From 30f436724b8ced57ff20a209690b3915ac5b8552 Mon Sep 17 00:00:00 2001
From: SkyratBot <59378654+SkyratBot@users.noreply.github.com>
Date: Mon, 14 Aug 2023 00:37:01 +0200
Subject: [PATCH] [MIRROR] More lua harddel fixes [MDB IGNORE] (#23064)

* More lua harddel fixes (#77556)

## About The Pull Request
Fixes some more lua harddel problems with lingering refs on the gc_guard
variable. This variable has been changed to a list instead and will get
cleared every time the SSlua subsystem fires so that lua instantiated
objects that are not tracked by the subsystem will essentially delete
themselves on the next tick, aka whenever the lua script sleeps.

Also removed the unnecessary and not completely functional
lua_reference_cleanup proc which wasn't even being called reliably
because the signal handler was the datum itself.

## Why It's Good For The Game
Fixes more harddel bugs, increases consistency.

Co-authored-by: Watermelon914 <3052169-Watermelon914@ users.noreply.gitlab.com>

* More lua harddel fixes

---------

Co-authored-by: Watermelon914 <37270891+Watermelon914@users.noreply.github.com>
Co-authored-by: Watermelon914 <3052169-Watermelon914@ users.noreply.gitlab.com>
---
 code/controllers/subsystem/lua.dm         |  4 +++-
 code/modules/admin/verbs/lua/_wrappers.dm |  8 ++------
 code/modules/admin/verbs/lua/helpers.dm   | 14 --------------
 3 files changed, 5 insertions(+), 21 deletions(-)

diff --git a/code/controllers/subsystem/lua.dm b/code/controllers/subsystem/lua.dm
index d8fb642c1c9..641416b7243 100644
--- a/code/controllers/subsystem/lua.dm
+++ b/code/controllers/subsystem/lua.dm
@@ -18,7 +18,8 @@ SUBSYSTEM_DEF(lua)
 	var/list/current_run = list()
 
 	/// Protects return values from getting GCed before getting converted to lua values
-	var/gc_guard
+	/// Gets cleared every tick.
+	var/list/gc_guard = list()
 
 /datum/controller/subsystem/lua/Initialize()
 	if(!CONFIG_GET(flag/auxtools_enabled))
@@ -99,6 +100,7 @@ SUBSYSTEM_DEF(lua)
 		sleeps.Cut()
 		resumes.Cut()
 
+	gc_guard.Cut()
 	var/list/current_sleeps = current_run["sleeps"]
 	var/list/affected_states = list()
 	while(length(current_sleeps))
diff --git a/code/modules/admin/verbs/lua/_wrappers.dm b/code/modules/admin/verbs/lua/_wrappers.dm
index d77d02de4ee..8e05453d29d 100644
--- a/code/modules/admin/verbs/lua/_wrappers.dm
+++ b/code/modules/admin/verbs/lua/_wrappers.dm
@@ -12,9 +12,7 @@
 	else
 		ret = HandleUserlessProcCall("lua", thing_to_call, proc_name, arguments)
 	if(isdatum(ret))
-		SSlua.gc_guard = ret
-		var/datum/ret_datum = ret
-		ret_datum.RegisterSignal(ret_datum, COMSIG_QDELETING, TYPE_PROC_REF(/datum, lua_reference_cleanup), override = TRUE)
+		SSlua.gc_guard += ret
 	return ret
 
 /proc/wrap_lua_global_proc_call(proc_name, list/arguments)
@@ -27,9 +25,7 @@
 	else
 		ret = HandleUserlessProcCall("lua", GLOBAL_PROC, proc_name, arguments)
 	if(isdatum(ret))
-		SSlua.gc_guard = ret
-		var/datum/ret_datum = ret
-		ret_datum.RegisterSignal(ret_datum, COMSIG_QDELETING, TYPE_PROC_REF(/datum, lua_reference_cleanup), override = TRUE)
+		SSlua.gc_guard += ret
 	return ret
 
 /proc/wrap_lua_print(state_id, list/arguments)
diff --git a/code/modules/admin/verbs/lua/helpers.dm b/code/modules/admin/verbs/lua/helpers.dm
index c0271e0bc72..66b7c835e9a 100644
--- a/code/modules/admin/verbs/lua/helpers.dm
+++ b/code/modules/admin/verbs/lua/helpers.dm
@@ -34,17 +34,3 @@
 #undef PROMISE_PENDING
 #undef PROMISE_RESOLVED
 #undef PROMISE_REJECTED
-
-/**
- * When a datum is created from lua, it gets held in `SSlua.gc_guard`, and later,
- * in the calling state datum's `var/list/references`, just in case it would be garbage
- * collected due to there not being any references that BYOND recognizes. To avoid harddels,
- * we register this proc as a signal handler any time a DM function called from lua returns
- * a datum.
- */
-/datum/proc/lua_reference_cleanup()
-	SIGNAL_HANDLER
-	if(SSlua.gc_guard == src)
-		SSlua.gc_guard = null
-	for(var/datum/lua_state/state in SSlua.states)
-		state.references -= src