Base implementation of /datum/persistent_client (#89449)

## About The Pull Request
Converts `/datum/player_details` into `/datum/persistent_client`.
Persistent Clients persist across connections. The only time a mob's
persistent client will change is if the ckey it's bound to logs into a
different mob, or the mob is deleted (duh).

Also adds PossessByPlayer() so that transfering mob control is cleaner
and makes more immediate sense if you don't know byond-fu.

## Why It's Good For The Game
Clients are an abstract representation of a connection that can be
dropped at almost any moment so putting things that should be stable to
access at any time onto an undying object is ideal. This allows for
future expansions like abstracting away client.screen and managing
everything cleanly.

code/__DEFINES/_helpers.dm

@@ -49,3 +49,6 @@
 /// A null statement to guard against EmptyBlock lint without necessitating the use of pass()
 /// Used to avoid proc-call overhead. But use sparingly. Probably pointless in most places.
 #define EMPTY_BLOCK_GUARD ;
+
+/// Abstraction over using mob.client to just check if there's a connected player.
+#define HAS_CONNECTED_PLAYER(mob) (mob.client)

code/__HELPERS/game.dm

@@ -184,7 +184,7 @@
 
 	ghost_player.client.prefs.safe_transfer_prefs_to(new_character)
 	new_character.dna.update_dna_identity()
-	new_character.key = ghost_player.key
+	new_character.PossessByPlayer(ghost_player.ckey)
 
 	return new_character
 

code/__HELPERS/logging/mob.dm

@@ -18,11 +18,10 @@
 
 	// Cannot use the list as a map if the key is a number, so we stringify it (thank you BYOND)
 	var/smessage_type = num2text(message_type, MAX_BITFLAG_DIGITS)
-	var/datum/player_details/client_details = client?.player_details
 
-	if(!isnull(client_details))
-		if(!islist(client_details.logging[smessage_type]))
-			client_details.logging[smessage_type] = list()
+	if(HAS_CONNECTED_PLAYER(src))
+		if(!islist(persistent_client.logging[smessage_type]))
+			persistent_client.logging[smessage_type] = list()
 
 	if(!islist(logging[smessage_type]))
 		logging[smessage_type] = list()
@@ -51,7 +50,7 @@
 
 	logging[smessage_type] += timestamped_message
 
-	if(client)
-		client.player_details.logging[smessage_type] += timestamped_message
+	if(HAS_CONNECTED_PLAYER(src))
+		persistent_client.logging[smessage_type] += timestamped_message
 
 	..()

code/__HELPERS/roundend.dm

@@ -661,7 +661,7 @@ GLOBAL_LIST_INIT(achievements_unlocked, list())
 
 /datum/controller/subsystem/ticker/proc/give_show_report_button(client/C)
 	var/datum/action/report/R = new
-	C.player_details.player_actions += R
+	C.persistent_client.player_actions += R
 	R.Grant(C.mob)
 	to_chat(C,span_infoplain("<a href='byond://?src=[REF(R)];report=1'>Show roundend report again</a>"))
 

code/controllers/subsystem/achievements.dm

@@ -59,10 +59,9 @@ SUBSYSTEM_DEF(achievements)
 				most_unlocked_achievement = instance
 	qdel(query)
 
-	for(var/i in GLOB.clients)
-		var/client/C = i
-		if(!C.player_details.achievements.initialized)
-			C.player_details.achievements.InitializeData()
+	for(var/client/C in GLOB.clients)
+		if(!C.persistent_client.achievements.initialized)
+			C.persistent_client.achievements.InitializeData()
 
 	return SS_INIT_SUCCESS
 
@@ -71,11 +70,12 @@ SUBSYSTEM_DEF(achievements)
 
 /datum/controller/subsystem/achievements/proc/save_achievements_to_db()
 	var/list/cheevos_to_save = list()
-	for(var/ckey in GLOB.player_details)
-		var/datum/player_details/PD = GLOB.player_details[ckey]
+	for(var/ckey in GLOB.persistent_clients_by_ckey)
+		var/datum/persistent_client/PD = GLOB.persistent_clients_by_ckey[ckey]
 		if(!PD || !PD.achievements)
 			continue
 		cheevos_to_save += PD.achievements.get_changed_data()
+
 	if(!length(cheevos_to_save))
 		return
 	SSdbcore.MassInsert(format_table_name("achievements"), cheevos_to_save, duplicate_key = TRUE)

code/controllers/subsystem/blackbox.dm

@@ -86,9 +86,8 @@ SUBSYSTEM_DEF(blackbox)
 		if (MS.rc_msgs.len)
 			record_feedback("tally", "radio_usage", MS.rc_msgs.len, "request console")
 
-	for(var/player_key in GLOB.player_details)
-		var/datum/player_details/PD = GLOB.player_details[player_key]
-		record_feedback("tally", "client_byond_version", 1, PD.full_byond_version())
+	for(var/datum/persistent_client/PC as anything in GLOB.persistent_clients)
+		record_feedback("tally", "client_byond_version", 1, PC.full_byond_version())
 
 /datum/controller/subsystem/blackbox/Shutdown()
 	sealed = FALSE

code/controllers/subsystem/dynamic/dynamic_rulesets_midround.dm

@@ -538,7 +538,7 @@
 /datum/dynamic_ruleset/midround/from_ghosts/xenomorph/generate_ruleset_body(mob/applicant)
 	var/obj/vent = pick_n_take(vents)
 	var/mob/living/carbon/alien/larva/new_xeno = new(vent.loc)
-	new_xeno.key = applicant.key
+	new_xeno.PossessByPlayer(applicant.ckey)
 	new_xeno.move_into_vent(vent)
 	message_admins("[ADMIN_LOOKUPFLW(new_xeno)] has been made into an alien by the midround ruleset.")
 	log_dynamic("[key_name(new_xeno)] was spawned as an alien by the midround ruleset.")
@@ -696,7 +696,7 @@
 
 /datum/dynamic_ruleset/midround/from_ghosts/space_ninja/generate_ruleset_body(mob/applicant)
 	var/mob/living/carbon/human/ninja = create_space_ninja(pick(spawn_locs))
-	ninja.key = applicant.key
+	ninja.PossessByPlayer(applicant.ckey)
 	ninja.mind.add_antag_datum(/datum/antagonist/ninja)
 
 	message_admins("[ADMIN_LOOKUPFLW(ninja)] has been made into a Space Ninja by the midround ruleset.")
@@ -769,7 +769,7 @@
 
 /datum/dynamic_ruleset/midround/from_ghosts/revenant/generate_ruleset_body(mob/applicant)
 	var/mob/living/basic/revenant/revenant = new(pick(spawn_locs))
-	revenant.key = applicant.key
+	revenant.PossessByPlayer(applicant.ckey)
 	message_admins("[ADMIN_LOOKUPFLW(revenant)] has been made into a revenant by the midround ruleset.")
 	log_game("[key_name(revenant)] was spawned as a revenant by the midround ruleset.")
 	return revenant

code/controllers/subsystem/vote.dm

@@ -240,7 +240,7 @@ SUBSYSTEM_DEF(vote)
 		voting_action.name = "Vote: [current_vote.override_question || current_vote.name]"
 		voting_action.Grant(new_voter.mob)
 
-		new_voter.player_details.player_actions += voting_action
+		new_voter.persistent_client.player_actions += voting_action
 		generated_actions += voting_action
 		if(current_vote.vote_sound && new_voter.prefs.read_preference(/datum/preference/toggle/sound_announcements))
 			SEND_SOUND(new_voter, sound(current_vote.vote_sound))
@@ -472,12 +472,12 @@ SUBSYSTEM_DEF(vote)
 
 // We also need to remove our action from the player actions when we're cleaning up.
 /datum/action/vote/Remove(mob/removed_from)
-	if(removed_from.client)
-		removed_from.client?.player_details.player_actions -= src
+	if(removed_from.persistent_client)
+		removed_from.persistent_client.player_actions -= src
 
 	else if(removed_from.ckey)
-		var/datum/player_details/associated_details = GLOB.player_details[removed_from.ckey]
-		associated_details?.player_actions -= src
+		var/datum/persistent_client/persistent_client = GLOB.persistent_clients_by_ckey[removed_from.ckey]
+		persistent_client?.player_actions -= src
 
 	return ..()
 

code/datums/achievements/_achievement_data.dm

@@ -131,4 +131,4 @@
 	set name = "Check achievements"
 	set desc = "See all of your achievements!"
 
