From 7c4a0f7abd76b316a95026dd760f893c6fab832b Mon Sep 17 00:00:00 2001
From: Vankata453 <78196474+Vankata453@users.noreply.github.com>
Date: Mon, 22 Jan 2024 20:47:02 +0200
Subject: [PATCH] Fix crash when performing undo/redo on deleted object

Previously, an assertion was used for performing this check, which was the cause of the crash. It wasn't taken into account performing undo/redo on a remotely-deleted object.

Additionally, the warning message now includes the class name of the object.
---
 src/supertux/game_object_manager.cpp | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/supertux/game_object_manager.cpp b/src/supertux/game_object_manager.cpp
index 8c170d77cf..64245f867b 100644
--- a/src/supertux/game_object_manager.cpp
+++ b/src/supertux/game_object_manager.cpp
@@ -394,7 +394,7 @@ GameObjectManager::apply_object_change(const GameObjectChange& change, bool trac
     case GameObjectChange::Action::DELETE:
     {
       if (!object)
-        throw std::runtime_error("Object does not exist.");
+        throw std::runtime_error("Object '" + change.name + "' does not exist.");
 
       object->m_track_undo = track_undo;
       object->remove_me();
@@ -404,7 +404,7 @@ GameObjectManager::apply_object_change(const GameObjectChange& change, bool trac
     case GameObjectChange::Action::MODIFY:
     {
       if (!object)
-        throw std::runtime_error("Object does not exist.");
+        throw std::runtime_error("Object '" + change.name + "' does not exist.");
 
       auto settings = object->get_settings();
       if (track_undo)
@@ -544,7 +544,8 @@ GameObjectManager::process_object_change(GameObjectChange& change)
   {
     case GameObjectChange::Action::CREATE: /** Object was added, remove it. */
     {
-      assert(object);
+      if (!object)
+        throw std::runtime_error("Object '" + change.name + "' no longer exists.");
 
       object->m_track_undo = false;
       object->remove_me();
@@ -566,7 +567,8 @@ GameObjectManager::process_object_change(GameObjectChange& change)
 
     case GameObjectChange::Action::MODIFY: /** Object was modified, revert settings. */
     {
-      assert(object);
+      if (!object)
+        throw std::runtime_error("Object '" + change.name + "' no longer exists.");
 
       auto settings = object->get_settings();
       settings.save_state();