Packaging can be fickle sometimes

[sajith]

I pushed a tag zfec-1.6.0.1r0 while testing #129 and that made subsequent packaging tests unhappy, because: "Invalid version: '1.6.0.1r0.post0.dev2'". See this CI run, for instance.

Building wheel...
  
  + python -m pip wheel /Users/runner/work/zfec/zfec --wheel-dir=/private/var/folders/0j/bwqcs4y508s2n4ck4dhf3rpc0000gn/T/cibw-run-9_yj0dwr/cp39-macosx_x86_64/built_wheel --no-deps
  Processing /Users/runner/work/zfec/zfec
    Installing build dependencies: started
    Installing build dependencies: finished with status 'done'
    Getting requirements to build wheel: started
    Getting requirements to build wheel: finished with status 'error'
    error: subprocess-exited-with-error
    
    × Getting requirements to build wheel did not run successfully.
    │ exit code: 1
    ╰─> [27 lines of output]
        Traceback (most recent call last):
          File "/private/var/folders/0j/bwqcs4y508s2n4ck4dhf3rpc0000gn/T/cibw-run-9_yj0dwr/cp39-macosx_x86_64/build/venv/lib/python3.9/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 353, in <module>
            main()
          File "/private/var/folders/0j/bwqcs4y508s2n4ck4dhf3rpc0000gn/T/cibw-run-9_yj0dwr/cp39-macosx_x86_64/build/venv/lib/python3.9/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 335, in main
            json_out['return_val'] = hook(**hook_input['kwargs'])
          File "/private/var/folders/0j/bwqcs4y508s2n4ck4dhf3rpc0000gn/T/cibw-run-9_yj0dwr/cp39-macosx_x86_64/build/venv/lib/python3.9/site-packages/pip/_vendor/pyproject_hooks/_in_process/_in_process.py", line 118, in get_requires_for_build_wheel
            return hook(config_settings)
          File "/private/var/folders/0j/bwqcs4y508s2n4ck4dhf3rpc0000gn/T/pip-build-env-gun4bnpq/overlay/lib/python3.9/site-packages/setuptools/build_meta.py", line 334, in get_requires_for_build_wheel
            return self._get_build_requires(config_settings, requirements=[])
          File "/private/var/folders/0j/bwqcs4y508s2n4ck4dhf3rpc0000gn/T/pip-build-env-gun4bnpq/overlay/lib/python3.9/site-packages/setuptools/build_meta.py", line 304, in _get_build_requires
            self.run_setup()
          File "/private/var/folders/0j/bwqcs4y508s2n4ck4dhf3rpc0000gn/T/pip-build-env-gun4bnpq/overlay/lib/python3.9/site-packages/setuptools/build_meta.py", line 522, in run_setup
            super().run_setup(setup_script=setup_script)
          File "/private/var/folders/0j/bwqcs4y508s2n4ck4dhf3rpc0000gn/T/pip-build-env-gun4bnpq/overlay/lib/python3.9/site-packages/setuptools/build_meta.py", line 320, in run_setup
            exec(code, locals())
          File "<string>", line 58, in <module>
          File "/private/var/folders/0j/bwqcs4y508s2n4ck4dhf3rpc0000gn/T/pip-build-env-gun4bnpq/overlay/lib/python3.9/site-packages/setuptools/__init__.py", line 117, in setup
            return distutils.core.setup(**attrs)
          File "/private/var/folders/0j/bwqcs4y508s2n4ck4dhf3rpc0000gn/T/pip-build-env-gun4bnpq/overlay/lib/python3.9/site-packages/setuptools/_distutils/core.py", line 148, in setup
            _setup_distribution = dist = klass(attrs)
          File "/private/var/folders/0j/bwqcs4y508s2n4ck4dhf3rpc0000gn/T/pip-build-env-gun4bnpq/overlay/lib/python3.9/site-packages/setuptools/dist.py", line 330, in __init__
            self.metadata.version = self._normalize_version(self.metadata.version)
          File "/private/var/folders/0j/bwqcs4y508s2n4ck4dhf3rpc0000gn/T/pip-build-env-gun4bnpq/overlay/lib/python3.9/site-packages/setuptools/dist.py", line 366, in _normalize_version
            normalized = str(Version(version))
          File "/private/var/folders/0j/bwqcs4y508s2n4ck4dhf3rpc0000gn/T/pip-build-env-gun4bnpq/overlay/lib/python3.9/site-packages/setuptools/_vendor/packaging/version.py", line 202, in __init__
            raise InvalidVersion(f"Invalid version: {version!r}")
        packaging.version.InvalidVersion: Invalid version: '1.6.0.1r0.post0.dev3'
        [end of output]
    
    note: This error originates from a subprocess, and is likely not a problem with pip.
  error: subprocess-exited-with-error
  
  × Getting requirements to build wheel did not run successfully.
  │ exit code: 1
  ╰─> See above for output.
  
  note: This error originates from a subprocess, and is likely not a problem with pip.

This probably should not be so fickle. Perhaps giving packaging setup the same treatment as tahoe-lafs/tahoe-lafs#1395 might help?

Also the rationale stated in https://tahoe-lafs.org/trac/tahoe-lafs/ticket/4133 applies here as well.