-	player_details.achievements.ui_interact(usr)
+	persistent_client.achievements.ui_interact(usr)

code/datums/achievements/misc_scores.dm

@@ -37,14 +37,16 @@
 
 /datum/award/score/progress/fish/proc/validate_early_joiners(datum/source)
 	for(var/client/client as anything in GLOB.clients)
-		var/datum/achievement_data/holder = client.player_details.achievements
+		var/datum/achievement_data/holder = client.persistent_client.achievements
 		if(!holder?.initialized)
 			continue
+
 		var/list/entries = holder.data[/datum/award/score/progress/fish]
 		var/list_copied = FALSE
 		for(var/fish_id in entries)
 			if(SSfishing.catchable_fish[fish_id])
 				continue
+
 			//make a new list, unbound from the cached awards data, so that the score can be updated at the end of the round.
 			if(!list_copied)
 				entries = entries.Copy()

code/datums/brain_damage/imaginary_friend.dm

@@ -69,7 +69,7 @@
 		qdel(src)
 		return
 
-	friend.key = ghost.key
+	friend.PossessByPlayer(ghost.ckey)
 	friend.attach_to_owner(owner)
 	friend.setup_appearance()
 	friend_initialized = TRUE

code/datums/brain_damage/split_personality.dm

@@ -56,7 +56,7 @@
 		qdel(src)
 		return
 
-	stranger_backseat.key = ghost.key
+	stranger_backseat.PossessByPlayer(ghost.ckey)
 	stranger_backseat.log_message("became [key_name(owner)]'s split personality.", LOG_GAME)
 	message_admins("[ADMIN_LOOKUPFLW(stranger_backseat)] became [ADMIN_LOOKUPFLW(owner)]'s split personality.")
 
@@ -222,7 +222,7 @@
 	set waitfor = FALSE
 	var/mob/chosen_one = SSpolling.poll_ghosts_for_target("Do you want to play as [span_danger("[owner.real_name]'s")] brainwashed mind?", poll_time = 7.5 SECONDS, checked_target = stranger_backseat, alert_pic = owner, role_name_text = "brainwashed mind")
 	if(chosen_one)
-		stranger_backseat.key = chosen_one.key
+		stranger_backseat.PossessByPlayer(chosen_one.ckey)
 	else
 		qdel(src)
 

code/datums/components/ghost_direct_control.dm

@@ -145,7 +145,7 @@
 
 	harbinger.log_message("took control of [new_body].", LOG_GAME)
 	// doesn't transfer mind because that transfers antag datum as well
-	new_body.key = harbinger.key
+	new_body.PossessByPlayer(harbinger.ckey)
 
 	// Already qdels due to below proc but just in case
 	qdel(src)

code/datums/components/ghostrole_on_revive.dm

@@ -101,7 +101,7 @@
 			aliver.death()
 			aliver.visible_message(span_deadsay("[aliver.name]'s soul is struggling to return!"))
 	else
-		aliver.key = chosen_one.key
+		aliver.PossessByPlayer(chosen_one.ckey)
 		on_successful_revive?.Invoke(aliver)
 		qdel(src)
 

code/datums/diseases/transformation.dm

@@ -74,7 +74,7 @@
 			if(affected_mob.mind)
 				affected_mob.mind.transfer_to(new_mob)
 			else
-				new_mob.key = affected_mob.key
+				new_mob.PossessByPlayer(affected_mob.ckey)
 		if(transformed_antag_datum)
 			new_mob.mind.add_antag_datum(transformed_antag_datum)
 		new_mob.name = affected_mob.real_name
@@ -89,14 +89,13 @@
 		to_chat(affected_mob, span_userdanger("Your mob has been taken over by a ghost! Appeal your job ban if you want to avoid this in the future!"))
 		message_admins("[key_name_admin(chosen_one)] has taken control of ([key_name_admin(affected_mob)]) to replace a jobbanned player.")
 		affected_mob.ghostize(FALSE)
-		affected_mob.key = chosen_one.key
+		affected_mob.PossessByPlayer(chosen_one.ckey)
 	else
 		to_chat(new_mob, span_userdanger("Your mob has been claimed by death! Appeal your job ban if you want to avoid this in the future!"))
 		new_mob.investigate_log("has been killed because there was no one to replace them as a job-banned player.", INVESTIGATE_DEATHS)
 		new_mob.death()
 		if (!QDELETED(new_mob))
 			new_mob.ghostize(can_reenter_corpse = FALSE)
-			new_mob.key = null
 
 /datum/disease/transformation/jungle_flu
 	name = "Jungle Flu"

code/datums/mind/_mind.dm

@@ -205,7 +205,7 @@
 
 	RegisterSignal(new_character, COMSIG_LIVING_DEATH, PROC_REF(set_death_time))
 	if(active || force_key_move)
-		new_character.key = key //now transfer the key to link the client to our new body
+		new_character.PossessByPlayer(key) //now transfer the key to link the client to our new body
 	if(new_character.client)
 		LAZYCLEARLIST(new_character.client.recent_examines)
 		new_character.client.init_verbs() // re-initialize character specific verbs

code/game/objects/effects/anomalies/anomalies_ectoplasm.dm

@@ -183,7 +183,7 @@
 		var/mob/living/basic/ghost/swarm/new_ghost = new(get_turf(src))
 		ghosts_spawned += new_ghost
 		new_ghost.ghostize(FALSE)
-		new_ghost.key = candidate_ghost.key
+		new_ghost.PossessByPlayer(candidate_ghost.key)
 		var/policy = get_policy(ROLE_ANOMALY_GHOST)
 		if(policy)
 			to_chat(new_ghost, policy)

code/game/objects/effects/anomalies/anomalies_pyroclastic.dm

@@ -53,7 +53,7 @@
 	// Failed to find a player, or somehow detonated prematurely
 	if(isnull(chosen_one))
 		return
-	pyro.key = chosen_one.key
+	pyro.PossessByPlayer(chosen_one.key)
 	pyro.mind.special_role = ROLE_PYROCLASTIC_SLIME
 	pyro.mind.add_antag_datum(/datum/antagonist/pyro_slime)
 	pyro.log_message("was made into a slime by pyroclastic anomaly", LOG_GAME)

code/game/objects/items/dice.dm

@@ -432,7 +432,7 @@
 			var/mob/chosen_one = SSpolling.poll_ghosts_for_target("Do you want to play as [span_danger("[user.real_name]'s")] [span_notice("Servant")]?", check_jobban = ROLE_WIZARD, role = ROLE_WIZARD, poll_time = 5 SECONDS, checked_target = human_servant, alert_pic = user, role_name_text = "dice servant")
 			if(chosen_one)
 				message_admins("[ADMIN_LOOKUPFLW(chosen_one)] was spawned as Dice Servant")
-				human_servant.key = chosen_one.key
+				human_servant.PossessByPlayer(chosen_one.key)
 
 			human_servant.equipOutfit(/datum/outfit/butler)
 			var/datum/mind/servant_mind = new /datum/mind()

code/modules/admin/admin.dm

@@ -286,7 +286,7 @@ ADMIN_VERB(create_or_modify_area, R_DEBUG, "Create Or Modify Area", "Create of m
 	log_admin("[key_name(usr)] stuffed [frommob.key] into [tomob.name].")
 	BLACKBOX_LOG_ADMIN_VERB("Ghost Drag Control")
 
-	tomob.key = frommob.key
+	tomob.PossessByPlayer(frommob.key)
 	tomob.client?.init_verbs()
 	qdel(frommob)
 

code/modules/admin/fun_balloon.dm

@@ -112,7 +112,7 @@
 
 		message_admins("[key_name_admin(C)] has taken control of ([key_name_admin(body)])")
 		body.ghostize(FALSE)
-		body.key = C.key
+		body.PossessByPlayer(C.key)
 		if (make_antag)
 			body.mind.add_antag_datum(antag_type)
 			continue

code/modules/admin/player_panel.dm

@@ -283,9 +283,8 @@
 				M_rname_as_key = null
 
 			var/previous_names_string = ""
-			var/datum/player_details/readable = GLOB.player_details[M.ckey]
-			if(readable)
-				previous_names_string = readable.get_played_names()
+			if(M.persistent_client)
+				previous_names_string = M.persistent_client.get_played_names()
 
 			//output for each mob
 			dat += {"

code/modules/admin/verbs/admingame.dm

@@ -62,11 +62,10 @@ ADMIN_VERB_ONLY_CONTEXT_MENU(show_player_panel, R_ADMIN, "Show Player Panel", mo
 
 	body += "<b>Mob type</b> = [player.type]<br><br>"
 
