Enhancement: Add PIL to runtime dependencies

[BigRoy]

Is there an existing issue for this?

• I have searched the existing issues.

Please describe the feature you have in mind and explain what the current shortcomings are?

In testing the new version (beta) of a supported host by OpenPype I noticed an upgrade to Python 3.10 within the host. Upon launching the host the OpenPype integration does not load correctly (and also breaks other bootstrapping of the host) due to OpenPype providing its PIL library on the PYTHONPATH which is incompatible with that Python version. The host has some scripts of its own which try to import the Pillow library, fail and thus break the startup procedure (even for some host-native tools).

How would you imagine the implementation of the feature?

Similar to other Python-version dependent dependencies this might need to become a runtime dependency, like ocio and otio with this PR #5206

Are there any labels you wish to add?

• I have added the relevant labels to the enhancement request.

Describe alternatives you've considered:

If the environment would be fully configured through rez (like ynput/ayon-core#816) more complex approaches could be taken where PIL does get provided for hosts who don't provide it themselves and we have a matching PIL library available for the Python version of that host version.

Additional context:

Due to the bootstrapping procedure the host also receives no registered host (install_host does not trigger).

[cuID:OP-6756]

[BigRoy]

This is somewhat solved in AYON with runtime dependencies, etc. - not perfect and there are still issues with AYON and Houdini but there are already issues open for that. I'll close this and we can continue on AYON somewhere when needed with a new issue.