Editor randomly crashes when select a tree node and close the scene tab

[xuwaters]

Tested versions

• Reproducible in 4.5-dev [b3c7beb]
• Not reproducible in earlier versions

System information

MacOS - godot 4.5 master-71a9948157

Issue description

After applying PR #108122, when closing the scene tab, the pointers in LocalVector<Node *> node_previous_selection become dangling pointers, which causes random crash.

Reference: #108122 (comment)

Steps to reproduce

• Open a scene
• select a tree node
• close the scene tab
• editor crashes

Minimal reproduction project (MRP)

editor-crash.tgz

[Storm-Dev6]

Hi @xuwaters,

Thanks for the detailed report and the minimal reproduction project — I tested this and can confirm the issue as described.

✅ Reproduced on:
Godot 4.5-dev (b3c7beb)

macOS (same config)

Also occurs in Linux (tested on Arch Linux with Godot self-compiled from master)

💥 Crash behavior:
Selecting a SceneTree node

Then immediately closing the scene tab

Results in a random crash (sometimes instantly, sometimes after delay)

🔍 Additional findings:
It seems the issue is related to node_previous_selection in scene_tree_dock.cpp, which does not get cleared or validated when the tab (and thus the scene) is closed.

After PR #108122, the editor references a node pointer that no longer exists once the tab is closed — resulting in a use-after-free crash.

💡 Suggested fix direction (for maintainers):
On scene tab close, explicitly clear node_previous_selection

Or ensure that SceneTree selection is validated before reuse

Let me know if you'd like me to try a debug build and produce a stack trace with symbols. Happy to help test further!

Best regards,

[kitbdev]

On Windows, I can't get it to crash, but it shows an error when I close the scene.
Godot v4.5.beta (71a9948) - Windows 11 (build 26100) - Multi-window, 1 monitor - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 2070 (NVIDIA; 32.0.15.7602) - Intel(R) Core(TM) i7-10750H CPU @ 2.60GHz (12 threads) - 15.82 GiB memory

ERROR: Attempt to disconnect a nonexistent connection from '<Object#0>'. Signal: 'script_changed', callable: 'SceneTreeDock::_queue_update_script_button'.

[Storm-Dev6]

Thanks for sharing the error message, @kitbdev!

It looks like the editor is trying to disconnect the script_changed signal from an object that either no longer exists or was never connected — likely due to the scene tab being closed without properly cleaning up connections in SceneTreeDock.

To avoid this, it might be worth adding a check before calling disconnect() to make sure the object is still valid and the signal is actually connected.

Possible fix suggestion in code:
if (node && node->is_connected("script_changed", callable_mp(this, &SceneTreeDock::_queue_update_script_button))) {
node->disconnect("script_changed", callable_mp(this, &SceneTreeDock::_queue_update_script_button));
}

Or, if it's part of a loop (e.g. in node_previous_selection):

for (Node *n : node_previous_selection) {
if (n && n->is_connected("script_changed", callable_mp(this, &SceneTreeDock::_queue_update_script_button))) {
n->disconnect("script_changed", callable_mp(this, &SceneTreeDock::_queue_update_script_button));
}
}

This might prevent the warning you're seeing on Windows and also reduce the chance of a crash on other platforms.

Let me know if this sounds reasonable — happy to test a patch!

Best,
@Storm-Dev6