BUILD: Fix duplicate files warning

[lithomas1]

• closes BUILD: 2.1.0 not installable via installer because of duplicate files in wheel #54888 (Replace xxxx with the GitHub issue number)
• Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added type annotations to new arguments/methods/functions.
• Added an entry in the latest doc/source/whatsnew/vX.X.X.rst file if fixing a bug or adding a new feature.

[WillAyd]

Is there a way for meson to automatically pick these up instead of manually having to specify? For sure doesn't change often, but would be nice to avoid hard coding

[lithomas1]

Is there a way for meson to automatically pick these up instead of manually having to specify? For sure doesn't change often, but would be nice to avoid hard coding

Sadly, I think it has to be hardcoded, since the meson devs discourage using things like wildcards that would let us include all pyi files at once.
(Luckily, this is only for _libs though, since we have a mix of C/Cython/Python sources in there.)

[lithomas1]

Will self merge then so this gets in for the release.

[eli-schwartz]

One thing you could do is offload the file list itself to a separate plaintext file containing one filename per line, and use it from meson as:

sources_to_install = fs_mod.read('sources.list').strip().split()

It's then much easier to statically verify through any means you like that the list of files is updated. You could have a CI script verify it as a test, for example, or auto refresh the file via a git-pre-commit hook.

This fulfills meson's requirement -- that any changes to the build plan are detected and force a reconfigure, so that running meson install will not result in outdated installdata that doesn't install all the files it was supposed to. Use of fs_mod.read() causes the file in question to become a regenerate dependency.