-	if(player.client)
+	if(HAS_CONNECTED_PLAYER(player))
 		body += "<b>Old names:</b> "
-		var/datum/player_details/deets = GLOB.player_details[player.ckey]
-		if(deets)
-			body += deets.get_played_names()
+		if(player.persistent_client)
+			body += player.persistent_client.get_played_names()
 		else
 			body += "<i>None?!</i>"
 		body += "<br><br>"
@@ -196,7 +195,7 @@ ADMIN_VERB(respawn_character, R_ADMIN, "Respawn Character", "Respawn a player th
 				var/mob/living/carbon/human/species/monkey/new_monkey = new
 				SSjob.send_to_late_join(new_monkey)
 				G_found.mind.transfer_to(new_monkey) //be careful when doing stuff like this! I've already checked the mind isn't in use
-				new_monkey.key = G_found.key
+				new_monkey.PossessByPlayer(G_found.key)
 				to_chat(new_monkey, "You have been fully respawned. Enjoy the game.", confidential = TRUE)
 				var/msg = span_adminnotice("[key_name_admin(user)] has respawned [new_monkey.key] as a filthy monkey.")
 				message_admins(msg)
@@ -231,7 +230,7 @@ ADMIN_VERB(respawn_character, R_ADMIN, "Respawn Character", "Respawn a player th
 	if(is_unassigned_job(new_character.mind.assigned_role))
 		new_character.mind.set_assigned_role(SSjob.get_job_type(SSjob.overflow_role))
 
-	new_character.key = G_found.key
+	new_character.PossessByPlayer(G_found.key)
 
 	/*
 	The code below functions with the assumption that the mob is already a traitor if they have a special role.

code/modules/admin/verbs/debug.dm

@@ -167,7 +167,9 @@ ADMIN_VERB(cmd_assume_direct_control, R_ADMIN, "Assume Direct Control", "Assume
 	var/mob/adminmob = user.mob
 	if(M.ckey)
 		M.ghostize(FALSE)
-	M.key = user.key
+
+	M.PossessByPlayer(user.key)
+
 	user.init_verbs()
 	if(isobserver(adminmob))
 		qdel(adminmob)

code/modules/admin/verbs/ert.dm

@@ -174,7 +174,7 @@
 				var/chosen_outfit = usr.client?.prefs?.read_preference(/datum/preference/choiced/brief_outfit)
 				usr.client.prefs.safe_transfer_prefs_to(admin_officer, is_antag = TRUE)
 				admin_officer.equipOutfit(chosen_outfit)
-				admin_officer.key = usr.key
+				admin_officer.PossessByPlayer(usr.key)
 
 			else
 				to_chat(usr, span_warning("Could not spawn you in as briefing officer as you are not a ghost!"))
@@ -232,7 +232,7 @@
 			else
 				ert_operative = new /mob/living/carbon/human(spawnloc)
 				chosen_candidate.client.prefs.safe_transfer_prefs_to(ert_operative, is_antag = TRUE)
-			ert_operative.key = chosen_candidate.key
+			ert_operative.PossessByPlayer(chosen_candidate.key)
 
 			if(ertemplate.enforce_human || !(ert_operative.dna.species.changesource_flags & ERT_SPAWN))
 				ert_operative.set_species(/datum/species/human)

code/modules/admin/verbs/individual_logging.dm

@@ -48,10 +48,9 @@
 	dat += "<hr style='background:#000000; border:0; height:1px'>"
 
 	var/log_source = M.logging
-	if(source == LOGSRC_CKEY && M.ckey)
-		var/datum/player_details/details = GLOB.player_details[M.ckey]
-		if(details) //we dont want to runtime if an admin aghosted
-			log_source = details.logging
+	if(source == LOGSRC_CKEY && M.persistent_client)
+		log_source = M.persistent_client.logging
+
 	var/list/concatenated_logs = list()
 	for(var/log_type in log_source)
 		var/nlog_type = text2num(log_type)
@@ -59,6 +58,7 @@
 			var/list/all_the_entrys = log_source[log_type]
 			for(var/entry in all_the_entrys)
 				concatenated_logs += "<b>[entry]</b><br>[all_the_entrys[entry]]"
+
 	if(length(concatenated_logs))
 		sortTim(concatenated_logs, cmp = GLOBAL_PROC_REF(cmp_text_dsc)) //Sort by timestamp.
 		dat += "<font size=2px>"

code/modules/admin/verbs/secrets.dm

@@ -639,7 +639,7 @@ ADMIN_VERB(secrets, R_NONE, "Secrets", "Abuse harder than you ever have before w
 				chosen_candidate = pick(candidates)
 				candidates -= chosen_candidate
 				nerd = new /mob/living/basic/drone/classic(spawnpoint)
-				nerd.key = chosen_candidate.key
+				nerd.PossessByPlayer(chosen_candidate.key)
 				nerd.log_message("has been selected as a Nanotrasen emergency response drone.", LOG_GAME)
 				teamsize--
 
@@ -716,7 +716,7 @@ ADMIN_VERB(secrets, R_NONE, "Secrets", "Abuse harder than you ever have before w
 			var/mob/chosen = players[1]
 			if (chosen.client)
 				chosen.client.prefs.safe_transfer_prefs_to(spawnedMob, is_antag = TRUE)
-				spawnedMob.key = chosen.key
+				spawnedMob.PossessByPlayer(chosen.key)
 			players -= chosen
 		if (ishuman(spawnedMob) && ispath(humanoutfit, /datum/outfit))
 			var/mob/living/carbon/human/H = spawnedMob

code/modules/antagonists/_common/antag_datum.dm

@@ -306,7 +306,7 @@ GLOBAL_LIST_EMPTY(antagonists)
 		message_admins("[key_name_admin(chosen_one)] has taken control of ([key_name_admin(owner)]) to replace antagonist banned player.")
 		log_game("[key_name(chosen_one)] has taken control of ([key_name(owner)]) to replace antagonist banned player.")
 		owner.current.ghostize(FALSE)
-		owner.current.key = chosen_one.key
+		owner.current.PossessByPlayer(chosen_one.key)
 	else
 		log_game("Couldn't find antagonist ban replacement for ([key_name(owner)]).")
 

code/modules/antagonists/_common/antag_spawner.dm

@@ -76,7 +76,7 @@
 	new /obj/effect/particle_effect/fluid/smoke(T)
 	var/mob/living/carbon/human/M = new/mob/living/carbon/human(T)
 	C.prefs.safe_transfer_prefs_to(M, is_antag = TRUE)
-	M.key = C.key
+	M.PossessByPlayer(C.key)
 	var/datum/mind/app_mind = M.mind
 
 	var/datum/antagonist/wizard/apprentice/app = new()
@@ -247,7 +247,7 @@
 	borg.mmi.brainmob.name = brainopsname
 	borg.real_name = borg.name
 
-	borg.key = C.key
+	borg.PossessByPlayer(C.key)
 
 	borg.mind.add_antag_datum(antag_datum, creator_op ? creator_op.get_team() : null)
 	borg.mind.special_role = special_role_name
@@ -290,7 +290,7 @@
 	var/mob/living/basic/demon/spawned = new demon_type(T)
 	new /obj/effect/dummy/phased_mob(T, spawned)
 
-	spawned.key = C.key
+	spawned.PossessByPlayer(C.key)
 
 /obj/item/antag_spawner/slaughter_demon/laughter
 	name = "vial of tickles"

code/modules/antagonists/changeling/headslug_eggs.dm

@@ -33,7 +33,7 @@
 
 	if(origin && (origin.current ? (origin.current.stat == DEAD) : origin.get_ghost()))
 		origin.transfer_to(spawned_monkey)
-		spawned_monkey.key = origin.key
+		spawned_monkey.PossessByPlayer(origin.key)
 		var/datum/antagonist/changeling/changeling_datum = origin.has_antag_datum(/datum/antagonist/changeling)
 		if(!changeling_datum)
 			changeling_datum = origin.add_antag_datum(/datum/antagonist/changeling/headslug)

code/modules/antagonists/cult/cult_items.dm

@@ -371,7 +371,7 @@ Striking a noncultist, however, will tear their flesh."}
 
 	// Get the heretic's new body and antag datum.
 	trapped_entity = trapped_mind?.current
-	trapped_entity.key = trapped_mind?.key
+	trapped_entity.PossessByPlayer(trapped_mind?.key)
 	var/datum/antagonist/heretic/heretic_holder = GET_HERETIC(trapped_entity)
 	if(!heretic_holder)
 		stack_trace("[soul_to_bind] in but not a heretic on the heretic soul blade.")

