Cannot activate addon: ModuleNotFoundError: No module named 'pkg_resources'

[Daniele Tamino]

Describe the bug
I installed blender 3.3LTS via snap on manjaro linux (sudo snap install blender --channel=3.3lts/stable --classic), then I downloaded phobos 2.0.0 from here.
Started blender, went into preferences -> addons, installed from file, and when I tried to enable it, it spent some time installing its dependencies and eventually failed with this error:

Checking requirements:
Looking in links: /tmp/tmpogrcc3ud
Requirement already satisfied: setuptools in ./.local/lib/python3.10/site-packages (65.5.0)
Requirement already satisfied: pip in ./.local/lib/python3.10/site-packages (23.3.2)
  Upgrading pip...
Defaulting to user installation because normal site-packages is not writeable
Requirement already satisfied: pip in ./.local/lib/python3.10/site-packages (23.3.2)
  Checking yaml
  Checking numpy
  Checking scipy
  Checking collada
  Checking pydot
  Checking lxml
  Checking networkx
  Checking trimesh
  Checking PIL
Phobos:All Phobos requirements have been installed.
Please restart Blender to activate the Phobos add-on!
Exception in module register(): /home/ilmagico/.config/blender/3.3/scripts/addons/phobos/__init__.py
Traceback (most recent call last):
  File "/home/ilmagico/.config/blender/3.3/scripts/addons/phobos/__init__.py", line 143, in register
    from . import io
  File "/home/ilmagico/.config/blender/3.3/scripts/addons/phobos/io/__init__.py", line 1, in <module>
    from . import representation
  File "/home/ilmagico/.config/blender/3.3/scripts/addons/phobos/io/representation.py", line 14, in <module>
    from .xml_factory import singular as _singular, plural as _plural
  File "/home/ilmagico/.config/blender/3.3/scripts/addons/phobos/io/xml_factory.py", line 10, in <module>
    import pkg_resources
ModuleNotFoundError: No module named 'pkg_resources'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/var/lib/snapd/snap/blender/4325/3.3/scripts/modules/addon_utils.py", line 369, in enable
    mod.register()
  File "/home/ilmagico/.config/blender/3.3/scripts/addons/phobos/__init__.py", line 213, in register
    raise ImportWarning(installation_finished_message)
ImportWarning: All Phobos requirements have been installed.
Please restart Blender to activate the Phobos add-on!

To Reproduce
Steps to reproduce the behavior:

1. Install blender 3.3LTS (via snap in my case)
2. Download Phobos 2.0.0
3. Install downloaded .zip addon into blender
4. Try to enable the addon

Expected behavior
The addon is enabled and works.

Note: the very first time, it also gave an error about trimesh, which was replaced by the one above after restarting blender. It might or might not be related:

Installing collected packages: numpy, trimesh
Successfully installed numpy-1.26.3 trimesh-4.0.8
  Checking PIL
  Installing package Pillow
Collecting Pillow
  Downloading pillow-10.2.0-cp310-cp310-manylinux_2_28_x86_64.whl.metadata (9.7 kB)
Downloading pillow-10.2.0-cp310-cp310-manylinux_2_28_x86_64.whl (4.5 MB)
   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 4.5/4.5 MB 46.5 MB/s eta 0:00:00
Installing collected packages: Pillow
Successfully installed Pillow-10.2.0
Phobos:All Phobos requirements have been installed.
Please restart Blender to activate the Phobos add-on!
Exception in module register(): /home/ilmagico/.config/blender/3.3/scripts/addons/phobos/__init__.py
Traceback (most recent call last):
  File "/home/ilmagico/.config/blender/3.3/scripts/addons/phobos/__init__.py", line 143, in register
    from . import io
  File "/home/ilmagico/.config/blender/3.3/scripts/addons/phobos/io/__init__.py", line 1, in <module>
    from . import representation
  File "/home/ilmagico/.config/blender/3.3/scripts/addons/phobos/io/representation.py", line 9, in <module>
    import trimesh
ModuleNotFoundError: No module named 'trimesh'

Desktop (please complete the following information):

• OS: Manjaro (rolling distro, just updated)
• Blender version 3.3.14
• debugging output (run setup.py --info): not sure where to find this

[Daniele Tamino]

I also just tried with the latest master branch straight from git, and I get the same error.

[AlpenAalAlex]

@ilmagico Please checkout the commit I just pushed and see if this fixes your issue

[Daniele Tamino]

@AlpenAalAlex Yep, that fixes it, thank you!!! I guess that should become a PR :)