Intermittent crash when saving edited script resources

[AberrantWolf]

Godot version:
4.0 (5f63682)

OS/device including version:
Windows 10 (10.0.19041)
64-bit build, observed on 64-bit debug/release-debug builds (others not attempted)

Issue description:
The Godot editor crashes (eventually) when saving a modified GDScript resource.

Steps to reproduce:

1. Create and open a new project.
2. Turn your scene into a 2D scene (haven't tried with 3D).
3. Select the root node and add a new script in the "Script" option of the inspector.
4. Accept the default options.
5. In the script editor, add or remove whitespace.
6. Save (via Ctrl+S -- accept the defaults for any prompts which may show up the first time)
7. Repeat steps 5 and 6 several times (always changing something each time).
8. After a half-dozen saves, the editor will crash.

I tracked the crash down what appears to be a String assignment/copy on line 1857 of script_editor_plugin.cpp, where the String path is assigned. The assignment goes into the CowData::_ref function, but the incoming reference appears to be invalid, even though if I navigate up the stack frame and examine what appears to be the relevant structures directly, the string which I believe is being assigned appears to be a valid string.

[ThakeeNathees]

I can conform the crash. (I've experience this before didn't know how to reproduce)
backtrace

>	godot.windows.tools.64.exe!CowData<wchar_t>::_ref(const CowData<wchar_t> & p_from) Line 349	C++
 	godot.windows.tools.64.exe!String::String(const String & p_str) Line 354	C++
 	godot.windows.tools.64.exe!Resource::get_path() Line 95	C++
 	godot.windows.tools.64.exe!ScriptEditor::_update_script_names() Line 1857	C++
 	godot.windows.tools.64.exe!ScriptEditor::_filesystem_changed() Line 2422	C++
 	godot.windows.tools.64.exe!call_with_variant_args_helper<ScriptEditor>(ScriptEditor * p_instance, void(ScriptEditor::*)() p_method, const Variant * * p_args, Callable::CallError & r_error, IndexSequence<> __formal) Line 136	C++
 	godot.windows.tools.64.exe!call_with_variant_args<ScriptEditor>(ScriptEditor * p_instance, void(ScriptEditor::*)() p_method, const Variant * * p_args, int p_argcount, Callable::CallError & r_error) Line 158	C++
 	godot.windows.tools.64.exe!CallableCustomMethodPointer<ScriptEditor>::call(const Variant * * p_arguments, int p_argcount, Variant & r_return_value, Callable::CallError & r_call_error) Line 185	C++
 	godot.windows.tools.64.exe!Callable::call(const Variant * * p_arguments, int p_argcount, Variant & r_return_value, Callable::CallError & r_call_error) Line 50	C++
 	godot.windows.tools.64.exe!Object::emit_signal(const StringName & p_name, const Variant * * p_args, int p_argcount) Line 1077	C++
 	godot.windows.tools.64.exe!Object::_emit_signal(const Variant * * p_args, int p_argcount, Callable::CallError & r_error) Line 1009	C++
 	godot.windows.tools.64.exe!MethodBindVarArg<Object>::call(Object * p_object, const Variant * * p_args, int p_arg_count, Callable::CallError & r_error) Line 333	C++
 	godot.windows.tools.64.exe!Object::call(const StringName & p_method, const Variant * * p_args, int p_argcount, Callable::CallError & r_error) Line 797	C++
 	godot.windows.tools.64.exe!Callable::call(const Variant * * p_arguments, int p_argcount, Variant & r_return_value, Callable::CallError & r_call_error) Line 52	C++
 	godot.windows.tools.64.exe!MessageQueue::_call_function(const Callable & p_callable, const Variant * p_args, int p_argcount, bool p_show_error) Line 259	C++
 	godot.windows.tools.64.exe!MessageQueue::flush() Line 306	C++
 	godot.windows.tools.64.exe!SceneTree::iteration(float p_time) Line 415	C++
 	godot.windows.tools.64.exe!Main::iteration() Line 2375	C++
 	godot.windows.tools.64.exe!OS_Windows::run() Line 627	C++
 	godot.windows.tools.64.exe!widechar_main(int argc, wchar_t * * argv) Line 163	C++
 	godot.windows.tools.64.exe!_main() Line 185	C++
 	godot.windows.tools.64.exe!main(int argc, char * * argv) Line 199	C++
 	godot.windows.tools.64.exe!WinMain(HINSTANCE__ * hInstance, HINSTANCE__ * hPrevInstance, char * lpCmdLine, int nCmdShow) Line 213	C++
 	[Inline Frame] godot.windows.tools.64.exe!invoke_main() Line 102	C++
 	godot.windows.tools.64.exe!__scrt_common_main_seh() Line 288	C++
 	kernel32.dll!00007ffb29437bd4()	Unknown
 	ntdll.dll!00007ffb2ac2ce51()	Unknown

