Nodes Object field still contains object after actual object is deleted #81712

New Issue

Ivan Perevala · 2020-10-14T20:15:46+02:00

Ivan Perevala commented

2020-10-14 20:15:46 +02:00

System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 1050 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 456.55

Blender Version
Broken: version: 2.90.0, branch: master, commit date: 2020-08-31 11:26, hash: 0330d1af29
Worked: (newest version of Blender that worked as expected)

Short description of error

Exact steps for others to reproduce the error

Exact steps needed to reproduce the issue:
- Open default *.blend file or file bellow (in this case go to step 4)
- Add any shading node which contains pointer to Object (for example, "Texture Coordinates" node)
- Delete object you just selected
- Check outliner object list and list of objects in node Object field. In node field object is still alive.

nodes_bug.blend

**System Information** Operating system: Windows-10-10.0.18362-SP0 64 Bits Graphics card: GeForce GTX 1050 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 456.55 **Blender Version** Broken: version: 2.90.0, branch: master, commit date: 2020-08-31 11:26, hash: `0330d1af29` Worked: (newest version of Blender that worked as expected) **Short description of error** ![nodes_bug.png](https://archive.blender.org/developer/F8990872/nodes_bug.png) **Exact steps for others to reproduce the error** * Exact steps needed to reproduce the issue: - Open default *.blend file or file bellow (in this case go to step 4) - Add any shading node which contains pointer to Object (for example, "Texture Coordinates" node) - Delete object you just selected - Check outliner object list and list of objects in node `Object` field. In node field object is still alive. [nodes_bug.blend](https://archive.blender.org/developer/F8990887/nodes_bug.blend)

Ivan Perevala commented

2020-10-14 20:15:46 +02:00

Added subscriber: @ivpe

Ivan Perevala commented

2020-10-14 20:21:28 +02:00

Update: just to play with: after exact steps open blend file view mode in outliner and select deleted object. Than press NUM "." in the viewport and become confused much more.

Germano Cavalcante commented

2020-10-14 21:01:26 +02:00

Added subscribers: @Sergey, @mano-wii

Germano Cavalcante commented

2020-10-14 21:01:26 +02:00

Thanks for the report,

I can confirm and I agree that it is strange, but as that is a 'POINTER' property, this behavior is kind of expected :
What happens is that 'POINTER' properties add a reference to the object. They work almost like a Fake User.
So the object is not really deleted, it remains saved in the file until this reference is removed.

Perhaps this property could be of type 'STRING', so this problem would be solved since only the name would matter.

This feature was introduced in df07a25d
@Sergey, would changing the type of this property to 'STRING' be a good change?

Thanks for the report, I can confirm and I agree that it is strange, but as that is a `'POINTER'` property, this behavior is kind of expected :\ What happens is that `'POINTER'` properties add a reference to the object. They work almost like a `Fake User`. So the object is not really deleted, it remains saved in the file until this reference is removed. Perhaps this property could be of type `'STRING'`, so this problem would be solved since only the name would matter. This feature was introduced in df07a25d @Sergey, would changing the type of this property to `'STRING'` be a good change?

Ivan Perevala commented

2020-10-14 21:22:17 +02:00

@mano-wii thank you for quick answer! Actually, I think this bug may be much more deeper. I found it while trying to solve issues with my own project (#81662 ) while searching for BKE_libblock_unlink call stack. There Object* pointers behave in the same way as here, keeping deleted object pointer. And I think that same behaviour may be in much more other places. So I hope for more deeper solution than replacing pointer to name/also if I will have a bit more time, I will do it by myself (but currently all I can do - just report an issue;))

@mano-wii thank you for quick answer! Actually, I think this bug may be much more deeper. I found it while trying to solve issues with my own project ([#81662 ](https://developer.blender.org/T81662)) while searching for `BKE_libblock_unlink` call stack. There `Object*` pointers behave in the same way as here, keeping deleted object pointer. And I think that same behaviour may be in much more other places. So I hope for more deeper solution than replacing pointer to name/also if I will have a bit more time, I will do it by myself (but currently all I can do - just report an issue;))

Philipp Oeser commented

2020-10-15 09:46:38 +02:00

Added subscribers: @mont29, @lichtwerk

Philipp Oeser commented

2020-10-15 09:46:38 +02:00

Changed status from 'Needs Triage' to: 'Confirmed'

