InvariantCulture,
 			"#### Test Merge {4}{0}{0}##### Server Instance{0}{5}{1}{0}{0}##### Revision{0}Origin: {6}{0}Merge Request: {2}{0}Server: {7}{3}",
 			Environment.NewLine,
-			repositorySettings.ShowTestMergeCommitters.Value
+			repositorySettings.ShowTestMergeCommitters!.Value
 				? String.Format(
 					CultureInfo.InvariantCulture,
 					"{0}{0}##### Merged By{0}{1}",
 					Environment.NewLine,
-					testMerge.MergedBy.Name)
+					testMerge.MergedBy!.Name)
 				: String.Empty,
 			testMerge.TargetCommitSha,
 			testMerge.Comment != null

src/Tgstation.Server.Host/Components/Deployment/Remote/IRemoteDeploymentManager.cs

@@ -34,7 +34,7 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 		/// <returns>A <see cref="ValueTask"/> representing the running operation.</returns>
 		ValueTask StageDeployment(
 			CompileJob compileJob,
-			Action<bool> activationCallback,
+			Action<bool>? activationCallback,
 			CancellationToken cancellationToken);
 
 		/// <summary>
@@ -66,18 +66,18 @@ namespace Tgstation.Server.Host.Components.Deployment.Remote
 		/// Post deployment comments to the test merge ticket.
 		/// </summary>
 		/// <param name="compileJob">The deployed <see cref="CompileJob"/>.</param>
-		/// <param name="previousRevisionInformation">The <see cref="RevisionInformation"/> of the previous deployment.</param>
+		/// <param name="previousRevisionInformation">The optional <see cref="RevisionInformation"/> of the previous deployment.</param>
 		/// <param name="repositorySettings">The <see cref="RepositorySettings"/>.</param>
-		/// <param name="repoOwner">The GitHub repostiory owner.</param>
-		/// <param name="repoName">The GitHub repostiory name.</param>
+		/// <param name="repoOwner">The remote repostiory owner.</param>
+		/// <param name="repoName">The remote repostiory name.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask"/> representing the running operation.</returns>
 		ValueTask PostDeploymentComments(
 			CompileJob compileJob,
-			RevisionInformation previousRevisionInformation,
+			RevisionInformation? previousRevisionInformation,
 			RepositorySettings repositorySettings,
-			string repoOwner,
-			string repoName,
+			string? repoOwner,
+			string? repoName,
 			CancellationToken cancellationToken);
 
 		/// <summary>

src/Tgstation.Server.Host/Components/Engine/ByondInstallation.cs

@@ -92,8 +92,8 @@ namespace Tgstation.Server.Host.Components.Engine
 			InstallationTask = installationTask ?? throw new ArgumentNullException(nameof(installationTask));
 			ArgumentNullException.ThrowIfNull(version);
 
-			if (version.Engine.Value != EngineType.Byond)
-				throw new ArgumentException($"Invalid EngineType: {version.Engine.Value}", nameof(version));
+			if (version.Engine != EngineType.Byond)
+				throw new ArgumentException($"Invalid EngineType: {version.Engine}", nameof(version));
 
 			Version = version ?? throw new ArgumentNullException(nameof(version));
 			ServerExePath = dreamDaemonPath ?? throw new ArgumentNullException(nameof(dreamDaemonPath));
@@ -108,7 +108,7 @@ namespace Tgstation.Server.Host.Components.Engine
 			IDmbProvider dmbProvider,
 			IReadOnlyDictionary<string, string> parameters,
 			DreamDaemonLaunchParameters launchParameters,
-			string logFilePath)
+			string? logFilePath)
 		{
 			ArgumentNullException.ThrowIfNull(dmbProvider);
 			ArgumentNullException.ThrowIfNull(parameters);
@@ -120,19 +120,19 @@ namespace Tgstation.Server.Host.Components.Engine
 				CultureInfo.InvariantCulture,
 				"{0} -port {1} -ports 1-65535 {2}-close -verbose -{3} -{4}{5}{6}{7} -params \"{8}\"",
 				dmbProvider.DmbName,
-				launchParameters.Port.Value,
-				launchParameters.AllowWebClient.Value
+				launchParameters.Port!.Value,
+				launchParameters.AllowWebClient!.Value
 					? "-webclient "
 					: String.Empty,
-				SecurityWord(launchParameters.SecurityLevel.Value),
-				VisibilityWord(launchParameters.Visibility.Value),
+				SecurityWord(launchParameters.SecurityLevel!.Value),
+				VisibilityWord(launchParameters.Visibility!.Value),
 				logFilePath != null
 					? $" -logself -log {logFilePath}"
 					: String.Empty, // DD doesn't output anything if -logself is set???
-				launchParameters.StartProfiler.Value
+				launchParameters.StartProfiler!.Value
 					? " -profile"
 					: String.Empty,
-				supportsMapThreads && launchParameters.MapThreads.Value != 0
+				supportsMapThreads && launchParameters.MapThreads!.Value != 0
 					? $" -map-threads {launchParameters.MapThreads.Value}"
 					: String.Empty,
 				parametersString);

src/Tgstation.Server.Host/Components/Engine/ByondInstallerBase.cs

@@ -98,7 +98,7 @@ namespace Tgstation.Server.Host.Components.Engine
 					IOManager.ConcatPath(
 						binPathForVersion,
 						GetDreamDaemonName(
-							version.Version,
+							version.Version!,
 							out var supportsCli))),
 				IOManager.ResolvePath(
 					IOManager.ConcatPath(
@@ -194,11 +194,11 @@ namespace Tgstation.Server.Host.Components.Engine
 		}
 
 		/// <inheritdoc />
-		public override async ValueTask<IEngineInstallationData> DownloadVersion(EngineVersion version, JobProgressReporter progressReporter, CancellationToken cancellationToken)
+		public override async ValueTask<IEngineInstallationData> DownloadVersion(EngineVersion version, JobProgressReporter? progressReporter, CancellationToken cancellationToken)
 		{
 			CheckVersionValidity(version);
 
-			var url = await GetDownloadZipUrl(version, cancellationToken);
+			var url = GetDownloadZipUrl(version);
 			Logger.LogTrace("Downloading {engineType} version {version} from {url}...", TargetEngineType, version, url);
 
 			await using var download = fileDownloader.DownloadFile(url, null);
@@ -231,13 +231,12 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// Create a <see cref="Uri"/> pointing to the location of the download for a given <paramref name="version"/>.
 		/// </summary>
 		/// <param name="version">The <see cref="EngineVersion"/> to create a <see cref="Uri"/> for.</param>
-		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
-		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in a new <see cref="Uri"/> pointing to the version download location.</returns>
-		ValueTask<Uri> GetDownloadZipUrl(EngineVersion version, CancellationToken cancellationToken)
+		/// <returns>A <see cref="Uri"/> pointing to the version download location.</returns>
+		Uri GetDownloadZipUrl(EngineVersion version)
 		{
 			CheckVersionValidity(version);
-			var url = String.Format(CultureInfo.InvariantCulture, ByondRevisionsUrlTemplate, version.Version.Major, version.Version.Minor);
-			return ValueTask.FromResult(new Uri(url));
+			var url = String.Format(CultureInfo.InvariantCulture, ByondRevisionsUrlTemplate, version.Version!.Major, version.Version.Minor);
+			return new Uri(url);
 		}
 	}
 }

src/Tgstation.Server.Host/Components/Engine/DelegatingEngineInstaller.cs

@@ -1,5 +1,5 @@
 using System;
-using System.Collections.Generic;
+using System.Collections.Frozen;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
@@ -15,15 +15,15 @@ namespace Tgstation.Server.Host.Components.Engine
 	sealed class DelegatingEngineInstaller : IEngineInstaller
 	{
 		/// <summary>
-		/// The <see cref="IReadOnlyDictionary{TKey, TValue}"/> mapping <see cref="EngineType"/>s to their appropriate <see cref="IEngineInstaller"/>.
+		/// The <see cref="FrozenDictionary{TKey, TValue}"/> mapping <see cref="EngineType"/>s to their appropriate <see cref="IEngineInstaller"/>.
 		/// </summary>
-		readonly IReadOnlyDictionary<EngineType, IEngineInstaller> delegatedInstallers;
+		readonly FrozenDictionary<EngineType, IEngineInstaller> delegatedInstallers;
 
 		/// <summary>
 		/// Initializes a new instance of the <see cref="DelegatingEngineInstaller"/> class.
 		/// </summary>
 		/// <param name="delegatedInstallers">The value of <see cref="delegatedInstallers"/>.</param>
-		public DelegatingEngineInstaller(IReadOnlyDictionary<EngineType, IEngineInstaller> delegatedInstallers)
+		public DelegatingEngineInstaller(FrozenDictionary<EngineType, IEngineInstaller> delegatedInstallers)
 		{
 			this.delegatedInstallers = delegatedInstallers ?? throw new ArgumentNullException(nameof(delegatedInstallers));
 		}
@@ -37,7 +37,7 @@ namespace Tgstation.Server.Host.Components.Engine
 			=> DelegateCall(version, installer => installer.CreateInstallation(version, path, installationTask));
 
 		/// <inheritdoc />
-		public ValueTask<IEngineInstallationData> DownloadVersion(EngineVersion version, JobProgressReporter jobProgressReporter, CancellationToken cancellationToken)
+		public ValueTask<IEngineInstallationData> DownloadVersion(EngineVersion version, JobProgressReporter? jobProgressReporter, CancellationToken cancellationToken)
 			=> DelegateCall(version, installer => installer.DownloadVersion(version, jobProgressReporter, cancellationToken));
 
 		/// <inheritdoc />
@@ -62,7 +62,7 @@ namespace Tgstation.Server.Host.Components.Engine
 		TReturn DelegateCall<TReturn>(EngineVersion version, Func<IEngineInstaller, TReturn> call)
 		{
 			ArgumentNullException.ThrowIfNull(version);
-			return call(delegatedInstallers[version.Engine.Value]);
+			return call(delegatedInstallers[version.Engine!.Value]);
 		}
 	}
 }

src/Tgstation.Server.Host/Components/Engine/EngineExecutableLock.cs

@@ -1,15 +1,19 @@
 using System.Collections.Generic;
+using System.Threading;
 using System.Threading.Tasks;
 
+using Microsoft.Extensions.Logging;
+
 using Tgstation.Server.Api.Models;
 using Tgstation.Server.Api.Models.Internal;
 using Tgstation.Server.Host.Components.Deployment;
+using Tgstation.Server.Host.System;
 using Tgstation.Server.Host.Utils;
 
 namespace Tgstation.Server.Host.Components.Engine
 {
 	/// <inheritdoc cref="IEngineExecutableLock" />
-	sealed class EngineExecutableLock : ReferenceCounter<IEngineInstallation>, IEngineExecutableLock
+	class EngineExecutableLock : ReferenceCounter<IEngineInstallation>, IEngineExecutableLock
 	{
 		/// <inheritdoc />
 		public EngineVersion Version => Instance.Version;
@@ -40,7 +44,7 @@ namespace Tgstation.Server.Host.Components.Engine
 			IDmbProvider dmbProvider,
 			IReadOnlyDictionary<string, string> parameters,
 			DreamDaemonLaunchParameters launchParameters,
-			string logFilePath)
+			string? logFilePath)
 			=> Instance.FormatServerArguments(
 				dmbProvider,
 				parameters,
@@ -49,5 +53,14 @@ namespace Tgstation.Server.Host.Components.Engine
 
 		/// <inheritdoc />
 		public string FormatCompilerArguments(string dmePath) => Instance.FormatCompilerArguments(dmePath);
+
+		/// <inheritdoc />
+		public ValueTask StopServerProcess(ILogger logger, IProcess process, string accessIdentifier, ushort port, CancellationToken cancellationToken)
+			=> Instance.StopServerProcess(
+				logger,
+				process,
+				accessIdentifier,
+				port,
+				cancellationToken);
 	}
 }

src/Tgstation.Server.Host/Components/Engine/EngineInstallationBase.cs

@@ -1,12 +1,16 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading;
 using System.Threading.Tasks;
 using System.Web;
 
+using Microsoft.Extensions.Logging;
+
 using Tgstation.Server.Api.Models;
 using Tgstation.Server.Api.Models.Internal;
 using Tgstation.Server.Host.Components.Deployment;
+using Tgstation.Server.Host.System;
 
 namespace Tgstation.Server.Host.Components.Engine
 {
@@ -56,6 +60,19 @@ namespace Tgstation.Server.Host.Components.Engine
 		public abstract string FormatCompilerArguments(string dmePath);
 
 		/// <inheritdoc />
-		public abstract string FormatServerArguments(IDmbProvider dmbProvider, IReadOnlyDictionary<string, string> parameters, DreamDaemonLaunchParameters launchParameters, string logFilePath);
+		public abstract string FormatServerArguments(
+			IDmbProvider dmbProvider,
+			IReadOnlyDictionary<string, string> parameters,
+			DreamDaemonLaunchParameters launchParameters,
+			string? logFilePath);
+
+		/// <inheritdoc />
+		public virtual async ValueTask StopServerProcess(ILogger logger, IProcess process, string accessIdentifier, ushort port, CancellationToken cancellationToken)
+		{
+			cancellationToken.ThrowIfCancellationRequested();
+			logger.LogTrace("Terminating engine server process...");
+			process.Terminate();
+			await process.Lifetime;
+		}
 	}
 }

src/Tgstation.Server.Host/Components/Engine/EngineInstallerBase.cs

@@ -52,7 +52,7 @@ namespace Tgstation.Server.Host.Components.Engine
 		public abstract ValueTask UpgradeInstallation(EngineVersion version, string path, CancellationToken cancellationToken);
 
 		/// <inheritdoc />
-		public abstract ValueTask<IEngineInstallationData> DownloadVersion(EngineVersion version, JobProgressReporter jobProgressReporter, CancellationToken cancellationToken);
+		public abstract ValueTask<IEngineInstallationData> DownloadVersion(EngineVersion version, JobProgressReporter? jobProgressReporter, CancellationToken cancellationToken);
 
 		/// <inheritdoc />
 		public abstract ValueTask TrustDmbPath(EngineVersion version, string fullDmbPath, CancellationToken cancellationToken);
@@ -64,7 +64,7 @@ namespace Tgstation.Server.Host.Components.Engine
 		protected void CheckVersionValidity(EngineVersion version)
 		{
 			ArgumentNullException.ThrowIfNull(version);
-			if (version.Engine.Value != TargetEngineType)
+			if (version.Engine!.Value != TargetEngineType)
 				throw new InvalidOperationException($"Non-{TargetEngineType} engine specified: {version.Engine.Value}");
 		}
 	}

src/Tgstation.Server.Host/Components/Engine/EngineManager.cs

@@ -32,7 +32,7 @@ namespace Tgstation.Server.Host.Components.Engine
 		const string ActiveVersionFileName = "ActiveVersion.txt";
 
 		/// <inheritdoc />
-		public EngineVersion ActiveVersion { get; private set; }
+		public EngineVersion? ActiveVersion { get; private set; }
 
 		/// <inheritdoc />
 		public IReadOnlyList<EngineVersion> InstalledVersions
@@ -118,9 +118,9 @@ namespace Tgstation.Server.Host.Components.Engine
 
 		/// <inheritdoc />
 		public async ValueTask ChangeVersion(
-			JobProgressReporter progressReporter,
+			JobProgressReporter? progressReporter,
 			EngineVersion version,
-			Stream customVersionStream,
+			Stream? customVersionStream,
 			bool allowInstallation,
 			CancellationToken cancellationToken)
 		{
@@ -143,7 +143,7 @@ namespace Tgstation.Server.Host.Components.Engine
 				await ioManager.WriteAllBytes(ActiveVersionFileName, Encoding.UTF8.GetBytes(stringVersion), cancellationToken);
 				await eventConsumer.HandleEvent(
 					EventType.EngineActiveVersionChange,
-					new List<string>
+					new List<string?>
 					{
 						ActiveVersion?.ToString(),
 						stringVersion,
@@ -160,7 +160,7 @@ namespace Tgstation.Server.Host.Components.Engine
 		}
 
 		/// <inheritdoc />
-		public async ValueTask<IEngineExecutableLock> UseExecutables(EngineVersion requiredVersion, string trustDmbFullPath, CancellationToken cancellationToken)
+		public async ValueTask<IEngineExecutableLock> UseExecutables(EngineVersion? requiredVersion, string? trustDmbFullPath, CancellationToken cancellationToken)
 		{
 			logger.LogTrace(
 				"Acquiring lock on BYOND version {version}...",
@@ -196,19 +196,21 @@ namespace Tgstation.Server.Host.Components.Engine
 
 			logger.LogTrace("DeleteVersion {version}", version);
 
-			if (version.Equals(ActiveVersion))
+			var activeVersion = ActiveVersion;
+			if (activeVersion != null && version.Equals(activeVersion))
 				throw new JobException(ErrorCode.EngineCannotDeleteActiveVersion);
 
 			ReferenceCountingContainer<IEngineInstallation, EngineExecutableLock> container;
 			logger.LogTrace("Waiting to acquire installedVersions lock...");
 			lock (installedVersions)
 			{
-				if (!installedVersions.TryGetValue(version, out container))
+				if (!installedVersions.TryGetValue(version, out var containerNullable))
 				{
 					logger.LogTrace("Version {version} already deleted.", version);
 					return;
 				}
 
+				container = containerNullable;
 				logger.LogTrace("Installation container acquired for deletion");
 			}
 
@@ -236,7 +238,8 @@ namespace Tgstation.Server.Host.Components.Engine
 				using (await SemaphoreSlimContext.Lock(changeDeleteSemaphore, cancellationToken))
 				{
 					// check again because it could have become the active version.
-					if (version.Equals(ActiveVersion))
+					activeVersion = ActiveVersion;
+					if (activeVersion != null && version.Equals(activeVersion))
 						throw new JobException(ErrorCode.EngineCannotDeleteActiveVersion);
 
 					bool proceed;
@@ -294,7 +297,7 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// <inheritdoc />
 		public async Task StartAsync(CancellationToken cancellationToken)
 		{
-			async ValueTask<byte[]> GetActiveVersion()
+			async ValueTask<byte[]?> GetActiveVersion()
 			{
 				var activeVersionFileExists = await ioManager.FileExists(ActiveVersionFileName, cancellationToken);
 				return !activeVersionFileExists ? null : await ioManager.ReadAllBytes(ActiveVersionFileName, cancellationToken);
@@ -319,12 +322,15 @@ namespace Tgstation.Server.Host.Components.Engine
 
 				var bytes = await ioManager.ReadAllBytes(versionFile, cancellationToken);
 				var text = Encoding.UTF8.GetString(bytes);
-				if (!EngineVersion.TryParse(text, out var version))
+				EngineVersion version;
+				if (!EngineVersion.TryParse(text, out var versionNullable))
 				{
 					logger.LogWarning("Cleaning path with unparsable version file: {versionPath}", ioManager.ResolvePath(path));
 					await ioManager.DeleteDirectory(path, cancellationToken); // cleanup
 					return;
 				}
+				else
+					version = versionNullable!;
 
 				try
 				{
@@ -360,11 +366,11 @@ namespace Tgstation.Server.Host.Components.Engine
 			{
 				var activeVersionString = Encoding.UTF8.GetString(activeVersionBytes);
 
