Fixed objects which store Lua callback functions to avoid attempting to use dead coroutines when deleting the reference to the callback function. Should fix crashes when coroutines are mixed with those objects.

Also improved the performance of World:rayCast and World:queryBoundingBox.

src/common/runtime.cpp

@@ -83,7 +83,7 @@ Reference *luax_refif(lua_State *L, int type)
 
 void luax_printstack(lua_State *L)
 {
-	for (int i = 1; i<=lua_gettop(L); i++)
+	for (int i = 1; i <= lua_gettop(L); i++)
 		std::cout << i << " - " << luaL_typename(L, i) << std::endl;
 }
 
@@ -590,8 +590,6 @@ int luax_insistregistry(lua_State *L, Registry r)
 {
 	switch (r)
 	{
-	case REGISTRY_GC:
-		return luax_insistlove(L, "_gc");
 	case REGISTRY_MODULES:
 		return luax_insistlove(L, "_modules");
 	case REGISTRY_OBJECTS:
@@ -605,8 +603,6 @@ int luax_getregistry(lua_State *L, Registry r)
 {
 	switch (r)
 	{
-	case REGISTRY_GC:
-		return luax_getlove(L, "_gc");
 	case REGISTRY_MODULES:
 		return luax_getlove(L, "_modules");
 	case REGISTRY_OBJECTS:
@@ -617,6 +613,39 @@ int luax_getregistry(lua_State *L, Registry r)
 	}
 }
 
+static const char *MAIN_THREAD_KEY = "_love_mainthread";
+
+lua_State *luax_insistpinnedthread(lua_State *L)
+{
+	lua_getfield(L, LUA_REGISTRYINDEX, MAIN_THREAD_KEY);
+
+	if (lua_isnoneornil(L, -1))
+	{
+		lua_pop(L, 1);
+
+		// lua_pushthread returns 1 if it's actually the main thread, but we
+		// can't actually get the real main thread if lua_pushthread doesn't
+		// return it (in Lua 5.1 at least), so we ignore that for now...
+		// We do store a strong reference to the current thread/coroutine in
+		// the registry, however.
+		lua_pushthread(L);
+		lua_pushvalue(L, -1);
+		lua_setfield(L, LUA_REGISTRYINDEX, MAIN_THREAD_KEY);
+	}
+
+	lua_State *thread = lua_tothread(L, -1);
+	lua_pop(L, 1);
+	return thread;
+}
+
+lua_State *luax_getpinnedthread(lua_State *L)
+{
+	lua_getfield(L, LUA_REGISTRYINDEX, MAIN_THREAD_KEY);
+	lua_State *thread = lua_tothread(L, -1);
+	lua_pop(L, 1);
+	return thread;
+}
+
 extern "C" int luax_typerror(lua_State *L, int narg, const char *tname)
 {
 	int argtype = lua_type(L, narg);