Ensure sufficient stack size for Lua values (#4482)

* Ensure sufficient stack size

* Fix Warning

* Fix formatting

* Rename variable and add docs

Author: BMagnu

code/scripting/lua/LuaFunction.cpp

@@ -172,12 +172,15 @@ LuaValueList LuaFunction::call(lua_State* L, const LuaValueList& args) const {
 		stackTop = lua_gettop(L);
 	}
 
+	if(!lua_checkstack(L, (int)args.size() + 1))
+		throw LuaException("Lua Stack Overflow!");
+
 	// Push the function onto the stack
-	this->pushValue(L);
+	this->pushValue(L, true);
 
 	// Push the arguments onto the stack
 	for (const auto& arg : args) {
-		arg.pushValue(L);
+		arg.pushValue(L, true);
 	}
 
 	// actually call the function now!

code/scripting/lua/LuaReference.cpp

@@ -80,10 +80,14 @@ bool UniqueLuaReference::isValid() const {
 	return true;
 }
 
-void UniqueLuaReference::pushValue(lua_State* thread) const
+void UniqueLuaReference::pushValue(lua_State* thread, bool manualStackAllocation) const
 {
 	Assertion(thread != nullptr, "Valid thread state must be specified!");
 
+	if (!manualStackAllocation) {
+		lua_checkstack(thread, 1);
+	}
+
 	if (this->isValid()) {
 		lua_rawgeti(thread, LUA_REGISTRYINDEX, this->getReference());
 	}

code/scripting/lua/LuaReference.h

@@ -100,8 +100,9 @@ class UniqueLuaReference {
 	/**
     * @brief Pushes the referenced value onto the stack.
     * @param thread A specific thread state to push the value to. nullptr for the default state of this reference
+	* @param manualStackAllocation Set to true if you manually allocate sufficient stack size before calling this function. Keep false unless you know what you are doing.
     */
-	void pushValue(lua_State* thread) const;
+	void pushValue(lua_State* thread, bool manualStackAllocation = false) const;
 };
 }
 

code/scripting/lua/LuaValue.cpp

@@ -88,10 +88,10 @@ bool LuaValue::isValid() const {
 	return _reference && _reference->isValid();
 }
 
-bool LuaValue::pushValue(lua_State* thread) const
+bool LuaValue::pushValue(lua_State* thread, bool manualStackAllocation) const
 {
 	if (this->_reference->isValid()) {
-		this->_reference->pushValue(thread);
+		this->_reference->pushValue(thread, manualStackAllocation);
 		return true;
 	} else {
 		return false;

code/scripting/lua/LuaValue.h

@@ -185,8 +185,9 @@ class LuaValue {
 	 * @brief Pushes this lua value onto the stack.
 	 * @param thread The thread stack onto which this value should be pushed. May be nullptr for the default state of
 	 * this value
+	 * @param manualStackAllocation Set to true if you manually allocate sufficient stack size before calling this function. Keep false unless you know what you are doing.
 	 */
-	bool pushValue(lua_State* thread) const;
+	bool pushValue(lua_State* thread, bool manualStackAllocation = false) const;
 
 	lua_State* getLuaState() const;