-				EngineVersion activeVersion;
+				EngineVersion? activeVersion;
 				bool hasRequestedActiveVersion;
 				lock (installedVersions)
 					hasRequestedActiveVersion = EngineVersion.TryParse(activeVersionString, out activeVersion)
-						&& installedVersions.ContainsKey(activeVersion);
+						&& installedVersions.ContainsKey(activeVersion!);
 
 				if (hasRequestedActiveVersion)
 					ActiveVersion = activeVersion; // not setting TCS because there's no need during init
@@ -384,15 +390,15 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// </summary>
 		/// <param name="progressReporter">The optional <see cref="JobProgressReporter"/> for the operation.</param>
 		/// <param name="version">The <see cref="EngineVersion"/> to install.</param>
-		/// <param name="customVersionStream">Custom zip file <see cref="Stream"/> to use. Will cause a <see cref="Version.Build"/> number to be added.</param>
+		/// <param name="customVersionStream">Optional custom zip file <see cref="Stream"/> to use. Will cause a <see cref="Version.Build"/> number to be added.</param>
 		/// <param name="neededForLock">If this BYOND version is required as part of a locking operation.</param>
 		/// <param name="allowInstallation">If an installation should be performed if the <paramref name="version"/> is not installed. If <see langword="false"/> and an installation is required an <see cref="InvalidOperationException"/> will be thrown.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in the <see cref="EngineExecutableLock"/>.</returns>
 		async ValueTask<EngineExecutableLock> AssertAndLockVersion(
-			JobProgressReporter progressReporter,
+			JobProgressReporter? progressReporter,
 			EngineVersion version,
-			Stream customVersionStream,
+			Stream? customVersionStream,
 			bool neededForLock,
 			bool allowInstallation,
 			CancellationToken cancellationToken)
@@ -413,7 +419,8 @@ namespace Tgstation.Server.Host.Components.Engine
 					while (installedVersions.ContainsKey(version));
 				}
 
-				installedOrInstalling = installedVersions.TryGetValue(version, out var installationContainer);
+				installedOrInstalling = installedVersions.TryGetValue(version, out var installationContainerNullable);
+				ReferenceCountingContainer<IEngineInstallation, EngineExecutableLock> installationContainer;
 				if (!installedOrInstalling)
 				{
 					if (!allowInstallation)
@@ -424,6 +431,8 @@ namespace Tgstation.Server.Host.Components.Engine
 						ioManager.ResolvePath(version.ToString()),
 						ourTcs.Task);
 				}
+				else
+					installationContainer = installationContainerNullable!;
 
 				installation = installationContainer.Instance;
 				installLock = installationContainer.AddReference();
@@ -497,7 +506,7 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// <param name="customVersionStream">Custom zip file <see cref="Stream"/> to use. Will cause a <see cref="Version.Build"/> number to be added.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask"/> representing the running operation.</returns>
-		async ValueTask InstallVersionFiles(JobProgressReporter progressReporter, EngineVersion version, Stream customVersionStream, CancellationToken cancellationToken)
+		async ValueTask InstallVersionFiles(JobProgressReporter? progressReporter, EngineVersion version, Stream? customVersionStream, CancellationToken cancellationToken)
 		{
 			var installFullPath = ioManager.ResolvePath(version.ToString());
 			async ValueTask DirectoryCleanup()
@@ -517,7 +526,7 @@ namespace Tgstation.Server.Host.Components.Engine
 
 					engineInstallationData = await engineInstaller.DownloadVersion(version, progressReporter, cancellationToken);
 
-					progressReporter.ReportProgress(null);
+					progressReporter?.ReportProgress(null);
 				}
 				else
 #pragma warning disable CA2000 // Dispose objects before losing scope, false positive

src/Tgstation.Server.Host/Components/Engine/IEngineInstallation.cs

@@ -1,9 +1,13 @@
 using System.Collections.Generic;
+using System.Threading;
 using System.Threading.Tasks;
 
+using Microsoft.Extensions.Logging;
+
 using Tgstation.Server.Api.Models;
 using Tgstation.Server.Api.Models.Internal;
 using Tgstation.Server.Host.Components.Deployment;
+using Tgstation.Server.Host.System;
 
 namespace Tgstation.Server.Host.Components.Engine
 {
@@ -51,7 +55,7 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// Return the command line arguments for launching with given <paramref name="launchParameters"/>.
 		/// </summary>
 		/// <param name="dmbProvider">The <see cref="IDmbProvider"/>.</param>
-		/// <param name="parameters">The map of parameter <see cref="string"/>s as a <see cref="IReadOnlyDictionary{TKey, TValue}"/>. Should NOT include the <see cref="DreamDaemonLaunchParameters.AdditionalParameters"/> of <paramref name="launchParameters"/>.</param>
+		/// <param name="parameters">The map of parameter <see cref="string"/>s as a <see cref="IReadOnlyDictionary{TKey, TValue}"/>. MUST include <see cref="Interop.DMApiConstants.ParamAccessIdentifier"/>. Should NOT include the <see cref="DreamDaemonLaunchParameters.AdditionalParameters"/> of <paramref name="launchParameters"/>.</param>
 		/// <param name="launchParameters">The <see cref="DreamDaemonLaunchParameters"/>.</param>
 		/// <param name="logFilePath">The full path to the log file, if any.</param>
 		/// <returns>The formatted arguments <see cref="string"/>.</returns>
@@ -59,7 +63,7 @@ namespace Tgstation.Server.Host.Components.Engine
 			IDmbProvider dmbProvider,
 			IReadOnlyDictionary<string, string> parameters,
 			DreamDaemonLaunchParameters launchParameters,
-			string logFilePath);
+			string? logFilePath);
 
 		/// <summary>
 		/// Return the command line arguments for compiling a given <paramref name="dmePath"/> if compilation is necessary.
@@ -67,5 +71,16 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// <param name="dmePath">The full path to the .dme to compile.</param>
 		/// <returns>The formatted arguments <see cref="string"/>.</returns>
 		string FormatCompilerArguments(string dmePath);
+
+		/// <summary>
+		/// Kills a given engine server <paramref name="process"/>.
+		/// </summary>
+		/// <param name="logger">The <see cref="ILogger"/> to write to.</param>
+		/// <param name="process">The <see cref="IProcess"/> to be terminated.</param>
+		/// <param name="accessIdentifier">The <see cref="Interop.DMApiParameters.AccessIdentifier"/> of the session.</param>
+		/// <param name="port">The port the server is running on.</param>
+		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
+		/// <returns>A <see cref="ValueTask"/> representing the running operation.</returns>
+		ValueTask StopServerProcess(ILogger logger, IProcess process, string accessIdentifier, ushort port, CancellationToken cancellationToken);
 	}
 }

src/Tgstation.Server.Host/Components/Engine/IEngineInstaller.cs

@@ -27,7 +27,7 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// <param name="jobProgressReporter">The optional <see cref="JobProgressReporter"/> for the operation.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in the <see cref="IEngineInstallationData"/> for the download.</returns>
-		ValueTask<IEngineInstallationData> DownloadVersion(EngineVersion version, JobProgressReporter jobProgressReporter, CancellationToken cancellationToken);
+		ValueTask<IEngineInstallationData> DownloadVersion(EngineVersion version, JobProgressReporter? jobProgressReporter, CancellationToken cancellationToken);
 
 		/// <summary>
 		/// Does actions necessary to get an extracted installation working.

src/Tgstation.Server.Host/Components/Engine/IEngineManager.cs

@@ -18,7 +18,7 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// <summary>
 		/// The currently active <see cref="EngineVersion"/>.
 		/// </summary>
-		EngineVersion ActiveVersion { get; }
+		EngineVersion? ActiveVersion { get; }
 
 		/// <summary>
 		/// The installed <see cref="EngineVersion"/>s.
@@ -35,9 +35,9 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask"/> representing the running operation.</returns>
 		ValueTask ChangeVersion(
-			JobProgressReporter progressReporter,
+			JobProgressReporter? progressReporter,
 			EngineVersion version,
-			Stream customVersionStream,
+			Stream? customVersionStream,
 			bool allowInstallation,
 			CancellationToken cancellationToken);
 
@@ -58,8 +58,8 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in the requested <see cref="IEngineExecutableLock"/>.</returns>
 		ValueTask<IEngineExecutableLock> UseExecutables(
-			EngineVersion requiredVersion,
-			string trustDmbFullPath,
+			EngineVersion? requiredVersion,
+			string? trustDmbFullPath,
 			CancellationToken cancellationToken);
 	}
 }

src/Tgstation.Server.Host/Components/Engine/OpenDreamInstallation.cs

@@ -1,11 +1,23 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Net.Mime;
+using System.Text;
+using System.Threading;
 using System.Threading.Tasks;
 
+using Microsoft.Extensions.Logging;
+
 using Tgstation.Server.Api.Models;
 using Tgstation.Server.Api.Models.Internal;
+using Tgstation.Server.Common.Http;
 using Tgstation.Server.Host.Components.Deployment;
+using Tgstation.Server.Host.Components.Interop;
 using Tgstation.Server.Host.IO;
+using Tgstation.Server.Host.System;
+using Tgstation.Server.Host.Utils;
 
 namespace Tgstation.Server.Host.Components.Engine
 {
@@ -40,28 +52,44 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// </summary>
 		readonly IIOManager ioManager;
 
+		/// <summary>
+		/// The <see cref="IAsyncDelayer"/> for the <see cref="OpenDreamInstallation"/>.
+		/// </summary>
+		readonly IAsyncDelayer asyncDelayer;
+
+		/// <summary>
+		/// The <see cref="IAbstractHttpClientFactory"/> for the <see cref="OpenDreamInstallation"/>.
+		/// </summary>
+		readonly IAbstractHttpClientFactory httpClientFactory;
+
 		/// <summary>
 		/// Initializes a new instance of the <see cref="OpenDreamInstallation"/> class.
 		/// </summary>
 		/// <param name="ioManager">The value of <see cref="ioManager"/>.</param>
+		/// <param name="asyncDelayer">The value of <see cref="asyncDelayer"/>.</param>
+		/// <param name="httpClientFactory">The value of <see cref="httpClientFactory"/>.</param>
 		/// <param name="serverExePath">The value of <see cref="ServerExePath"/>.</param>
 		/// <param name="compilerExePath">The value of <see cref="CompilerExePath"/>.</param>
 		/// <param name="installationTask">The value of <see cref="InstallationTask"/>.</param>
 		/// <param name="version">The value of <see cref="Version"/>.</param>
 		public OpenDreamInstallation(
 			IIOManager ioManager,
+			IAsyncDelayer asyncDelayer,
+			IAbstractHttpClientFactory httpClientFactory,
 			string serverExePath,
 			string compilerExePath,
 			Task installationTask,
 			EngineVersion version)
 		{
 			this.ioManager = ioManager ?? throw new ArgumentNullException(nameof(ioManager));
+			this.asyncDelayer = asyncDelayer ?? throw new ArgumentNullException(nameof(asyncDelayer));
+			this.httpClientFactory = httpClientFactory ?? throw new ArgumentNullException(nameof(httpClientFactory));
 			ServerExePath = serverExePath ?? throw new ArgumentNullException(nameof(serverExePath));
 			CompilerExePath = compilerExePath ?? throw new ArgumentNullException(nameof(compilerExePath));
 			InstallationTask = installationTask ?? throw new ArgumentNullException(nameof(installationTask));
 			Version = version ?? throw new ArgumentNullException(nameof(version));
 
-			if (version.Engine.Value != EngineType.OpenDream)
+			if (version.Engine!.Value != EngineType.OpenDream)
 				throw new ArgumentException($"Invalid EngineType: {version.Engine.Value}", nameof(version));
 		}
 
@@ -70,21 +98,86 @@ namespace Tgstation.Server.Host.Components.Engine
 			IDmbProvider dmbProvider,
 			IReadOnlyDictionary<string, string> parameters,
 			DreamDaemonLaunchParameters launchParameters,
-			string logFilePath)
+			string? logFilePath)
 		{
 			ArgumentNullException.ThrowIfNull(dmbProvider);
 			ArgumentNullException.ThrowIfNull(parameters);
 			ArgumentNullException.ThrowIfNull(launchParameters);
 
+			if (!parameters.TryGetValue(DMApiConstants.ParamAccessIdentifier, out var accessIdentifier))
+				throw new ArgumentException($"parameters must have \"{DMApiConstants.ParamAccessIdentifier}\" set!", nameof(parameters));
+
 			var parametersString = EncodeParameters(parameters, launchParameters);
 
-			var loggingEnabled = logFilePath != null;
-			var arguments = $"--cvar {(loggingEnabled ? $"log.path=\"{ioManager.GetDirectoryName(logFilePath)}\" --cvar log.format=\"{ioManager.GetFileName(logFilePath)}\"" : "log.enabled=false")} --cvar log.runtimelog=false --cvar net.port={launchParameters.Port.Value} --cvar opendream.topic_port=0 --cvar opendream.world_params=\"{parametersString}\" --cvar opendream.json_path=\"./{dmbProvider.DmbName}\"";
+			var arguments = $"--cvar {(logFilePath != null ? $"log.path=\"{ioManager.GetDirectoryName(logFilePath)}\" --cvar log.format=\"{ioManager.GetFileName(logFilePath)}\"" : "log.enabled=false")} --cvar watchdog.token={accessIdentifier} --cvar log.runtimelog=false --cvar net.port={launchParameters.Port!.Value} --cvar opendream.topic_port=0 --cvar opendream.world_params=\"{parametersString}\" --cvar opendream.json_path=\"./{dmbProvider.DmbName}\"";
 			return arguments;
 		}
 
 		/// <inheritdoc />
 		public override string FormatCompilerArguments(string dmePath)
 			=> $"--suppress-unimplemented --notices-enabled \"{dmePath ?? throw new ArgumentNullException(nameof(dmePath))}\"";
+
+		/// <inheritdoc />
+		public override async ValueTask StopServerProcess(
+			ILogger logger,
+			IProcess process,
+			string accessIdentifier,
+			ushort port,
+			CancellationToken cancellationToken)
+		{
+			const int MaximumTerminationSeconds = 5;
+
+			logger.LogTrace("Attempting Robust.Server graceful exit (Timeout: {seconds}s)...", MaximumTerminationSeconds);
+			var timeout = asyncDelayer.Delay(TimeSpan.FromSeconds(MaximumTerminationSeconds), cancellationToken);
+			var lifetime = process.Lifetime;
+
+			var stopwatch = Stopwatch.StartNew();
+			try
+			{
+				using var httpClient = httpClientFactory.CreateClient();
+				using var request = new HttpRequestMessage();
+				request.Headers.Add("WatchdogToken", accessIdentifier);
+				request.RequestUri = new Uri($"http://localhost:{port}/shutdown");
+				request.Content = new StringContent(
+					"{\"Reason\":\"TGS session termination\"}",
+					Encoding.UTF8,
+					new MediaTypeHeaderValue(MediaTypeNames.Application.Json));
+				request.Method = HttpMethod.Post;
+
+				var responseTask = httpClient.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, cancellationToken);
+				try
+				{
+					await Task.WhenAny(timeout, lifetime, responseTask);
+					if (responseTask.IsCompleted)
+					{
+						using var response = await responseTask;
+						if (response.IsSuccessStatusCode)
+						{
+							logger.LogDebug("Robust.Server responded to the shutdown command successfully ({requestMs}ms). Waiting for exit...", stopwatch.ElapsedMilliseconds);
+							await Task.WhenAny(timeout, lifetime);
+						}
+					}
+
+					if (!lifetime.IsCompleted)
+						logger.LogWarning("Robust.Server graceful exit timed out!");
+				}
+				catch (Exception ex) when (ex is not OperationCanceledException)
+				{
+					logger.LogDebug(ex, "Unable to send graceful exit request to Robust.Server watchdog API!");
+				}
+
+				if (lifetime.IsCompleted)
+				{
+					logger.LogTrace("Robust.Server exited without termination");
+					return;
+				}
+			}
+			finally
+			{
+				logger.LogTrace("Robust.Server graceful shutdown attempt took {totalMs}ms", stopwatch.ElapsedMilliseconds);
+			}
+
+			await base.StopServerProcess(logger, process, accessIdentifier, port, cancellationToken);
+		}
 	}
 }

src/Tgstation.Server.Host/Components/Engine/OpenDreamInstaller.cs

@@ -8,12 +8,14 @@ using Microsoft.Extensions.Options;
 
 using Tgstation.Server.Api.Models;
 using Tgstation.Server.Common.Extensions;
+using Tgstation.Server.Common.Http;
 using Tgstation.Server.Host.Common;
 using Tgstation.Server.Host.Components.Repository;
 using Tgstation.Server.Host.Configuration;
 using Tgstation.Server.Host.IO;
 using Tgstation.Server.Host.Jobs;
 using Tgstation.Server.Host.System;
+using Tgstation.Server.Host.Utils;
 
 namespace Tgstation.Server.Host.Components.Engine
 {
@@ -50,6 +52,16 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// </summary>
 		protected IProcessExecutor ProcessExecutor { get; }
 
+		/// <summary>
+		/// The <see cref="GeneralConfiguration"/> for the <see cref="OpenDreamInstaller"/>.
+		/// </summary>
+		protected GeneralConfiguration GeneralConfiguration { get; }
+
+		/// <summary>
+		/// The <see cref="Configuration.SessionConfiguration"/> for the <see cref="OpenDreamInstaller"/>.
+		/// </summary>
+		protected SessionConfiguration SessionConfiguration { get; }
+
 		/// <summary>
 		/// The <see cref="IPlatformIdentifier"/> for the <see cref="OpenDreamInstaller"/>.
 		/// </summary>
@@ -61,9 +73,14 @@ namespace Tgstation.Server.Host.Components.Engine
 		readonly IRepositoryManager repositoryManager;
 
 		/// <summary>
-		/// The <see cref="GeneralConfiguration"/> for the <see cref="OpenDreamInstaller"/>.
+		/// The <see cref="IAsyncDelayer"/> for the <see cref="OpenDreamInstaller"/>.
 		/// </summary>
-		protected GeneralConfiguration GeneralConfiguration { get; }
+		readonly IAsyncDelayer asyncDelayer;
+
+		/// <summary>
+		/// The <see cref="IAbstractHttpClientFactory"/> for the <see cref="OpenDreamInstaller"/>.
+		/// </summary>
+		readonly IAbstractHttpClientFactory httpClientFactory;
 
 		/// <summary>
 		/// Initializes a new instance of the <see cref="OpenDreamInstaller"/> class.
@@ -73,20 +90,29 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// <param name="platformIdentifier">The value of <see cref="platformIdentifier"/>.</param>
 		/// <param name="processExecutor">The value of <see cref="ProcessExecutor"/>.</param>
 		/// <param name="repositoryManager">The value of <see cref="repositoryManager"/>.</param>
+		/// <param name="asyncDelayer">The value of <see cref="asyncDelayer"/>.</param>
+		/// <param name="httpClientFactory">The value of <see cref="httpClientFactory"/>.</param>
 		/// <param name="generalConfigurationOptions">The <see cref="IOptions{TOptions}"/> containing value of <see cref="GeneralConfiguration"/>.</param>
+		/// <param name="sessionConfigurationOptions">The <see cref="IOptions{TOptions}"/> containing value of <see cref="SessionConfiguration"/>.</param>
 		public OpenDreamInstaller(
 			IIOManager ioManager,
 			ILogger<OpenDreamInstaller> logger,
 			IPlatformIdentifier platformIdentifier,
 			IProcessExecutor processExecutor,
 			IRepositoryManager repositoryManager,
-			IOptions<GeneralConfiguration> generalConfigurationOptions)
+			IAsyncDelayer asyncDelayer,
+			IAbstractHttpClientFactory httpClientFactory,
+			IOptions<GeneralConfiguration> generalConfigurationOptions,
+			IOptions<SessionConfiguration> sessionConfigurationOptions)
 			: base(ioManager, logger)
 		{
 			this.platformIdentifier = platformIdentifier ?? throw new ArgumentNullException(nameof(platformIdentifier));
 			ProcessExecutor = processExecutor ?? throw new ArgumentNullException(nameof(processExecutor));
 			this.repositoryManager = repositoryManager ?? throw new ArgumentNullException(nameof(repositoryManager));
+			this.asyncDelayer = asyncDelayer ?? throw new ArgumentNullException(nameof(asyncDelayer));
+			this.httpClientFactory = httpClientFactory ?? throw new ArgumentNullException(nameof(httpClientFactory));
 			GeneralConfiguration = generalConfigurationOptions?.Value ?? throw new ArgumentNullException(nameof(generalConfigurationOptions));
+			SessionConfiguration = sessionConfigurationOptions?.Value ?? throw new ArgumentNullException(nameof(sessionConfigurationOptions));
 		}
 
