Reuse packaging code for version parsing

[Thomas Bechtold]

pbr implements it's own logic to parse PEP0440 versions. But pbr does that incomplete (i.e. local versions like 1.1.0dev3+local4 are not supported).
Why not using the code from the pypi packaging module which supports all possible versioning schemas mentioned in PEP440?

[Clark Boylan (cboylan)]

Part of that is because PBR explicitly supports a subset of PEP440 as I understand it. Specifically the versioning scheme at https://docs.openstack.org/pbr/latest/user/semver.html which is semver made to be compatible with PEP440.

Another reason for it is PBR cannot have any dependencies so any external code would have to be vendored in.

[Ben Nemec (bnemec)]

Yeah, I don't think this will work for the reasons Clark mentioned.