code/modules/antagonists/cult/runes.dm

@@ -771,7 +771,7 @@ GLOBAL_VAR_INIT(narsie_summon_count, 0)
 			to_chat(mob_to_revive.mind, "Your physical form has been taken over by another soul due to your inactivity! Ahelp if you wish to regain your form.")
 			message_admins("[key_name_admin(chosen_one)] has taken control of ([key_name_admin(mob_to_revive)]) to replace an AFK player.")
 			mob_to_revive.ghostize(FALSE)
-			mob_to_revive.key = chosen_one.key
+			mob_to_revive.PossessByPlayer(chosen_one.key)
 		else
 			fail_invoke()
 			return
@@ -1035,7 +1035,7 @@ GLOBAL_VAR_INIT(narsie_summon_count, 0)
 				old_mind = ghost_to_spawn.mind, \
 				old_body = ghost_to_spawn.mind.current, \
 			)
-		new_human.key = ghost_to_spawn.key
+		new_human.PossessByPlayer(ghost_to_spawn.key)
 		var/datum/antagonist/cult/created_cultist = new_human.mind?.add_antag_datum(/datum/antagonist/cult)
 		created_cultist?.silent = TRUE
 		to_chat(new_human, span_cult_italic("<b>You are a servant of the Geometer. You have been made semi-corporeal by the cult of Nar'Sie, and you are to serve them at all costs.</b>"))

code/modules/antagonists/heretic/heretic_knowledge.dm

@@ -424,7 +424,7 @@
 	summoned.move_resist = initial(summoned.move_resist)
 
 	summoned.ghostize(FALSE)
-	summoned.key = chosen_one.key
+	summoned.PossessByPlayer(chosen_one.key)
 
 	user.log_message("created a [summoned.name], controlled by [key_name(chosen_one)].", LOG_GAME)
 	message_admins("[ADMIN_LOOKUPFLW(user)] created a [summoned.name], [ADMIN_LOOKUPFLW(summoned)].")

code/modules/antagonists/heretic/knowledge/flesh_lore.dm

@@ -167,7 +167,7 @@
 			return FALSE
 		message_admins("[key_name_admin(chosen_one)] has taken control of ([key_name_admin(soon_to_be_ghoul)]) to replace an AFK player.")
 		soon_to_be_ghoul.ghostize(FALSE)
-		soon_to_be_ghoul.key = chosen_one.key
+		soon_to_be_ghoul.PossessByPlayer(chosen_one.key)
 
 	selected_atoms -= soon_to_be_ghoul
 	make_ghoul(user, soon_to_be_ghoul)

code/modules/antagonists/heretic/structures/lock_final.dm

@@ -73,7 +73,7 @@
 			return FALSE
 	var/monster_type = pick(monster_types)
 	var/mob/living/monster = new monster_type(loc)
-	monster.key = user.key
+	monster.PossessByPlayer(user.key)
 	monster.set_name()
 	var/datum/antagonist/heretic_monster/woohoo_free_antag = new(src)
 	monster.mind.add_antag_datum(woohoo_free_antag)

code/modules/antagonists/nukeop/datums/operative_team.dm

@@ -194,7 +194,7 @@
 
 	var/mob/living/carbon/human/nukie = new(spawn_loc)
 	chosen_one.client.prefs.safe_transfer_prefs_to(nukie, is_antag = TRUE)
-	nukie.key = chosen_one.key
+	nukie.PossessByPlayer(chosen_one.key)
 
 	var/datum/antagonist/nukeop/antag_datum = new()
 	antag_datum.send_to_spawnpoint = FALSE

code/modules/antagonists/space_dragon/carp_rift.dm

@@ -265,7 +265,7 @@
 
 	if(!is_listed)
 		ckey_list += user.ckey
-	newcarp.key = user.key
+	newcarp.PossessByPlayer(user.key)
 	newcarp.set_name()
 	var/datum/antagonist/space_carp/carp_antag = new(src)
 	newcarp.mind.add_antag_datum(carp_antag)

code/modules/antagonists/wizard/equipment/soulstone.dm

@@ -392,7 +392,7 @@
 	soulstone_spirit.AddComponent(/datum/component/soulstoned, src)
 	soulstone_spirit.name = "Shade of [victim.real_name]"
 	soulstone_spirit.real_name = "Shade of [victim.real_name]"
-	soulstone_spirit.key = shade_controller.key
+	soulstone_spirit.PossessByPlayer(shade_controller.key)
 	soulstone_spirit.copy_languages(victim, LANGUAGE_MIND)//Copies the old mobs languages into the new mob holder.
 	if(user)
 		soulstone_spirit.copy_languages(user, LANGUAGE_MASTER)
@@ -516,7 +516,7 @@
 		seek_master.Grant(newstruct)
 
 	if (isnull(target.mind))
-		newstruct.key = target.key
+		newstruct.PossessByPlayer(target.key)
 	else
 		target.mind.transfer_to(newstruct, force_key_move = TRUE)
 	var/atom/movable/screen/alert/bloodsense/sense_alert

code/modules/basketball/controller.dm

@@ -198,7 +198,7 @@ GLOBAL_VAR(basketball_game)
 				old_mind = player_client.mob.mind, \
 				old_body = player_client.mob.mind.current, \
 			)
-		baller.key = player_key
+		baller.PossessByPlayer(player_key)
 
 		SEND_SOUND(baller, sound('sound/items/whistle/whistle.ogg', volume=30))
 		if(is_player_referee)

code/modules/bitrunning/components/avatar_connection.dm

@@ -32,7 +32,7 @@
 	server_ref = WEAKREF(server)
 	server.avatar_connection_refs.Add(WEAKREF(src))
 
-	avatar.key = old_body.key
+	avatar.PossessByPlayer(old_body.key)
 	ADD_TRAIT(avatar, TRAIT_NO_MINDSWAP, REF(src)) // do not remove this one
 	ADD_TRAIT(old_body, TRAIT_MIND_TEMPORARILY_GONE, REF(src))
 

code/modules/bitrunning/server/threats.dm

@@ -111,7 +111,7 @@
 	mutation_target.gib(DROP_ALL_REMAINS)
 
 	var/datum/mind/ghost_mind = ghost.mind
-	new_mob.key = ghost.key
+	new_mob.PossessByPlayer(ghost.key)
 
 	if(ghost_mind)
 		new_mob.AddComponent(/datum/component/temporary_body, ghost_mind, ghost_mind.current, TRUE)

code/modules/buildmode/buildmode.dm

@@ -30,7 +30,7 @@
 	holder = c
 	buttons = list()
 	li_cb = CALLBACK(src, PROC_REF(post_login))
-	holder.player_details.post_login_callbacks += li_cb
+	holder.persistent_client.post_login_callbacks += li_cb
 	holder.show_popup_menus = FALSE
 	create_buttons()
 	holder.screen += buttons
@@ -47,7 +47,7 @@
 /datum/buildmode/Destroy()
 	close_switchstates()
 	close_preview()
-	holder.player_details.post_login_callbacks -= li_cb
+	holder.persistent_client.post_login_callbacks -= li_cb
 	li_cb = null
 	holder = null
 	modebutton = null

code/modules/client/client_defines.dm

@@ -138,7 +138,7 @@
 	var/list/credits
 
 	///these persist between logins/logouts during the same round.
-	var/datum/player_details/player_details
+	var/datum/persistent_client/persistent_client
 
 	///Should only be a key-value list of north/south/east/west = atom/movable/screen.
 	var/list/char_render_holders

code/modules/client/client_procs.dm

@@ -249,6 +249,17 @@ GLOBAL_LIST_INIT(blacklisted_builds, list(
 	GLOB.clients += src
 	GLOB.directory[ckey] = src
 
+	var/reconnecting = FALSE
+	if(GLOB.persistent_clients_by_ckey[ckey])
+		reconnecting = TRUE
+		persistent_client = GLOB.persistent_clients_by_ckey[ckey]
+		persistent_client.byond_build = byond_build
+		persistent_client.byond_version = byond_version
+	else
+		persistent_client = new(ckey)
+		persistent_client.byond_build = byond_build
+		persistent_client.byond_version = byond_version
+
 	if(byond_version >= 516)
 		winset(src, null, list("browser-options" = "find,refresh,byondstorage"))
 
@@ -328,18 +339,6 @@ GLOBAL_LIST_INIT(blacklisted_builds, list(
 				else
 					message_admins(span_danger("<B>[message_type]: </B></span><span class='notice'>Connecting player [key_name_admin(src)] has the same [matches] as [joined_player_ckey](no longer logged in)<b>[in_round]</b>. "))
 					log_admin_private("[message_type]: Connecting player [key_name(src)] has the same [matches] as [joined_player_ckey](no longer logged in)[in_round].")
-	var/reconnecting = FALSE
-	if(GLOB.player_details[ckey])
-		reconnecting = TRUE
-		player_details = GLOB.player_details[ckey]
-		player_details.byond_version = byond_version
-		player_details.byond_build = byond_build
-	else
-		player_details = new(ckey)
-		player_details.byond_version = byond_version
-		player_details.byond_build = byond_build
-		GLOB.player_details[ckey] = player_details
-
 
 	. = ..() //calls mob.Login()
 
