[cristianchiriac]

Description of the change

Closes #686.

Matplotlib 3.12 moves Axes.ArtistList to matplotlib.artist.ArtistList (matplotlib/matplotlib#31794). On the class, Axes.ArtistList is now a deprecated property, so subscripting it in stereographic_plot.py raises TypeError: '_deprecated_property' object is not subscriptable. That happens at import time, so import orix.plot (and everything importing orix.crystal_map) fails.

This imports ArtistList from matplotlib.artist when it exists, falls back to maxes.Axes.ArtistList on older Matplotlib, and uses it in the three type annotations. black then puts COLLECTION_TYPES and the return annotation of _get_collection() on one line each. There's also a line in the Fixed section of CHANGELOG.rst.

Progress of the PR

• Docstrings for all functions (no new functions)
• Unit tests with pytest for all lines. The new import is exercised by every test that imports orix.plot. The fallback branch is marked pragma: no cover because only one branch runs per Matplotlib version.
• Clean code style by running black via pre-commit (black 26.5.1, isort 9.0.2)

Minimal example of the bug fix or new feature

>>> import matplotlib
>>> matplotlib.__version__
'3.12.0.dev696+gd2115ba4e'
>>> import orix.plot  # before: TypeError: '_deprecated_property' object is not subscriptable

Tested on Python 3.12 with pytest orix/tests/test_plot: 111 passed, 13 skipped with Matplotlib 3.11.2, and the same with the 3.12.0.dev696 nightly wheel. Without the change, the nightly fails at import.

For reviewers

• The PR title is short, concise, and will make sense 1 year later.
• New functions are imported in corresponding __init__.py.
• New features, API changes, and deprecations are mentioned in the unreleased
  section in CHANGELOG.rst.
• Contributor(s) are listed correctly in __credits__ in orix/__init__.py and in
  .zenodo.json.

[argerlt]

For consistency, with more recent ORIX practices, please change ArtistList to mArtistList to denote it as a class inherited from matplotlib, and not an ORIX class.

try:  # Matplotlib >= 3.12
    from matplotlib.artist import ArtistList as mArtistList
except ImportError:  # pragma: no cover
    mArtistList = maxes.Axes.ArtistList

Otherwise, this is great, thank you for contributing to this project.