From 686cab81846fecc79959656ef9355be82c2214e6 Mon Sep 17 00:00:00 2001
From: jakubg1 <24206305+jakubg1@users.noreply.github.com>
Date: Wed, 1 Apr 2026 02:10:00 +0200
Subject: [PATCH] Fix a segfault when calling `api.dynobj_putvalues()`

An undocumented change from the previous commit:
- When the Lua script is not able to find an object, the message is now printed to `errors.txt`, not just to `log.txt`.
---
 scripting/lua.cpp | 30 ++++++++++++++++++++++++------
 scripting/lua.h   |  4 ++--
 2 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/scripting/lua.cpp b/scripting/lua.cpp
index e9932f19..91fb8df2 100644
--- a/scripting/lua.cpp
+++ b/scripting/lua.cpp
@@ -98,6 +98,27 @@ void lua::push_memcell_values(lua_State *L, const TMemCell *mc)
 	lua_settable(L, -3);
 }
 
+memcell_values lua::get_memcell_values(lua_State *L)
+{
+	memcell_values mc{nullptr, 0.0, 0.0};
+	lua_pushstring(L, "str");
+	lua_gettable(L, -2);
+	if (lua_isstring(L, -1))
+		mc.str = lua_tostring(L, -1);
+	lua_pop(L, 1);
+	lua_pushstring(L, "num1");
+	lua_gettable(L, -2);
+	if (lua_isnumber(L, -1))
+		mc.num1 = lua_tonumber(L, -1);
+	lua_pop(L, 1);
+	lua_pushstring(L, "num2");
+	lua_gettable(L, -2);
+	if (lua_isnumber(L, -1))
+		mc.num2 = lua_tonumber(L, -1);
+	lua_pop(L, 1);
+	return mc;
+}
+
 int lua::scriptapi_event_create(lua_State *L)
 {
 	std::string name = lua_tostring(L, 1);
@@ -261,17 +282,14 @@ int lua::scriptapi_train_getname(lua_State *L)
 int lua::scriptapi_dynobj_putvalues(lua_State *L)
 {
 	auto *dyn = static_cast<TDynamicObject *>(lua_touserdata(L, 1));
-	auto *mc = static_cast<memcell_values *>(lua_touserdata(L, 2));
-	std::string str = mc->str;
-	double num1 = mc->num1;
-	double num2 = mc->num2;
+	auto [str, num1, num2] = get_memcell_values(L);
 	if (!dyn)
 		return 0;
 	TLocation loc{};
 	if (dyn->Mechanik)
-		dyn->Mechanik->PutCommand(std::string(str), num1, num2, loc);
+		dyn->Mechanik->PutCommand(str, num1, num2, loc);
 	else
-		dyn->MoverParameters->PutCommand(std::string(str), num1, num2, loc);
+		dyn->MoverParameters->PutCommand(str, num1, num2, loc);
 	return 0;
 }
 
diff --git a/scripting/lua.h b/scripting/lua.h
index bb5359f9..1578ffd8 100644
--- a/scripting/lua.h
+++ b/scripting/lua.h
@@ -5,6 +5,7 @@
 class basic_event;
 class TMemCell;
 class TDynamicObject;
+struct memcell_values { const char *str; double num1; double num2; };
 
 class lua
 {
@@ -44,6 +45,5 @@ public:
 	static void unref(lua_State *L, int ref);
 	static void dispatch_event(lua_State *L, int handler, basic_event *event, const TDynamicObject *activator);
 	static void push_memcell_values(lua_State *L, const TMemCell *mc);
-
-	struct memcell_values { const char *str; double num1; double num2; };
+	static memcell_values get_memcell_values(lua_State *L);
 };