 		/// <inheritdoc />
@@ -99,6 +125,8 @@ namespace Tgstation.Server.Host.Components.Engine
 			GetExecutablePaths(path, out var serverExePath, out var compilerExePath);
 			return new OpenDreamInstallation(
 				IOManager,
+				asyncDelayer,
+				httpClientFactory,
 				serverExePath,
 				compilerExePath,
 				installationTask,
@@ -106,7 +134,7 @@ namespace Tgstation.Server.Host.Components.Engine
 		}
 
 		/// <inheritdoc />
-		public override async ValueTask<IEngineInstallationData> DownloadVersion(EngineVersion version, JobProgressReporter jobProgressReporter, CancellationToken cancellationToken)
+		public override async ValueTask<IEngineInstallationData> DownloadVersion(EngineVersion version, JobProgressReporter? jobProgressReporter, CancellationToken cancellationToken)
 		{
 			CheckVersionValidity(version);
 
@@ -131,7 +159,7 @@ namespace Tgstation.Server.Host.Components.Engine
 					Logger.LogTrace("OD repo seems to already exist, attempting load and fetch...");
 					repo = await repositoryManager.LoadRepository(cancellationToken);
 
-					await repo.FetchOrigin(
+					await repo!.FetchOrigin(
 						progressSection1,
 						null,
 						null,
@@ -142,7 +170,7 @@ namespace Tgstation.Server.Host.Components.Engine
 				var progressSection2 = jobProgressReporter?.CreateSection("Checking out OpenDream version", 0.5f);
 
 				var committish = version.SourceSHA
-					?? $"{GeneralConfiguration.OpenDreamGitTagPrefix}{version.Version.Semver()}";
+					?? $"{GeneralConfiguration.OpenDreamGitTagPrefix}{version.Version!.Semver()}";
 
 				await repo.CheckoutObject(
 					committish,
@@ -232,11 +260,14 @@ namespace Tgstation.Server.Host.Components.Engine
 						null,
 						!GeneralConfiguration.OpenDreamSuppressInstallOutput,
 						!GeneralConfiguration.OpenDreamSuppressInstallOutput);
+
+					if (SessionConfiguration.LowPriorityDeploymentProcesses)
+						buildProcess.AdjustPriority(false);
+
 					using (cancellationToken.Register(() => buildProcess.Terminate()))
 						buildExitCode = await buildProcess.Lifetime;
 
-					string output;
-
+					string? output;
 					if (!GeneralConfiguration.OpenDreamSuppressInstallOutput)
 					{
 						var buildOutputTask = buildProcess.GetCombinedOutput(cancellationToken);

src/Tgstation.Server.Host/Components/Engine/PosixByondInstaller.cs

@@ -93,7 +93,7 @@ namespace Tgstation.Server.Host.Components.Engine
 			var basePath = IOManager.ConcatPath(path, ByondBinPath);
 
 			var ddTask = WriteAndMakeExecutable(
-				IOManager.ConcatPath(basePath, GetDreamDaemonName(version.Version, out _)),
+				IOManager.ConcatPath(basePath, GetDreamDaemonName(version.Version!, out _)),
 				dreamDaemonScript);
 
 			var dmTask = WriteAndMakeExecutable(

src/Tgstation.Server.Host/Components/Engine/WindowsByondInstaller.cs

@@ -71,6 +71,11 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// </summary>
 		readonly GeneralConfiguration generalConfiguration;
 
+		/// <summary>
+		/// The <see cref="SessionConfiguration"/> for the <see cref="WindowsByondInstaller"/>.
+		/// </summary>
+		readonly SessionConfiguration sessionConfiguration;
+
 		/// <summary>
 		/// The <see cref="SemaphoreSlim"/> for the <see cref="WindowsByondInstaller"/>.
 		/// </summary>
@@ -86,6 +91,7 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// </summary>
 		/// <param name="processExecutor">The value of <see cref="processExecutor"/>.</param>
 		/// <param name="generalConfigurationOptions">The <see cref="IOptions{TOptions}"/> containing the value of <see cref="generalConfiguration"/>.</param>
+		/// <param name="sessionConfigurationOptions">The <see cref="IOptions{TOptions}"/> containing the value of <see cref="sessionConfiguration"/>.</param>
 		/// <param name="ioManager">The <see cref="IIOManager"/> for the <see cref="ByondInstallerBase"/>.</param>
 		/// <param name="fileDownloader">The <see cref="IFileDownloader"/> for the <see cref="ByondInstallerBase"/>.</param>
 		/// <param name="logger">The <see cref="ILogger"/> for the <see cref="ByondInstallerBase"/>.</param>
@@ -94,11 +100,13 @@ namespace Tgstation.Server.Host.Components.Engine
 			IIOManager ioManager,
 			IFileDownloader fileDownloader,
 			IOptions<GeneralConfiguration> generalConfigurationOptions,
+			IOptions<SessionConfiguration> sessionConfigurationOptions,
 			ILogger<WindowsByondInstaller> logger)
 			: base(ioManager, logger, fileDownloader)
 		{
 			this.processExecutor = processExecutor ?? throw new ArgumentNullException(nameof(processExecutor));
 			generalConfiguration = generalConfigurationOptions?.Value ?? throw new ArgumentNullException(nameof(generalConfigurationOptions));
+			sessionConfiguration = sessionConfigurationOptions?.Value ?? throw new ArgumentNullException(nameof(sessionConfigurationOptions));
 
 			var documentsDirectory = Environment.GetFolderPath(
 				Environment.SpecialFolder.MyDocuments,
@@ -120,14 +128,19 @@ namespace Tgstation.Server.Host.Components.Engine
 			CheckVersionValidity(version);
 			ArgumentNullException.ThrowIfNull(path);
 
+			var noPromptTrustedTask = SetNoPromptTrusted(path, cancellationToken);
+			var installDirectXTask = InstallDirectX(path, cancellationToken);
 			var tasks = new List<ValueTask>(3)
 			{
-				SetNoPromptTrusted(path, cancellationToken),
-				InstallDirectX(path, cancellationToken),
+				noPromptTrustedTask,
+				installDirectXTask,
 			};
 
 			if (!generalConfiguration.SkipAddingByondFirewallException)
-				tasks.Add(AddDreamDaemonToFirewall(version, path, cancellationToken));
+			{
+				var firewallTask = AddDreamDaemonToFirewall(version, path, cancellationToken);
+				tasks.Add(firewallTask);
+			}
 
 			return ValueTaskExtensions.WhenAll(tasks);
 		}
@@ -230,7 +243,7 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// <returns>A <see cref="ValueTask"/> representing the running operation.</returns>
 		async ValueTask AddDreamDaemonToFirewall(EngineVersion version, string path, CancellationToken cancellationToken)
 		{
-			var dreamDaemonName = GetDreamDaemonName(version.Version, out var usesDDExe);
+			var dreamDaemonName = GetDreamDaemonName(version.Version!, out var usesDDExe);
 
 			var dreamDaemonPath = IOManager.ResolvePath(
 				IOManager.ConcatPath(
@@ -251,6 +264,7 @@ namespace Tgstation.Server.Host.Components.Engine
 					Logger,
 					ruleName,
 					dreamDaemonPath,
+					sessionConfiguration.LowPriorityDeploymentProcesses,
 					cancellationToken);
 			}
 			catch (Exception ex)

src/Tgstation.Server.Host/Components/Engine/WindowsOpenDreamInstaller.cs

@@ -7,11 +7,13 @@ using Microsoft.Extensions.Options;
 
 using Tgstation.Server.Api.Models;
 using Tgstation.Server.Common.Extensions;
+using Tgstation.Server.Common.Http;
 using Tgstation.Server.Host.Components.Repository;
 using Tgstation.Server.Host.Configuration;
 using Tgstation.Server.Host.IO;
 using Tgstation.Server.Host.Jobs;
 using Tgstation.Server.Host.System;
+using Tgstation.Server.Host.Utils;
 
 namespace Tgstation.Server.Host.Components.Engine
 {
@@ -33,7 +35,10 @@ namespace Tgstation.Server.Host.Components.Engine
 		/// <param name="platformIdentifier">The <see cref="IPlatformIdentifier"/> for the <see cref="OpenDreamInstaller"/>.</param>
 		/// <param name="processExecutor">The <see cref="IProcessExecutor"/> for the <see cref="OpenDreamInstaller"/>.</param>
 		/// <param name="repositoryManager">The <see cref="IRepositoryManager"/> for the <see cref="OpenDreamInstaller"/>.</param>
+		/// <param name="asyncDelayer">The <see cref="IAsyncDelayer"/> for the <see cref="OpenDreamInstaller"/>.</param>
+		/// <param name="httpClientFactory">The <see cref="IAbstractHttpClientFactory"/> for the <see cref="OpenDreamInstaller"/>.</param>
 		/// <param name="generalConfigurationOptions">The <see cref="IOptions{TOptions}"/> of <see cref="GeneralConfiguration"/> for the <see cref="OpenDreamInstaller"/>.</param>
+		/// <param name="sessionConfigurationOptions">The <see cref="IOptions{TOptions}"/> of <see cref="SessionConfiguration"/> for the <see cref="OpenDreamInstaller"/>.</param>
 		/// <param name="linkFactory">The value of <see cref="linkFactory"/>.</param>
 		public WindowsOpenDreamInstaller(
 			IIOManager ioManager,
@@ -41,7 +46,10 @@ namespace Tgstation.Server.Host.Components.Engine
 			IPlatformIdentifier platformIdentifier,
 			IProcessExecutor processExecutor,
 			IRepositoryManager repositoryManager,
+			IAsyncDelayer asyncDelayer,
+			IAbstractHttpClientFactory httpClientFactory,
 			IOptions<GeneralConfiguration> generalConfigurationOptions,
+			IOptions<SessionConfiguration> sessionConfigurationOptions,
 			IFilesystemLinkFactory linkFactory)
 			: base(
 				ioManager,
@@ -49,7 +57,10 @@ namespace Tgstation.Server.Host.Components.Engine
 				platformIdentifier,
 				processExecutor,
 				repositoryManager,
-				generalConfigurationOptions)
+				asyncDelayer,
+				httpClientFactory,
+				generalConfigurationOptions,
+				sessionConfigurationOptions)
 		{
 			this.linkFactory = linkFactory ?? throw new ArgumentNullException(nameof(linkFactory));
 		}
@@ -112,6 +123,7 @@ namespace Tgstation.Server.Host.Components.Engine
 					Logger,
 					ruleName,
 					serverExePath,
+					SessionConfiguration.LowPriorityDeploymentProcesses,
 					cancellationToken);
 			}
 			catch (Exception ex)

src/Tgstation.Server.Host/Components/Events/EventConsumer.cs

@@ -19,7 +19,7 @@ namespace Tgstation.Server.Host.Components.Events
 		/// <summary>
 		/// The <see cref="IWatchdog"/> for the <see cref="EventConsumer"/>.
 		/// </summary>
-		IWatchdog watchdog;
+		IWatchdog? watchdog;
 
 		/// <summary>
 		/// Initializes a new instance of the <see cref="EventConsumer"/> class.
@@ -31,7 +31,7 @@ namespace Tgstation.Server.Host.Components.Events
 		}
 
 		/// <inheritdoc />
-		public async ValueTask HandleEvent(EventType eventType, IEnumerable<string> parameters, bool deploymentPipeline, CancellationToken cancellationToken)
+		public async ValueTask HandleEvent(EventType eventType, IEnumerable<string?> parameters, bool deploymentPipeline, CancellationToken cancellationToken)
 		{
 			ArgumentNullException.ThrowIfNull(parameters);
 
@@ -50,10 +50,9 @@ namespace Tgstation.Server.Host.Components.Events
 		public void SetWatchdog(IWatchdog watchdog)
 		{
 			ArgumentNullException.ThrowIfNull(watchdog);
-			if (this.watchdog != null)
+			var oldWatchdog = Interlocked.CompareExchange(ref this.watchdog, watchdog, null);
+			if (oldWatchdog != null)
 				throw new InvalidOperationException("watchdog already set!");
-
-			this.watchdog = watchdog;
 		}
 	}
 }

src/Tgstation.Server.Host/Components/Events/IEventConsumer.cs

@@ -17,6 +17,6 @@ namespace Tgstation.Server.Host.Components.Events
 		/// <param name="deploymentPipeline">If this event is part of the deployment pipeline.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask"/> representing the running operation.</returns>
-		ValueTask HandleEvent(EventType eventType, IEnumerable<string> parameters, bool deploymentPipeline, CancellationToken cancellationToken);
+		ValueTask HandleEvent(EventType eventType, IEnumerable<string?> parameters, bool deploymentPipeline, CancellationToken cancellationToken);
 	}
 }

src/Tgstation.Server.Host/Components/Events/NoopEventConsumer.cs

@@ -10,7 +10,7 @@ namespace Tgstation.Server.Host.Components.Events
 	sealed class NoopEventConsumer : IEventConsumer
 	{
 		/// <inheritdoc />
-		public ValueTask HandleEvent(EventType eventType, IEnumerable<string> parameters, bool deploymentPipeline, CancellationToken cancellationToken)
+		public ValueTask HandleEvent(EventType eventType, IEnumerable<string?> parameters, bool deploymentPipeline, CancellationToken cancellationToken)
 			=> ValueTask.CompletedTask;
 	}
 }

src/Tgstation.Server.Host/Components/IInstanceCoreProvider.cs

@@ -10,6 +10,6 @@
 		/// </summary>
 		/// <param name="instance">The <see cref="Instance"/> to get the <see cref="IInstanceCore"/> for.</param>
 		/// <returns>The <see cref="IInstanceCore"/> if it is online, <see langword="null"/> otherwise.</returns>
-		IInstanceCore GetInstance(Models.Instance instance);
+		IInstanceCore? GetInstance(Models.Instance instance);
 	}
 }

src/Tgstation.Server.Host/Components/IInstanceManager.cs

@@ -19,6 +19,6 @@ namespace Tgstation.Server.Host.Components
 		/// </summary>
 		/// <param name="metadata">The <see cref="Models.Instance"/> of the desired <see cref="IInstance"/>.</param>
 		/// <returns>The <see cref="IInstance"/> associated with the given <paramref name="metadata"/> if it is online, <see langword="null"/> otherwise.</returns>
-		IInstanceReference GetInstanceReference(Api.Models.Instance metadata);
+		IInstanceReference? GetInstanceReference(Api.Models.Instance metadata);
 	}
 }

src/Tgstation.Server.Host/Components/Instance.cs

@@ -93,12 +93,12 @@ namespace Tgstation.Server.Host.Components
 		/// <summary>
 		/// The auto update <see cref="Task"/>.
 		/// </summary>
-		Task timerTask;
+		Task? timerTask;
 
 		/// <summary>
 		/// <see cref="CancellationTokenSource"/> for <see cref="timerTask"/>.
 		/// </summary>
-		CancellationTokenSource timerCts;
+		CancellationTokenSource? timerCts;
 
 		/// <summary>
 		/// Initializes a new instance of the <see cref="Instance"/> class.
@@ -183,7 +183,7 @@ namespace Tgstation.Server.Host.Components
 			using (LogContext.PushProperty(SerilogContextHelper.InstanceIdContextProperty, metadata.Id))
 			{
 				await Task.WhenAll(
-					SetAutoUpdateInterval(metadata.AutoUpdateInterval.Value).AsTask(),
+					SetAutoUpdateInterval(metadata.Require(x => x.AutoUpdateInterval)).AsTask(),
 					Configuration.StartAsync(cancellationToken),
 					EngineManager.StartAsync(cancellationToken),
 					Chat.StartAsync(cancellationToken),
@@ -221,7 +221,7 @@ namespace Tgstation.Server.Host.Components
 				if (timerTask != null)
 				{
 					logger.LogTrace("Cancelling auto-update task");
-					timerCts.Cancel();
+					timerCts!.Cancel();
 					timerCts.Dispose();
 					toWait = timerTask;
 					timerTask = null;
@@ -253,7 +253,7 @@ namespace Tgstation.Server.Host.Components
 		}
 
 		/// <inheritdoc />
-		public CompileJob LatestCompileJob() => dmbFactory.LatestCompileJob();
+		public CompileJob? LatestCompileJob() => dmbFactory.LatestCompileJob();
 
 		/// <summary>
 		/// The <see cref="JobEntrypoint"/> for updating the repository.
@@ -266,7 +266,7 @@ namespace Tgstation.Server.Host.Components
 		/// <returns>A <see cref="ValueTask"/> representing the running operation.</returns>
 #pragma warning disable CA1502 // Cyclomatic complexity
 		ValueTask RepositoryAutoUpdateJob(
-			IInstanceCore core,
+			IInstanceCore? core,
 			IDatabaseContextFactory databaseContextFactory,
 			Job job,
 			JobProgressReporter progressReporter,
@@ -315,18 +315,18 @@ namespace Tgstation.Server.Host.Components
 						cancellationToken);
 
 					var hasDbChanges = false;
-					RevisionInformation currentRevInfo = null;
-					Models.Instance attachedInstance = null;
-					async ValueTask UpdateRevInfo(string currentHead, bool onOrigin, IEnumerable<TestMerge> updatedTestMerges)
+					RevisionInformation? currentRevInfo = null;
+					Models.Instance? attachedInstance = null;
+					async ValueTask UpdateRevInfo(string currentHead, bool onOrigin, IEnumerable<TestMerge>? updatedTestMerges)
 					{
 						if (currentRevInfo == null)
 						{
 							logger.LogTrace("Loading revision info for commit {sha}...", startSha[..7]);
 							currentRevInfo = await databaseContext
-							.RevisionInformations
+								.RevisionInformations
 								.AsQueryable()
-								.Where(x => x.CommitSha == startSha && x.Instance.Id == metadata.Id)
-								.Include(x => x.ActiveTestMerges)
+								.Where(x => x.CommitSha == startSha && x.InstanceId == metadata.Id)
+								.Include(x => x.ActiveTestMerges!)
 									.ThenInclude(x => x.TestMerge)
 								.FirstOrDefaultAsync(cancellationToken);
 						}
@@ -364,12 +364,9 @@ namespace Tgstation.Server.Host.Components
 
 						if (!onOrigin)
 						{
-							var testMerges = updatedTestMerges ?? oldRevInfo.ActiveTestMerges.Select(x => x.TestMerge);
+							var testMerges = updatedTestMerges ?? oldRevInfo!.ActiveTestMerges!.Select(x => x.TestMerge);
 							var revInfoTestMerges = testMerges.Select(
-								testMerge => new RevInfoTestMerge
-								{
-									TestMerge = testMerge,
-								})
+								testMerge => new RevInfoTestMerge(testMerge, currentRevInfo))
 								.ToList();
 
 							currentRevInfo.ActiveTestMerges = revInfoTestMerges;
@@ -382,21 +379,21 @@ namespace Tgstation.Server.Host.Components
 					// build current commit data if it's missing
 					await UpdateRevInfo(repo.Head, false, null);
 