Philipp Oeser commented

2020-10-15 09:46:38 +02:00

@mano-wii: dont think changing this to a string would be good (breaks on renaming)

The deleted object will be removed from all scenes, collections, constraints usage on other objects, modifiers usage on other objects, ... more... but not materials on other objects.
Constraints and modifiers happens more or less automatically because these dont increase usercount - which means that when the object is deleted, it reaches zero users -- and will be gone completely.
I am a bit surprised that usage inside materials increases usercount, whereas usage inside constraints and modifiers doesnt.
If the usercount does not decrease for the material usage, the object does not reach zero users and thus will not be gone completely but kept instead.

This is probably a (design) question that @mont29 can answer best [but will confirm the behaviour for now -- even though this is probably by design]

Users can be checked with this snippet btw:

bpy.data.user_map(subset=(D.objects['Camera'], ))

@mano-wii: dont think changing this to a string would be good (breaks on renaming) The deleted object will be removed from all scenes, collections, constraints usage on other objects, modifiers usage on other objects, ... more... but not materials on other objects. Constraints and modifiers happens more or less automatically because these dont increase usercount - which means that when the object is deleted, it reaches zero users -- and will be gone completely. I am a bit surprised that usage inside materials increases usercount, whereas usage inside constraints and modifiers doesnt. If the usercount does not decrease for the material usage, the object does not reach zero users and thus will not be gone completely but kept instead. This is probably a (design) question that @mont29 can answer best [but will confirm the behaviour for now -- even though this is probably by design] Users can be checked with this snippet btw: ``` bpy.data.user_map(subset=(D.objects['Camera'], )) ```

Bastien Montagne commented

2020-10-15 11:16:32 +02:00

Changed status from 'Confirmed' to: 'Archived'

Bastien Montagne closed this issue

2020-10-15 11:16:32 +02:00

Bastien Montagne self-assigned this 2020-10-15 11:16:32 +02:00

Bastien Montagne commented

2020-10-15 11:16:32 +02:00

There is no bug here, if you want to fully nuke an object use shift-X (Delete Global) option.

There is no bug here, if you want to fully nuke an object use `shift-X` (Delete Global) option.

Philipp Oeser commented

2020-10-15 11:27:13 +02:00

In #81712#1034613, @mont29 wrote:
if you want to fully nuke an object use shift-X (Delete Global) option.

After all this time, I still wasnt aware of this one! Thx for the heads up!

> In #81712#1034613, @mont29 wrote: > if you want to fully nuke an object use `shift-X` (Delete Global) option. After all this time, I still wasnt aware of this one! Thx for the heads up!

Ivan Perevala commented

2020-10-15 11:38:50 +02:00

In #81712#1034613, @mont29 wrote:
There is no bug here, if you want to fully nuke an object use shift-X (Delete Global) option.

Yes, thats works!) I looked at documentation and (it was only just my own opinion) maybe it should be documented here?
https://docs.blender.org/manual/en/dev/scene_layout/object/editing/delete.html

> In #81712#1034613, @mont29 wrote: > There is no bug here, if you want to fully nuke an object use `shift-X` (Delete Global) option. Yes, thats works!) I looked at documentation and (it was only just my own opinion) maybe it should be documented here? https://docs.blender.org/manual/en/dev/scene_layout/object/editing/delete.html

Bastien Montagne commented

2020-10-15 13:22:24 +02:00

In #81712#1034648, @ivpe wrote:

In #81712#1034613, @mont29 wrote:
There is no bug here, if you want to fully nuke an object use shift-X (Delete Global) option.

Yes, thats works!) I looked at documentation and (it was only just my own opinion) maybe it should be documented here?
https://docs.blender.org/manual/en/dev/scene_layout/object/editing/delete.html

Good point, done, thanks

> In #81712#1034648, @ivpe wrote: >> In #81712#1034613, @mont29 wrote: >> There is no bug here, if you want to fully nuke an object use `shift-X` (Delete Global) option. > > Yes, thats works!) I looked at documentation and (it was only just my own opinion) maybe it should be documented here? > https://docs.blender.org/manual/en/dev/scene_layout/object/editing/delete.html Good point, done, thanks

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Nodes Object field still contains object after actual object is deleted #81712