[Xrayez]

Reverting #40647 helps the crash with the call stack above, but then I get another crash while repeating the same reproduction steps (Windows 10 too):

godot.windows.tools.64.exe!Node::get_configuration_warning() Line 2675 (d:\src\godot\4\scene\main\node.cpp:2675)
godot.windows.tools.64.exe!SceneTreeEditor::_add_nodes(Node * p_node, TreeItem * p_parent) Line 253 (d:\src\godot\4\editor\scene_tree_editor.cpp:253)
godot.windows.tools.64.exe!SceneTreeEditor::_update_tree() Line 530 (d:\src\godot\4\editor\scene_tree_editor.cpp:530)
godot.windows.tools.64.exe!MethodBind0<SceneTreeEditor>::call(Object * p_object, const Variant * * p_args, int p_arg_count, Callable::CallError & r_error) Line 149 (d:\src\godot\4\core\method_bind.gen.inc:149)
godot.windows.tools.64.exe!Object::call(const StringName & p_method, const Variant * * p_args, int p_argcount, Callable::CallError & r_error) Line 797 (d:\src\godot\4\core\object.cpp:797)
godot.windows.tools.64.exe!Callable::call(const Variant * * p_arguments, int p_argcount, Variant & r_return_value, Callable::CallError & r_call_error) Line 52 (d:\src\godot\4\core\callable.cpp:52)
godot.windows.tools.64.exe!MessageQueue::_call_function(const Callable & p_callable, const Variant * p_args, int p_argcount, bool p_show_error) Line 259 (d:\src\godot\4\core\message_queue.cpp:259)
godot.windows.tools.64.exe!MessageQueue::flush() Line 306 (d:\src\godot\4\core\message_queue.cpp:306)
godot.windows.tools.64.exe!SceneTree::iteration(float p_time) Line 415 (d:\src\godot\4\scene\main\scene_tree.cpp:415)
godot.windows.tools.64.exe!Main::iteration() Line 2375 (d:\src\godot\4\main\main.cpp:2375)
godot.windows.tools.64.exe!OS_Windows::run() Line 627 (d:\src\godot\4\platform\windows\os_windows.cpp:627)
godot.windows.tools.64.exe!widechar_main(int argc, wchar_t * * argv) Line 163 (d:\src\godot\4\platform\windows\godot_windows.cpp:163)
godot.windows.tools.64.exe!_main() Line 185 (d:\src\godot\4\platform\windows\godot_windows.cpp:185)
godot.windows.tools.64.exe!main(int argc, char * * argv) Line 199 (d:\src\godot\4\platform\windows\godot_windows.cpp:199)
godot.windows.tools.64.exe!WinMain(HINSTANCE__ * hInstance, HINSTANCE__ * hPrevInstance, char * lpCmdLine, int nCmdShow) Line 213 (d:\src\godot\4\platform\windows\godot_windows.cpp:213)
[Inline Frame] godot.windows.tools.64.exe!invoke_main() Line 102 (d:\agent\_work\4\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:102)
godot.windows.tools.64.exe!__scrt_common_main_seh() Line 288 (d:\agent\_work\4\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288)
kernel32.dll!00007ffb7cf77bd4() (Unknown Source:0)
ntdll.dll!00007ffb7d8cce51() (Unknown Source:0)

So I'm not sure if there's something wrong with #40647 or it may have just revealed some regression (need bisect?)

@ThakeeNathees @AberrantWolf for how long have you experienced this crash?

[AberrantWolf]

for how long have you experienced this crash?

I've only been building from code for the last 3 days. Definitely from yesterday, though. Possibly not the day before, but I don't recall (and didn't edit much code that day).

[ThakeeNathees]

for how long have you experienced this crash?

me too yesterday. must be caused by a very recent change.

[Xrayez]

Should be fixed by #41399. All those crashes are related to script resources being manually unreferenced in a thread, which explains intermittent crashes, so indeed #40647 is not a cause.

for how long have you experienced this crash?

me too yesterday. must be caused by a very recent change.

Yeah it is caused by #41359.