-					var preserveTestMerges = repositorySettings.AutoUpdatesKeepTestMerges.Value;
+					var preserveTestMerges = repositorySettings.AutoUpdatesKeepTestMerges!.Value;
 					var remoteDeploymentManager = remoteDeploymentManagerFactory.CreateRemoteDeploymentManager(
 						metadata,
-						repo.RemoteGitProvider.Value);
+						repo.RemoteGitProvider!.Value);
 
 					var updatedTestMerges = await remoteDeploymentManager.RemoveMergedTestMerges(
 						repo,
 						repositorySettings,
-						currentRevInfo,
+						currentRevInfo!,
 						cancellationToken);
 
 					var result = await repo.MergeOrigin(
 						NextProgressReporter("Merge Origin"),
-						repositorySettings.CommitterName,
-						repositorySettings.CommitterEmail,
+						repositorySettings.CommitterName!,
+						repositorySettings.CommitterEmail!,
 						true,
 						cancellationToken);
 
@@ -435,7 +432,7 @@ namespace Tgstation.Server.Host.Components
 							NextProgressReporter(StageName),
 							repositorySettings.AccessUser,
 							repositorySettings.AccessToken,
-							repositorySettings.UpdateSubmodules.Value,
+							repositorySettings.UpdateSubmodules!.Value,
 							true,
 							cancellationToken);
 
@@ -443,7 +440,7 @@ namespace Tgstation.Server.Host.Components
 
 						currentRevInfo = await databaseContext.RevisionInformations
 							.AsQueryable()
-							.Where(x => x.CommitSha == currentHead && x.Instance.Id == metadata.Id)
+							.Where(x => x.CommitSha == currentHead && x.InstanceId == metadata.Id)
 							.FirstOrDefaultAsync(cancellationToken);
 
 						if (currentHead != startSha && currentRevInfo == default)
@@ -453,19 +450,19 @@ namespace Tgstation.Server.Host.Components
 					}
 
 					// synch if necessary
-					if (repositorySettings.AutoUpdatesSynchronize.Value && startSha != repo.Head && (shouldSyncTracked || repositorySettings.PushTestMergeCommits.Value))
+					if (repositorySettings.AutoUpdatesSynchronize!.Value && startSha != repo.Head && (shouldSyncTracked || repositorySettings.PushTestMergeCommits!.Value))
 					{
-						var pushedOrigin = await repo.Sychronize(
+						var pushedOrigin = await repo.Synchronize(
 							NextProgressReporter("Synchronize"),
 							repositorySettings.AccessUser,
 							repositorySettings.AccessToken,
-							repositorySettings.CommitterName,
-							repositorySettings.CommitterEmail,
+							repositorySettings.CommitterName!,
+							repositorySettings.CommitterEmail!,
 							shouldSyncTracked,
 							true,
 							cancellationToken);
 						var currentHead = repo.Head;
-						if (currentHead != currentRevInfo.CommitSha)
+						if (currentHead != currentRevInfo!.CommitSha)
 							await UpdateRevInfo(currentHead, pushedOrigin, null);
 					}
 
@@ -517,6 +514,9 @@ namespace Tgstation.Server.Host.Components
 						Job compileProcessJob;
 						using (var repo = await RepositoryManager.LoadRepository(cancellationToken))
 						{
+							if (repo == null)
+								throw new JobException(Api.Models.ErrorCode.RepoMissing);
+
 							var deploySha = repo.Head;
 							if (deploySha == null)
 							{

src/Tgstation.Server.Host/Components/InstanceFactory.cs

@@ -150,7 +150,7 @@ namespace Tgstation.Server.Host.Components
 		/// </summary>
 		/// <param name="instanceIOManager">The instance's <see cref="IIOManager"/>.</param>
 		/// <returns>The <see cref="IIOManager"/> for the instance's "Game" directory.</returns>
-		static IIOManager CreateGameIOManager(IIOManager instanceIOManager) => new ResolvingIOManager(instanceIOManager, "Game");
+		static ResolvingIOManager CreateGameIOManager(IIOManager instanceIOManager) => new(instanceIOManager, "Game");
 
 #pragma warning disable CA1502 // TODO: Decomplexify
 		/// <summary>
@@ -324,13 +324,13 @@ namespace Tgstation.Server.Host.Components
 							configuration, // watchdog doesn't need itself as an event consumer
 							remoteDeploymentManagerFactory,
 							metadata,
-							metadata.DreamDaemonSettings);
+							metadata.DreamDaemonSettings!);
 						try
 						{
 							eventConsumer.SetWatchdog(watchdog);
 							commandFactory.SetWatchdog(watchdog);
 
-							Instance instance = null;
+							Instance? instance = null;
 							var dreamMaker = new DreamMaker(
 								engineManager,
 								gameIoManager,
@@ -404,6 +404,6 @@ namespace Tgstation.Server.Host.Components
 		/// </summary>
 		/// <param name="metadata">The <see cref="Models.Instance"/>.</param>
 		/// <returns>The <see cref="IIOManager"/> for the <paramref name="metadata"/>.</returns>
-		IIOManager CreateInstanceIOManager(Models.Instance metadata) => new ResolvingIOManager(ioManager, metadata.Path);
+		ResolvingIOManager CreateInstanceIOManager(Models.Instance metadata) => new(ioManager, metadata.Path!);
 	}
 }

src/Tgstation.Server.Host/Components/InstanceManager.cs

@@ -21,6 +21,7 @@ using Tgstation.Server.Host.Database;
 using Tgstation.Server.Host.Extensions;
 using Tgstation.Server.Host.IO;
 using Tgstation.Server.Host.Jobs;
+using Tgstation.Server.Host.Models;
 using Tgstation.Server.Host.Security;
 using Tgstation.Server.Host.Swarm;
 using Tgstation.Server.Host.System;
@@ -115,7 +116,7 @@ namespace Tgstation.Server.Host.Components
 		readonly Dictionary<string, IBridgeHandler> bridgeHandlers;
 
 		/// <summary>
-		/// <see cref="SemaphoreSlim"/> used to guard calls to <see cref="OnlineInstance(Models.Instance, CancellationToken)"/> and <see cref="OfflineInstance(Models.Instance, Models.User, CancellationToken)"/>.
+		/// <see cref="SemaphoreSlim"/> used to guard calls to <see cref="OnlineInstance(Models.Instance, CancellationToken)"/> and <see cref="OfflineInstance(Models.Instance, User, CancellationToken)"/>.
 		/// </summary>
 		readonly SemaphoreSlim instanceStateChangeSemaphore;
 
@@ -147,12 +148,12 @@ namespace Tgstation.Server.Host.Components
 		/// <summary>
 		/// The original <see cref="IConsole.Title"/> of <see cref="console"/>.
 		/// </summary>
-		readonly string originalConsoleTitle;
+		readonly string? originalConsoleTitle;
 
 		/// <summary>
 		/// The <see cref="Task"/> returned by <see cref="Initialize(CancellationToken)"/>.
 		/// </summary>
-		Task startupTask;
+		Task? startupTask;
 
 		/// <summary>
 		/// If the <see cref="InstanceManager"/> has been <see cref="DisposeAsync"/>'d.
@@ -241,13 +242,13 @@ namespace Tgstation.Server.Host.Components
 		}
 
 		/// <inheritdoc />
-		public IInstanceReference GetInstanceReference(Api.Models.Instance metadata)
+		public IInstanceReference? GetInstanceReference(Api.Models.Instance metadata)
 		{
 			ArgumentNullException.ThrowIfNull(metadata);
 
 			lock (instances)
 			{
-				if (!instances.TryGetValue(metadata.Id.Value, out var instance))
+				if (!instances.TryGetValue(metadata.Require(x => x.Id), out var instance))
 					return null;
 
 				return instance.AddReference();
@@ -263,7 +264,7 @@ namespace Tgstation.Server.Host.Components
 			using var instanceReferenceCheck = GetInstanceReference(instance);
 			if (instanceReferenceCheck != null)
 				throw new InvalidOperationException("Cannot move an online instance!");
-			var newPath = instance.Path;
+			var newPath = instance.Path!;
 			try
 			{
 				await ioManager.MoveDirectory(oldPath, newPath, cancellationToken);
@@ -326,22 +327,23 @@ namespace Tgstation.Server.Host.Components
 		}
 
 		/// <inheritdoc />
-		public async ValueTask OfflineInstance(Models.Instance metadata, Models.User user, CancellationToken cancellationToken)
+		public async ValueTask OfflineInstance(Models.Instance metadata, User user, CancellationToken cancellationToken)
 		{
 			ArgumentNullException.ThrowIfNull(metadata);
 
 			using (await SemaphoreSlimContext.Lock(instanceStateChangeSemaphore, cancellationToken))
 			{
-				ReferenceCountingContainer<IInstance, InstanceWrapper> container;
+				ReferenceCountingContainer<IInstance, InstanceWrapper>? container;
+				var instanceId = metadata.Require(x => x.Id);
 				lock (instances)
 				{
-					if (!instances.TryGetValue(metadata.Id.Value, out container))
+					if (!instances.TryGetValue(instanceId, out container))
 					{
 						logger.LogDebug("Not offlining removed instance {instanceId}", metadata.Id);
 						return;
 					}
 
-					instances.Remove(metadata.Id.Value);
+					instances.Remove(instanceId);
 				}
 
 				logger.LogInformation("Offlining instance ID {instanceId}", metadata.Id);
@@ -351,27 +353,29 @@ namespace Tgstation.Server.Host.Components
 					await container.OnZeroReferences.WaitAsync(cancellationToken);
 
 					// we are the one responsible for cancelling his jobs
-					var tasks = new List<ValueTask<Models.Job>>();
+					ValueTask<Job?[]> groupedTask = default;
 					await databaseContextFactory.UseContext(
 						async db =>
 						{
 							var jobs = await db
 								.Jobs
 								.AsQueryable()
-								.Where(x => x.Instance.Id == metadata.Id && !x.StoppedAt.HasValue)
-								.Select(x => new Models.Job(x.Id.Value))
+								.Where(x => x.Instance!.Id == metadata.Id && !x.StoppedAt.HasValue)
+								.Select(x => new Job(x.Id!.Value))
 								.ToListAsync(cancellationToken);
-							foreach (var job in jobs)
-								tasks.Add(jobService.CancelJob(job, user, true, cancellationToken));
+
+							groupedTask = ValueTaskExtensions.WhenAll(
+								jobs.Select(job => jobService.CancelJob(job, user, true, cancellationToken)),
+								jobs.Count);
 						});
 
-					await ValueTaskExtensions.WhenAll(tasks);
+					await groupedTask;
 				}
 				catch
 				{
 					// not too late to change your mind
 					lock (instances)
-						instances.Add(metadata.Id.Value, container);
+						instances.Add(instanceId, container);
 
 					throw;
 				}
@@ -393,9 +397,10 @@ namespace Tgstation.Server.Host.Components
 		{
 			ArgumentNullException.ThrowIfNull(metadata);
 
+			var instanceId = metadata.Require(x => x.Id);
 			using var lockContext = await SemaphoreSlimContext.Lock(instanceStateChangeSemaphore, cancellationToken);
 			lock (instances)
-				if (instances.ContainsKey(metadata.Id.Value))
+				if (instances.ContainsKey(instanceId))
 				{
 					logger.LogDebug("Aborting instance creation due to it seemingly already being online");
 					return;
@@ -411,7 +416,7 @@ namespace Tgstation.Server.Host.Components
 				{
 					lock (instances)
 						instances.Add(
-							metadata.Id.Value,
+							instanceId,
 							new ReferenceCountingContainer<IInstance, InstanceWrapper>(instance));
 				}
 				catch (Exception ex)
@@ -453,6 +458,12 @@ namespace Tgstation.Server.Host.Components
 				using (cancellationToken.Register(shutdownCancellationTokenSource.Cancel))
 					try
 					{
+						if (startupTask == null)
+						{
+							logger.LogWarning("InstanceManager was never started!");
+							return;
+						}
+
 						logger.LogDebug("Stopping instance manager...");
 
 						if (!startupTask.IsCompleted)
@@ -485,7 +496,7 @@ namespace Tgstation.Server.Host.Components
 					finally
 					{
 						if (originalConsoleTitle != null)
-							console.Title = originalConsoleTitle;
+							console.SetTitle(originalConsoleTitle);
 					}
 			}
 			catch (Exception ex)
@@ -495,18 +506,25 @@ namespace Tgstation.Server.Host.Components
 		}
 
 		/// <inheritdoc />
-		public async ValueTask<BridgeResponse> ProcessBridgeRequest(BridgeParameters parameters, CancellationToken cancellationToken)
+		public async ValueTask<BridgeResponse?> ProcessBridgeRequest(BridgeParameters parameters, CancellationToken cancellationToken)
 		{
 			ArgumentNullException.ThrowIfNull(parameters);
 
-			IBridgeHandler bridgeHandler = null;
+			var accessIdentifier = parameters.AccessIdentifier;
+			if (accessIdentifier == null)
+			{
+				logger.LogWarning("Received invalid bridge request with null access identifier!");
+				return null;
+			}
+
+			IBridgeHandler? bridgeHandler = null;
 			for (var i = 0; bridgeHandler == null && i < 30; ++i)
 			{
 				// There's a miniscule time period where we could potentially receive a bridge request and not have the registration ready when we launch DD
 				// This is a stopgap
 				Task delayTask = Task.CompletedTask;
 				lock (bridgeHandlers)
-					if (!bridgeHandlers.TryGetValue(parameters.AccessIdentifier, out bridgeHandler))
+					if (!bridgeHandlers.TryGetValue(accessIdentifier, out bridgeHandler))
 						delayTask = asyncDelayer.Delay(TimeSpan.FromMilliseconds(100), cancellationToken);
 
 				await delayTask;
@@ -514,9 +532,9 @@ namespace Tgstation.Server.Host.Components
 
 			if (bridgeHandler == null)
 				lock (bridgeHandlers)
-					if (!bridgeHandlers.TryGetValue(parameters.AccessIdentifier, out bridgeHandler))
+					if (!bridgeHandlers.TryGetValue(accessIdentifier, out bridgeHandler))
 					{
-						logger.LogWarning("Received invalid bridge request with access identifier: {accessIdentifier}", parameters.AccessIdentifier);
+						logger.LogWarning("Received invalid bridge request with access identifier: {accessIdentifier}", accessIdentifier);
 						return null;
 					}
 
@@ -528,7 +546,8 @@ namespace Tgstation.Server.Host.Components
 		{
 			ArgumentNullException.ThrowIfNull(bridgeHandler);
 
-			var accessIdentifier = bridgeHandler.DMApiParameters.AccessIdentifier;
+			var accessIdentifier = bridgeHandler.DMApiParameters.AccessIdentifier
+				?? throw new InvalidOperationException("Attempted bridge registration with null AccessIdentifier!");
 			lock (bridgeHandlers)
 			{
 				bridgeHandlers.Add(accessIdentifier, bridgeHandler);
@@ -546,11 +565,11 @@ namespace Tgstation.Server.Host.Components
 		}
 
 		/// <inheritdoc />
-		public IInstanceCore GetInstance(Models.Instance metadata)
+		public IInstanceCore? GetInstance(Models.Instance metadata)
 		{
 			lock (instances)
 			{
-				instances.TryGetValue(metadata.Id.Value, out var container);
+				instances.TryGetValue(metadata.Require(x => x.Id), out var container);
 				return container?.Instance;
 			}
 		}
@@ -565,7 +584,7 @@ namespace Tgstation.Server.Host.Components
 			try
 			{
 				logger.LogInformation("{versionString}", assemblyInformationProvider.VersionString);
-				console.Title = assemblyInformationProvider.VersionString;
+				console.SetTitle(assemblyInformationProvider.VersionString);
 
 				CheckSystemCompatibility();
 
@@ -574,13 +593,13 @@ namespace Tgstation.Server.Host.Components
 
 				await InitializeSwarm(cancellationToken);
 
-				List<Models.Instance> dbInstances = null;
+				List<Models.Instance>? dbInstances = null;
 
 				async ValueTask EnumerateInstances(IDatabaseContext databaseContext)
 					=> dbInstances = await databaseContext
 						.Instances
 						.AsQueryable()
-						.Where(x => x.Online.Value && x.SwarmIdentifer == swarmConfiguration.Identifier)
+						.Where(x => x.Online!.Value && x.SwarmIdentifer == swarmConfiguration.Identifier)
 						.Include(x => x.RepositorySettings)
 						.Include(x => x.ChatSettings)
 							.ThenInclude(x => x.Channels)
@@ -594,7 +613,7 @@ namespace Tgstation.Server.Host.Components
 
 				await Task.WhenAll(instanceEnumeration.AsTask(), factoryStartup, jobManagerStartup);
 
-				var instanceOnliningTasks = dbInstances.Select(
+				var instanceOnliningTasks = dbInstances!.Select(
 					async metadata =>
 					{
 						try
@@ -609,10 +628,11 @@ namespace Tgstation.Server.Host.Components
 
 				await Task.WhenAll(instanceOnliningTasks);
 
-				jobService.Activate(this);
-
 				logger.LogInformation("Server ready!");
 				readyTcs.SetResult();
+
+				// this needs to happen after the HTTP API opens with readyTcs otherwise it can race and cause failed bridge requests with 503's
+				jobService.Activate(this);
 			}
 			catch (OperationCanceledException ex)
 			{

src/Tgstation.Server.Host/Components/InstanceWrapper.cs

@@ -58,6 +58,6 @@ namespace Tgstation.Server.Host.Components
 		public ValueTask SetAutoUpdateInterval(uint newInterval) => Instance.SetAutoUpdateInterval(newInterval);
 
 		/// <inheritdoc />
-		public CompileJob LatestCompileJob() => Instance.LatestCompileJob();
+		public CompileJob? LatestCompileJob() => Instance.LatestCompileJob();
 	}
 }

src/Tgstation.Server.Host/Components/Interop/Bridge/BridgeParameters.cs

@@ -24,12 +24,12 @@ namespace Tgstation.Server.Host.Components.Interop.Bridge
 		/// <summary>
 		/// The DMAPI <see cref="global::System.Version"/> for <see cref="BridgeCommandType.Startup"/> requests.
 		/// </summary>
-		public Version Version { get; set; }
+		public Version? Version { get; set; }
 
 		/// <summary>
 		/// The DMAPI <see cref="CustomCommand"/>s for <see cref="BridgeCommandType.Startup"/> requests.
 		/// </summary>
-		public ICollection<CustomCommand> CustomCommands { get; set; }
+		public ICollection<CustomCommand>? CustomCommands { get; set; }
 
 		/// <summary>
 		/// The minimum required <see cref="DreamDaemonSecurity"/> level for <see cref="BridgeCommandType.Startup"/> requests.
@@ -39,16 +39,25 @@ namespace Tgstation.Server.Host.Components.Interop.Bridge
 		/// <summary>
 		/// The <see cref="Interop.ChatMessage"/> for <see cref="BridgeCommandType.ChatSend"/> requests.
 		/// </summary>
-		public ChatMessage ChatMessage { get; set; }
+		public ChatMessage? ChatMessage { get; set; }
 
