From 639075af1efef88dcd03ed2f1aac85ecafac33e8 Mon Sep 17 00:00:00 2001
From: Jordan Brown <Cyberboss@users.noreply.github.com>
Date: Sun, 2 Oct 2022 14:08:37 -0400
Subject: [PATCH] Fix hashing on write of 0-length files

---
 .../IO/SynchronousIOManager.cs                      | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/Tgstation.Server.Host/IO/SynchronousIOManager.cs b/src/Tgstation.Server.Host/IO/SynchronousIOManager.cs
index 9d474a474f..a3e04375c1 100644
--- a/src/Tgstation.Server.Host/IO/SynchronousIOManager.cs
+++ b/src/Tgstation.Server.Host/IO/SynchronousIOManager.cs
@@ -97,7 +97,18 @@ namespace Tgstation.Server.Host.IO
 				// suppressed due to only using for consistency checks
 				using (var sha1 = SHA1.Create())
 				{
-					string GetSha1(Stream dataToHash) => dataToHash != null && dataToHash.Length != 0 ? String.Join(String.Empty, sha1.ComputeHash(dataToHash).Select(b => b.ToString("x2", CultureInfo.InvariantCulture))) : null;
+					string GetSha1(Stream dataToHash)
+					{
+						if (dataToHash == null)
+							return null;
+
+						byte[] sha1Computed = dataToHash.Length != 0
+							? sha1.ComputeHash(dataToHash)
+							: sha1.ComputeHash(Array.Empty<byte>());
+
+						return String.Join(String.Empty, sha1Computed.Select(b => b.ToString("x2", CultureInfo.InvariantCulture)));
+					}
+
 					var originalSha1 = GetSha1(file);
 					if (originalSha1 != sha1InOut)
 					{