ID User Decriment Error #84885

New Issue

Christopher Gearhart · 2021-01-20T06:21:55+01:00

2021-01-20 06:21:55 +01:00

System Information
Operating system: Mac OS
Graphics card: AMD Radeon Pro 5500M 8 GB

Blender Version
Broken: 2.80, 2.83, 2.91, and 2.92 from buildbot January 20th (c2e6969c56)
Worked: 2.79

Short description of error
I've been getting this error consistently since 2.80 and it still shows up in 2.91:

ERROR (bke.lib_id): /Users/blender/blender-buildbot/macos_291/blender.git/source/blender/blenkernel/intern/lib_id.c:292 id_us_min: ID user decrement error: OBcube (from '[Main]'): 1 <= 1

Blender occasionally crashes after this. I'm assuming the crash is related.

Exact steps for others to reproduce the error

I get the error when using an addon, and I've narrowed it down to the following cause:

A PointerProperty registered via the addon is set to an object (PointerProp is type bpy.types.Object, and is a sub-property of a PropertyGroup registered to the scene as a CollectionProperty; not sure if any of that's relevant)
The project is saved, then Blender & the project file are closed and reopened
The object prints the error above (starting with ERROR (bke.lib_id):...) when it is unlinked from the scene or deleted, or even if the PointerProperty from step 1 is referenced via code.

I've tried for a few hours now to recreate this in a simple situation with a basic script but I can't do it. It comes up very consistently when using the addon, and given my research I know where the error is coming from, but I'm not sure exactly what to do to simplify it and give exact steps to reproduce.

Please let me know what further information I need to give if any. I'm hoping the issue cropping up here will be apparent with what information I've already given.

EDIT: I've been asked to include the addon as well as an example file. Attached below:

bricker_v2-3-0_demo.zip ID User Decriment Error.blend

Exact steps to reproduce:

Open the attached blend file
Install the attached addon
Run {nav Bricker > Delete Model} from the right hand 'UI' menu
Note the error printed to the terminal. This printout comes from line 297 in 'bricker/operators/delete_model.py'

**System Information** Operating system: Mac OS Graphics card: AMD Radeon Pro 5500M 8 GB **Blender Version** Broken: 2.80, 2.83, 2.91, and 2.92 from buildbot January 20th (c2e6969c56ef) Worked: 2.79 **Short description of error** I've been getting this error consistently since 2.80 and it still shows up in 2.91: ``` ERROR (bke.lib_id): /Users/blender/blender-buildbot/macos_291/blender.git/source/blender/blenkernel/intern/lib_id.c:292 id_us_min: ID user decrement error: OBcube (from '[Main]'): 1 <= 1 ``` Blender occasionally crashes after this. I'm assuming the crash is related. **Exact steps for others to reproduce the error** I get the error when using an addon, and I've narrowed it down to the following cause: 1. A PointerProperty registered via the addon is set to an object (PointerProp is type `bpy.types.Object`, and is a sub-property of a PropertyGroup registered to the scene as a CollectionProperty; not sure if any of that's relevant) 3. The project is saved, then Blender & the project file are closed and reopened 4. The object prints the error above (starting with `ERROR (bke.lib_id):`...) when it is unlinked from the scene or deleted, or even if the PointerProperty from step 1 is referenced via code. I've tried for a few hours now to recreate this in a simple situation with a basic script but I can't do it. It comes up very consistently when using the addon, and given my research I know where the error is coming from, but I'm not sure exactly what to do to simplify it and give exact steps to reproduce. Please let me know what further information I need to give if any. I'm hoping the issue cropping up here will be apparent with what information I've already given. EDIT: I've been asked to include the addon as well as an example file. Attached below: [bricker_v2-3-0_demo.zip](https://archive.blender.org/developer/F9589608/bricker_v2-3-0_demo.zip) [ID User Decriment Error.blend](https://archive.blender.org/developer/F9589610/ID_User_Decriment_Error.blend) Exact steps to reproduce: 1. Open the attached blend file 2. Install the attached addon 3. Run {nav Bricker > Delete Model} from the right hand 'UI' menu 4. Note the error printed to the terminal. This printout comes from line 297 in 'bricker/operators/delete_model.py'

Christopher Gearhart commented

2021-01-20 06:21:55 +01:00

Added subscriber: @bblanimation

Philipp Oeser commented

2021-01-20 09:59:52 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2021-01-20 09:59:52 +01:00

Changed status from 'Needs Triage' to: 'Needs User Info'

Philipp Oeser commented

2021-01-20 09:59:52 +01:00

We also had e.g.
#71250 (ID user decrement error for Collections with ID properties in ViewLayer) or
#81345 (ID user decrement error when removing object which is referred to with a PointerProperty)

But to really proceedwith this issue, we'd have to have an example, reproducable script snippet where this happens.
Please continue to investigate if this can be reproduced in a simple scenario, as an alternative, you could also show this in the "real" Addon and share this here (with repro steps)

Will mark as "Needs Info from User" for now.

We also had e.g. #71250 (ID user decrement error for Collections with ID properties in ViewLayer) or #81345 (ID user decrement error when removing object which is referred to with a PointerProperty) But to really proceedwith this issue, we'd have to have an example, reproducable script snippet where this happens. Please continue to investigate if this can be reproduced in a simple scenario, as an alternative, you could also show this in the "real" Addon and share this here (with repro steps) Will mark as "Needs Info from User" for now.

