Cloning materials with too smart ShaderNodeCustomGroup breaks user counters of both source and target nodes #72317

New Issue

Maxim Vasiliev · 2019-12-10T00:33:10+01:00

Maxim Vasiliev commented

2019-12-10 00:33:10 +01:00

System Information
Operating system: Linux-5.0.0-37-generic-x86_64-with-debian-buster-sid 64 Bits
Graphics card: GeForce GT 730/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 418.56

Blender Version
Broken: version: 2.82 (sub 4), branch: master, commit date: 2019-12-08 18:49, hash: 761111efb8
Worked: (optional)

Short description of error
Some of my shader nodes need to have separate node trees for each their copies.

It seems quite legal to do like this:

    def copy(self, node):
        self.node_tree = bpy.data.node_groups.new('newtree', 'ShaderNodeTree')

When the material is cloned (via ops.material.new), it makes the original tree.users == 0, and new tree.users == 2
Source node becomes zombie and dies after reloading or orphan cleaning.
Target node becomes undead and cannot die because of zero users.

Exact steps for others to reproduce the error

run attached script from command line: blender --factory-startup --background --python test_op_mat_clone.py
observe output: all trees are expected to have 1 users

test_op_mat_clone.py

**System Information** Operating system: Linux-5.0.0-37-generic-x86_64-with-debian-buster-sid 64 Bits Graphics card: GeForce GT 730/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 418.56 **Blender Version** Broken: version: 2.82 (sub 4), branch: master, commit date: 2019-12-08 18:49, hash: `761111efb8` Worked: (optional) **Short description of error** Some of my shader nodes need to have separate node trees for each their copies. It seems quite legal to do like this: ``` def copy(self, node): self.node_tree = bpy.data.node_groups.new('newtree', 'ShaderNodeTree') ``` When the material is cloned (via `ops.material.new`), it makes the original tree.users == 0, and new tree.users == 2 Source node becomes zombie and dies after reloading or orphan cleaning. Target node becomes undead and cannot die because of zero users. **Exact steps for others to reproduce the error** 1. run attached script from command line: `blender --factory-startup --background --python test_op_mat_clone.py` 2. observe output: all trees are expected to have 1 users [test_op_mat_clone.py](https://archive.blender.org/developer/F8233166/test_op_mat_clone.py)

Maxim Vasiliev commented

2019-12-10 00:33:10 +01:00

Added subscriber: @qwiglydee

Maxim Vasiliev commented

2019-12-10 06:36:38 +01:00

This comment was removed by @qwiglydee

*This comment was removed by @qwiglydee*

Maxim Vasiliev changed title from ~~Copying materials with custom nodes messes up users counters and may produce bogus orphaned and overused trees~~ to Copying materials (or single-usering node groups) with custom nodes messes up users counters and may produce bogus orphaned and overused trees

2019-12-10 09:19:13 +01:00

Maxim Vasiliev commented

2019-12-10 10:47:57 +01:00

This comment was removed by @qwiglydee

*This comment was removed by @qwiglydee*

Simon Wendsche commented

2019-12-10 12:03:26 +01:00

Added subscriber: @BYOB

Maxim Vasiliev changed title from ~~Copying materials (or single-usering node groups) with custom nodes messes up users counters and may produce bogus orphaned and overused trees~~ to Cloning materials with too smart ShaderNodeCustomGroup breaks user counters of both source and target nodes

2019-12-19 02:37:47 +01:00

Jacques Lucke commented

2019-12-29 16:43:12 +01:00

Added subscriber: @JacquesLucke

Jacques Lucke commented

2019-12-29 16:43:12 +01:00

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

Jacques Lucke commented

2019-12-29 16:43:12 +01:00

Please redo your tests and properly store a reference to a node tree in a node as described in https://developer.blender.org/T72579#839420.

Dalai Felinto commented

2020-01-13 18:34:46 +01:00

Added subscriber: @dfelinto

Dalai Felinto commented

2020-01-13 18:34:46 +01:00

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

Dalai Felinto closed this issue

2020-01-13 18:34:46 +01:00

Dalai Felinto self-assigned this 2020-01-13 18:34:46 +01:00

Dalai Felinto commented

2020-01-13 18:34:46 +01:00

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.

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.

Maxim Vasiliev commented

2020-01-14 11:28:12 +01:00

What is the policy, @dfelinto ?

Additional information is provided in referenced tasks.
The bug exists and it breakes and will break some shader add-ons.

Investigation is conducted, root cause of this and many other existing and potential bugs is discovered, fix is submitted, along with autotests.
What is a (more) proper way to help making blender better?

Do you have some kind of "fsck off, patches are not welcome" policy?

What is the policy, @dfelinto ? Additional information is provided in referenced tasks. The bug exists and it breakes and will break some shader add-ons. Investigation is conducted, root cause of this and many other existing and potential bugs is discovered, fix is submitted, along with autotests. What is a (more) proper way to help making blender better? Do you have some kind of "fsck off, patches are not welcome" policy?

Robert Guetzkow commented

2020-01-14 11:35:30 +01:00

Added subscriber: @rjg

Robert Guetzkow commented

2020-01-14 11:35:30 +01:00

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

Robert Guetzkow reopened this issue

2020-01-14 11:35:30 +01:00

Robert Guetzkow commented

2020-01-14 11:35:30 +01:00

@qwiglydee this is done more or less automatically for all open tickets that have the status Needs Information from User after a week without any activity. This is documented in the Triaging Playbook - No reply after a week . I guess this was unintentionally closed without checking the patches/progress and certainly your contributions are welcome.

I'll reopen the task.

@qwiglydee this is done more or less automatically for all open tickets that have the status `Needs Information from User` after a week without any activity. This is documented in the [Triaging Playbook - No reply after a week ](https://wiki.blender.org/wiki/Process/Bug_Reports/Triaging_Playbook). I guess this was unintentionally closed without checking the patches/progress and certainly your contributions are welcome. I'll reopen the task.

Maxim Vasiliev commented

2020-01-14 12:41:54 +01:00

Oh. Ok.

Then I'll put retated information here to avoid any non-automated confusion.

According to my debugging, the bug occurs because python method Node::copy is called from BKE_node_copy_ex, while refcounter of nested nodetree is in inconsistent state, and reinitializing node_tree inside the method breakes it even further.
The counters are corrected later in code of BKE_id_copy_ex, in the call of BKE_library_foreach_ID_link, after all material data is completely copied.

Proposed fix D6484 moves the call to supposedly more appropriate place.
A test for this case is in D6420.

Oh. Ok. Then I'll put retated information here to avoid any non-automated confusion. According to my debugging, the bug occurs because python method `Node::copy` is called from `BKE_node_copy_ex`, while refcounter of nested nodetree is in inconsistent state, and reinitializing `node_tree` inside the method breakes it even further. The counters are corrected later in code of `BKE_id_copy_ex`, in the call of `BKE_library_foreach_ID_link`, after all material data is completely copied. Proposed fix [D6484](https://archive.blender.org/developer/D6484) moves the call to supposedly more appropriate place. A test for this case is in [D6420](https://archive.blender.org/developer/D6420).

Philipp Oeser commented

2020-01-20 11:57:22 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2020-01-20 11:57:22 +01:00

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

Philipp Oeser commented

2020-01-20 11:57:22 +01:00

Can confirm.

Dalai Felinto removed their assignment 2020-02-04 19:28:00 +01:00

Philipp Oeser removed the

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

Cloning materials with too smart ShaderNodeCustomGroup breaks user counters of both source and target nodes #72317