 		/// <summary>
 		/// The <see cref="ChunkData"/> for <see cref="BridgeCommandType.Chunk"/> requests.
 		/// </summary>
-		public ChunkData Chunk { get; set; }
+		public ChunkData? Chunk { get; set; }
 
 		/// <summary>
 		/// The port that should be used to send world topics, if not the default.
 		/// </summary>
 		public ushort? TopicPort { get; set; }
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="BridgeParameters"/> class.
+		/// </summary>
+		/// <param name="accessIdentifier">The access identifier for the <see cref="DMApiParameters"/>.</param>
+		public BridgeParameters(string accessIdentifier)
+			: base(accessIdentifier)
+		{
+		}
 	}
 }

src/Tgstation.Server.Host/Components/Interop/Bridge/BridgeRegistration.cs

@@ -1,38 +1,19 @@
 using System;
 
+using Tgstation.Server.Host.Utils;
+
 namespace Tgstation.Server.Host.Components.Interop.Bridge
 {
 	/// <inheritdoc />
-	sealed class BridgeRegistration : IBridgeRegistration
+	sealed class BridgeRegistration : DisposeInvoker, IBridgeRegistration
 	{
-		/// <summary>
-		/// <see langword="lock"/> <see cref="object"/> for accessing <see cref="onDispose"/>.
-		/// </summary>
-		readonly object lockObject;
-
-		/// <summary>
-		/// <see cref="Action"/> to run when <see cref="Dispose"/>d.
-		/// </summary>
-		Action onDispose;
-
 		/// <summary>
 		/// Initializes a new instance of the <see cref="BridgeRegistration"/> class.
 		/// </summary>
-		/// <param name="onDispose">The value of <see cref="onDispose"/>.</param>
-		public BridgeRegistration(Action onDispose)
+		/// <param name="disposeAction">The <see cref="IDisposable.Dispose"/> action for the <see cref="DisposeInvoker"/>.</param>
+		public BridgeRegistration(Action disposeAction)
+			: base(disposeAction)
 		{
-			this.onDispose = onDispose ?? throw new ArgumentNullException(nameof(onDispose));
-			lockObject = new object();
-		}
-
-		/// <inheritdoc />
-		public void Dispose()
-		{
-			lock (lockObject)
-			{
-				onDispose?.Invoke();
-				onDispose = null;
-			}
 		}
 	}
 }

src/Tgstation.Server.Host/Components/Interop/Bridge/BridgeResponse.cs

@@ -15,11 +15,11 @@ namespace Tgstation.Server.Host.Components.Interop.Bridge
 		/// <summary>
 		/// The <see cref="Bridge.RuntimeInformation"/> for <see cref="BridgeCommandType.Startup"/> requests.
 		/// </summary>
-		public RuntimeInformation RuntimeInformation { get; set; }
+		public RuntimeInformation? RuntimeInformation { get; set; }
 
 		/// <summary>
 		/// The <see cref="ChunkData.SequenceId"/>s missing from a chunked request.
 		/// </summary>
-		public IReadOnlyCollection<uint> MissingChunks { get; set; }
+		public IReadOnlyCollection<uint>? MissingChunks { get; set; }
 	}
 }

src/Tgstation.Server.Host/Components/Interop/Bridge/IBridgeDispatcher.cs

@@ -14,6 +14,6 @@ namespace Tgstation.Server.Host.Components.Interop.Bridge
 		/// <param name="parameters">The <see cref="BridgeParameters"/> to handle.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in the <see cref="BridgeResponse"/> for the request or <see langword="null"/> if the request could not be dispatched.</returns>
-		ValueTask<BridgeResponse> ProcessBridgeRequest(BridgeParameters parameters, CancellationToken cancellationToken);
+		ValueTask<BridgeResponse?> ProcessBridgeRequest(BridgeParameters parameters, CancellationToken cancellationToken);
 	}
 }

src/Tgstation.Server.Host/Components/Interop/Bridge/RuntimeInformation.cs

@@ -91,11 +91,11 @@ namespace Tgstation.Server.Host.Components.Interop.Bridge
 				OriginCommitSha = dmbProvider.CompileJob.RevisionInformation.OriginCommitSha,
 			};
 
-			TestMerges = (IReadOnlyCollection<TestMergeInformation>)dmbProvider
+			TestMerges = (IReadOnlyCollection<TestMergeInformation>?)dmbProvider
 				.CompileJob
 				.RevisionInformation
-				.ActiveTestMerges?
-				.Select(x => x.TestMerge)
+				.ActiveTestMerges
+				?.Select(x => x.TestMerge)
 				.Select(x => new TestMergeInformation(x, Revision))
 				.ToList()
 				?? Array.Empty<TestMergeInformation>();

src/Tgstation.Server.Host/Components/Interop/Bridge/TestMergeInformation.cs

@@ -18,10 +18,10 @@ namespace Tgstation.Server.Host.Components.Interop.Bridge
 		/// <summary>
 		/// Backing field for <see cref="TargetCommitSha"/> needed to continue to support DMAPI 5.
 		/// </summary>
-		public string PullRequestRevision { get; set; }
+		public string? PullRequestRevision { get; set; }
 
 		/// <inheritdoc />
-		public override string TargetCommitSha
+		public override string? TargetCommitSha
 		{
 			get => PullRequestRevision;
 			set => PullRequestRevision = value;

src/Tgstation.Server.Host/Components/Interop/ChatEmbed.cs

@@ -10,63 +10,63 @@ namespace Tgstation.Server.Host.Components.Interop
 		/// <summary>
 		/// The title of the embed.
 		/// </summary>
-		public string Title { get; set; }
+		public string? Title { get; set; }
 
 		/// <summary>
 		/// The description of the embed.
 		/// </summary>
-		public string Description { get; set; }
+		public string? Description { get; set; }
 
 		/// <summary>
 		/// The URL of the embed.
 		/// </summary>
 #pragma warning disable CA1056 // Uri properties should not be strings
-		public string Url { get; set; }
+		public string? Url { get; set; }
 #pragma warning restore CA1056 // Uri properties should not be strings
 
 		/// <summary>
 		/// The ISO 8601 timestamp of the embed.
 		/// </summary>
-		public string Timestamp { get; set; }
+		public string? Timestamp { get; set; }
 
 		/// <summary>
 		/// The colour of the embed in the format hex "#AARRGGBB".
 		/// </summary>
-		public string Colour { get; set; }
+		public string? Colour { get; set; }
 
 		/// <summary>
 		/// The <see cref="ChatEmbedFooter"/>.
 		/// </summary>
-		public ChatEmbedFooter Footer { get; set; }
+		public ChatEmbedFooter? Footer { get; set; }
 
 		/// <summary>
 		/// The <see cref="ChatEmbedMedia"/> for an image.
 		/// </summary>
-		public ChatEmbedMedia Image { get; set; }
+		public ChatEmbedMedia? Image { get; set; }
 
 		/// <summary>
 		/// The <see cref="ChatEmbedMedia"/> for a thumbnail.
 		/// </summary>
-		public ChatEmbedMedia Thumbnail { get; set; }
+		public ChatEmbedMedia? Thumbnail { get; set; }
 
 		/// <summary>
 		/// The <see cref="ChatEmbedMedia"/> for a video.
 		/// </summary>
-		public ChatEmbedMedia Video { get; set; }
+		public ChatEmbedMedia? Video { get; set; }
 
 		/// <summary>
 		/// The <see cref="ChatEmbedProvider"/>.
 		/// </summary>
-		public ChatEmbedProvider Provider { get; set; }
+		public ChatEmbedProvider? Provider { get; set; }
 
 		/// <summary>
 		/// The <see cref="ChatEmbedAuthor"/>.
 		/// </summary>
-		public ChatEmbedAuthor Author { get; set; }
+		public ChatEmbedAuthor? Author { get; set; }
 
 		/// <summary>
 		/// The <see cref="ChatEmbedField"/>s.
 		/// </summary>
-		public ICollection<ChatEmbedField> Fields { get; set; }
+		public ICollection<ChatEmbedField>? Fields { get; set; }
 	}
 }

src/Tgstation.Server.Host/Components/Interop/ChatEmbedAuthor.cs

@@ -9,12 +9,12 @@
 		/// Gets the icon URL of the author.
 		/// </summary>
 #pragma warning disable CA1056 // Uri properties should not be strings
-		public string IconUrl { get; set; }
+		public string? IconUrl { get; set; }
 
 		/// <summary>
 		/// Gets the proxied icon URL of the thumbnail.
 		/// </summary>
-		public string ProxyIconUrl { get; set; }
+		public string? ProxyIconUrl { get; set; }
 #pragma warning restore CA1056 // Uri properties should not be strings
 	}
 }

src/Tgstation.Server.Host/Components/Interop/ChatEmbedField.cs

@@ -8,12 +8,12 @@
 		/// <summary>
 		/// Gets the name of the field.
 		/// </summary>
-		public string Name { get; set; }
+		public string? Name { get; set; }
 
 		/// <summary>
 		/// Gets the value of the field.
 		/// </summary>
-		public string Value { get; set; }
+		public string? Value { get; set; }
 
 		/// <summary>
 		/// Gets a value indicating whether the field should display inline.

src/Tgstation.Server.Host/Components/Interop/ChatEmbedFooter.cs

@@ -8,18 +8,18 @@
 		/// <summary>
 		/// Gets the text of the footer.
 		/// </summary>
-		public string Text { get; set; }
+		public string? Text { get; set; }
 
 		/// <summary>
 		/// Gets the URL of the footer icon. Only supports http(s) and attachments.
 		/// </summary>
 #pragma warning disable CA1056 // Uri properties should not be strings
-		public string IconUrl { get; set; }
+		public string? IconUrl { get; set; }
 
 		/// <summary>
 		/// Gets the proxied icon URL.
 		/// </summary>
-		public string ProxyIconUrl { get; set; }
+		public string? ProxyIconUrl { get; set; }
 #pragma warning restore CA1056 // Uri properties should not be strings
 	}
 }

src/Tgstation.Server.Host/Components/Interop/ChatEmbedMedia.cs

@@ -9,12 +9,12 @@
 		/// Gets the source URL of the media. Only supports http(s) and attachments.
 		/// </summary>
 #pragma warning disable CA1056 // Uri properties should not be strings
-		public string Url { get; set; }
+		public string? Url { get; set; }
 
 		/// <summary>
 		/// Gets the proxied URL of the media.
 		/// </summary>
-		public string ProxyUrl { get; set; }
+		public string? ProxyUrl { get; set; }
 #pragma warning restore CA1056 // Uri properties should not be strings
 
 		/// <summary>

src/Tgstation.Server.Host/Components/Interop/ChatEmbedProvider.cs

@@ -8,13 +8,13 @@
 		/// <summary>
 		/// Gets the name of the provider.
 		/// </summary>
-		public string Name { get; set; }
+		public string? Name { get; set; }
 
 		/// <summary>
 		/// Gets the URL of the provider.
 		/// </summary>
 #pragma warning disable CA1056 // Uri properties should not be strings
-		public string Url { get; set; }
+		public string? Url { get; set; }
 #pragma warning restore CA1056 // Uri properties should not be strings
 	}
 }

src/Tgstation.Server.Host/Components/Interop/ChatMessage.cs

@@ -10,6 +10,6 @@ namespace Tgstation.Server.Host.Components.Interop
 		/// <summary>
 		/// The <see cref="ICollection{T}"/> of <see cref="Chat.ChannelRepresentation.Id"/>s to sent the <see cref="MessageContent"/> to. Must be safe to parse as <see cref="ulong"/>s.
 		/// </summary>
-		public ICollection<string> ChannelIds { get; set; }
+		public ICollection<string>? ChannelIds { get; set; }
 	}
 }

src/Tgstation.Server.Host/Components/Interop/ChunkData.cs

@@ -14,6 +14,6 @@
 		/// <summary>
 		/// The partial JSON payload of the chunk.
 		/// </summary>
-		public string Payload { get; set; }
+		public string? Payload { get; set; }
 	}
 }

src/Tgstation.Server.Host/Components/Interop/Chunker.cs

@@ -14,6 +14,11 @@ namespace Tgstation.Server.Host.Components.Interop
 	/// </summary>
 	abstract class Chunker
 	{
+		/// <summary>
+		/// The <see cref="ILogger"/> for the <see cref="Chunker"/>.
+		/// </summary>
+		protected ILogger<Chunker> Logger { get; }
+
 		/// <summary>
 		/// Gets a payload ID for use in a new <see cref="ChunkSetInfo"/>.
 		/// </summary>
@@ -39,11 +44,6 @@ namespace Tgstation.Server.Host.Components.Interop
 		/// </summary>
 		uint highestSeenPayloadId;
 
-		/// <summary>
-		/// The <see cref="ILogger"/> for the <see cref="Chunker"/>.
-		/// </summary>
-		protected ILogger<Chunker> Logger { get; }
-
 		/// <summary>
 		/// Initializes a new instance of the <see cref="Chunker"/> class.
 		/// </summary>
@@ -64,11 +64,12 @@ namespace Tgstation.Server.Host.Components.Interop
 		/// <param name="chunk">The <see cref="ChunkData"/>.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in the <typeparamref name="TResponse"/> for the chunked request.</returns>
-		protected async ValueTask<TResponse> ProcessChunk<TCommunication, TResponse>(
-			Func<TCommunication, CancellationToken, ValueTask<TResponse>> completionCallback,
-			Func<string, TResponse> chunkErrorCallback,
-			ChunkData chunk,
+		protected async ValueTask<TResponse?> ProcessChunk<TCommunication, TResponse>(
+			Func<TCommunication, CancellationToken, ValueTask<TResponse?>> completionCallback,
+			Func<string, TResponse?> chunkErrorCallback,
+			ChunkData? chunk,
 			CancellationToken cancellationToken)
+			where TCommunication : class
 			where TResponse : IMissingPayloadsCommunication, new()
 		{
 			if (chunk == null)
@@ -80,6 +81,9 @@ namespace Tgstation.Server.Host.Components.Interop
 			if (!chunk.SequenceId.HasValue)
 				return chunkErrorCallback("Missing chunk sequenceId!");
 
+			if (chunk.Payload == null)
+				return chunkErrorCallback("Missing chunk payload!");
+
 			ChunkSetInfo requestInfo;
 			string[] payloads;
 			lock (chunkSets)
@@ -102,13 +106,13 @@ namespace Tgstation.Server.Host.Components.Interop
 
 				if (chunk.TotalChunks != requestInfo.TotalChunks)
 				{
-					chunkSets.Remove(requestInfo.PayloadId.Value);
+					chunkSets.Remove(requestInfo.PayloadId!.Value);
 					return chunkErrorCallback("Received differing total chunks for same payloadId! Invalidating payloadId!");
 				}
 
 				if (payloads[chunk.SequenceId.Value] != null && payloads[chunk.SequenceId.Value] != chunk.Payload)
 				{
-					chunkSets.Remove(requestInfo.PayloadId.Value);
+					chunkSets.Remove(requestInfo.PayloadId!.Value);
 					return chunkErrorCallback("Received differing payload for same sequenceId! Invalidating payloadId!");
 				}
 
@@ -125,10 +129,10 @@ namespace Tgstation.Server.Host.Components.Interop
 					};
 
 				Logger.LogTrace("Received all chunks for P{payloadId}, processing request...", requestInfo.PayloadId);
-				chunkSets.Remove(requestInfo.PayloadId.Value);
+				chunkSets.Remove(requestInfo.PayloadId!.Value);
 			}
 
-			TCommunication completedCommunication;
+			TCommunication? completedCommunication;
 			var fullCommunicationJson = String.Concat(payloads);
 			try
 			{
@@ -137,9 +141,12 @@ namespace Tgstation.Server.Host.Components.Interop
 			catch (Exception ex)
 			{
 				Logger.LogDebug(ex, "Bad chunked communication for payload {payloadId}!", requestInfo.PayloadId);
-				return chunkErrorCallback("Chunked request completed with bad JSON!");
+				completedCommunication = null;
 			}
 
+			if (completedCommunication == null)
+				return chunkErrorCallback("Chunked request completed with bad JSON!");
+
 			return await completionCallback(completedCommunication, cancellationToken);
 		}
 	}

src/Tgstation.Server.Host/Components/Interop/DMApiConstants.cs

@@ -40,12 +40,12 @@ namespace Tgstation.Server.Host.Components.Interop
 		public const uint MaximumBridgeRequestLength = 8198;
 
 		/// <summary>
-		/// The maximum length in bytes of a <see cref="global::Byond.TopicSender.ITopicClient"/> payload.
+		/// The maximum length in bytes of a <see cref="Byond.TopicSender.ITopicClient"/> payload.
 		/// </summary>
 		public const uint MaximumTopicRequestLength = 65528;
 
 		/// <summary>
-		/// The maximum length in bytes of a <see cref="global::Byond.TopicSender.ITopicClient"/> response.
+		/// The maximum length in bytes of a <see cref="Byond.TopicSender.ITopicClient"/> response.
 		/// </summary>
 		public const uint MaximumTopicResponseLength = 65529;
 

src/Tgstation.Server.Host/Components/Interop/DMApiParameters.cs

@@ -1,4 +1,5 @@
-using System.ComponentModel.DataAnnotations;
+using System;
+using System.ComponentModel.DataAnnotations;
 
 namespace Tgstation.Server.Host.Components.Interop
 {
@@ -12,5 +13,23 @@ namespace Tgstation.Server.Host.Components.Interop
 		/// </summary>
 		[Required]
 		public string AccessIdentifier { get; set; }
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="DMApiParameters"/> class.
+		/// </summary>
+		/// <param name="accessIdentifier">The value of <see cref="AccessIdentifier"/>.</param>
+		public DMApiParameters(string accessIdentifier)
+		{
+			AccessIdentifier = accessIdentifier ?? throw new ArgumentNullException(nameof(accessIdentifier));
+		}
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="DMApiParameters"/> class.
+		/// </summary>
+		/// <remarks>For use by EFCore only.</remarks>
+		protected DMApiParameters()
+		{
+			AccessIdentifier = null!;
+		}
 	}
 }

src/Tgstation.Server.Host/Components/Interop/DMApiResponse.cs

@@ -8,6 +8,6 @@
 		/// <summary>
 		/// Any errors in the client's parameters.
 		/// </summary>
-		public string ErrorMessage { get; set; }
+		public string? ErrorMessage { get; set; }
 	}
 }

src/Tgstation.Server.Host/Components/Interop/IMissingPayloadsCommunication.cs

@@ -10,6 +10,6 @@ namespace Tgstation.Server.Host.Components.Interop
 		/// <summary>
 		/// The <see cref="ChunkData.SequenceId"/>s missing from a chunked request.
 		/// </summary>
-		IReadOnlyCollection<uint> MissingChunks { get; set; }
+		IReadOnlyCollection<uint>? MissingChunks { get; set; }
 	}
 }

src/Tgstation.Server.Host/Components/Interop/MessageContent.cs

@@ -8,11 +8,11 @@
 		/// <summary>
 		/// The message <see cref="string"/>.
 		/// </summary>
-		public string Text { get; set; }
+		public string? Text { get; set; }
 
 		/// <summary>
 		/// The <see cref="ChatEmbed"/>.
 		/// </summary>
-		public ChatEmbed Embed { get; set; }
+		public ChatEmbed? Embed { get; set; }
 	}
 }

src/Tgstation.Server.Host/Components/Interop/Topic/ChunkedTopicParameters.cs

@@ -8,7 +8,7 @@ namespace Tgstation.Server.Host.Components.Interop.Topic
 	sealed class ChunkedTopicParameters : TopicParameters, IMissingPayloadsCommunication, IChunkPayloadId
 	{
 		/// <inheritdoc />
-		public IReadOnlyCollection<uint> MissingChunks { get; set; }
+		public IReadOnlyCollection<uint>? MissingChunks { get; set; }
 