@@ -586,6 +585,8 @@ GLOBAL_LIST_INIT(blacklisted_builds, list(
 
 	GLOB.clients -= src
 	GLOB.directory -= ckey
+	persistent_client.client = null
+
 	log_access("Logout: [key_name(src)]")
 	GLOB.ahelp_tickets.ClientLogout(src)
 	GLOB.interviews.client_logout(src)
@@ -1040,11 +1041,11 @@ GLOBAL_LIST_INIT(blacklisted_builds, list(
 
 ///Redirect proc that makes it easier to call the unlock achievement proc. Achievement type is the typepath to the award, user is the mob getting the award, and value is an optional variable used for leaderboard value increments
 /client/proc/give_award(achievement_type, mob/user, value = 1)
-	return player_details.achievements.unlock(achievement_type, user, value)
+	return persistent_client.achievements.unlock(achievement_type, user, value)
 
 ///Redirect proc that makes it easier to get the status of an achievement. Achievement type is the typepath to the award.
 /client/proc/get_award_status(achievement_type, mob/user, value = 1)
-	return player_details.achievements.get_achievement_status(achievement_type)
+	return persistent_client.achievements.get_achievement_status(achievement_type)
 
 ///Gives someone hearted status for OOC, from behavior commendations
 /client/proc/adjust_heart(duration = 24 HOURS)

code/modules/client/persistent_client.dm

@@ -1,55 +1,86 @@
 
-///assoc list of ckey -> /datum/player_details
-GLOBAL_LIST_EMPTY_TYPED(player_details, /datum/player_details)
+///assoc list of ckey -> /datum/persistent_client
+GLOBAL_LIST_EMPTY_TYPED(persistent_clients_by_ckey, /datum/persistent_client)
+/// A flat list of all persistent clients, for her looping pleasure.
+GLOBAL_LIST_EMPTY_TYPED(persistent_clients, /datum/persistent_client)
 
 /// Tracks information about a client between log in and log outs
-/datum/player_details
+/datum/persistent_client
+	/// The true client
+	var/client/client
+	/// The mob this persistent client is currently bound to.
+	var/mob/mob
+
+	/// Major version of BYOND this client is using.
+	var/byond_version
+	/// Build number of BYOND this client is using.
+	var/byond_build
+
 	/// Action datums assigned to this player
 	var/list/datum/action/player_actions = list()
 	/// Tracks client action logging
 	var/list/logging = list()
+
 	/// Callbacks invoked when this client logs in again
 	var/list/post_login_callbacks = list()
 	/// Callbacks invoked when this client logs out
 	var/list/post_logout_callbacks = list()
+
 	/// List of names this key played under this round
 	/// assoc list of name -> mob tag
 	var/list/played_names = list()
 	/// Lazylist of preference slots this client has joined the round under
 	/// Numbers are stored as strings
 	var/list/joined_as_slots
-	/// Major version of BYOND this client is using.
-	var/byond_version
-	/// Build number of BYOND this client is using.
-	var/byond_build
+
 	/// Tracks achievements they have earned
 	var/datum/achievement_data/achievements
+
 	/// World.time this player last died
 	var/time_of_death = 0
 
-/datum/player_details/New(key)
-	achievements = new(key)
+/datum/persistent_client/New(ckey, client)
+	src.client = client
+	achievements = new(ckey)
+	GLOB.persistent_clients_by_ckey[ckey] = src
+	GLOB.persistent_clients += src
+
+/datum/persistent_client/Destroy(force)
+	SHOULD_CALL_PARENT(FALSE)
+	. = QDEL_HINT_LETMELIVE
+	CRASH("Who the FUCK tried to delete a persistent client? Get your head checked you leadskull.")
+
+/// Setter for the mob var, handles both references.
+/datum/persistent_client/proc/set_mob(mob/new_mob)
+	if(mob == new_mob)
+		return
+
+	mob?.persistent_client = null
+	new_mob?.persistent_client?.set_mob(null)
+
+	mob = new_mob
+	new_mob?.persistent_client = src
 
 /// Writes all of the `played_names` into an HTML-escaped string.
-/datum/player_details/proc/get_played_names()
+/datum/persistent_client/proc/get_played_names()
 	var/list/previous_names = list()
 	for(var/previous_name in played_names)
 		previous_names += html_encode("[previous_name] ([played_names[previous_name]])")
 	return previous_names.Join("; ")
 
 /// Returns the full version string (i.e 515.1642) of the BYOND version and build.
-/datum/player_details/proc/full_byond_version()
+/datum/persistent_client/proc/full_byond_version()
 	if(!byond_version)
 		return "Unknown"
 	return "[byond_version].[byond_build || "xxx"]"
 
-/// Adds the new names to the player's played_names list on their /datum/player_details for use of admins.
+/// Adds the new names to the player's played_names list on their /datum/persistent_client for use of admins.
 /// `ckey` should be their ckey, and `data` should be an associative list with the keys being the names they played under and the values being the unique mob ID tied to that name.
 /proc/log_played_names(ckey, data)
 	if(!ckey)
 		return
 
-	var/datum/player_details/writable = GLOB.player_details[ckey]
+	var/datum/persistent_client/writable = GLOB.persistent_clients_by_ckey[ckey]
 	if(isnull(writable))
 		return
 

code/modules/clothing/head/mind_monkey_helmet.dm

@@ -94,7 +94,7 @@
 		user.dropItemToGround(src)
 		return
 
-	magnification.key = chosen_one.key
+	magnification.PossessByPlayer(chosen_one.key)
 	playsound(src, 'sound/machines/microwave/microwave-end.ogg', 100, FALSE)
 	to_chat(magnification, span_notice("You're a mind magnified monkey! Protect your helmet with your life- if you lose it, your sentience goes with it!"))
 	var/policy = get_policy(ROLE_MONKEY_HELMET)

code/modules/deathmatch/deathmatch_lobby.dm

@@ -148,7 +148,7 @@
 			old_body = observer.mind.current, \
 		)
 	new_player.equipOutfit(loadout) // Loadout
-	new_player.key = ckey
+	new_player.PossessByPlayer(ckey)
 	players_info["mob"] = new_player
 
 	for(var/datum/deathmatch_modifier/modifier as anything in modifiers)

code/modules/events/ghost_role/alien_infestation.dm

@@ -71,7 +71,7 @@
 		var/obj/vent = pick_n_take(vents)
 		var/mob/dead/observer/selected = pick_n_take(candidates)
 		var/mob/living/carbon/alien/larva/new_xeno = new(vent.loc)
-		new_xeno.key = selected.key
+		new_xeno.PossessByPlayer(selected.key)
 		new_xeno.move_into_vent(vent)
 
 		spawncount--

code/modules/events/ghost_role/revenant_event.dm

@@ -51,7 +51,7 @@
 		return MAP_ERROR
 
 	var/mob/living/basic/revenant/revvie = new(pick(spawn_locs))
-	revvie.key = chosen_one.key
+	revvie.PossessByPlayer(chosen_one.key)
 	message_admins("[ADMIN_LOOKUPFLW(revvie)] has been made into a revenant by an event.")
 	revvie.log_message("was spawned as a revenant by an event.", LOG_GAME)
 	spawned_mobs += revvie

code/modules/events/ghost_role/sentience.dm

@@ -87,7 +87,7 @@ GLOBAL_LIST_INIT(high_priority_sentience, typecacheof(list(
 
 		spawned_animals++
 
-		selected.key = picked_candidate.key
+		selected.PossessByPlayer(picked_candidate.key)
 
 		selected.grant_all_languages(UNDERSTOOD_LANGUAGE, grant_omnitongue = FALSE, source = LANGUAGE_ATOM)
 

code/modules/events/ghost_role/space_dragon.dm

@@ -26,7 +26,7 @@
 	if(isnull(spawn_location))
 		return MAP_ERROR
 	var/mob/living/basic/space_dragon/dragon = new(spawn_location)
-	dragon.key = chosen_one.key
+	dragon.PossessByPlayer(chosen_one.key)
 	dragon.mind.add_antag_datum(/datum/antagonist/space_dragon)
 	playsound(dragon, 'sound/effects/magic/ethereal_exit.ogg', 50, TRUE, -1)
 	message_admins("[ADMIN_LOOKUPFLW(dragon)] has been made into a Space Dragon by an event.")

code/modules/events/ghost_role/space_ninja.dm

@@ -24,7 +24,7 @@
 		return NOT_ENOUGH_PLAYERS
 	//spawn the ninja and assign the candidate
 	var/mob/living/carbon/human/ninja = create_space_ninja(spawn_location)
-	ninja.key = chosen_one.key
+	ninja.PossessByPlayer(chosen_one.key)
 	ninja.mind.add_antag_datum(/datum/antagonist/ninja)
 	spawned_mobs += ninja
 	message_admins("[ADMIN_LOOKUPFLW(ninja)] has been made into a space ninja by an event.")

