xref to #24001

I think that this or something similar needs to make it into 3.7 to fix #24641 being partially incorrect; or #24641 needs to be temporarily reverted for 3.7.

____________________________ test_user_fonts_win32 ____________________________
[gw1] win32 -- Python 3.10.8 C:\hostedtoolcache\windows\Python\3.10.8\x64\python.exe

    @pytest.mark.skipif(sys.platform != 'win32', reason='Windows only')
    def test_user_fonts_win32():
        if not (os.environ.get('APPVEYOR') or os.environ.get('TF_BUILD')):
            pytest.xfail("This test should only run on CI (appveyor or azure) "
                         "as the developer's font directory should remain "
                         "unchanged.")
    
        font_test_file = 'mpltest.ttf'
    
        # Precondition: the test font should not be available
        fonts = findSystemFonts()
        if any(font_test_file in font for font in fonts):
            pytest.skip(f'{font_test_file} already exists in system fonts')
    
        user_fonts_dir = MSUserFontDirectories[0]
    
        # Make sure that the user font directory exists (this is probably not the
        # case on Windows versions < 1809)
        os.makedirs(user_fonts_dir)
    
        # Copy the test font to the user font directory
        shutil.copy(Path(__file__).parent / font_test_file, user_fonts_dir)
    
        # Now, the font should be available
        fonts = findSystemFonts()
>       assert any(font_test_file in font for font in fonts)
E       assert False
E        +  where False = any(<generator object test_user_fonts_win32.<locals>.<genexpr> at 0x000002364CB2A8F0>)

https://dev.azure.com/matplotlib/matplotlib/_build/results?buildId=30184&view=logs&j=595c9a33-3ac5-58f0-6ce6-44c63ffdfe86&t=6405dc77-f20a-51d5-22e4-a611ccc41f2e&l=182

The failure is definitely caused by this change

Also, I dunno if this is sensible but I modified the test to run it on my local machine, and I'm now getting the same failure, w/ the same message:

@pytest.mark.skipif(sys.platform != 'win32', reason='Windows only')
def test_user_fonts_win32():
    font_test_file = 'mpltest.ttf'

    # Precondition: the test font should not be available
    fonts = findSystemFonts()
    if any(font_test_file in font for font in fonts):
        pytest.skip(f'{font_test_file} already exists in system fonts')

    user_fonts_dir = Path(MSUserFontDirectories[0])

    # Make sure that the user font directory exists (this is probably not the
    # case on Windows versions < 1809)
    user_fonts_dir.mkdir(exist_ok=True)

    # Copy the test font to the user font directory
    shutil.copy(Path(__file__).parent / font_test_file, user_fonts_dir)

    assert (user_fonts_dir/font_test_file).exists()

    # Now, the font should be available
    fonts = findSystemFonts()

    assert any(font_test_file in font for font in fonts)
    (Path(user_fonts_dir)/font_test_file).unlink()
    assert not (Path(user_fonts_dir)/font_test_file).exists()

ETA: if this is sensible, then I'll wrap up "temp copy" in a context manager.

ETA2: I have no idea why the test is failing b/c the directory for writing the tempfile is identical when fontpaths is set or when it's empty

C:\Users\story\AppData\Local\Microsoft\Windows\Fonts\mpltest.ttf
C:\Users\story\AppData\Local\Microsoft\Windows\Fonts\mpltest.ttf

while this is flipped:

findSystemFonts folders: {WindowsPath('C:/Windows/Fonts'), WindowsPath('C:/Users/story/AppData/Local/Microsoft/Windows/Fonts')}
findSystemFonts folders: {WindowsPath('C:/Users/story/AppData/Local/Microsoft/Windows/Fonts'), WindowsPath('C:/Windows/Fonts')}

and I checked and yeah the file is in AppData

Also, I dunno if this is sensible but I modified the test to run it on my local machine, and I'm now getting the same failure, w/ the same message:

Ah, are you saying the test is wrong? I think we maybe should be calling AddFontResourceEx for that test instead of directly copying the file.

Ah, are you saying the test is wrong?

No, just that I'm not sure why I can't run it locally if I create and clean-up the file during the test?

I guess what I would like to confirm is; if you use Explorer to copy a new font there, does it get added to the registry? Does it only do so if you use the Install button on the font viewer? What about if you have a Python script that copies the font there; does the registry update automatically, or do you have to open the directory in Explorer to refresh it, or does nothing update the registry?

if you use Explorer to copy a new font there, does it get added to the registry?

No
Also "'SOFTWARE\Microsoft\Windows\CurrentVersion\Fonts'" doesn't exist at least on my machine

Does it only do so if you use the Install button on the font viewer?

Yup

What about if you have a Python script that copies the font there; does the registry update automatically,

nope

or do you have to open the directory in Explorer to refresh it

that doesn't seem to work either

ETA: as far as I can tell, that test works because it's checking if a file put into a folder is found in the folder, completely bypassing the registry.

Per discussion on this weeks dev call:

• go with windows registry only
• xfail the test
  • defer questions of how to test this to later
  • do we want to change the registry as part of the test?
  • opt in to running locally?
  • flag to only run an CI + windows?
• need a manual test that this works
  • download a new font
  • use windows way to install it
  • remove mpl's font cache
  • verify the new font can be found
• add behavior change note

@story645 Can you please confirm that this works as expected for fonts installed as Windows expects and merge if you are satisfied?

heads up that I won't be able to get to this til tomorrow night/sunday