 		/// <inheritdoc />
 		public uint? PayloadId { get; set; }

src/Tgstation.Server.Host/Components/Interop/Topic/EventNotification.cs

@@ -20,14 +20,14 @@ namespace Tgstation.Server.Host.Components.Interop.Topic
 		/// <summary>
 		/// The set of parameters.
 		/// </summary>
-		public IReadOnlyCollection<string> Parameters { get; }
+		public IReadOnlyCollection<string?> Parameters { get; }
 
 		/// <summary>
 		/// Initializes a new instance of the <see cref="EventNotification"/> class.
 		/// </summary>
 		/// <param name="eventType">The value of <see cref="Type"/>.</param>
 		/// <param name="parameters">The <see cref="IEnumerable{T}"/> that forms the value of <see cref="Parameters"/>.</param>
-		public EventNotification(EventType eventType, IEnumerable<string> parameters = null)
+		public EventNotification(EventType eventType, IEnumerable<string?> parameters)
 		{
 			Type = eventType;
 			Parameters = parameters?.ToList() ?? throw new ArgumentNullException(nameof(parameters));

src/Tgstation.Server.Host/Components/Interop/Topic/TopicParameters.cs

@@ -20,12 +20,12 @@ namespace Tgstation.Server.Host.Components.Interop.Topic
 		/// <summary>
 		/// The <see cref="Topic.ChatCommand"/> for <see cref="TopicCommandType.ChatCommand"/> requests.
 		/// </summary>
-		public ChatCommand ChatCommand { get; }
+		public ChatCommand? ChatCommand { get; }
 
 		/// <summary>
 		/// The <see cref="Topic.EventNotification"/> for <see cref="TopicCommandType.EventNotification"/> requests.
 		/// </summary>
-		public EventNotification EventNotification { get; }
+		public EventNotification? EventNotification { get; }
 
 		/// <summary>
 		/// The new port for <see cref="TopicCommandType.ChangePort"/> or <see cref="TopicCommandType.ServerPortUpdate"/> requests.
@@ -40,27 +40,27 @@ namespace Tgstation.Server.Host.Components.Interop.Topic
 		/// <summary>
 		/// The new <see cref="Api.Models.NamedEntity.Name"/> for <see cref="TopicCommandType.InstanceRenamed"/> requests.
 		/// </summary>
-		public string NewInstanceName { get; }
+		public string? NewInstanceName { get; }
 
 		/// <summary>
 		/// The message to broadcast for <see cref="TopicCommandType.Broadcast"/> requests.
 		/// </summary>
-		public string BroadcastMessage { get; }
+		public string? BroadcastMessage { get; }
 
 		/// <summary>
 		/// The <see cref="Interop.ChatUpdate"/> for <see cref="TopicCommandType.ChatChannelsUpdate"/> requests.
 		/// </summary>
-		public ChatUpdate ChatUpdate { get; }
+		public ChatUpdate? ChatUpdate { get; }
 
 		/// <summary>
 		/// The new server <see cref="Version"/> after a reattach.
 		/// </summary>
-		public Version NewServerVersion { get; }
+		public Version? NewServerVersion { get; }
 
 		/// <summary>
 		/// The <see cref="ChunkData"/> for a partial request.
 		/// </summary>
-		public ChunkData Chunk { get; }
+		public ChunkData? Chunk { get; }
 
 		/// <summary>
 		/// Whether or not the <see cref="TopicParameters"/> constitute a priority request.
@@ -188,6 +188,7 @@ namespace Tgstation.Server.Host.Components.Interop.Topic
 		/// </summary>
 		/// <param name="commandType">The value of <see cref="CommandType"/>.</param>
 		protected TopicParameters(TopicCommandType commandType)
+			: base(String.Empty) // access identifier gets set before send
 		{
 			CommandType = commandType;
 		}

src/Tgstation.Server.Host/Components/Interop/Topic/TopicResponse.cs

@@ -12,29 +12,29 @@ namespace Tgstation.Server.Host.Components.Interop.Topic
 		/// <summary>
 		/// The text to reply with as the result of a <see cref="TopicCommandType.ChatCommand"/> request, if any. Deprecated circa Interop 5.4.0.
 		/// </summary>
-		public string CommandResponseMessage { get; set; }
+		public string? CommandResponseMessage { get; set; }
 
 		/// <summary>
 		/// The <see cref="ChatMessage"/> response from a <see cref="ChatCommand"/>. Added in Interop 5.4.0.
 		/// </summary>
-		public ChatMessage CommandResponse { get; set; }
+		public ChatMessage? CommandResponse { get; set; }
 
 		/// <summary>
 		/// The <see cref="ChatMessage"/>s to send as the result of a <see cref="TopicCommandType.EventNotification"/> request, if any.
 		/// </summary>
-		public ICollection<ChatMessage> ChatResponses { get; set; }
+		public ICollection<ChatMessage>? ChatResponses { get; set; }
 
 		/// <summary>
 		/// The DMAPI <see cref="CustomCommand"/>s for <see cref="TopicCommandType.ServerRestarted"/> requests.
 		/// </summary>
-		public ICollection<CustomCommand> CustomCommands { get; set; }
+		public ICollection<CustomCommand>? CustomCommands { get; set; }
 
 		/// <summary>
 		/// The <see cref="ChunkData"/> for a partial response.
 		/// </summary>
-		public ChunkData Chunk { get; set; }
+		public ChunkData? Chunk { get; set; }
 
 		/// <inheritdoc />
-		public IReadOnlyCollection<uint> MissingChunks { get; set; }
+		public IReadOnlyCollection<uint>? MissingChunks { get; set; }
 	}
 }

src/Tgstation.Server.Host/Components/Repository/DefaultGitRemoteFeatures.cs

@@ -21,10 +21,10 @@ namespace Tgstation.Server.Host.Components.Repository
 		public RemoteGitProvider? RemoteGitProvider => Api.Models.RemoteGitProvider.Unknown;
 
 		/// <inheritdoc />
-		public string RemoteRepositoryOwner => null;
+		public string? RemoteRepositoryOwner => null;
 
 		/// <inheritdoc />
-		public string RemoteRepositoryName => null;
+		public string? RemoteRepositoryName => null;
 
 		/// <inheritdoc />
 		public ValueTask<Models.TestMerge> GetTestMerge(

src/Tgstation.Server.Host/Components/Repository/GitHubRemoteFeatures.cs

@@ -25,12 +25,6 @@ namespace Tgstation.Server.Host.Components.Repository
 		/// <inheritdoc />
 		public override RemoteGitProvider? RemoteGitProvider => Api.Models.RemoteGitProvider.GitHub;
 
-		/// <inheritdoc />
-		public override string RemoteRepositoryOwner { get; }
-
-		/// <inheritdoc />
-		public override string RemoteRepositoryName { get; }
-
 		/// <summary>
 		/// The <see cref="IGitHubServiceFactory"/> for the <see cref="GitHubRemoteFeatures"/>.
 		/// </summary>
@@ -46,13 +40,6 @@ namespace Tgstation.Server.Host.Components.Repository
 			: base(logger, remoteUrl)
 		{
 			this.gitHubServiceFactory = gitHubServiceFactory ?? throw new ArgumentNullException(nameof(gitHubServiceFactory));
-
-			ArgumentNullException.ThrowIfNull(remoteUrl);
-
-			RemoteRepositoryOwner = remoteUrl.Segments[1].TrimEnd('/');
-			RemoteRepositoryName = remoteUrl.Segments[2].TrimEnd('/');
-			if (RemoteRepositoryName.EndsWith(".git", StringComparison.OrdinalIgnoreCase))
-				RemoteRepositoryName = RemoteRepositoryName[0..^4];
 		}
 
 		/// <inheritdoc />
@@ -65,9 +52,9 @@ namespace Tgstation.Server.Host.Components.Repository
 				? gitHubServiceFactory.CreateService(repositorySettings.AccessToken)
 				: gitHubServiceFactory.CreateService();
 
-			PullRequest pr = null;
-			ApiException exception = null;
-			string errorMessage = null;
+			PullRequest? pr = null;
+			ApiException? exception = null;
+			string? errorMessage = null;
 			try
 			{
 				pr = await gitHubService.GetPullRequest(RemoteRepositoryOwner, RemoteRepositoryName, parameters.Number, cancellationToken);

src/Tgstation.Server.Host/Components/Repository/GitLabRemoteFeatures.cs

@@ -30,12 +30,6 @@ namespace Tgstation.Server.Host.Components.Repository
 		/// <inheritdoc />
 		public override RemoteGitProvider? RemoteGitProvider => Api.Models.RemoteGitProvider.GitLab;
 
-		/// <inheritdoc />
-		public override string RemoteRepositoryOwner { get; }
-
-		/// <inheritdoc />
-		public override string RemoteRepositoryName { get; }
-
 		/// <summary>
 		/// Initializes a new instance of the <see cref="GitLabRemoteFeatures"/> class.
 		/// </summary>
@@ -44,10 +38,6 @@ namespace Tgstation.Server.Host.Components.Repository
 		public GitLabRemoteFeatures(ILogger<GitLabRemoteFeatures> logger, Uri remoteUrl)
 			: base(logger, remoteUrl)
 		{
-			RemoteRepositoryOwner = remoteUrl.Segments[1].TrimEnd('/');
-			RemoteRepositoryName = remoteUrl.Segments[2].TrimEnd('/');
-			if (RemoteRepositoryName.EndsWith(".git", StringComparison.OrdinalIgnoreCase))
-				RemoteRepositoryName = RemoteRepositoryName[0..^4];
 		}
 
 		/// <inheritdoc />

src/Tgstation.Server.Host/Components/Repository/GitRemoteFeaturesBase.cs

@@ -25,10 +25,10 @@ namespace Tgstation.Server.Host.Components.Repository
 		public abstract RemoteGitProvider? RemoteGitProvider { get; }
 
 		/// <inheritdoc />
-		public abstract string RemoteRepositoryOwner { get; }
+		public string RemoteRepositoryOwner { get; }
 
 		/// <inheritdoc />
-		public abstract string RemoteRepositoryName { get; }
+		public string RemoteRepositoryName { get; }
 
 		/// <summary>
 		/// The <see cref="ILogger"/> for the <see cref="GitRemoteFeaturesBase"/>.
@@ -50,6 +50,11 @@ namespace Tgstation.Server.Host.Components.Repository
 			Logger = logger ?? throw new ArgumentNullException(nameof(logger));
 			ArgumentNullException.ThrowIfNull(remoteUrl);
 
+			RemoteRepositoryOwner = remoteUrl.Segments[1].TrimEnd('/');
+			RemoteRepositoryName = remoteUrl.Segments[2].TrimEnd('/');
+			if (RemoteRepositoryName.EndsWith(".git", StringComparison.OrdinalIgnoreCase))
+				RemoteRepositoryName = RemoteRepositoryName[0..^4];
+
 			cachedLookups = new Dictionary<TestMergeParameters, Models.TestMerge>();
 		}
 
@@ -62,18 +67,18 @@ namespace Tgstation.Server.Host.Components.Repository
 			ArgumentNullException.ThrowIfNull(parameters);
 			ArgumentNullException.ThrowIfNull(repositorySettings);
 
-			Models.TestMerge result;
+			Models.TestMerge? result;
 			lock (cachedLookups)
 				if (cachedLookups.TryGetValue(parameters, out result))
-					Logger.LogTrace("Using cache for test merge #{0}", parameters.Number);
+					Logger.LogTrace("Using cache for test merge #{testMergeNumber}", parameters.Number);
 
 			if (result == null)
 			{
-				Logger.LogTrace("Retrieving metadata for test merge #{0}...", parameters.Number);
+				Logger.LogTrace("Retrieving metadata for test merge #{testMergeNumber}...", parameters.Number);
 				result = await GetTestMergeImpl(parameters, repositorySettings, cancellationToken);
 				lock (cachedLookups)
 					if (!cachedLookups.TryAdd(parameters, result))
-						Logger.LogError("Race condition on adding test merge #{0}!", parameters.Number);
+						Logger.LogError("Race condition on adding test merge #{testMergeNumber}!", parameters.Number);
 			}
 
 			return result;

src/Tgstation.Server.Host/Components/Repository/GitRemoteFeaturesFactory.cs

@@ -78,7 +78,7 @@ namespace Tgstation.Server.Host.Components.Repository
 				case "GIT.GITLAB.COM":
 					return RemoteGitProvider.GitLab;
 				default:
-					logger.LogTrace("Unknown git remote: {0}", origin);
+					logger.LogDebug("Unknown git remote: {origin}", origin);
 					return RemoteGitProvider.Unknown;
 			}
 		}

src/Tgstation.Server.Host/Components/Repository/ICredentialsProvider.cs

@@ -16,7 +16,7 @@ namespace Tgstation.Server.Host.Components.Repository
 		/// <param name="username">The optional username to use in the <see cref="CredentialsHandler"/>.</param>
 		/// <param name="password">The optional password to use in the <see cref="CredentialsHandler"/>.</param>
 		/// <returns>A new <see cref="CredentialsHandler"/>.</returns>
-		CredentialsHandler GenerateCredentialsHandler(string username, string password);
+		CredentialsHandler GenerateCredentialsHandler(string? username, string? password);
 
 		/// <summary>
 		/// Rethrow the authentication failure message as a <see cref="JobException"/> if it is one.

src/Tgstation.Server.Host/Components/Repository/IRepository.cs

@@ -44,18 +44,18 @@ namespace Tgstation.Server.Host.Components.Repository
 		/// Checks out a given <paramref name="committish"/>.
 		/// </summary>
 		/// <param name="committish">The sha or reference to checkout.</param>
-		/// <param name="username">The username used for fetching from submodule repositories.</param>
-		/// <param name="password">The password used for fetching from submodule repositories.</param>
+		/// <param name="username">The optional username used for fetching from submodule repositories.</param>
+		/// <param name="password">The optional password used for fetching from submodule repositories.</param>
 		/// <param name="updateSubmodules">If a submodule update should be attempted after the merge.</param>
 		/// <param name="progressReporter">The optional <see cref="JobProgressReporter"/> to report progress of the operation.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask"/> representing the running operation.</returns>
 		ValueTask CheckoutObject(
 			string committish,
-			string username,
-			string password,
+			string? username,
+			string? password,
 			bool updateSubmodules,
-			JobProgressReporter progressReporter,
+			JobProgressReporter? progressReporter,
 			CancellationToken cancellationToken);
 
 		/// <summary>
@@ -64,8 +64,8 @@ namespace Tgstation.Server.Host.Components.Repository
 		/// <param name="testMergeParameters">The <see cref="TestMergeParameters"/> of the pull request.</param>
 		/// <param name="committerName">The name of the merge committer.</param>
 		/// <param name="committerEmail">The e-mail of the merge committer.</param>
-		/// <param name="username">The username used to fetch from the origin and submodule repositories.</param>
-		/// <param name="password">The password used to fetch from the origin and submodule repositories.</param>
+		/// <param name="username">The optional username used to fetch from the origin and submodule repositories.</param>
+		/// <param name="password">The optional password used to fetch from the origin and submodule repositories.</param>
 		/// <param name="updateSubmodules">If a submodule update should be attempted after the merge.</param>
 		/// <param name="progressReporter">The <see cref="JobProgressReporter"/> to report progress of the operation.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
@@ -74,8 +74,8 @@ namespace Tgstation.Server.Host.Components.Repository
 			TestMergeParameters testMergeParameters,
 			string committerName,
 			string committerEmail,
-			string username,
-			string password,
+			string? username,
+			string? password,
 			bool updateSubmodules,
 			JobProgressReporter progressReporter,
 			CancellationToken cancellationToken);
@@ -84,15 +84,15 @@ namespace Tgstation.Server.Host.Components.Repository
 		/// Fetch commits from the origin repository.
 		/// </summary>
 		/// <param name="progressReporter">The optional <see cref="JobProgressReporter"/> to report progress of the operation.</param>
-		/// <param name="username">The username to fetch from the origin repository.</param>
-		/// <param name="password">The password to fetch from the origin repository.</param>
+		/// <param name="username">The optional username to fetch from the origin repository.</param>
+		/// <param name="password">The optional password to fetch from the origin repository.</param>
 		/// <param name="deploymentPipeline">If any events created should be marked as part of the deployment pipeline.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask"/> representing the running operation.</returns>
 		ValueTask FetchOrigin(
-			JobProgressReporter progressReporter,
-			string username,
-			string password,
+			JobProgressReporter? progressReporter,
+			string? username,
+			string? password,
 			bool deploymentPipeline,
 			CancellationToken cancellationToken);
 
@@ -100,16 +100,16 @@ namespace Tgstation.Server.Host.Components.Repository
 		/// Requires the current HEAD to be a tracked reference. Hard resets the reference to what it tracks on the origin repository.
 		/// </summary>
 		/// <param name="progressReporter">The <see cref="JobProgressReporter"/> to report progress of the operation.</param>
-		/// <param name="username">The username used for fetching from submodule repositories.</param>
-		/// <param name="password">The password used for fetching from submodule repositories.</param>
+		/// <param name="username">The optional username used for fetching from submodule repositories.</param>
+		/// <param name="password">The optional password used for fetching from submodule repositories.</param>
 		/// <param name="updateSubmodules">If a submodule update should be attempted after the merge.</param>
 		/// <param name="deploymentPipeline">If any events created should be marked as part of the deployment pipeline.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in the SHA of the new HEAD.</returns>
 		ValueTask ResetToOrigin(
 			JobProgressReporter progressReporter,
-			string username,
-			string password,
+			string? username,
+			string? password,
 			bool updateSubmodules,
 			bool deploymentPipeline,
 			CancellationToken cancellationToken);
@@ -151,10 +151,10 @@ namespace Tgstation.Server.Host.Components.Repository
 		/// <param name="deploymentPipeline">If any events created should be marked as part of the deployment pipeline.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in <see langword="true"/> if commits were pushed to the tracked origin reference, <see langword="false"/> otherwise.</returns>
-		ValueTask<bool> Sychronize(
+		ValueTask<bool> Synchronize(
 			JobProgressReporter progressReporter,
-			string username,
-			string password,
+			string? username,
+			string? password,
 			string committerName,
 			string committerEmail,
 			bool synchronizeTrackedBranch,

src/Tgstation.Server.Host/Components/Repository/IRepositoryManager.cs

@@ -26,25 +26,25 @@ namespace Tgstation.Server.Host.Components.Repository
 		/// </summary>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in the loaded <see cref="IRepository"/> if it exists, <see langword="null"/> otherwise.</returns>
-		ValueTask<IRepository> LoadRepository(CancellationToken cancellationToken);
+		ValueTask<IRepository?> LoadRepository(CancellationToken cancellationToken);
 
