Crash on undo: Unlinking Scene Collection from Object Properties panel #126549

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Albert-OShea · 2024-08-20T14:28:52+02:00

Albert-OShea commented

2024-08-20 14:28:52 +02:00

System Information
Operating system: Windows-10-10.0.22621-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 536.99

Blender Version
Broken: version: 4.2.1 LTS, branch: blender-v4.2-release, commit date: 2024-08-19 11:21, hash: 396f546c9d82
Worked: 4.1

Short description of error
Blender can crash when undoing an attempt at unlinking the Scene Collection through object properties (shouldn't this be impossible in the first place?)

Exact steps for others to reproduce the error

In provided blend file, go to the Object Properties of the Cube.

Go to the Collections panel. Click the dropdown next to Scene Collection, then click Unlink Collection.

Once the Cube is gone, undo that step. Sometimes Blender will immediately crash upon doing this once, sometimes it takes a few repeats before it crashes.

**System Information** Operating system: Windows-10-10.0.22621-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 536.99 **Blender Version** Broken: version: 4.2.1 LTS, branch: blender-v4.2-release, commit date: 2024-08-19 11:21, hash: `396f546c9d82` Worked: 4.1 **Short description of error** Blender can crash when undoing an attempt at unlinking the Scene Collection through object properties (shouldn't this be impossible in the first place?) **Exact steps for others to reproduce the error** In provided blend file, go to the Object Properties of the Cube. Go to the Collections panel. Click the dropdown next to `Scene Collection`, then click Unlink Collection. ![Screenshot 2024-08-20 222219.png](/attachments/e7710470-17f5-4461-95d6-be51ca0ff70e) Once the Cube is gone, undo that step. Sometimes Blender will immediately crash upon doing this once, sometimes it takes a few repeats before it crashes.

Screenshot 2024-08-20 222219.png

487 KiB

scene_collection_crash.blend

656 KiB

Albert-OShea added the

labels 2024-08-20 14:28:53 +02:00

Pratik Borhade commented

2024-08-21 05:28:49 +02:00

Hi, thanks for the report. Can confirm the crash (works perfect in 4.1)

Pratik Borhade added

and removed

labels 2024-08-21 05:29:03 +02:00

Pratik Borhade commented

2024-08-21 05:48:37 +02:00

Tracking down the exact commit is bit hard since crash is bit intermittent (sometimes crashes on operator execution, on undo, reopening the file, etc.)

Pratik Borhade commented

2024-08-21 07:05:16 +02:00

Looks like scene collection id is freed id_free(bmain, id, free_flag, false); in id_delete().
AFAICS, this was not the case in 4.1 (object was present in scene after operator execution)
I suspect crash introduced with f2e481a519
@mont29 ^

Looks like scene collection id is freed `id_free(bmain, id, free_flag, false);` in `id_delete()`. AFAICS, this was not the case in 4.1 (object was present in scene after operator execution) I suspect crash introduced with f2e481a5197b128fa89c3bf5ae2eb7f77037c3d9 @mont29 ^

Bastien Montagne commented

2024-08-21 11:39:03 +02:00

This has nothing to do with f2e481a519 I believe, and i do not know how this could have worked in 4.1 or ever. Issue here is this 'unlink collection' operator allowing to unlink a Scene main collection, which is totally forbidden and unsupported.

I suspect that previously low-level delete ID code would fail to delete that main collection, while new code is rightfully not doing such a check (this should be the responsibility of calling code).

Fix incoming.

This has nothing to do with f2e481a519 I believe, and i do not know how this could have worked in 4.1 or ever. Issue here is this 'unlink collection' operator allowing to unlink a Scene main collection, which is totally forbidden and unsupported. I suspect that previously low-level delete ID code would fail to delete that main collection, while new code is rightfully not doing such a check (this should be the responsibility of calling code). Fix incoming.

👍 1

Bastien Montagne referenced this issue from a commit

2024-08-21 11:48:17 +02:00

Fix #126549: Forbid unlinking Scene main collection.

Bastien Montagne closed this issue

2024-08-21 11:48:18 +02:00

Blender Bot added

and removed