Unable to use custom icon as bl_icon for Custom Node Tree #85213

New Issue

Zach Eastin · 2021-01-29T21:47:13+01:00

Zach Eastin commented

2021-01-29 21:47:13 +01:00

System Information
Operating system: Windows 10
Graphics card: Nvidia RTX 2080 ti

Blender Version
Broken: 2.83.10
Worked: Not sure if ever worked

Short description of error
When setting the icon for a custom node tree you can only set it to the blender icons. It seems like the node tree is loaded or checked before it is registered as the variable custom_icons always is called before it can be assigned as an image preview.

Exact steps for others to reproduce the error
Based on the attached .blend file just try to install and enable the addon. Depending on what is commented out the error will either say
'NoneType' object is not subscriptable if custom_icons is set to None initially
or
KeyError: 'logo' if custom_icons is set to bpy.utils.previews.new() initially

IconTest.zip

**System Information** Operating system: Windows 10 Graphics card: Nvidia RTX 2080 ti **Blender Version** Broken: 2.83.10 Worked: Not sure if ever worked **Short description of error** When setting the icon for a custom node tree you can only set it to the blender icons. It seems like the node tree is loaded or checked before it is registered as the variable `custom_icons` always is called before it can be assigned as an image preview. **Exact steps for others to reproduce the error** Based on the attached .blend file just try to install and enable the addon. Depending on what is commented out the error will either say `'NoneType' object is not subscriptable` if `custom_icons` is set to `None` initially or `KeyError: 'logo'` if `custom_icons` is set to `bpy.utils.previews.new()` initially [IconTest.zip](https://archive.blender.org/developer/F9604369/IconTest.zip)

Zach Eastin commented

2021-01-29 21:47:13 +01:00

Added subscriber: @Zeastin

Robert Guetzkow commented

2021-01-30 14:42:41 +01:00

Added subscriber: @rjg

Robert Guetzkow commented

2021-01-30 14:42:41 +01:00

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

Robert Guetzkow closed this issue

2021-01-30 14:42:41 +01:00

Robert Guetzkow commented

2021-01-30 14:42:41 +01:00

For bl_icon you have to assign a valid enum as listed in the Python API docs .

'NoneType' object is not subscriptable if custom_icons is set to None initially

If you assign None to a variable and then try to access it like and array that results in this error

KeyError: 'logo' if custom_icons is set to bpy.utils.previews.new() initially

If there is no entry with the key logo then this is the error you will see. Initially the collection doesn't contain any entry.

If you need help learning or using Blender, please post a question on one of our [community websites ]], for instance https:*blender.stackexchange.com/ , https:*blenderartists.org/ or the [ https:*blender.chat/channel/support | #support channel on Blender chat . The bug tracker is only for bug reports.

For `bl_icon` you have to assign a valid enum as listed in the [Python API docs ](https://docs.blender.org/api/current/bpy.types.NodeTree.html#bpy.types.NodeTree.bl_icon). > 'NoneType' object is not subscriptable if custom_icons is set to None initially If you assign `None` to a variable and then try to access it like and array that results in this error > KeyError: 'logo' if custom_icons is set to bpy.utils.previews.new() initially If there is no entry with the key `logo` then this is the error you will see. Initially the collection doesn't contain any entry. If you need help learning or using Blender, please post a question on one of our [community websites ]], for instance [[ https:*blender.stackexchange.com/ | Blender's StackExchange ]], [[ https:*blenderartists.org/ | blenderartists.org ]] or the [[ https:*blender.chat/channel/support | #support channel on Blender chat ](https:*www.blender.org/community/). The bug tracker is only for bug reports.

Zach Eastin commented

2021-02-02 23:53:08 +01:00

@rjg Thank you for your response!
Apologies, but this would seem like unexpected behavior since almost everywhere else you can add an icon you can also add a custom icon even if it is an icon_value.
And the reason I added it as a bug was due to the seeming brain dead obvious errors in that no matter what I initially assigned to custom_icons it is never given anything before the Node Tree tries to access it. In the addon I included in my message you might have noticed that custom_icon should be filled before it is referenced by bl_icon. I was not seeking help in learning. Thank you for your time

@rjg Thank you for your response! Apologies, but this would seem like unexpected behavior since almost everywhere else you can add an icon you can also add a custom icon even if it is an icon_value. And the reason I added it as a bug was due to the seeming brain dead obvious errors in that no matter what I initially assigned to `custom_icons` it is never given anything before the Node Tree tries to access it. In the addon I included in my message you might have noticed that `custom_icon` should be filled before it is referenced by bl_icon. I was not seeking help in learning. Thank you for your time

Robert Guetzkow commented

2021-02-03 00:09:08 +01:00

@Zeastin the errors you are getting are entirely unrelated to whether bl_icon allows to assign a custom icon. Even if it would be supported the script wouldn't work. In both variations the variable doesn't contain the data you're expecting at the time it is accessed, hence the error message that one time it is None and thus you can't access it with an index, and the other time because the collection doesn't contain an entry with the key logo. If it is unclear to you why that is the case, then please create a question on Blender's Stack Exchange , post a link to it here and I will try to answer it.

@Zeastin the errors you are getting are entirely unrelated to whether `bl_icon` allows to assign a custom icon. Even if it would be supported the script wouldn't work. In both variations the variable doesn't contain the data you're expecting at the time it is accessed, hence the error message that one time it is `None` and thus you can't access it with an index, and the other time because the collection doesn't contain an entry with the key `logo`. If it is unclear to you why that is the case, then please create a question on [Blender's Stack Exchange ](https://blender.stackexchange.com/), post a link to it here and I will try to answer it.

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Unable to use custom icon as bl_icon for Custom Node Tree #85213