Using RefCounted objects as thread bind parameters causes segfault on exit

[SpiceOctopus]

Tested versions

• Reproducible in 4.3

System information

Linux 6.12.7 and Windows 11. Appears to be system independent.

Issue description

Binding an object that inherits from RefCounted to a callable that is passed to WorkerThreadPool.add_task() will produce a stale reference.

I am not entirely sure at which point it is missing a decrement (or if that is something I should be handling manually).
The behavior does seem unintended.

Steps to reproduce

func _ready():
	var test = TestObject.new() # empty object that extends RefCounted
	print(test.get_reference_count()) # prints 1
	var id = WorkerThreadPool.add_task(threadproc.bind(test))
	WorkerThreadPool.wait_for_task_completion(id)
	print(test.get_reference_count()) # prints 2

func threadproc(obj : RefCounted):
	print(obj.get_reference_count()) # prints 3

Run as a build outside of the editor, close the program -> segfault on exit. On Windows the program will crash on exit and write EventLog entries.

Minimal reproduction project (MRP)

Archive.zip

[matheusmdx]

I was unable to reproduce this issue, tested both in editor and in exported version. I added prints in the TestObject._init and in the predelete notification, the object inits normally, do the prints 1, 3 and 2 and after print the predelete notification, no crashes or logs when i close the program.

Godot v4.3.stable - Windows 10.0.19045 - Vulkan (Forward+) - dedicated AMD Radeon RX 580 2048SP (Advanced Micro Devices, Inc.; 31.0.21921.1000) - AMD Ryzen 5 3600 6-Core Processor (12 Threads)

[SpiceOctopus]

This is strange, when I tested earlier this was causing segfaults with 100% reproducibility.
When I test that same code again it does not do it now. Maybe I messed up an export.

If I remove the WorkerThreadPool.wait_for_task_completion(id) it will segfault again.

This might play into another problem.
WorkerThreadPool.wait_for_task_completion() has been weirdly unreliable for me in the past.
The documentation states that it must be called for any started task. Yet whenever I implemented it that way it would error out and tell me that the task does not exist when called after the task had finished.