MAINT, CI: check _distributor_init.py contents

[tylerjereddy]

• following on from continued problems reported here:
  Performance issue on macOS arm64 (M1) when installing from wheels (2x libopenblas) scipy/scipy#15050

• draft in code to check that MacOS wheels get
  the same _distributor_init.py as the one present
  in the wheels repo, rather than the generic nearly-empty
  copy actually present in the 1.7.3 release

• we've had two pull requests about this and it slipped through into
  a release despite 3 sets of eyes so need to be careful here;
  I'd like to see the test script added here failing for MacOS in CI
  like it does locally, before attempting a fix

• this is likely still WIP, since relative paths/directories
  can be confusing to predict in the wheels/multibuild control
  flow, which also flushes in and out of containers I think, etc.
  (this probably contributed to the original problem)

• the script did seem to work in a quick local check though, complaining
  about our new MacOS file inclusion, but happy with the long-standing
  windows wheel inclusion for dirs containing wheels for each OS type:

python verify_init.py /Users/treddy/rough_work/scipy/release_173/release/installers/windows
python verify_init.py /Users/treddy/rough_work/scipy/release_173/release/installers/linux
python verify_init.py /Users/treddy/rough_work/scipy/release_173/release/installers/mac

Traceback (most recent call last):
  File "verify_init.py", line 40, in <module>
    check_for_dist_init(input_dir=input_dir)
  File "verify_init.py", line 34, in check_for_dist_init
    raise ValueError(f"Contents of _distributor_init.py incorrect for
{wheel_file}")
ValueError: Contents of _distributor_init.py incorrect for
/Users/treddy/rough_work/scipy/release_173/release/installers/mac/scipy-1.7.3-cp39-cp39-macosx_10_9_x86_64.whl

• we could go a step farther here and error out on Linux if the contents of _distributor_init.py did match the copy in the wheels repo, since they should not for that platform, though my primary focus is to be strict on the platforms that do need the adjustments (MacOS/Windows)

[rgommers]

Failures look as expected here. I'll push the fix for inclusion of the file on macOS and see that this turns green.

[rgommers]

The bug was in gh-145, the fix was missed a second /scipy.

[tylerjereddy]

The appveyor fails probably mean I still don't fully grasp the working directory situation there, I suppose we could just delete the check in appveyor for now if we only want to address the immediate issue

[rgommers]

The appveyor fails probably mean I still don't fully grasp the working directory situation there, I suppose we could just delete the check in appveyor for now if we only want to address the immediate issue

That looks like the right order of doing things to me.

[rgommers]

I did look at it, and I don't see an obvious mistake in what you did in appveyor.yml.

[isuruf]

https://github.com/MacPython/scipy-wheels/blob/master/appveyor.yml#L146 needs to be a copy instead of a move

[tylerjereddy]

good catch, I've pushed the appveyor adjustment in

[tylerjereddy]

Ok, CI is perfect now, I'll proceed with merge and backport.