Random crash when trying to open a scene

[KoBeWi]

Godot version

4.2 eb4301b

System information

Windows 10.0.19045 - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1060 (NVIDIA; 30.0.15.1403) - Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz (8 Threads)

Issue description

Sometimes when trying to open a scene from filesystem dock, the editor will crash. It happened 3 times to me already, but I don't know what exactly causes it.

[0] FileSystemDock::_select_file (C:\godot_source\editor\filesystem_dock.cpp:1115)
[1] FileSystemDock::_select_file (C:\godot_source\editor\filesystem_dock.cpp:1115)
[2] FileSystemDock::_tree_activate_file (C:\godot_source\editor\filesystem_dock.cpp:1187)
[3] call_with_variant_args_helper<FileSystemDock> (C:\godot_source\core\variant\binder_common.h:308)
[4] call_with_variant_args<FileSystemDock> (C:\godot_source\core\variant\binder_common.h:418)
[5] CallableCustomMethodPointer<FileSystemDock>::call (C:\godot_source\core\object\callable_method_pointer.h:105)
[6] Callable::callp (C:\godot_source\core\variant\callable.cpp:51)
[7] Object::emit_signalp (C:\godot_source\core\object\object.cpp:1073)
[8] Node::emit_signalp (C:\godot_source\scene\main\node.cpp:3577)
[9] Object::emit_signal<> (C:\godot_source\core\object\object.h:891)
[10] Tree::gui_input (C:\godot_source\scene\gui\tree.cpp:3867)
[11] Control::_call_gui_input (C:\godot_source\scene\gui\control.cpp:1806)
[12] Viewport::_gui_call_input (C:\godot_source\scene\main\viewport.cpp:1565)
[13] Viewport::_gui_input_event (C:\godot_source\scene\main\viewport.cpp:1794)
[14] Viewport::push_input (C:\godot_source\scene\main\viewport.cpp:3129)
[15] Window::_window_input (C:\godot_source\scene\main\window.cpp:1482)
[16] call_with_variant_args_helper<Window,Ref<InputEvent> const &,0> (C:\godot_source\core\variant\binder_common.h:303)
[17] call_with_variant_args<Window,Ref<InputEvent> const &> (C:\godot_source\core\variant\binder_common.h:418)
[18] CallableCustomMethodPointer<Window,Ref<InputEvent> const &>::call (C:\godot_source\core\object\callable_method_pointer.h:105)
[19] Callable::callp (C:\godot_source\core\variant\callable.cpp:51)
[20] DisplayServerWindows::_dispatch_input_event (C:\godot_source\platform\windows\display_server_windows.cpp:2612)
[21] DisplayServerWindows::_dispatch_input_events (C:\godot_source\platform\windows\display_server_windows.cpp:2577)
[22] Input::_parse_input_event_impl (C:\godot_source\core\input\input.cpp:722)
[23] Input::flush_buffered_events (C:\godot_source\core\input\input.cpp:979)
[24] DisplayServerWindows::process_events (C:\godot_source\platform\windows\display_server_windows.cpp:2296)
[25] OS_Windows::run (C:\godot_source\platform\windows\os_windows.cpp:1479)
[26] widechar_main (C:\godot_source\platform\windows\godot_windows.cpp:182)
[27] _main (C:\godot_source\platform\windows\godot_windows.cpp:204)
[28] main (C:\godot_source\platform\windows\godot_windows.cpp:218)
[29] WinMain (C:\godot_source\platform\windows\godot_windows.cpp:232)
[30] __scrt_common_main_seh (D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288)
[31] <couldn't map PC to fn name>

Steps to reproduce

1. Open a project
2. Open a scene

I think the scene needs to be opened early enough.

Minimal reproduction project

N/A

[YuriSizov]

I've also experienced a crash today after trying to open a scene from the filesystem dock. It was a project that I hadn't touched in a bit, and the debugger pointed to some code related to ResourceImporterTexture. Happened only once.

Edit: I was mistaken, it's the scene importer.

[KoBeWi]

Is this a sequel to #79999? 🤔

I looked at #79981 again. Apparently there can be multiple ResourceImporterTexture instances. So I guess this can trigger crash:

1. ResourceImporterTexture A gets created
2. Singleton is assigned to ResourceImporterTexture A
3. ResourceImporterTexture B gets created
4. ResourceImporterTexture A is destroyed
5. There is no ResourceImporterTexture singleton anymore

If threading is involved it could probably happen, idk.

[YuriSizov]

I haven't looked into the reasoning, but it feels very wrong that this class can have multiple instances (reasonably), but also has a singleton which can be assigned to any instance that was created first. Why do we need a singleton? If we really need it, then we should initialize (and destroy) one instance in main.cpp or something.

[aaronfranke]

I am getting the same crash on macOS, here is the stack trace (I shortened godot.macos.editor.arm64 to godot):

0   ???   0x600003c42650 ???
1   godot    0x104421fd8 FileSystemDock::_tree_activate_file() + 388
2   godot    0x106edb57c Object::emit_signalp(StringName const&, Variant const**, int) + 492
3   godot    0x105329800 Tree::gui_input(Ref<InputEvent> const&) + 7004
4   godot    0x1050dce38 Control::_call_gui_input(Ref<InputEvent> const&) + 616
5   godot    0x104fd90e0 Viewport::_gui_call_input(Control*, Ref<InputEvent> const&) + 484
6   godot    0x104fda018 Viewport::_gui_input_event(Ref<InputEvent>) + 1380
7   godot    0x104fe11e0 Viewport::push_input(Ref<InputEvent> const&, bool) + 756
8   godot    0x10501ed40 Window::_window_input(Ref<InputEvent> const&) + 608
9   godot    0x10503c6b0 0x102958000 + 40781488
10  godot    0x102cc81a4 DisplayServerMacOS::_dispatch_input_event(Ref<InputEvent> const&) + 448
11  godot    0x106abb2a4 Input::_parse_input_event_impl(Ref<InputEvent> const&, bool) + 3952
12  godot    0x106ab8718 Input::flush_buffered_events() + 136
13  godot    0x102cdc824 DisplayServerMacOS::process_events() + 472
14  godot    0x102cc20e4 OS_MacOS::run() + 104
15  godot    0x102ceb9b0 main + 304
16  dyld     0x183fdbf28 start + 2236

[YuriSizov]

I was mistaken, it's the scene importer. scene_singleton is empty. Which is a valid possibility because that's the constructor:

ResourceImporterScene::ResourceImporterScene(bool p_animation_import) {
	if (p_animation_import) {
		animation_singleton = this;
	} else {
		scene_singleton = this;
	}
	animation_importer = p_animation_import;
}

Edit: Seems that both instances are created in the EditorNode constructor. However, these are reference counted instances, so I guess at some point we get into a state where nothing references them and they get destroyed?