code/modules/events/holiday/xmas.dm

@@ -89,6 +89,6 @@
 	if(isnull(chosen_one))
 		return NOT_ENOUGH_PLAYERS
 	santa = new /mob/living/carbon/human(pick(GLOB.blobstart))
-	santa.key = chosen_one.key
+	santa.PossessByPlayer(chosen_one.key)
 	var/datum/antagonist/santa/A = new
 	santa.mind.add_antag_datum(A)

code/modules/events/wizard/imposter.dm

@@ -23,7 +23,7 @@
 		I.name = I.dna.real_name
 		I.updateappearance(mutcolor_update=1)
 		I.domutcheck()
-		I.key = chosen_one.key
+		I.PossessByPlayer(chosen_one.key)
 		var/datum/antagonist/wizard/master = M.has_antag_datum(/datum/antagonist/wizard)
 		if(!master.wiz_team)
 			master.create_wiz_team()

code/modules/fishing/fish/types/ruins.dm

@@ -104,7 +104,7 @@
 /obj/item/fish/soul/proc/good_ending(mob/living/user)
 	var/mob/living/basic/spaceman/soulman = new(get_turf(user))
 	if(prob(80)) // the percentage is important.
-		soulman.ckey = user.ckey
+		soulman.PossessByPlayer(user.ckey)
 		to_chat(soulman, span_notice("You finally feel at peace."))
 	user.gib()
 	qdel(src)

code/modules/hydroponics/grown/replicapod.dm

@@ -181,9 +181,9 @@
 		podman.real_name = "Pod Person ([rand(1,999)])"
 	mind.transfer_to(podman)
 	if(ckey)
-		podman.ckey = ckey
+		podman.PossessByPlayer(ckey)
 	else
-		podman.ckey = ckey_holder
+		podman.PossessByPlayer(ckey_holder)
 	podman.gender = blood_gender
 	podman.faction |= factions
 	if(!features["mcolor"])

code/modules/mafia/roles/roles.dm

@@ -122,7 +122,7 @@
 			old_mind = player.mob.mind, \
 			old_body = player.mob.mind.current, \
 		)
-	body.key = player.key
+	body.PossessByPlayer(player.key)
 
 /**
  * Tests kill immunities, if nothing prevents the kill, kills this role.

code/modules/mining/lavaland/megafauna_loot.dm

@@ -456,7 +456,7 @@
 		using = FALSE
 		return
 
-	soul.ckey = ghost.ckey
+	soul.PossessByPlayer(ghost.ckey)
 	soul.copy_languages(master, LANGUAGE_MASTER) //Make sure the sword can understand and communicate with the master.
 	soul.faction = list("[REF(master)]")
 	balloon_alert(master, "the scythe glows")

code/modules/mob/dead/new_player/new_player.dm

@@ -90,14 +90,16 @@
 	else
 		to_chat(src, span_notice("Teleporting failed. Ahelp an admin please"))
 		stack_trace("There's no freaking observer landmark available on this map or you're making observers before the map is initialised")
-	observer.key = key
+
+	observer.PossessByPlayer(key)
 	observer.client = client
 	observer.set_ghost_appearance()
 	if(observer.client && observer.client.prefs)
 		observer.real_name = observer.client.prefs.read_preference(/datum/preference/name/real_name)
 		observer.name = observer.real_name
 		observer.client.init_verbs()
-		observer.client.player_details.time_of_death = world.time
+		observer.persistent_client.time_of_death = world.time
+
 	observer.update_appearance()
 	observer.stop_sound_channel(CHANNEL_LOBBYMUSIC)
 	deadchat_broadcast(" has observed.", "<b>[observer.real_name]</b>", follow_target = observer, turf_target = get_turf(observer), message_type = DEADCHAT_DEATHRATTLE)
@@ -151,7 +153,7 @@
 /mob/dead/new_player/proc/AttemptLateSpawn(rank)
 	// Check that they're picking someone new for new character respawning
 	if(CONFIG_GET(flag/allow_respawn) == RESPAWN_FLAG_NEW_CHARACTER)
-		if("[client.prefs.default_slot]" in client.player_details.joined_as_slots)
+		if("[client.prefs.default_slot]" in persistent_client.joined_as_slots)
 			tgui_alert(usr, "You already have played this character in this round!")
 			return FALSE
 
@@ -263,8 +265,9 @@
 
 	mind.active = FALSE //we wish to transfer the key manually
 	var/mob/living/spawning_mob = mind.assigned_role.get_spawn_mob(client, destination)
-	if(QDELETED(src) || !client)
+	if(QDELETED(src) || !HAS_CONNECTED_PLAYER(src))
 		return // Disconnected while checking for the appearance ban.
+
 	if(!isAI(spawning_mob)) // Unfortunately there's still snowflake AI code out there.
 		// transfer_to sets mind to null
 		var/datum/mind/preserved_mind = mind
@@ -272,7 +275,7 @@
 		preserved_mind.transfer_to(spawning_mob) //won't transfer key since the mind is not active
 		preserved_mind.set_original_character(spawning_mob)
 
-	LAZYADD(client.player_details.joined_as_slots, "[client.prefs.default_slot]")
+	LAZYADD(persistent_client.joined_as_slots, "[client.prefs.default_slot]")
 	client.init_verbs()
 	. = spawning_mob
 	new_character = .
@@ -282,7 +285,7 @@
 	. = new_character
 	if(!.)
 		return
-	new_character.key = key //Manually transfer the key to log them in,
+	new_character.PossessByPlayer(key) //Manually transfer the key to log them in,
 	new_character.stop_sound_channel(CHANNEL_LOBBYMUSIC)
 	var/area/joined_area = get_area(new_character.loc)
 	if(joined_area)

code/modules/mob/dead/observer/observer.dm

@@ -283,7 +283,7 @@ Works together with spawning an observer, noted above.
 	var/mob/dead/observer/ghost = new(src) // Transfer safety to observer spawning proc.
 	SStgui.on_transfer(src, ghost) // Transfer NanoUIs.
 	ghost.can_reenter_corpse = can_reenter_corpse
-	ghost.key = key
+	ghost.PossessByPlayer(key)
 	ghost.client?.init_verbs()
 	if(!can_reenter_corpse)// Disassociates observer mind from the body mind
 		ghost.mind = null
@@ -293,7 +293,7 @@ Works together with spawning an observer, noted above.
 	if(isliving(former_mob))
 		recordable_time = former_mob.timeofdeath
 
-	ghost.client?.player_details.time_of_death = recordable_time
+	ghost.persistent_client?.time_of_death = recordable_time
 	SEND_SIGNAL(src, COMSIG_MOB_GHOSTIZED)
 	return ghost
 
@@ -386,7 +386,7 @@ This is the proc mobs get to turn into a ghost. Forked from ghostize due to comp
 	SStgui.on_transfer(src, mind.current) // Transfer NanoUIs.
 	if(mind.current.stat == DEAD && SSlag_switch.measures[DISABLE_DEAD_KEYLOOP])
 		to_chat(src, span_warning("To leave your body again use the Ghost verb."))
-	mind.current.key = key
+	mind.current.PossessByPlayer(key)
 	mind.current.client.init_verbs()
 	return TRUE
 
@@ -680,7 +680,7 @@ This is the proc mobs get to turn into a ghost. Forked from ghostize due to comp
 		to_chat(src, span_warning("Someone has taken this body while you were choosing!"))
 		return FALSE
 
-	target.key = key
+	target.PossessByPlayer(key)
 	target.faction = list(FACTION_NEUTRAL)
 	return TRUE
 

code/modules/mob/living/basic/bots/_bots.dm

@@ -719,7 +719,7 @@ GLOBAL_LIST_INIT(command_strings, list(
 		if(isnull(mind))
 			mind.transfer_to(paicard.pai)
 		else
-			paicard.pai.key = key
+			paicard.pai.PossessByPlayer(key)
 	else
 		ghostize(FALSE) // The pAI card that just got ejected was dead.
 

