pip: On PyPy, binary wheels broken on pip==20.0.1

Environment

• pip version: 20.0.1
• Python version: PyPy (tested with 7.2.0 and 7.3.0)
• OS: tested on linux, likely affects other OS as well

Description If you try to install a manylinux wheel (such as the ones produced here), pip 20.0.1 complains:

xxx.whl is not a supported wheel on this platform.

pip==19.3.1 installs it correctly.

Expected behavior I would expect the wheel to be installed correctly 😃

How to Reproduce

First, download and install PyPy 7.2.0, and install pip==19.3.1:

$ wget -q  https://bitbucket.org/pypy/pypy/downloads/pypy2.7-v7.2.0-linux64.tar.bz2
$ tar xf pypy2.7-v7.2.0-linux64.tar.bz2 
homer pip-bug $ ./pypy2.7-v7.2.0-linux64/bin/pypy -m ensurepip
[...]
homer pip-bug $ ./pypy2.7-v7.2.0-linux64/bin/pypy -m pip install -U pip==19.3.1
[...]
Successfully installed pip-19.3.1

Then, download and install a manylinux wheel: it works correctly:

$ wget -q https://antocuni.github.io/pypy-wheels/manylinux2010/psutil/psutil-5.6.5-pp272-pypy_41-manylinux2010_x86_64.whl

$ ./pypy2.7-v7.2.0-linux64/bin/pypy -m pip install psutil-5.6.5-pp272-pypy_41-manylinux2010_x86_64.whl 
[...]
Successfully installed psutil-5.6.5

Finally, upgrade to pip 20.0.1 and try again:

$ ./pypy2.7-v7.2.0-linux64/bin/pypy -m pip install -U pip==20.0.1
[...]
Successfully installed pip-20.0.1

$ ./pypy2.7-v7.2.0-linux64/bin/pypy -m pip install psutil-5.6.5-pp272-pypy_41-manylinux2010_x86_64.whl 
[...]
ERROR: psutil-5.6.5-pp272-pypy_41-manylinux2010_x86_64.whl is not a supported wheel on this platform.

I tried it with PyPy 7.3.0 as well, same result.

More info

I tried to debug it a bit. I managed to reduce the difference to this snippet:

from pip._internal import pep425tags
from pip._internal.models.wheel import Wheel

print 'Supported tags'
tags = pep425tags.get_supported()
for tag in tags:
    print '   ', tag

print
print 'File tags'
wheel = Wheel('psutil-5.6.5-pp272-pypy_41-manylinux2010_x86_64.whl')
for tag in wheel.file_tags:
    print '   ', tag

With pip==20.0.1, I get this:

Supported tags
    pp27-pypy_41-manylinux2014_x86_64
    pp27-pypy_41-manylinux2010_x86_64
    pp27-pypy_41-manylinux1_x86_64
    pp27-pypy_41-linux_x86_64
    [...]

File tags
    pp272-pypy_41-manylinux2010_x86_64

Note that “supported tags” start with pp27-, while “file tags” start with pp272-, so Wheel.supported returns False.