 		/// <summary>
 		/// Clone the repository at <paramref name="url"/>.
 		/// </summary>
 		/// <param name="url">The <see cref="Uri"/> of the remote repository to clone.</param>
-		/// <param name="initialBranch">The branch to clone.</param>
-		/// <param name="username">The username to clone from <paramref name="url"/>.</param>
-		/// <param name="password">The password to clone from <paramref name="url"/>.</param>
+		/// <param name="initialBranch">The optional branch to clone.</param>
+		/// <param name="username">The optional username to clone from <paramref name="url"/>.</param>
+		/// <param name="password">The optional password to clone from <paramref name="url"/>.</param>
 		/// <param name="progressReporter">The optional <see cref="JobProgressReporter"/> for progress of the clone.</param>
 		/// <param name="recurseSubmodules">If submodules should be recusively cloned and initialized.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask{TResult}"/> resulting i the newly cloned <see cref="IRepository"/>, <see langword="null"/> if one already exists.</returns>
-		ValueTask<IRepository> CloneRepository(
+		ValueTask<IRepository?> CloneRepository(
 			Uri url,
-			string initialBranch,
-			string username,
-			string password,
-			JobProgressReporter progressReporter,
+			string? initialBranch,
+			string? username,
+			string? password,
+			JobProgressReporter? progressReporter,
 			bool recurseSubmodules,
 			CancellationToken cancellationToken);
 

src/Tgstation.Server.Host/Components/Repository/LibGit2RepositoryFactory.cs

@@ -80,7 +80,7 @@ namespace Tgstation.Server.Host.Components.Repository
 			TaskScheduler.Current);
 
 		/// <inheritdoc />
-		public CredentialsHandler GenerateCredentialsHandler(string username, string password) => (a, b, supportedCredentialTypes) =>
+		public CredentialsHandler GenerateCredentialsHandler(string? username, string? password) => (a, b, supportedCredentialTypes) =>
 		{
 			var hasCreds = username != null;
 			var supportsUserPass = supportedCredentialTypes.HasFlag(SupportedCredentialTypes.UsernamePassword);

src/Tgstation.Server.Host/Components/Repository/Repository.cs

@@ -17,12 +17,13 @@ using Tgstation.Server.Host.Configuration;
 using Tgstation.Server.Host.Extensions;
 using Tgstation.Server.Host.IO;
 using Tgstation.Server.Host.Jobs;
+using Tgstation.Server.Host.Utils;
 
 namespace Tgstation.Server.Host.Components.Repository
 {
 	/// <inheritdoc />
 #pragma warning disable CA1506 // TODO: Decomplexify
-	sealed class Repository : IRepository
+	sealed class Repository : DisposeInvoker, IRepository
 	{
 		/// <summary>
 		/// The default username for committers.
@@ -53,10 +54,10 @@ namespace Tgstation.Server.Host.Components.Repository
 		public RemoteGitProvider? RemoteGitProvider => gitRemoteFeatures.RemoteGitProvider;
 
 		/// <inheritdoc />
-		public string RemoteRepositoryOwner => gitRemoteFeatures.RemoteRepositoryOwner;
+		public string? RemoteRepositoryOwner => gitRemoteFeatures.RemoteRepositoryOwner;
 
 		/// <inheritdoc />
-		public string RemoteRepositoryName => gitRemoteFeatures.RemoteRepositoryName;
+		public string? RemoteRepositoryName => gitRemoteFeatures.RemoteRepositoryName;
 
 		/// <inheritdoc />
 		public bool Tracking => Reference != null && libGitRepo.Head.IsTracking;
@@ -115,16 +116,6 @@ namespace Tgstation.Server.Host.Components.Repository
 		/// </summary>
 		readonly GeneralConfiguration generalConfiguration;
 
-		/// <summary>
-		/// <see cref="Action"/> to be taken when <see cref="Dispose"/> is called.
-		/// </summary>
-		readonly Action onDispose;
-
-		/// <summary>
-		/// If the <see cref="Repository"/> was disposed.
-		/// </summary>
-		bool disposed;
-
 		/// <summary>
 		/// Initializes a new instance of the <see cref="Repository"/> class.
 		/// </summary>
@@ -137,7 +128,7 @@ namespace Tgstation.Server.Host.Components.Repository
 		/// <param name="gitRemoteFeaturesFactory">The <see cref="IGitRemoteFeaturesFactory"/> to provide the value of <see cref="gitRemoteFeatures"/>.</param>
 		/// <param name="logger">The value of <see cref="logger"/>.</param>
 		/// <param name="generalConfiguration">The value of <see cref="generalConfiguration"/>.</param>
-		/// <param name="onDispose">The value if <see cref="onDispose"/>.</param>
+		/// <param name="disposeAction">The <see cref="IDisposable.Dispose"/> action for the <see cref="DisposeInvoker"/>.</param>
 		public Repository(
 			LibGit2Sharp.IRepository libGitRepo,
 			ILibGit2Commands commands,
@@ -148,7 +139,8 @@ namespace Tgstation.Server.Host.Components.Repository
 			IGitRemoteFeaturesFactory gitRemoteFeaturesFactory,
 			ILogger<Repository> logger,
 			GeneralConfiguration generalConfiguration,
-			Action onDispose)
+			Action disposeAction)
+			: base(disposeAction)
 		{
 			this.libGitRepo = libGitRepo ?? throw new ArgumentNullException(nameof(libGitRepo));
 			this.commands = commands ?? throw new ArgumentNullException(nameof(commands));
@@ -160,35 +152,18 @@ namespace Tgstation.Server.Host.Components.Repository
 
 			this.logger = logger ?? throw new ArgumentNullException(nameof(logger));
 			this.generalConfiguration = generalConfiguration ?? throw new ArgumentNullException(nameof(generalConfiguration));
-			this.onDispose = onDispose ?? throw new ArgumentNullException(nameof(onDispose));
 
 			gitRemoteFeatures = gitRemoteFeaturesFactory.CreateGitRemoteFeatures(this);
 		}
 
-		/// <inheritdoc />
-		public void Dispose()
-		{
-			lock (onDispose)
-			{
-				if (disposed)
-					return;
-
-				disposed = true;
-			}
-
-			logger.LogTrace("Disposing...");
-			libGitRepo.Dispose();
-			onDispose();
-		}
-
 		/// <inheritdoc />
 #pragma warning disable CA1506 // TODO: Decomplexify
 		public async ValueTask<TestMergeResult> AddTestMerge(
 			TestMergeParameters testMergeParameters,
 			string committerName,
 			string committerEmail,
-			string username,
-			string password,
+			string? username,
+			string? password,
 			bool updateSubmodules,
 			JobProgressReporter progressReporter,
 			CancellationToken cancellationToken)
@@ -227,12 +202,12 @@ namespace Tgstation.Server.Host.Components.Repository
 
 			var originalCommit = libGitRepo.Head;
 
-			MergeResult result = null;
+			MergeResult? result = null;
 
 			var progressFactor = 1.0 / (updateSubmodules ? 3 : 2);
 
 			var sig = new Signature(new Identity(committerName, committerEmail), DateTimeOffset.UtcNow);
-			List<string> conflictedPaths = null;
+			List<string>? conflictedPaths = null;
 			await Task.Factory.StartNew(
 				() =>
 				{
@@ -316,17 +291,17 @@ namespace Tgstation.Server.Host.Components.Repository
 				DefaultIOManager.BlockingTaskCreationOptions,
 				TaskScheduler.Current);
 
-			if (result.Status == MergeStatus.Conflicts)
+			if (result!.Status == MergeStatus.Conflicts)
 			{
 				var arguments = new List<string>
 				{
 					originalCommit.Tip.Sha,
-					testMergeParameters.TargetCommitSha,
+					testMergeParameters.TargetCommitSha!,
 					originalCommit.FriendlyName ?? UnknownReference,
 					testMergeBranchName,
 				};
 
-				arguments.AddRange(conflictedPaths);
+				arguments.AddRange(conflictedPaths!);
 
 				await eventConsumer.HandleEvent(
 					EventType.RepoMergeConflict,
@@ -365,10 +340,10 @@ namespace Tgstation.Server.Host.Components.Repository
 
 			await eventConsumer.HandleEvent(
 				EventType.RepoAddTestMerge,
-				new List<string>
+				new List<string?>
 				{
 					testMergeParameters.Number.ToString(CultureInfo.InvariantCulture),
-					testMergeParameters.TargetCommitSha,
+					testMergeParameters.TargetCommitSha!,
 					testMergeParameters.Comment,
 				},
 				false,
@@ -384,10 +359,10 @@ namespace Tgstation.Server.Host.Components.Repository
 		/// <inheritdoc />
 		public async ValueTask CheckoutObject(
 			string committish,
-			string username,
-			string password,
+			string? username,
+			string? password,
 			bool updateSubmodules,
-			JobProgressReporter progressReporter,
+			JobProgressReporter? progressReporter,
 			CancellationToken cancellationToken)
 		{
 			ArgumentNullException.ThrowIfNull(committish);
@@ -418,9 +393,9 @@ namespace Tgstation.Server.Host.Components.Repository
 
 		/// <inheritdoc />
 		public async ValueTask FetchOrigin(
-			JobProgressReporter progressReporter,
-			string username,
-			string password,
+			JobProgressReporter? progressReporter,
+			string? username,
+			string? password,
 			bool deploymentPipeline,
 			CancellationToken cancellationToken)
 		{
@@ -468,8 +443,8 @@ namespace Tgstation.Server.Host.Components.Repository
 		/// <inheritdoc />
 		public async ValueTask ResetToOrigin(
 			JobProgressReporter progressReporter,
-			string username,
-			string password,
+			string? username,
+			string? password,
 			bool updateSubmodules,
 			bool deploymentPipeline,
 			CancellationToken cancellationToken)
@@ -566,8 +541,8 @@ namespace Tgstation.Server.Host.Components.Repository
 		{
 			ArgumentNullException.ThrowIfNull(progressReporter);
 
-			MergeResult result = null;
-			Branch trackedBranch = null;
+			MergeResult? result = null;
+			Branch? trackedBranch = null;
 
 			var oldHead = libGitRepo.Head;
 			var oldTip = oldHead.Tip;
@@ -616,14 +591,14 @@ namespace Tgstation.Server.Host.Components.Repository
 				DefaultIOManager.BlockingTaskCreationOptions,
 				TaskScheduler.Current);
 
-			if (result.Status == MergeStatus.Conflicts)
+			if (result!.Status == MergeStatus.Conflicts)
 			{
 				await eventConsumer.HandleEvent(
 					EventType.RepoMergeConflict,
 					new List<string>
 					{
 						oldTip.Sha,
-						trackedBranch.Tip.Sha,
+						trackedBranch!.Tip.Sha,
 						oldHead.FriendlyName ?? UnknownReference,
 						trackedBranch.FriendlyName,
 					},
@@ -636,10 +611,10 @@ namespace Tgstation.Server.Host.Components.Repository
 		}
 
 		/// <inheritdoc />
-		public async ValueTask<bool> Sychronize(
+		public async ValueTask<bool> Synchronize(
 			JobProgressReporter progressReporter,
-			string username,
-			string password,
+			string? username,
+			string? password,
 			string committerName,
 			string committerEmail,
 			bool synchronizeTrackedBranch,
@@ -867,13 +842,21 @@ namespace Tgstation.Server.Host.Components.Repository
 			DefaultIOManager.BlockingTaskCreationOptions,
 			TaskScheduler.Current);
 
+		/// <inheritdoc />
+		protected override void DisposeImpl()
+		{
+			logger.LogTrace("Disposing...");
+			libGitRepo.Dispose();
+			base.DisposeImpl();
+		}
+
 		/// <summary>
 		/// Runs a blocking force checkout to <paramref name="committish"/>.
 		/// </summary>
 		/// <param name="committish">The committish to checkout.</param>
 		/// <param name="progressReporter">The optional <see cref="JobProgressReporter"/> for the operation.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
-		void RawCheckout(string committish, JobProgressReporter progressReporter, CancellationToken cancellationToken)
+		void RawCheckout(string committish, JobProgressReporter? progressReporter, CancellationToken cancellationToken)
 		{
 			logger.LogTrace("Checkout: {committish}", committish);
 
@@ -1008,15 +991,15 @@ namespace Tgstation.Server.Host.Components.Repository
 		/// Recusively update all <see cref="Submodule"/>s in the <see cref="libGitRepo"/>.
 		/// </summary>
 		/// <param name="progressReporter">Optional <see cref="JobProgressReporter"/> of the operation.</param>
-		/// <param name="username">The username for the <see cref="credentialsProvider"/>.</param>
-		/// <param name="password">The password for the <see cref="credentialsProvider"/>.</param>
+		/// <param name="username">The optional username for the <see cref="credentialsProvider"/>.</param>
+		/// <param name="password">The optional password for the <see cref="credentialsProvider"/>.</param>
 		/// <param name="deploymentPipeline">If any events created should be marked as part of the deployment pipeline.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask"/> representing the running operation.</returns>
 		async ValueTask UpdateSubmodules(
-			JobProgressReporter progressReporter,
-			string username,
-			string password,
+			JobProgressReporter? progressReporter,
+			string? username,
+			string? password,
 			bool deploymentPipeline,
 			CancellationToken cancellationToken)
 		{

src/Tgstation.Server.Host/Components/Repository/RepositoryManager.cs

@@ -118,12 +118,12 @@ namespace Tgstation.Server.Host.Components.Repository
 		}
 
 		/// <inheritdoc />
-		public async ValueTask<IRepository> CloneRepository(
+		public async ValueTask<IRepository?> CloneRepository(
 			Uri url,
-			string initialBranch,
-			string username,
-			string password,
-			JobProgressReporter progressReporter,
+			string? initialBranch,
+			string? username,
+			string? password,
+			JobProgressReporter? progressReporter,
 			bool recurseSubmodules,
 			CancellationToken cancellationToken)
 		{
@@ -208,7 +208,7 @@ namespace Tgstation.Server.Host.Components.Repository
 		}
 
 		/// <inheritdoc />
-		public async ValueTask<IRepository> LoadRepository(CancellationToken cancellationToken)
+		public async ValueTask<IRepository?> LoadRepository(CancellationToken cancellationToken)
 		{
 			logger.LogTrace("Begin LoadRepository...");
 			lock (semaphore)

src/Tgstation.Server.Host/Components/Repository/RepositoryUpdateService.cs

@@ -85,16 +85,18 @@ namespace Tgstation.Server.Host.Components.Repository
 			IDatabaseContext databaseContext,
 			ILogger logger,
 			Models.Instance instance,
-			string lastOriginCommitSha,
-			Action<Models.RevisionInformation> revInfoSink,
+			string? lastOriginCommitSha,
+			Action<Models.RevisionInformation>? revInfoSink,
 			CancellationToken cancellationToken)
 		{
 			var repoSha = repository.Head;
 
 			IQueryable<Models.RevisionInformation> ApplyQuery(IQueryable<Models.RevisionInformation> query) => query
-				.Where(x => x.CommitSha == repoSha && x.Instance.Id == instance.Id)
+				.Where(x => x.CommitSha == repoSha && x.InstanceId == instance.Id)
 				.Include(x => x.CompileJobs)
-				.Include(x => x.ActiveTestMerges).ThenInclude(x => x.TestMerge).ThenInclude(x => x.MergedBy);
+				.Include(x => x.ActiveTestMerges!)
+					.ThenInclude(x => x.TestMerge)
+						.ThenInclude(x => x.MergedBy);
 
 			var revisionInfo = await ApplyQuery(databaseContext.RevisionInformations).FirstOrDefaultAsync(cancellationToken);
 
@@ -103,7 +105,7 @@ namespace Tgstation.Server.Host.Components.Repository
 				revisionInfo = databaseContext
 					.RevisionInformations
 					.Local
-					.Where(x => x.CommitSha == repoSha && x.Instance.Id == instance.Id)
+					.Where(x => x.CommitSha == repoSha && x.InstanceId == instance.Id)
 					.FirstOrDefault();
 
 			var needsDbUpdate = revisionInfo == default;
@@ -123,7 +125,7 @@ namespace Tgstation.Server.Host.Components.Repository
 					databaseContext.RevisionInformations.Add(revisionInfo);
 			}
 
-			revisionInfo.OriginCommitSha ??= lastOriginCommitSha;
+			revisionInfo!.OriginCommitSha ??= lastOriginCommitSha;
 			if (revisionInfo.OriginCommitSha == null)
 			{
 				revisionInfo.OriginCommitSha = repoSha;
@@ -145,13 +147,15 @@ namespace Tgstation.Server.Host.Components.Repository
 		/// <returns>A <see cref="ValueTask"/> representing the running operation.</returns>
 #pragma warning disable CA1502, CA1506 // TODO: Decomplexify
 		public async ValueTask RepositoryUpdateJob(
-			IInstanceCore instance,
+			IInstanceCore? instance,
 			IDatabaseContextFactory databaseContextFactory,
 			Job job,
 			JobProgressReporter progressReporter,
 			CancellationToken cancellationToken)
 #pragma warning restore CA1502, CA1506
 		{
+			ArgumentNullException.ThrowIfNull(instance);
+
 			_ = job; // shuts up an IDE warning
 
 			var repoManager = instance.RepositoryManager;
@@ -160,23 +164,23 @@ namespace Tgstation.Server.Host.Components.Repository
 
 			var startReference = repo.Reference;
 			var startSha = repo.Head;
-			string postUpdateSha = null;
+			string? postUpdateSha = null;
 
 			var newTestMerges = model.NewTestMerges != null && model.NewTestMerges.Count > 0;
 
 			if (newTestMerges && repo.RemoteGitProvider == RemoteGitProvider.Unknown)
 				throw new JobException(ErrorCode.RepoUnsupportedTestMergeRemote);
 
-			var committerName = currentModel.ShowTestMergeCommitters.Value
+			var committerName = (currentModel.ShowTestMergeCommitters!.Value
 				? initiatingUser.Name
-				: currentModel.CommitterName;
+				: currentModel.CommitterName)!;
 
 			var hardResettingToOriginReference = model.UpdateFromOrigin == true && model.Reference != null;
 
 			var numSteps = (model.NewTestMerges?.Count ?? 0) + (model.UpdateFromOrigin == true ? 1 : 0) + (!modelHasShaOrReference ? 2 : (hardResettingToOriginReference ? 3 : 1));
 			var progressFactor = 1.0 / numSteps;
 
-			JobProgressReporter NextProgressReporter(string stage)
+			JobProgressReporter NextProgressReporter(string? stage)
 			{
 				return progressReporter.CreateSection(stage, progressFactor);
 			}
@@ -184,19 +188,19 @@ namespace Tgstation.Server.Host.Components.Repository
 			progressReporter.ReportProgress(0);
 
 			// get a base line for where we are
-			Models.RevisionInformation lastRevisionInfo = null;
+			Models.RevisionInformation? lastRevisionInfo = null;
 
 			var attachedInstance = new Models.Instance
 			{
 				Id = instanceId,
 			};
 
-			ValueTask CallLoadRevInfo(Models.TestMerge testMergeToAdd = null, string lastOriginCommitSha = null) => databaseContextFactory
+			ValueTask CallLoadRevInfo(Models.TestMerge? testMergeToAdd = null, string? lastOriginCommitSha = null) => databaseContextFactory
 				.UseContext(
 					async databaseContext =>
 					{
 						databaseContext.Instances.Attach(attachedInstance);
-						var previousRevInfo = lastRevisionInfo;
+						var previousRevInfo = lastRevisionInfo!;
 						var needsUpdate = await LoadRevisionInformation(
 							repo,
 							databaseContext,
@@ -223,13 +227,11 @@ namespace Tgstation.Server.Host.Components.Repository
 							testMergeToAdd.MergedBy = mergedBy;
 							testMergeToAdd.MergedAt = DateTimeOffset.UtcNow;
 
-							foreach (var activeTestMerge in previousRevInfo.ActiveTestMerges)
-								lastRevisionInfo.ActiveTestMerges.Add(activeTestMerge);
+							var activeTestMerges = lastRevisionInfo!.ActiveTestMerges!;
+							foreach (var activeTestMerge in previousRevInfo.ActiveTestMerges!)
+								activeTestMerges.Add(activeTestMerge);
 