code/modules/mob/living/basic/guardian/guardian_creator.dm

@@ -117,7 +117,7 @@ GLOBAL_LIST_INIT(guardian_radial_images, setup_guardian_radial())
 	var/datum/guardian_fluff/guardian_theme = GLOB.guardian_themes[theme]
 	var/mob/living/basic/guardian/summoned_guardian = new guardian_path(user, guardian_theme)
 	summoned_guardian.set_summoner(user, different_person = TRUE)
-	summoned_guardian.key = candidate.key
+	summoned_guardian.PossessByPlayer(candidate.key)
 	user.log_message("has summoned [key_name(summoned_guardian)], a [summoned_guardian.creator_name] holoparasite.", LOG_GAME)
 	summoned_guardian.log_message("was summoned as a [summoned_guardian.creator_name] holoparasite.", LOG_GAME)
 	to_chat(user, guardian_theme.get_fluff_string(summoned_guardian.guardian_type))

code/modules/mob/living/basic/guardian/guardian_verbs.dm

@@ -180,7 +180,7 @@
 	to_chat(owner, span_boldholoparasite("The personality of <font color=\"[chosen_guardian.guardian_colour]\">[chosen_guardian.theme.name]</font> has been successfully reset."))
 	message_admins("[key_name_admin(chosen_one)] has taken control of ([ADMIN_LOOKUPFLW(chosen_guardian)])")
 	chosen_guardian.ghostize(FALSE)
-	chosen_guardian.key = chosen_one.key
+	chosen_guardian.PossessByPlayer(chosen_one.key)
 	COOLDOWN_START(chosen_guardian, resetting_cooldown, 5 MINUTES)
 	chosen_guardian.guardian_rename() //give it a new color and name, to show it's a new person
 	chosen_guardian.guardian_recolour()

code/modules/mob/living/basic/pets/parrot/poly.dm

@@ -67,7 +67,7 @@
 		if(mind)
 			mind.transfer_to(specter)
 		else
-			specter.key = key
+			specter.PossessByPlayer(key)
 	return ..()
 
 /mob/living/basic/parrot/poly/get_static_list_of_phrases() // there's only one poly, so there should only be one ongoing list of phrases. i guess

code/modules/mob/living/basic/slime/actions.dm

@@ -149,7 +149,7 @@
 	new_slime.set_combat_mode(TRUE)
 
 	if(isnull(mind))
-		new_slime.key = key
+		new_slime.PossessByPlayer(key)
 	else
 		mind.transfer_to(new_slime)
 

code/modules/mob/living/basic/space_fauna/revenant/revenant_items.dm

@@ -71,7 +71,7 @@
 	var/user_name = old_ckey
 	if(isnull(revenant.client))
 		var/mob/potential_user = get_new_user()
-		revenant.key = potential_user.key
+		revenant.PossessByPlayer(potential_user.key)
 		user_name = potential_user.ckey
 		qdel(potential_user)
 

code/modules/mob/living/brain/brain_item.dm

@@ -77,7 +77,7 @@
 			if(brainmob.mind)
 				brainmob.mind.transfer_to(brain_owner)
 			else
-				brain_owner.key = brainmob.key
+				brain_owner.PossessByPlayer(brainmob.key)
 
 			brain_owner.set_suicide(HAS_TRAIT(brainmob, TRAIT_SUICIDED))
 

code/modules/mob/living/brain/posibrain.dm

@@ -155,7 +155,7 @@ GLOBAL_VAR(posibrain_notify_cooldown)
 	if(candidate.mind && !isobserver(candidate))
 		candidate.mind.transfer_to(brainmob)
 	else
-		brainmob.ckey = candidate.ckey
+		brainmob.PossessByPlayer(candidate.ckey)
 	name = "[initial(name)] ([brainmob.name])"
 	var/policy = get_policy(ROLE_POSIBRAIN)
 	if(policy)

code/modules/mob/living/carbon/alien/special/alien_embryo.dm

@@ -119,7 +119,7 @@
 
 	var/atom/xeno_loc = get_turf(owner)
 	var/mob/living/carbon/alien/larva/new_xeno = new(xeno_loc)
-	new_xeno.key = ghost.key
+	new_xeno.PossessByPlayer(ghost.key)
 	SEND_SOUND(new_xeno, sound('sound/mobs/non-humanoids/hiss/hiss5.ogg',0,0,0,100)) //To get the player's attention
 	new_xeno.add_traits(list(TRAIT_HANDS_BLOCKED, TRAIT_IMMOBILIZED, TRAIT_NO_TRANSFORM), type) //so we don't move during the bursting animation
 	new_xeno.SetInvisibility(INVISIBILITY_MAXIMUM, id=type)

code/modules/mob/living/death.dm

@@ -193,6 +193,7 @@
 
 	if (client)
 		client.move_delay = initial(client.move_delay)
-		client.player_details.time_of_death = timeofdeath
+
+	persistent_client?.time_of_death = timeofdeath
 
 	return TRUE

code/modules/mob/living/living.dm

@@ -1781,7 +1781,7 @@
 
 	// Well, no mmind, guess we should try to move a key over
 	else if(key)
-		new_mob.key = key
+		new_mob.PossessByPlayer(key)
 
 /mob/living/proc/unfry_mob() //Callback proc to tone down spam from multiple sizzling frying oil dipping.
 	REMOVE_TRAIT(src, TRAIT_OIL_FRIED, "cooking_oil_react")
@@ -2932,7 +2932,7 @@ GLOBAL_LIST_EMPTY(fire_appearances)
 		summoned_guardian.fully_replace_character_name(null, picked_name)
 	if(picked_color)
 		summoned_guardian.set_guardian_colour(picked_color)
-	summoned_guardian.key = guardian_client?.key
+	summoned_guardian.PossessByPlayer(guardian_client?.key)
 	guardian_client?.init_verbs()
 	if(del_mob)
 		qdel(old_mob)

code/modules/mob/living/simple_animal/bot/bot.dm

@@ -1097,7 +1097,7 @@ Pass a positive integer as an argument to override a bot's default speed.
 	if(mind && paicard.pai)
 		mind.transfer_to(paicard.pai)
 	else if(paicard.pai)
-		paicard.pai.key = key
+		paicard.pai.PossessByPlayer(key)
 	else
 		ghostize(FALSE) // The pAI card that just got ejected was dead.
 	key = null

code/modules/mob/living/simple_animal/hostile/megafauna/colossus.dm

@@ -468,7 +468,7 @@
 		var/be_helper = tgui_alert(usr, "Become a Lightgeist? (Warning, You can no longer be revived!)", "Lightgeist Deployment", list("Yes", "No"))
 		if((be_helper == "Yes") && !QDELETED(src) && isobserver(user))
 			var/mob/living/basic/lightgeist/deployable = new(get_turf(loc))
-			deployable.key = user.key
+			deployable.PossessByPlayer(user.key)
 
 /obj/machinery/anomalous_crystal/possessor //Allows you to bodyjack small animals, then exit them at your leisure, but you can only do this once per activation. Because they blow up. Also, if the bodyjacked animal dies, SO DO YOU.
 	observer_desc = "When activated, this crystal allows you to take over small animals, and then exit them at the possessors leisure. Exiting the animal kills it, and if you die while possessing the animal, you die as well."

code/modules/mob/living/simple_animal/hostile/mining_mobs/elites/elite.dm

@@ -206,7 +206,7 @@ While using this makes the system rely on OnFire, it still gives options for tim
 	visible_message(span_boldwarning("[mychild] emerges from [src]!"))
 	playsound(loc,'sound/effects/phasein.ogg', 200, 0, 50, TRUE, TRUE)
 	if(boosted)
-		mychild.key = elitemind.key
+		mychild.PossessByPlayer(elitemind.key)
 		mychild.sentience_act()
 		notify_ghosts(
 			"\A [mychild] has been awakened in \the [get_area(src)]!",

code/modules/mob/login.dm

@@ -31,6 +31,8 @@
 		return FALSE
 
 	canon_client = client
+	client.persistent_client.set_mob(src)
+
 	add_to_player_list()
 	lastKnownIP = client.address
 	computer_id = client.computer_id
@@ -108,13 +110,12 @@
 		else
 			client.change_view(getScreenSize(client.prefs.read_preference(/datum/preference/toggle/widescreen)))
 
-		if(client.player_details.player_actions.len)
-			for(var/datum/action/A in client.player_details.player_actions)
-				A.Grant(src)
+		for(var/datum/action/A as anything in persistent_client.player_actions)
+			A.Grant(src)
 
-		for(var/foo in client.player_details.post_login_callbacks)
-			var/datum/callback/CB = foo
+		for(var/datum/callback/CB as anything in persistent_client.post_login_callbacks)
 			CB.Invoke()
+
 		log_played_names(
 			client.ckey,
 			list(

code/modules/mob/mob.dm

@@ -29,6 +29,8 @@
 	else if(ckey)
 		stack_trace("Mob without client but with associated ckey, [ckey], has been deleted.")
 
