Fix crash from Lua prompts when exiting the game completely

The problem is that Engine outlives GameController and thus also LuaScriptInterface. The solution is to not try to access LSI's lua_State if it doesn't exist; this is the case in Engine's dtor.

This is ugly as hell and the root of the problem is the cursed ownership model of LuaComponents and Windows by Engine, which I don't think I'll be fixing any time soon.

src/gui/dialogues/LegacyDialogues.h

@@ -1,11 +0,0 @@
-#pragma once
-
-//Legacy blocking prompts
-//This are not implemented here, but rather in the engine bootstrapper
-bool ConfirmUI(String title, String message, String confirmText) {}
-
-void ErrorUI(String title, String message) {}
-
-void InformationUI(String title, String message) {}
-
-String MessagePromptUI(String title, String message, String text, String placeholder) {}

src/lua/LuaButton.cpp

@@ -16,8 +16,7 @@ Luna<LuaButton>::RegType LuaButton::methods[] = {
 };
 
 LuaButton::LuaButton(lua_State * l) :
-	LuaComponent(l),
-	actionFunction(l)
+	LuaComponent(l)
 {
 	int posX = luaL_optinteger(l, 1, 0);
 	int posY = luaL_optinteger(l, 2, 0);

src/lua/LuaCheckbox.cpp

@@ -16,8 +16,7 @@ Luna<LuaCheckbox>::RegType LuaCheckbox::methods[] = {
 };
 
 LuaCheckbox::LuaCheckbox(lua_State * l) :
-	LuaComponent(l),
-	actionFunction(l)
+	LuaComponent(l)
 {
 	int posX = luaL_optinteger(l, 1, 0);
 	int posY = luaL_optinteger(l, 2, 0);

src/lua/LuaScriptInterface.cpp

@@ -465,7 +465,7 @@ tpt.partsdata = nil");
 		lua_setmetatable(l, top);
 	}
 
-	tptPart = new LuaSmartRef(l);
+	tptPart = new LuaSmartRef();
 	tptPart->Assign(l, -1);
 	lua_pop(l, 1);
 #endif
@@ -510,14 +510,14 @@ tpt.partsdata = nil");
 	}
 	lua_setfield(l, tptProperties, "eltransition");
 
-	lua_gr_func_v = std::vector<LuaSmartRef>(PT_NUM, l);
+	lua_gr_func_v = std::vector<LuaSmartRef>(PT_NUM);
 	lua_gr_func = &lua_gr_func_v[0];
-	lua_el_func_v = std::vector<LuaSmartRef>(PT_NUM, l);
+	lua_el_func_v = std::vector<LuaSmartRef>(PT_NUM);
 	lua_el_func = &lua_el_func_v[0];
 	lua_el_mode_v = std::vector<int>(PT_NUM, 0);
 	lua_el_mode = &lua_el_mode_v[0];
 
-	gameControllerEventHandlers = std::vector<LuaSmartRef>(std::variant_size<GameControllerEvent>::value, l);
+	gameControllerEventHandlers = std::vector<LuaSmartRef>(std::variant_size<GameControllerEvent>::value);
 	for (auto &ref : gameControllerEventHandlers)
 	{
 		lua_newtable(l);
@@ -525,10 +525,10 @@ tpt.partsdata = nil");
 		lua_pop(l, 1);
 	}
 
-	luaCtypeDrawHandlers = std::vector<LuaSmartRef>(PT_NUM, l);
-	luaCreateHandlers = std::vector<LuaSmartRef>(PT_NUM, l);
-	luaCreateAllowedHandlers = std::vector<LuaSmartRef>(PT_NUM, l);
-	luaChangeTypeHandlers = std::vector<LuaSmartRef>(PT_NUM, l);
+	luaCtypeDrawHandlers = std::vector<LuaSmartRef>(PT_NUM);
+	luaCreateHandlers = std::vector<LuaSmartRef>(PT_NUM);
+	luaCreateAllowedHandlers = std::vector<LuaSmartRef>(PT_NUM);
+	luaChangeTypeHandlers = std::vector<LuaSmartRef>(PT_NUM);
 