-							lastRevisionInfo.ActiveTestMerges.Add(new RevInfoTestMerge
-							{
-								TestMerge = testMergeToAdd,
-							});
+							activeTestMerges.Add(new RevInfoTestMerge(testMergeToAdd, lastRevisionInfo));
 							lastRevisionInfo.PrimaryTestMerge = testMergeToAdd;
 
 							needsUpdate = true;
@@ -242,7 +244,7 @@ namespace Tgstation.Server.Host.Components.Repository
 			await CallLoadRevInfo();
 
 			// apply new rev info, tracking applied test merges
-			ValueTask UpdateRevInfo(Models.TestMerge testMergeToAdd = null) => CallLoadRevInfo(testMergeToAdd, lastRevisionInfo.OriginCommitSha);
+			ValueTask UpdateRevInfo(Models.TestMerge? testMergeToAdd = null) => CallLoadRevInfo(testMergeToAdd, lastRevisionInfo!.OriginCommitSha);
 
 			try
 			{
@@ -263,21 +265,21 @@ namespace Tgstation.Server.Host.Components.Repository
 						var fastForward = await repo.MergeOrigin(
 							NextProgressReporter("Merge Origin"),
 							committerName,
-							currentModel.CommitterEmail,
+							currentModel.CommitterEmail!,
 							false,
 							cancellationToken);
 						if (!fastForward.HasValue)
 							throw new JobException(ErrorCode.RepoMergeConflict);
-						lastRevisionInfo.OriginCommitSha = await repo.GetOriginSha(cancellationToken);
+						lastRevisionInfo!.OriginCommitSha = await repo.GetOriginSha(cancellationToken);
 						await UpdateRevInfo();
 						if (fastForward.Value)
 						{
-							await repo.Sychronize(
+							await repo.Synchronize(
 								NextProgressReporter("Sychronize"),
 								currentModel.AccessUser,
 								currentModel.AccessToken,
-								currentModel.CommitterName,
-								currentModel.CommitterEmail,
+								currentModel.CommitterName!,
+								currentModel.CommitterEmail!,
 								true,
 								false,
 								cancellationToken);
@@ -288,7 +290,7 @@ namespace Tgstation.Server.Host.Components.Repository
 					}
 				}
 
-				var updateSubmodules = currentModel.UpdateSubmodules.Value;
+				var updateSubmodules = currentModel.UpdateSubmodules!.Value;
 
 				// checkout/hard reset
 				if (modelHasShaOrReference)
@@ -302,7 +304,7 @@ namespace Tgstation.Server.Host.Components.Repository
 
 					if (validCheckoutSha || validCheckoutReference)
 					{
-						var committish = model.CheckoutSha ?? model.Reference;
+						var committish = model.CheckoutSha ?? model.Reference!;
 						var isSha = await repo.IsSha(committish, cancellationToken);
 
 						if ((isSha && model.Reference != null) || (!isSha && model.CheckoutSha != null))
@@ -331,12 +333,12 @@ namespace Tgstation.Server.Host.Components.Repository
 							updateSubmodules,
 							false,
 							cancellationToken);
-						await repo.Sychronize(
+						await repo.Synchronize(
 							NextProgressReporter("Synchronize"),
 							currentModel.AccessUser,
 							currentModel.AccessToken,
-							currentModel.CommitterName,
-							currentModel.CommitterEmail,
+							currentModel.CommitterName!,
+							currentModel.CommitterEmail!,
 							true,
 							false,
 							cancellationToken);
@@ -344,7 +346,7 @@ namespace Tgstation.Server.Host.Components.Repository
 
 						// repo head is on origin so force this
 						// will update the db if necessary
-						lastRevisionInfo.OriginCommitSha = repo.Head;
+						lastRevisionInfo!.OriginCommitSha = repo.Head;
 					}
 				}
 
@@ -355,19 +357,20 @@ namespace Tgstation.Server.Host.Components.Repository
 						throw new JobException(ErrorCode.RepoTestMergeInvalidRemote);
 
 					// bit of sanitization
-					foreach (var newTestMergeWithoutTargetCommitSha in model.NewTestMerges.Where(x => String.IsNullOrWhiteSpace(x.TargetCommitSha)))
+					var newTestMergeModels = model.NewTestMerges!;
+					foreach (var newTestMergeWithoutTargetCommitSha in newTestMergeModels.Where(x => String.IsNullOrWhiteSpace(x.TargetCommitSha)))
 						newTestMergeWithoutTargetCommitSha.TargetCommitSha = null;
 
 					var repoOwner = repo.RemoteRepositoryOwner;
 					var repoName = repo.RemoteRepositoryName;
 
 					// optimization: if we've already merged these exact same commits in this fashion before, just find the rev info for it and check it out
-					Models.RevisionInformation revInfoWereLookingFor = null;
+					Models.RevisionInformation? revInfoWereLookingFor = null;
 					bool needToApplyRemainingPrs = true;
-					if (lastRevisionInfo.OriginCommitSha == lastRevisionInfo.CommitSha)
+					if (lastRevisionInfo!.OriginCommitSha == lastRevisionInfo.CommitSha)
 					{
 						bool cantSearch = false;
-						foreach (var newTestMerge in model.NewTestMerges)
+						foreach (var newTestMerge in newTestMergeModels)
 						{
 							if (newTestMerge.TargetCommitSha != null)
 #pragma warning disable CA1308 // Normalize strings to uppercase
@@ -391,56 +394,58 @@ namespace Tgstation.Server.Host.Components.Repository
 
 						if (!cantSearch)
 						{
-							List<Models.RevisionInformation> dbPull = null;
+							List<Models.RevisionInformation>? dbPull = null;
 
 							await databaseContextFactory.UseContext(
 								async databaseContext =>
 									dbPull = await databaseContext.RevisionInformations
 										.AsQueryable()
-										.Where(x => x.Instance.Id == instanceId
-										&& x.OriginCommitSha == lastRevisionInfo.OriginCommitSha
-										&& x.ActiveTestMerges.Count <= model.NewTestMerges.Count
-										&& x.ActiveTestMerges.Count > 0)
-										.Include(x => x.ActiveTestMerges)
-										.ThenInclude(x => x.TestMerge)
+										.Where(x => x.InstanceId == instanceId
+											&& x.OriginCommitSha == lastRevisionInfo.OriginCommitSha
+											&& x.ActiveTestMerges!.Count <= newTestMergeModels.Count
+											&& x.ActiveTestMerges!.Count > 0)
+										.Include(x => x.ActiveTestMerges!)
+											.ThenInclude(x => x.TestMerge)
 										.ToListAsync(cancellationToken));
 
 							// split here cause this bit has to be done locally
-							revInfoWereLookingFor = dbPull
-								.Where(x => x.ActiveTestMerges.Count == model.NewTestMerges.Count
-								&& x.ActiveTestMerges.Select(y => y.TestMerge)
-								.All(y => model.NewTestMerges.Any(z =>
-								y.Number == z.Number
-								&& y.TargetCommitSha.StartsWith(z.TargetCommitSha, StringComparison.Ordinal)
-								&& (y.Comment?.Trim().ToUpperInvariant() == z.Comment?.Trim().ToUpperInvariant() || z.Comment == null))))
+							revInfoWereLookingFor = dbPull!
+								.Where(x => x.ActiveTestMerges!.Count == newTestMergeModels.Count
+									&& x.ActiveTestMerges
+										.Select(y => y.TestMerge)
+										.All(y => newTestMergeModels
+											.Any(z =>
+												y.Number == z.Number
+												&& y.TargetCommitSha!.StartsWith(z.TargetCommitSha!, StringComparison.Ordinal)
+												&& (y.Comment?.Trim().ToUpperInvariant() == z.Comment?.Trim().ToUpperInvariant() || z.Comment == null))))
 								.FirstOrDefault();
 
-							if (revInfoWereLookingFor == default && model.NewTestMerges.Count > 1)
+							if (revInfoWereLookingFor == default && newTestMergeModels.Count > 1)
 							{
 								// okay try to add at least SOME prs we've seen before
-								var listedNewTestMerges = model.NewTestMerges.ToList();
+								var listedNewTestMerges = newTestMergeModels.ToList();
 
 								var appliedTestMergeIds = new List<long>();
 
-								Models.RevisionInformation lastGoodRevInfo = null;
+								Models.RevisionInformation? lastGoodRevInfo = null;
 								do
 								{
 									foreach (var newTestMergeParameters in listedNewTestMerges)
 									{
-										revInfoWereLookingFor = dbPull
+										revInfoWereLookingFor = dbPull!
 											.Where(testRevInfo =>
 											{
 												if (testRevInfo.PrimaryTestMerge == null)
 													return false;
 
-												var testMergeMatch = model.NewTestMerges.Any(testTestMerge =>
+												var testMergeMatch = newTestMergeModels.Any(testTestMerge =>
 												{
 													var numberMatch = testRevInfo.PrimaryTestMerge.Number == testTestMerge.Number;
 													if (!numberMatch)
 														return false;
 
-													var shaMatch = testRevInfo.PrimaryTestMerge.TargetCommitSha.StartsWith(
-														testTestMerge.TargetCommitSha,
+													var shaMatch = testRevInfo.PrimaryTestMerge.TargetCommitSha!.StartsWith(
+														testTestMerge.TargetCommitSha!,
 														StringComparison.Ordinal);
 													if (!shaMatch)
 														return false;
@@ -453,7 +458,7 @@ namespace Tgstation.Server.Host.Components.Repository
 													return false;
 
 												var previousTestMergesMatch = testRevInfo
-													.ActiveTestMerges
+													.ActiveTestMerges!
 													.Select(previousRevInfoTestMerge => previousRevInfoTestMerge.TestMerge)
 													.All(previousTestMerge => appliedTestMergeIds.Contains(previousTestMerge.Id));
 
@@ -464,7 +469,7 @@ namespace Tgstation.Server.Host.Components.Repository
 										if (revInfoWereLookingFor != null)
 										{
 											lastGoodRevInfo = revInfoWereLookingFor;
-											appliedTestMergeIds.Add(revInfoWereLookingFor.PrimaryTestMerge.Id);
+											appliedTestMergeIds.Add(revInfoWereLookingFor.PrimaryTestMerge!.Id);
 											listedNewTestMerges.Remove(newTestMergeParameters);
 											break;
 										}
@@ -485,16 +490,17 @@ namespace Tgstation.Server.Host.Components.Repository
 					if (revInfoWereLookingFor != null)
 					{
 						// goteem
-						logger.LogDebug("Reusing existing SHA {sha}...", revInfoWereLookingFor.CommitSha);
-						await repo.ResetToSha(revInfoWereLookingFor.CommitSha, NextProgressReporter($"Reset to {revInfoWereLookingFor.CommitSha[..7]}"), cancellationToken);
+						var commitSha = revInfoWereLookingFor.CommitSha!;
+						logger.LogDebug("Reusing existing SHA {sha}...", commitSha);
+						await repo.ResetToSha(commitSha, NextProgressReporter($"Reset to {commitSha[..7]}"), cancellationToken);
 						lastRevisionInfo = revInfoWereLookingFor;
 					}
 
 					if (needToApplyRemainingPrs)
 					{
-						foreach (var newTestMerge in model.NewTestMerges)
+						foreach (var newTestMerge in newTestMergeModels)
 						{
-							if (lastRevisionInfo.ActiveTestMerges.Any(x => x.TestMerge.Number == newTestMerge.Number))
+							if (lastRevisionInfo.ActiveTestMerges!.Any(x => x.TestMerge.Number == newTestMerge.Number))
 								throw new JobException(ErrorCode.RepoDuplicateTestMerge);
 
 							var fullTestMergeTask = repo.GetTestMerge(newTestMerge, currentModel, cancellationToken);
@@ -502,7 +508,7 @@ namespace Tgstation.Server.Host.Components.Repository
 							var mergeResult = await repo.AddTestMerge(
 								newTestMerge,
 								committerName,
-								currentModel.CommitterEmail,
+								currentModel.CommitterEmail!,
 								currentModel.AccessUser,
 								currentModel.AccessToken,
 								updateSubmodules,
@@ -513,7 +519,7 @@ namespace Tgstation.Server.Host.Components.Repository
 								throw new JobException(
 									ErrorCode.RepoTestMergeConflict,
 									new JobException(
-										$"Test Merge #{newTestMerge.Number} at {newTestMerge.TargetCommitSha[..7]} conflicted! Conflicting files:{Environment.NewLine}{String.Join(Environment.NewLine, mergeResult.ConflictingFiles.Select(file => $"\t- /{file}"))}"));
+										$"Test Merge #{newTestMerge.Number} at {newTestMerge.TargetCommitSha![..7]} conflicted! Conflicting files:{Environment.NewLine}{String.Join(Environment.NewLine, mergeResult.ConflictingFiles!.Select(file => $"\t- /{file}"))}"));
 
 							Models.TestMerge fullTestMerge;
 							try
@@ -544,14 +550,14 @@ namespace Tgstation.Server.Host.Components.Repository
 				}
 
 				var currentHead = repo.Head;
-				if (currentModel.PushTestMergeCommits.Value && (startSha != currentHead || (postUpdateSha != null && postUpdateSha != currentHead)))
+				if (currentModel.PushTestMergeCommits!.Value && (startSha != currentHead || (postUpdateSha != null && postUpdateSha != currentHead)))
 				{
-					await repo.Sychronize(
+					await repo.Synchronize(
 						NextProgressReporter("Synchronize"),
 						currentModel.AccessUser,
 						currentModel.AccessToken,
-						currentModel.CommitterName,
-						currentModel.CommitterEmail,
+						currentModel.CommitterName!,
+						currentModel.CommitterEmail!,
 						false,
 						false,
 						cancellationToken);

src/Tgstation.Server.Host/Components/Repository/TestMergeResult.cs

@@ -17,6 +17,6 @@ namespace Tgstation.Server.Host.Components.Repository
 		/// <summary>
 		/// List of conflicting file paths relative to the repository root. Only present if <see cref="Status"/> is <see cref="MergeStatus.Conflicts"/>.
 		/// </summary>
-		public IReadOnlyList<string> ConflictingFiles { get; init; }
+		public IReadOnlyList<string>? ConflictingFiles { get; init; }
 	}
 }

src/Tgstation.Server.Host/Components/Session/CombinedTopicResponse.cs

@@ -5,26 +5,26 @@ using Tgstation.Server.Host.Components.Interop.Topic;
 namespace Tgstation.Server.Host.Components.Session
 {
 	/// <summary>
-	/// Combines a <see cref="global::Byond.TopicSender.TopicResponse"/> with a <see cref="TopicResponse"/>.
+	/// Combines a <see cref="Byond.TopicSender.TopicResponse"/> with a <see cref="TopicResponse"/>.
 	/// </summary>
 	sealed class CombinedTopicResponse
 	{
 		/// <summary>
-		/// The raw <see cref="global::Byond.TopicSender.TopicResponse"/>.
+		/// The raw <see cref="Byond.TopicSender.TopicResponse"/>.
 		/// </summary>
-		public global::Byond.TopicSender.TopicResponse ByondTopicResponse { get; }
+		public Byond.TopicSender.TopicResponse ByondTopicResponse { get; }
 
 		/// <summary>
 		/// The interop <see cref="TopicResponse"/>, if any.
 		/// </summary>
-		public TopicResponse InteropResponse { get; }
+		public TopicResponse? InteropResponse { get; }
 
 		/// <summary>
 		/// Initializes a new instance of the <see cref="CombinedTopicResponse"/> class.
 		/// </summary>
 		/// <param name="byondTopicResponse">The value of <see cref="ByondTopicResponse"/>.</param>
 		/// <param name="interopResponse">The optional value of <see cref="InteropResponse"/>.</param>
-		public CombinedTopicResponse(global::Byond.TopicSender.TopicResponse byondTopicResponse, TopicResponse interopResponse)
+		public CombinedTopicResponse(Byond.TopicSender.TopicResponse byondTopicResponse, TopicResponse? interopResponse)
 		{
 			ByondTopicResponse = byondTopicResponse ?? throw new ArgumentNullException(nameof(byondTopicResponse));
 			InteropResponse = interopResponse;

src/Tgstation.Server.Host/Components/Session/ISessionController.cs

@@ -32,7 +32,7 @@ namespace Tgstation.Server.Host.Components.Session
 		/// <summary>
 		/// The DMAPI <see cref="Version"/>.
 		/// </summary>
-		Version DMApiVersion { get; }
+		Version? DMApiVersion { get; }
 
 		/// <summary>
 		/// Gets the <see cref="CompileJob"/> associated with the <see cref="ISessionController"/>.
@@ -96,7 +96,7 @@ namespace Tgstation.Server.Host.Components.Session
 		/// <param name="parameters">The <see cref="TopicParameters"/> to send.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in the <see cref="TopicResponse"/> of /world/Topic().</returns>
-		ValueTask<TopicResponse> SendCommand(TopicParameters parameters, CancellationToken cancellationToken);
+		ValueTask<TopicResponse?> SendCommand(TopicParameters parameters, CancellationToken cancellationToken);
 
 		/// <summary>
 		/// Attempts to change the current <see cref="RebootState"/> to <paramref name="newRebootState"/>.

src/Tgstation.Server.Host/Components/Session/ISessionControllerFactory.cs

@@ -16,14 +16,14 @@ namespace Tgstation.Server.Host.Components.Session
 		/// Create a <see cref="ISessionController"/> from a freshly launch DreamDaemon instance.
 		/// </summary>
 		/// <param name="dmbProvider">The <see cref="IDmbProvider"/> to use.</param>
-		/// <param name="currentByondLock">The current <see cref="IEngineExecutableLock"/> if any.</param>
+		/// <param name="currentByondLock">The current <see cref="IEngineExecutableLock"/>. if any.</param>
 		/// <param name="launchParameters">The <see cref="DreamDaemonLaunchParameters"/> to use. <see cref="DreamDaemonLaunchParameters.SecurityLevel"/> will be updated with the minumum required security level for the launch.</param>
 		/// <param name="apiValidate">If the <see cref="ISessionController"/> should only validate the DMAPI then exit.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in a new <see cref="ISessionController"/>.</returns>
 		ValueTask<ISessionController> LaunchNew(
 			IDmbProvider dmbProvider,
-			IEngineExecutableLock currentByondLock,
+			IEngineExecutableLock? currentByondLock,
 			DreamDaemonLaunchParameters launchParameters,
 			bool apiValidate,
 			CancellationToken cancellationToken);
@@ -34,7 +34,7 @@ namespace Tgstation.Server.Host.Components.Session
 		/// <param name="reattachInformation">The <see cref="ReattachInformation"/> to use.</param>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in a new <see cref="ISessionController"/> on success or <see langword="null"/> on failure to reattach.</returns>
-		ValueTask<ISessionController> Reattach(
+		ValueTask<ISessionController?> Reattach(
 			ReattachInformation reattachInformation,
 			CancellationToken cancellationToken);
 	}

src/Tgstation.Server.Host/Components/Session/ISessionPersistor.cs

@@ -29,7 +29,7 @@ namespace Tgstation.Server.Host.Components.Session
 		/// </summary>
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
 		/// <returns>A <see cref="ValueTask{TResult}"/> resulting in the stored <see cref="ReattachInformation"/> if any.</returns>
-		ValueTask<ReattachInformation> Load(CancellationToken cancellationToken);
+		ValueTask<ReattachInformation?> Load(CancellationToken cancellationToken);
 
 		/// <summary>
 		/// Clear any stored <see cref="ReattachInformation"/>.