+	persistent_client?.set_mob(null)
+
 	remove_from_mob_list()
 	remove_from_dead_mob_list()
 	remove_from_alive_mob_list()
@@ -107,6 +109,17 @@
 	. = ..()
 	tag = "mob_[next_mob_id++]"
 
+/// Assigns a (c)key to this mob.
+/mob/proc/PossessByPlayer(ckey)
+	SHOULD_NOT_OVERRIDE(TRUE)
+	if(isnull(ckey))
+		return
+
+	if(!istext(ckey))
+		CRASH("Tried to assign a mob a non-text ckey, wtf?!")
+
+	src.ckey = ckey(ckey)
+
 /mob/serialize_list(list/options, list/semvers)
 	. = ..()
 
@@ -780,14 +793,14 @@
 		qdel(M)
 		return
 
-	M.key = key
+	M.PossessByPlayer(key)
 
 /// Checks if the mob can respawn yet according to the respawn delay
 /mob/proc/check_respawn_delay(override_delay = 0)
 	if(!override_delay && !CONFIG_GET(number/respawn_delay))
 		return TRUE
 
-	var/death_time = world.time - client.player_details.time_of_death
+	var/death_time = world.time - persistent_client.time_of_death
 
 	var/required_delay = override_delay || CONFIG_GET(number/respawn_delay)
 
@@ -1535,8 +1548,7 @@
 	if(!canon_client)
 		return
 
-	for(var/foo in canon_client.player_details.post_logout_callbacks)
-		var/datum/callback/CB = foo
+	for(var/datum/callback/CB as anything in persistent_client.post_logout_callbacks)
 		CB.Invoke()
 
 	if(canon_client?.movingmob)

code/modules/mob/mob_defines.dm

@@ -27,6 +27,8 @@
 	/// We also need to clear this var/do other cleanup in client/Destroy, since that happens before logout
 	/// HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH
 	var/client/canon_client
+	/// It's like a client, but persists! Persistent clients will stick to a mob until the client in question is logged into a different mob.
+	var/datum/persistent_client/persistent_client
 
 	var/shift_to_open_context_menu = TRUE
 

code/modules/mob/mob_helpers.dm

@@ -376,7 +376,7 @@
 		to_chat(M, "Your mob has been taken over by a ghost!")
 		message_admins("[key_name_admin(chosen_one)] has taken control of ([ADMIN_LOOKUPFLW(M)])")
 		M.ghostize(FALSE)
-		M.key = chosen_one.key
+		M.PossessByPlayer(chosen_one.key)
 		M.client?.init_verbs()
 		return TRUE
 	else

code/modules/mob/mob_transformation_simple.dm

@@ -67,7 +67,7 @@
 
 		mind.transfer_to(desired_mob, 1) // second argument to force key move to new mob
 	else
-		desired_mob.key = key
+		desired_mob.PossessByPlayer(key)
 
 	SEND_SIGNAL(src, COMSIG_MOB_CHANGED_TYPE, desired_mob)
 	if(delete_old_mob)

code/modules/mob/transform_procs.dm

@@ -155,7 +155,7 @@
 			mind.active = FALSE
 		mind.transfer_to(new_borg, TRUE)
 	else if(transfer_after)
-		new_borg.key = key
+		new_borg.PossessByPlayer(key)
 
 	if(new_borg.mmi)
 		new_borg.mmi.name = "[initial(new_borg.mmi.name)]: [real_name]"
@@ -222,7 +222,7 @@
 			new_xeno = new /mob/living/carbon/alien/adult/drone(loc)
 
 	new_xeno.set_combat_mode(TRUE)
-	new_xeno.key = key
+	new_xeno.PossessByPlayer(key)
 
 	to_chat(new_xeno, span_boldnotice("You are now an alien."))
 	qdel(src)
@@ -254,7 +254,7 @@
 	else
 		new_slime = new /mob/living/basic/slime(loc)
 	new_slime.set_combat_mode(TRUE)
-	new_slime.key = key
+	new_slime.PossessByPlayer(key)
 
 	to_chat(new_slime, span_boldnotice("You are now a slime. Skreee!"))
 	qdel(src)
@@ -262,7 +262,7 @@
 
 /mob/proc/become_overmind(starting_points = OVERMIND_STARTING_POINTS)
 	var/mob/eye/blob/B = new /mob/eye/blob(get_turf(src), starting_points)
-	B.key = key
+	B.PossessByPlayer(key)
 	. = B
 	qdel(src)
 
@@ -282,7 +282,7 @@
 
 	var/mob/living/basic/pet/dog/corgi/new_corgi = new /mob/living/basic/pet/dog/corgi (loc)
 	new_corgi.set_combat_mode(TRUE)
-	new_corgi.key = key
+	new_corgi.PossessByPlayer(key)
 
 	to_chat(new_corgi, span_boldnotice("You are now a Corgi. Yap Yap!"))
 	qdel(src)
@@ -333,7 +333,7 @@
 	if(mind)
 		mind.transfer_to(new_gorilla)
 	else
-		new_gorilla.key = key
+		new_gorilla.PossessByPlayer(key)
 	to_chat(new_gorilla, span_boldnotice("You are now a gorilla. Ooga ooga!"))
 	qdel(src)
 	return new_gorilla
@@ -365,7 +365,7 @@
 
 	var/mob/living/new_mob = new mobpath(src.loc)
 
-	new_mob.key = key
+	new_mob.PossessByPlayer(key)
 	new_mob.set_combat_mode(TRUE)
 
 	to_chat(new_mob, span_boldnotice("You suddenly feel more... animalistic."))
@@ -384,7 +384,7 @@
 
 	var/mob/living/new_mob = new mobpath(src.loc)
 
-	new_mob.key = key
+	new_mob.PossessByPlayer(key)
 	new_mob.set_combat_mode(TRUE)
 	to_chat(new_mob, span_boldnotice("You feel more... animalistic."))
 

code/modules/mob_spawn/mob_spawn.dm

@@ -242,7 +242,7 @@
 		if(mob_possessor.mind)
 			mob_possessor.mind.transfer_to(spawned_mob, force_key_move = TRUE)
 		else
-			spawned_mob.key = mob_possessor.key
+			spawned_mob.PossessByPlayer(mob_possessor.key)
 	var/datum/mind/spawned_mind = spawned_mob.mind
 	if(spawned_mind)
 		spawned_mob.mind.set_assigned_role_with_greeting(SSjob.get_job_type(spawner_job_path))

code/modules/pai/card.dm

@@ -212,7 +212,7 @@
 	var/mob/living/silicon/pai/new_pai = new(src)
 	new_pai.name = candidate.name || pick(GLOB.ninja_names)
 	new_pai.real_name = new_pai.name
-	new_pai.key = candidate.ckey
+	new_pai.PossessByPlayer(candidate.ckey)
 	set_personality(new_pai)
 	SSpai.candidates -= ckey
 	return TRUE

code/modules/pai/debug.dm

@@ -24,7 +24,7 @@
 
 	pai.name = chosen_name
 	pai.real_name = pai.name
-	pai.key = choice.key
+	pai.PossessByPlayer(choice.key)
 	card.set_personality(pai)
 	if(SSpai.candidates[key])
 		SSpai.candidates -= key
@@ -38,7 +38,7 @@
 /mob/proc/make_pai(delete_old)
 	var/obj/item/pai_card/card = new(src)
 	var/mob/living/silicon/pai/pai = new(card)
-	pai.key = key
+	pai.PossessByPlayer(key)
 	pai.name = name
 	card.set_personality(pai)
 	if(delete_old)

code/modules/projectiles/projectile/magic.dm

@@ -378,7 +378,7 @@
 	if(chosen_one)
 		to_chat(target, span_boldnotice("You have been noticed by a ghost and it has possessed you!"))
 		var/mob/dead/observer/ghosted_target = target.ghostize(FALSE)
-		target.key = chosen_one.key
+		target.PossessByPlayer(chosen_one.key)
 		trauma.add_friend(ghosted_target)
 	else
 		to_chat(target, span_notice("Your mind has managed to go unnoticed in the spirit world."))

code/modules/research/xenobiology/xenobiology.dm

@@ -736,7 +736,7 @@
 		being_used = FALSE
 		return
 
-	dumb_mob.key = ghost.key
+	dumb_mob.PossessByPlayer(ghost.key)
 	dumb_mob.mind.enslave_mind_to_creator(user)
 	SEND_SIGNAL(dumb_mob, COMSIG_SIMPLEMOB_SENTIENCEPOTION, user)
 

code/modules/spells/spell_types/pointed/mind_transfer.dm

@@ -129,7 +129,7 @@
 
 	// Just in case the swappee's key wasn't grabbed by transfer_to...
 	if(to_swap_key)
-		caster.key = to_swap_key
+		caster.PossessByPlayer(to_swap_key)
 
 	// MIND TRANSFER END
 

tgstation.dme

@@ -3797,7 +3797,7 @@
 #include "code\modules\client\client_defines.dm"
 #include "code\modules\client\client_procs.dm"
 #include "code\modules\client\message.dm"
-#include "code\modules\client\player_details.dm"
+#include "code\modules\client\persistent_client.dm"
 #include "code\modules\client\preferences.dm"
 #include "code\modules\client\preferences_menu.dm"
 #include "code\modules\client\preferences_savefile.dm"