Merge pull request #83 from cortex-command-community/lua-crash-fix

Lua Crash Fix

Author: Causeless

CHANGELOG.md

@@ -20,6 +20,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 - Fixed an issue that could cause post-effects to appear very blurry.
 
+- Fixed a rare crash that could occur depending on Lua garbage collection and async processing.
+
 </details>
 
 ## [Release v6.1.0] - 2024/02/15

Source/Lua/LuaAdapters.cpp

@@ -4,6 +4,8 @@
 #include "LuabindObjectWrapper.h"
 #include "LuaMan.h"
 
+#include "lj_obj.h"
+
 using namespace RTE;
 
 std::unordered_map<std::string, std::function<LuabindObjectWrapper*(Entity*, lua_State*)>> LuaAdaptersEntityCast::s_EntityToLuabindObjectCastFunctions = {};
@@ -295,11 +297,8 @@ void LuaAdaptersScene::CalculatePathAsync2(Scene* luaSelfObject, const luabind::
 	// So, luabind::object is a weak reference, holding just a stack and a position in the stack
 	// This means it's unsafe to store on the C++ side if we do basically anything with the lua state before using it
 	// As such, we need to store this function somewhere safely within our Lua state for us to access later when we need it
-	// It looks like Luabind constructs temporary interpreters and really doesn't like if you destroy these luabind objects
-	// In any case, it's extremely unsafe to use! For example capturing the callback by value into the lambdas causes random crashes
-	// Even if we did literally nothing with it except capture it into a no-op lambda
-	// TODO: validate this is still actually the case. Changes to lua may have fixed this
-	lua_State* luaState = callbackParam.interpreter();
+	lua_State* luaState = mainthread(G(callbackParam.interpreter())); // Get the main thread for the state, in case we're a temp lua thread
+
 	static int currentCallbackId = 0;
 	int thisCallbackId = currentCallbackId++;
 	if (luabind::type(callbackParam) == LUA_TFUNCTION && callbackParam.is_valid()) {

external/meson.build

@@ -1,3 +1,4 @@
 subdir('include')
 subdir('lib')
 subdir('sources')
+external_inc_dirs += include_directories('sources/LuaJIT-2.1/src')