Add public method to cleanup font configuration temporary directory

[max-blau]

The temp directory used store some downloaded bytes for fonts is sometimes not being cleaned up automatically via the __del__ dunder method. This commit exposes a cleanup method to allow users to handle this cleanup themselves if it affects their workflow.

tests:

➜ ~/work/fork/WeasyPrint (expose-font-cleanup-method) [weasyprint] $ pytest tests/test_fonts.py
================================================================================================================ test session starts ================================================================================================================
platform darwin -- Python 3.10.18, pytest-9.0.2, pluggy-1.6.0
rootdir: /Users/maxblau/work/fork/WeasyPrint
configfile: pyproject.toml
collected 8 items

tests/test_fonts.py ........                                                                                                                                                                                                                  [100%]

================================================================================================================= 8 passed in 0.14s =================================================================================================================

[max-blau]

@liZe I don't have permissions to add reviewers, here's a PR for the workaround we discussed in #2090

[liZe]

@max-blau Why did you close this pull request?

[max-blau]

@liZe sorry, meant to post a comment.
It's not needed - you can just do something like this instead:

font_config = FontConfiguration()
del font_config

[max-blau]

@liZe nevermind - probably due to other implementation details in weasyprint, just subtracting the ref count of the FontConfiguration instance isn't enough to get the garbage collector to delete it.
Re-opening this - although its also possible to just call __del__ directly as a user - if thats OK with you, then this change could be dropped.

[liZe]

Hi!

Thanks again for your pull request.

Re-opening this - although its also possible to just call __del__ directly as a user - if thats OK with you, then this change could be dropped.

I’ve spent some time trying to play with your pull request, and… I think you’re right.

No matter how hard we will try, there’s no reliable way to remove this folder because of how Fontconfig and Windows work, so even your test may fail if we actually use @font-face fonts in it.

And we don’t want to support and maintain public API that should be an implementation detail.

If you’re not on Windows, calling __del__ should reliably work, and that’s the best workaround in my opinion.

Sorry for taking so much time to come to this conclusion too 🙏, but I guess we had to go through these questions.