 	//make tpt.* a metatable
 	lua_newtable(l);
@@ -697,8 +697,7 @@ static int beginMessageBox(lua_State* l)
 	auto title = PickIfType(l, 1, String("Title"));
 	auto message = PickIfType(l, 2, String("Message"));
 	auto large = PickIfType(l, 3, false);
-	auto *luacon_ci = static_cast<LuaScriptInterface *>(commandInterface);
-	auto cb = std::make_shared<LuaSmartRef>(luacon_ci->l); // * Bind to main lua state (might be different from l).
+	auto cb = std::make_shared<LuaSmartRef>(); // * Bind to main lua state (might be different from l).
 	cb->Assign(l, lua_gettop(l));
 	new InformationMessage(title, message, large, { [cb]() {
 		auto *luacon_ci = static_cast<LuaScriptInterface *>(commandInterface);
@@ -722,8 +721,7 @@ static int beginMessageBox(lua_State* l)
 static int beginThrowError(lua_State* l)
 {
 	auto errorMessage = PickIfType(l, 1, String("Error text"));
-	auto *luacon_ci = static_cast<LuaScriptInterface *>(commandInterface);
-	auto cb = std::make_shared<LuaSmartRef>(luacon_ci->l); // * Bind to main lua state (might be different from l).
+	auto cb = std::make_shared<LuaSmartRef>(); // * Bind to main lua state (might be different from l).
 	cb->Assign(l, lua_gettop(l));
 	new ErrorMessage("Error", errorMessage, { [cb]() {
 		auto *luacon_ci = static_cast<LuaScriptInterface *>(commandInterface);
@@ -750,8 +748,7 @@ static int beginInput(lua_State* l)
 	auto prompt = PickIfType(l, 2, String("Enter some text:"));
 	auto text = PickIfType(l, 3, String(""));
 	auto shadow = PickIfType(l, 4, String(""));
-	auto *luacon_ci = static_cast<LuaScriptInterface *>(commandInterface);
-	auto cb = std::make_shared<LuaSmartRef>(luacon_ci->l); // * Bind to main lua state (might be different from l).
+	auto cb = std::make_shared<LuaSmartRef>(); // * Bind to main lua state (might be different from l).
 	cb->Assign(l, lua_gettop(l));
 	auto handle = [cb](std::optional<String> input) {
 		auto *luacon_ci = static_cast<LuaScriptInterface *>(commandInterface);
@@ -790,8 +787,7 @@ static int beginConfirm(lua_State *l)
 	auto title = PickIfType(l, 1, String("Title"));
 	auto message = PickIfType(l, 2, String("Message"));
 	auto buttonText = PickIfType(l, 3, String("Confirm"));
-	auto *luacon_ci = static_cast<LuaScriptInterface *>(commandInterface);
-	auto cb = std::make_shared<LuaSmartRef>(luacon_ci->l); // * Bind to main lua state (might be different from l).
+	auto cb = std::make_shared<LuaSmartRef>(); // * Bind to main lua state (might be different from l).
 	cb->Assign(l, lua_gettop(l));
 	auto handle = [cb](int result) {
 		auto *luacon_ci = static_cast<LuaScriptInterface *>(commandInterface);
@@ -875,7 +871,7 @@ int LuaScriptInterface::interface_addComponent(lua_State * l)
 		luaL_typerror(l, 1, "Component");
 	if (luacon_ci->Window && luaComponent)
 	{
-		auto ok = luacon_ci->grabbed_components.insert(std::make_pair(luaComponent, LuaSmartRef(l)));
+		auto ok = luacon_ci->grabbed_components.insert(std::make_pair(luaComponent, LuaSmartRef()));
 		if (ok.second)
 		{
 			auto it = ok.first;
@@ -5108,7 +5104,7 @@ int LuaScriptInterface::luatpt_getscript(lua_State* l)
 	auto filename = tpt_lua_checkByteString(l, 2);
 	auto runScript = PickIfType(l, 3, false);
 
