AttributeGroup API: "active" is meaningless (always refers to all attributes, not the specific AttributeGroup) -- e.g. mesh.color_attributes.active #107194

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opened 2023-04-20 21:14:33 +02:00 by Scurest · 13 comments

Scurest commented

2023-04-20 21:14:33 +02:00

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Blender Version
Broken: blender-3.5.1-candidate+v35.eaf13ebc6776-linux.x86_64-release
Worked: blender-3.3.6-stable+v33.948f8298b982-linux.x86_64-release

Short description of error
Accessing the active color attribute through mesh.color_attributes.active returns mesh.attributes["position"] instead.

API is basically broken since eae36be372
the particular example in this report was exposed by 1af62cb3bf

Exact steps for others to reproduce the error

Create a new cube.
Open Python Console and do:

>>> C.object.data.color_attributes.active
bpy.data.meshes['Cube'].attributes["position"]

Try the same thing in 3.3. It correctly returns None.

**Blender Version** Broken: blender-3.5.1-candidate+v35.eaf13ebc6776-linux.x86_64-release Worked: blender-3.3.6-stable+v33.948f8298b982-linux.x86_64-release **Short description of error** Accessing the active color attribute through `mesh.color_attributes.active` returns `mesh.attributes["position"]` instead. API is basically broken since eae36be372 the particular example in this report was exposed by 1af62cb3bf **Exact steps for others to reproduce the error** 1. Create a new cube. 2. Open Python Console and do: ```Py >>> C.object.data.color_attributes.active bpy.data.meshes['Cube'].attributes["position"] ``` 3. Try the same thing in 3.3. It correctly returns `None`.

Scurest added the

labels 2023-04-20 21:14:34 +02:00

Scurest commented

2023-04-20 21:19:06 +02:00

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Also if you create a color attribute by going into Vertex Paint mode, it will still incorrectly return attributes["position"]. If you create a color attribute by going through the Properties editor however, it behaves correctly.

Also if you create a color attribute by going into Vertex Paint mode, it will still incorrectly return `attributes["position"]`. If you create a color attribute by going through the Properties editor however, it behaves correctly.

Pratik Borhade commented

2023-04-21 07:00:51 +02:00

Member

Hi, thanks for the report. I can confirm. Checking...

Hi, thanks for the report. I can confirm. Checking...

Pratik Borhade added

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labels 2023-04-21 07:01:10 +02:00

Pratik Borhade commented

2023-04-21 07:42:50 +02:00

Member

Caused by 1af62cb3bf
@HooglyBoogly ^

Caused by 1af62cb3bf46f0cd328ab0840a1363eca938c628 @HooglyBoogly ^

Pratik Borhade added

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labels 2023-04-21 07:43:00 +02:00

Pratik Borhade changed title from ~~Python: wrong mesh.color_attributes.active~~ to Regression: Python: wrong mesh.color_attributes.active

2023-04-21 07:43:07 +02:00

Martijn Versteegh commented

2023-04-21 09:05:26 +02:00

Member

I can have a look, have been busy in this area.

I can have a look, have been busy in this area.

Philipp Oeser commented

2023-04-21 09:09:06 +02:00

Member

Note: even in 3.3, the logic is wrong.
color_attributes.active will always return the active attribute (no matter if color or not).
It just happens to be that in 3.3, there is no real attribute there yet on the default cube

Same seems to be true for setting btw.
See rna_AttributeGroup_active_get / rna_AttributeGroup_active_set, this does not have a relation the AttributeGroup, this just handles all attributes.

Note: even in 3.3, the logic is wrong. `color_attributes.active` will always return the active attribute (no matter if color or not). It just happens to be that in 3.3, there is no real attribute there yet on the default cube Same seems to be true for setting btw. See `rna_AttributeGroup_active_get` / `rna_AttributeGroup_active_set`, this does not have a relation the AttributeGroup, this just handles **all** attributes.

Philipp Oeser commented

2023-04-21 09:15:04 +02:00

Member

Not sure if the original plan with attributes was really to have multiple AttributeGroup , @brecht @HooglyBoogly ?

eae36be372 made up a new AttributeGroup, breaking some of the API...

Not sure if the original plan with attributes was really to have multiple `AttributeGroup` , @brecht @HooglyBoogly ? eae36be372a6 made up a new `AttributeGroup`, breaking some of the API...

Philipp Oeser changed title from ~~Regression: Python: wrong mesh.color_attributes.active~~ to AttributeGroup API: "active" is meaningless (always refers to all attributes, not the specific AttributeGroup) -- e.g. mesh.color_attributes.active

2023-04-21 09:17:54 +02:00

Martijn Versteegh commented

2023-04-21 09:29:24 +02:00

Member

Hm. this make it a bit above my pay grade ;-) .

I could still look into it if others don't have time, but I'd be slow.

Hm. this make it a bit above my pay grade ;-) . I *could* still look into it if others don't have time, but I'd be slow.

Philipp Oeser commented

2023-04-21 09:41:44 +02:00

Member

Thinking about it further, making some of the API specific to the actual AttributeGroup, we could get rid of lots of handling of color vs. other attributes:

active_color vs active
active_color_index vs active_index
render_color_index, default_color_name, active_color_name, ... could all just be in the colors AttributeGroup
no need for active_color string handling on mesh, really, could just be retrieved from active (on the right AttributeGroup)

Thinking about it further, making some of the API specific to the actual `AttributeGroup`, we could get rid of lots of handling of color vs. other attributes: - `active_color` vs `active` - `active_color_index` vs `active_index` - `render_color_index`, `default_color_name`, `active_color_name`, ... could all just be in the colors `AttributeGroup` - no need for active_color string handling on mesh, really, could just be retrieved from active (on the right `AttributeGroup`)

Martijn Versteegh commented

2023-04-21 09:56:19 +02:00

Member

but I see there's also a rna_AttributeGroup_active_color_get shouldn't it just use that one instead? That does limit the search to color attributes.

but I see there's also a rna_AttributeGroup_active_*color*_get shouldn't it just use that one instead? That *does* limit the search to color attributes.

Martijn Versteegh commented

2023-04-21 10:08:59 +02:00

Member

C.object.data.color_attributes.active_color does call the correct function and return the correct result. But that's rather counterintuitive

I think @lichtwerk 's suggestion above is the way to go.

C.object.data.color_attributes.active_color *does* call the correct function and return the correct result. But that's rather counterintuitive I think @lichtwerk 's suggestion above is the way to go.

Martijn Versteegh commented

2023-04-25 22:22:35 +02:00

Member

As a workaround, using C.object.data.color_attributes.active_color gives the correct result.

As a workaround, using `C.object.data.color_attributes.active_color` gives the correct result.

Martijn Versteegh commented

2023-05-26 16:54:41 +02:00

Member

Just as PSA: I don't have time to look into this at the moment. In case someone hoped I would ;-)

Just as PSA: I don't have time to look into this at the moment. In case someone hoped I would ;-)

Martijn Versteegh commented

2023-06-16 15:46:45 +02:00

Member

I think this is not a bug per-se . It's more a case of bad documentation and a slightly clumsy api.

I think we could remove the hi prio

I think this is not a bug per-se . It's more a case of bad documentation and a slightly clumsy api. I think we could remove the hi prio

Pratik Borhade added

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labels 2023-06-17 12:57:22 +02:00

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