Robert Guetzkow commented

2021-01-20 10:06:06 +01:00

Added subscriber: @rjg

Robert Guetzkow commented

2021-01-20 10:06:06 +01:00

Could you provide us with a link to the add-on? It might be that it is improperly implemented and does something that is not permitted. For instance it may keep references to data while modifying the container. Common mistakes that can lead to crashes are explained in the Gotcha page of the API docs.

Could you provide us with a link to the add-on? It might be that it is improperly implemented and does something that is not permitted. For instance it may keep references to data while modifying the container. Common mistakes that can lead to crashes are explained in the [Gotcha page ](https://docs.blender.org/api/current/info_gotcha.html#help-my-script-crashes-blender) of the API docs.

Bastien Montagne commented

2021-01-20 10:33:02 +01:00

Added subscriber: @mont29

Bastien Montagne commented

2021-01-20 10:33:02 +01:00

@lichtwerk please do not tag projects until report is fully validated. only adds noise in those projects then.

Christopher Gearhart commented

2021-01-20 16:09:39 +01:00

Sure thing – I've attached the addon as well as an example file above. I double checked the code where the error occurs and there are no lingering references to the data after it's removed, as far as I can tell.

Christopher Gearhart commented

2021-01-20 16:16:23 +01:00

Update: I also tried modifying the list created at line 284 of 'bricker/operators/delete_model.py' so that it simply stores the names of the objects rather than references to them. This didn't fix the issue - still got the same error.

Philipp Oeser commented

2021-01-20 19:01:26 +01:00

Changed status from 'Needs User Info' to: 'Needs Triage'

Philipp Oeser commented

2021-01-22 16:41:40 +01:00

First note: you are overriding existing operators:

OBJECT_OT_duplicate_move_override uses bl_idname = "object.duplicate_move"
OBJECT_OT_duplicate_override uses bl_idname = "object.duplicate"
OBJECT_OT_delete_override uses bl_idname = "object.delete"

Not 100% this is officially supported? Is this documented suggested somwhere?
Installing the Addon in a Debug build will already assert:

BLI_assert failed: source/blender/blenlib/intern/BLI_ghash.c:462, ghash_insert_ex(), at '(gh->flag & GHASH_FLAG_ALLOW_DUPES) || (BLI_ghash_haskey(gh, key) == 0)'

Simply tried renaming the operators (of course this will probably do something completely different then), Assert goes away, and the "ID user decrement error" also goes away.
WIth the original Addon, when removing Bricker_Cube_parent, it will have LIB_FAKEUSER, with my changes it wont.

First note: you are overriding existing operators: - OBJECT_OT_duplicate_move_override uses bl_idname = "object.duplicate_move" - OBJECT_OT_duplicate_override uses bl_idname = "object.duplicate" - OBJECT_OT_delete_override uses bl_idname = "object.delete" Not 100% this is officially supported? Is this documented suggested somwhere? Installing the Addon in a Debug build will already assert: ``` BLI_assert failed: source/blender/blenlib/intern/BLI_ghash.c:462, ghash_insert_ex(), at '(gh->flag & GHASH_FLAG_ALLOW_DUPES) || (BLI_ghash_haskey(gh, key) == 0)' ``` Simply tried renaming the operators (of course this will probably do something completely different then), Assert goes away, and the "ID user decrement error" also goes away. WIth the original Addon, when removing `Bricker_Cube_parent`, it will have `LIB_FAKEUSER`, with my changes it wont.

Philipp Oeser commented

2021-01-22 18:00:27 +01:00

Will need to have another look with fresh eyes (above is not the root cause, it is just another issue with this particular Addon).
Of course it would help to isolate this as much as possible {same as in #81345}, but will check again next week.

Will need to have another look with fresh eyes (above is not the root cause, it is just another issue with this particular Addon). Of course it would help to isolate this as much as possible {same as in #81345}, but will check again next week.

Philipp Oeser commented

2021-01-26 17:33:06 +01:00

Changed status from 'Needs Triage' to: 'Needs User Info'

Philipp Oeser commented

2021-01-26 17:33:06 +01:00

@bblanimation: sorry, but given the fact that this might turn out to be a bag of mixed issues, I would like to ask for a simplified / more isolated example code snippet.

Philipp Oeser commented

2021-02-11 17:43:20 +01:00

Changed status from 'Needs User Info' to: 'Archived'

Philipp Oeser closed this issue

2021-02-11 17:43:20 +01:00

Philipp Oeser commented

2021-02-11 17:43:20 +01:00

Afraid we have to close this now, please report this again if you can isolate this to a minimal script example as in #81345.

No activity for more than a week. As per the tracker policy we assume the issue is gone and can be closed.
Thanks again for the report. If the problem persists please open a new report with the required information.

Afraid we have to close this now, please report this again if you can isolate this to a minimal script example as in #81345. No activity for more than a week. As per the tracker policy we assume the issue is gone and can be closed. Thanks again for the report. If the problem persists please open a new report with the required information.

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ID User Decriment Error #84885