-	auto cb = std::make_shared<LuaSmartRef>(luacon_ci->l); // * Bind to main lua state (might be different from l).
+	auto cb = std::make_shared<LuaSmartRef>(); // * Bind to main lua state (might be different from l).
 	cb->Assign(l, lua_gettop(l));
 	luacon_ci->scriptDownloadComplete = [cb](const GetScriptStatus &status) {
 		auto *luacon_ci = static_cast<LuaScriptInterface *>(commandInterface);

src/lua/LuaSlider.cpp

@@ -16,8 +16,7 @@ Luna<LuaSlider>::RegType LuaSlider::methods[] = {
 };
 
 LuaSlider::LuaSlider(lua_State * l) :
-	LuaComponent(l),
-	onValueChangedFunction(l)
+	LuaComponent(l)
 {
 	int posX = luaL_optinteger(l, 1, 0);
 	int posY = luaL_optinteger(l, 2, 0);

src/lua/LuaSmartRef.cpp

@@ -1,17 +1,14 @@
 #include "LuaSmartRef.h"
+#include "LuaScriptInterface.h"
 
 void LuaSmartRef::Clear()
 {
-	luaL_unref(rootl, LUA_REGISTRYINDEX, ref);
+	auto *luacon_ci = static_cast<LuaScriptInterface *>(commandInterface);
+	if (luacon_ci)
+	{
+		luaL_unref(luacon_ci->l, LUA_REGISTRYINDEX, ref);
 		ref = LUA_REFNIL;
-}
-
-LuaSmartRef::LuaSmartRef(lua_State *l) :
-	ref(LUA_REFNIL)
-{
-	tpt_lua_getmainthread(l);
-	rootl = lua_tothread(l, -1);
-	lua_pop(l, 1);
+	}
 }
 
 LuaSmartRef::~LuaSmartRef()

src/lua/LuaSmartRef.h

@@ -3,11 +3,9 @@
 
 class LuaSmartRef
 {
-	int ref;
-	lua_State *rootl;
+	int ref = LUA_REFNIL;
 
 public:
-	LuaSmartRef(lua_State *l);
 	~LuaSmartRef();
 	void Assign(lua_State *l, int index); // Copies the value before getting reference, stack unchanged.
 	void Clear();

src/lua/LuaTextbox.cpp

@@ -16,8 +16,7 @@ Luna<LuaTextbox>::RegType LuaTextbox::methods[] = {
 };
 
 LuaTextbox::LuaTextbox(lua_State * l) :
-	LuaComponent(l),
-	onTextChangedFunction(l)
+	LuaComponent(l)
 {
 	this->l = l;
 	int posX = luaL_optinteger(l, 1, 0);

src/lua/LuaWindow.cpp

@@ -35,21 +35,7 @@ Luna<LuaWindow>::RegType LuaWindow::methods[] = {
 	{0, 0}
 };
 
-LuaWindow::LuaWindow(lua_State * l) :
-	onInitializedFunction(l),
-	onExitFunction(l),
-	onTickFunction(l),
-	onDrawFunction(l),
-	onFocusFunction(l),
-	onBlurFunction(l),
-	onTryExitFunction(l),
-	onTryOkayFunction(l),
-	onMouseMoveFunction(l),
-	onMouseDownFunction(l),
-	onMouseUpFunction(l),
-	onMouseWheelFunction(l),
-	onKeyPressFunction(l),
-	onKeyReleaseFunction(l)
+LuaWindow::LuaWindow(lua_State * l)
 {
 	this->l = l;
 	int posX = luaL_optinteger(l, 1, 1);
@@ -122,7 +108,7 @@ int LuaWindow::addComponent(lua_State * l)
 		luaL_typerror(l, 1, "Component");
 	if (luaComponent)
 	{
-		auto ok = grabbed_components.insert(std::make_pair(luaComponent, LuaSmartRef(l)));
+		auto ok = grabbed_components.insert(std::make_pair(luaComponent, LuaSmartRef()));
 		if (ok.second)
 		{
 			auto it = ok.first;