Race condition resulting in use after free in `WidgetInfo::PathChanged`

Operating System Info

Windows 11

Other OS

No response

OBS Studio Version

30.1.0

OBS Studio Version (Other)

No response

OBS Studio Log URL

https://obsproject.com/logs/aP4AAo30fJPRYWhb

OBS Studio Crash Log URL

https://obsproject.com/logs/Ol0L0Xm59rUj0a5b

Expected Behavior

There should not be a race condition.

Current Behavior

WidgetInfo::PathChanged is called when clicking the button to change a path, which pops up the dialog box for choosing a path. If the widgets refresh in the meantime, while the dialog box is open, the underlying path widget gets destructed underneath, meaning that when returning from the dialog box a use after free happens and OBS crashes.

Steps to Reproduce

1. Click the button to change a path.
2. Trigger a properties refresh in the meantime via obs_source_update_properties.
3. The widgets now get rebuilt and the currently in use path widget gets destructed.
4. Close the dialog box by choosing a path.
5. The use after free happens and OBS crashes.

Anything else we should know?

One variant of the dialog box gets opened here:
https://github.com/obsproject/obs-studio/blob/69e7eb2c7de9a530bae955b00217c1caaf006d54/UI/properties-view.cpp#L1815-L1823

Use after free then triggered here:
https://github.com/obsproject/obs-studio/blob/69e7eb2c7de9a530bae955b00217c1caaf006d54/UI/properties-view.cpp#L1833-L1834

Start with UI/properties-view.cpp around lines 1815-1834, reading the dialog-opening path and the WidgetInfo::PathChanged callback. Reproduce the five steps while triggering obs_source_update_properties during the dialog, then verify the path-selection workflow no longer crashes when the widgets refresh.