KeyError caffe2/ when installing torch 1.5.1+cpu

[pawamoy]

• I have searched the issue tracker and believe that this is not a duplicate.

It's actually quite similar to the last comment of #500.

Steps to reproduce

$ pdm install -v
...
Install torch 1.5.1+cpu failed
Error occurs: 
Traceback (most recent call last):
  File "/usr/lib64/python3.8/concurrent/futures/thread.py", line 57, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/usr/local/lib/python3.8/site-packages/pdm/installers/synchronizers.py", line 190, in install_candidate
    self.manager.install(can)
  File "/usr/local/lib/python3.8/site-packages/pdm/installers/manager.py", line 31, in install
    installer(candidate.build(), self.environment, candidate.direct_url())
  File "/usr/local/lib/python3.8/site-packages/pdm/installers/installers.py", line 74, in install_wheel
    _install_wheel(
  File "/usr/local/lib/python3.8/site-packages/pdm/installers/installers.py", line 173, in _install_wheel
    for record_elements, stream in source.get_contents():
  File "/usr/local/lib/python3.8/site-packages/installer/sources.py", line 165, in get_contents
    record = record_mapping.pop(item.filename)
KeyError: 'caffe2/'

EDIT: ah, you might not be able to reproduce since torch CPU versions are not on pypi.org I think...

Actual behavior

It seems PDM 1.8.1 / installer has troube installing torch 1.5.1+cpu.

Expected behavior

I think versions of PDM before the ones using installer were able to install torch 1.5.1+cpu without issues.

Environment Information

Running in CI, so I don't have the output of the PDM info commands, but it's CPython 3.8.3 on Linux and PDM 1.8.1.

[pawamoy]

Ah, I think it's a simple bug in installer: pop(item.filename) -> pop(item.filename, None). Let me close and open again there.

[pawamoy]

I guess it means the wheel for torch 1.5.1+cpu is broken though.