Exporting file results in blender error

[Clockwork-Muse]

Blender is throwing an error while still successfully exporting a model:

Known pipe types:
  glxGraphicsPipe
(all display modules loaded.)
Blender 2.91.0 (hash 0f45cab862b8 built 2020-11-25 08:51:08)
Warning: Falling back to the standard locale ("C")
Read prefs: /home/someuser/.config/blender/2.91/config/userpref.blend
found bundled python: /blender/2.91/python
srcroot: /panda/models/
Exporting: ['/panda/models/untitled.blend']
Export to: /tmp/
Read blend: /panda/models/untitled.blend
Converting .blend file (/panda/models/untitled.blend) to .gltf (/tmp/untitled.gltf)
Traceback (most recent call last):
  File "/blender/2.91/scripts/addons/io_scene_gltf2/__init__.py", line 76, in on_export_format_changed
    operator = sfile.active_operator
AttributeError: 'NoneType' object has no attribute 'active_operator'
File "/blender/2.91/scripts/addons/io_scene_gltf2/__init__.py", line 73, in on_export_format_changed
'/blender/2.91/python/lib/python3.7/site-packages/libextern_draco.so' exists, draco mesh compression is available
00:42:58 | INFO: Starting glTF 2.0 export
00:42:58 | INFO: Extracting primitive: Cube
00:42:58 | INFO: Primitives created: 1
00:42:58 | INFO: Finished glTF 2.0 export in 0.010235786437988281 s

... I'm not entirely sure that this is a blend2bam issue, but it may be due to how the export is being called. The error is not generated when the export is done manually from inside blender.

This is happening when just loading a default file.

Blender 2.91
panda3d-blend2bam 0.17
panda3d-gltf 0.11
repro.zip

[AndyMender]

Running into the same issue on my Arch Linux installation:
Blender 2.91
panda3d-blend2bam 0.18
panda3d-gltf 0.12

There is a DracoPy package in PyPi, but it doesn't provide the missing SO file: https://pypi.org/project/DracoPy/

Still, blend -> bam conversion seems to work for a basic Blender cube object (as seen in Panda Viewer):

[Moguri]

Looks like using the glTF exporter in Blender in background mode is broken: https://developer.blender.org/T83188

There really isn't anything blend2bam can do about this situation, so it seems that blend2bam will not work with 2.91 until this is fixed upstream.

[Moguri]

I should have paid a bit more attention to this. blend2bam still works, it just outputs that extra error. That error does not prevent blend2bam from working correctly. So, this will just be a quick of running blend2bam on 2.91. This has been fixed upstream so newer releases of Blender will not display this error. I am closing this as "wont't fix".