Fix regression with C# build editor crash due to EditorHelpHighlighter

[dalexeev]

• Fixes Godot (C#) source build frequently crashes on launch #89610.
• Fixes .Net / Windows / Main Branch: Editor Sometimes Crashes in Random Spot non-dev build #89709.

The crash is caused by double free.

Thread 1 "godot.linuxbsd." received signal SIGABRT, Aborted.

#0  __pthread_kill_implementation (no_tid=0, signo=6, threadid=<optimized out>) at ./nptl/pthread_kill.c:44
#1  __pthread_kill_internal (signo=6, threadid=<optimized out>) at ./nptl/pthread_kill.c:78
#2  __GI___pthread_kill (threadid=<optimized out>, signo=signo@entry=6) at ./nptl/pthread_kill.c:89
#3  0x00007ffff7c428e6 in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/raise.c:26
#4  0x00007ffff7c268b7 in __GI_abort () at ./stdlib/abort.c:79
#5  0x00007ffff7c27750 in __libc_message (fmt=fmt@entry=0x7ffff7dc3b34 "%s\n") at ../sysdeps/posix/libc_fatal.c:150
#6  0x00007ffff7ca3ce7 in malloc_printerr (str=str@entry=0x7ffff7dc6a40 "double free or corruption (!prev)") at ./malloc/malloc.c:5765
#7  0x00007ffff7ca5cdc in _int_free_merge_chunk (av=0x7ffff7dfeca0 <main_arena>, p=0x55555d673b80, size=880) at ./malloc/malloc.c:4672
#8  0x00007ffff7ca5fd9 in _int_free (av=0x7ffff7dfeca0 <main_arena>, p=<optimized out>, have_lock=<optimized out>) at ./malloc/malloc.c:4639
#9  0x00007ffff7ca8873 in __GI___libc_free (mem=<optimized out>) at ./malloc/malloc.c:3391
#10 0x0000555556de22ca in memdelete<Script> (p_class=0x55555d673ba0) at ./core/os/memory.h:119
#11 memdelete<Script> (p_class=0x55555d673ba0) at ./core/os/memory.h:111
#12 Ref<Script>::unref (this=0x55556fa21ad0) at ./core/object/ref_counted.h:210
#13 Ref<Script>::~Ref (this=0x55556fa21ad0, __in_chrg=<optimized out>) at ./core/object/ref_counted.h:223
#14 EditorHelpHighlighter::~EditorHelpHighlighter (this=0x55556fa21a50, __in_chrg=<optimized out>) at editor/editor_help.cpp:3579
#15 0x0000555556de4959 in memdelete<EditorHelpHighlighter> (p_class=0x55556fa21a50) at ./core/os/memory.h:111
#16 EditorHelpHighlighter::free_singleton () at editor/editor_help.cpp:3442
#17 0x0000555556eadadc in EditorNode::~EditorNode (this=0x55555fbcbb90, __in_chrg=<optimized out>) at editor/editor_node.cpp:7439
#18 0x0000555557e30772 in memdelete<Node> (p_class=0x55555fbcbb90) at ./core/os/memory.h:111
#19 memdelete<Node> (p_class=0x55555fbcbb90) at ./core/os/memory.h:111
#20 Node::_notification (this=0x55555fb5b950, p_notification=<optimized out>) at scene/main/node.cpp:235
#21 0x000055555a1e831e in Object::_predelete (this=0x55555fb5b950) at core/object/object.cpp:199
#22 predelete_handler (p_object=p_object@entry=0x55555fb5b950) at core/object/object.cpp:2135
#23 0x0000555557e7274f in memdelete<Window> (p_class=0x55555fb5b950) at ./core/os/memory.h:111
#24 SceneTree::finalize (this=0x55555fb5b440) at scene/main/scene_tree.cpp:630
#25 0x0000555555aff38c in main (argc=<optimized out>, argv=0x7fffffffe418) at platform/linuxbsd/godot_linuxbsd.cpp:86

I'm guessing this is related to SelfList:

godot/modules/mono/csharp_script.cpp

Lines 2841 to 2863 in 99ff024

	CSharpScript::CSharpScript() {
	_clear();
	#ifdef DEBUG_ENABLED
	{
	MutexLock lock(CSharpLanguage::get_singleton()->script_instances_mutex);
	CSharpLanguage::get_singleton()->script_list.add(&script_list);
	}
	#endif
	}
	CSharpScript::~CSharpScript() {
	#ifdef DEBUG_ENABLED
	{
	MutexLock lock(CSharpLanguage::get_singleton()->script_instances_mutex);
	CSharpLanguage::get_singleton()->script_list.remove(&script_list);
	}
	#endif
	if (GDMonoCache::godot_api_cache_updated) {
	GDMonoCache::managed_callbacks.ScriptManagerBridge_RemoveScriptBridge(this);
	}
	}

To save the C# highlighting, I added a hack to EditorStandardSyntaxHighlighter. In the future we should refactor, the highlighter should probably not depend on Script and TextEdit.

[paulloz]

Not 100% certain, but those feel related too? I'm quite positive for the first one, a little less so the other two.

• .Net / Windows / Main Branch: Editor Sometimes Crashes in Random Spot non-dev build #89709
• Godot (C#) on MacOS - Editor crashes on exit and sometimes when opening a project #89612
• macOS 4.3 dev5 crashes on attaching C# script #89722

[akien-mga]

Thanks!