pip 20 breaks supported_wheels.py?

[anthrotype]

After the recently updated pip 20.0.1, the multibuild's supported_wheels.py script (which filters wheel filenames not supported on the current platform) is no longer working.
It returns nothing, whereas if I downgrade to pip==19.3.1 it works as before.
I am not sure what exactly changed.

[anthrotype]

it looks like the old pip's get_supported() would return list of tuples, now it returns a list of packaging.Tag objects. I got it working with this patch:

diff --git a/supported_wheels.py b/supported_wheels.py
index 41abc37..7d54ec4 100755
--- a/supported_wheels.py
+++ b/supported_wheels.py
@@ -28,7 +28,10 @@ def tags_for(fname):
 
 
 def main():
-    supported = set(get_supported())
+    supported = {
+        (tag.interpreter, tag.abi, tag.platform) if not isinstance(tag, tuple) else tag
+        for tag in get_supported()
+    }
     for fname in sys.argv[1:]:
         tags = set(tags_for(fname))
         if supported.intersection(tags):

alternatively we could check isinstance(tag, packaging.tags.Tag) but then we'd need to import packaging.

[hugovk]

Here's where it was changed in pip:

• "Use packaging.tags.Tag in place of Tuple"
• pypa/pip@80b2c82
• PR Use packaging.tags.Tag to represent tag throughout the code pypa/pip#7563
• Released in pip 20.0.0

[matthew-brett]

Ugh - dammit, how frustrating. They've changed their API again. @anthrotype - any chance of a PR?

[gaborbernat]

Ugh - dammit, how frustrating. They've changed their API again. @anthrotype - any chance of a PR?

They don't offer a programmatic API at all... so the fact they've changed their internal private implementation detail not sure if it warrants frustration.

[pfmoore]

FWIW, we've switched to using packaging.tags (which we vendor, and wrap internally to provide a similar interface to the previous custom implementation). So a more robust, longer-term solution would be to use packaging.tags directly. (Not criticising your decision to make a fast fix by adapting your use of the pip function, just suggesting a future improvement you could make).

[matthew-brett]

@pfmoore - thanks - that's an excellent suggestion.

[matthew-brett]

packaging.tags solution added in #302