Update python version regex and fix version ordering

[amazimbe]

What are you trying to accomplish?

Link to issue
Update our python version implementation to be conformant with the python version specification here: https://peps.python.org/pep-0440/#appendix-b-parsing-version-strings-with-regular-expressions

I'm updating the regex for version formats to be the one specified in the python version specification.

Anything you want to highlight for special attention from reviewers?

How will you know you've accomplished your goal?

Checklist

• I have run the complete test suite to ensure all tests and linters pass.
• I have thoroughly tested my code changes to ensure they work as expected, including adding additional tests for new functionality.
• I have written clear and descriptive commit messages.
• I have provided a detailed description of the changes in the pull request, including the problem it addresses, how it fixes the problem, and any relevant details about the implementation.
• I have ensured that the code is well-documented and easy to understand.

[kbukum1]

Is there a merged python regex update changes related to this test cases? Or this is refining the test cases? I couldn't see the regex changes here?

[amazimbe]

I saw this red flag while adding the test cases and was curious to find out what the sorted list looks like.

 expected: ["", "0.9", "1.0.0-alpha", "1.0.0-a.1", "1.0.0-beta", "1.0.0-b.2", "1.0.0-beta.11", "1.0.0-rc.1", "1", "1.0.0.post", "1.0.0+gc1", "1.post2", "1.post2+gc1", "1.post2+gc1.2", "1.post2+gc1.11", "1.0.0.post11", "1.0.2", "1.0.11", "2016.1", "1!0.1.0", "2!0.1.0", "10!0.1.0"]
            got: ["", "0.9", "1", "1!0.1.0", "1.0.0+gc1", "1.0.0-a.1", "1.0.0-alpha", "1.0.0-b.2", "1.0.0-beta", "1.0.0-beta.11", "1.0.0-rc.1", "1.0.0.post", "1.0.0.post11", "1.0.11", "1.0.2", "1.post2", "1.post2+gc1", "1.post2+gc1.11", "1.post2+gc1.2", "10!0.1.0", "2!0.1.0", "2016.1"]

There are a few things wrong with this output. The first is that it's not sorting version epocs correctly. In ascending order, versions like "1!1.0" should come after versions without an epoch like "0.9" which is equivalent to 0!0.9.

The epocs also need to be ordered numerically as in "1!0.1.0", "2!0.1.0", "10!0.1.0" and this is not the case here where we are ordering alphabetically.

We are also ordering versions without epochs alphabetically rather than numerically and that is why we have "1.0.11" appear before "1.0.2". The python version spec is clear on this

All numeric components MUST be interpreted and ordered according to their numeric value, not as text strings.

Finally, the sort order for versions with suffixes is also incorrect. The python spec say the correct order is .devN, aN, bN, rcN, , .postN and within each suffix we should sort numerically where applicable.

So "1.0.0-alpha" < "1.0.0-a.1" but we're seeing the opposite. Likewise, in the commented out test "1" < "1.0.0.post" but that's not what we get.

[amazimbe]

Is there a merged python regex update changes related to this test cases? Or this is refining the test cases? I couldn't see the regex changes here?

It's coming. It's got python regex features and converting those to ruby has been problematic so far.

VERSION_PATTERN = r"""
    v?
    (?:
        (?:(?P<epoch>[0-9]+)!)?                           # epoch
        (?P<release>[0-9]+(?:\.[0-9]+)*)                  # release segment
        (?P<pre>                                          # pre-release
            [-_\.]?
            (?P<pre_l>(a|b|c|rc|alpha|beta|pre|preview))
            [-_\.]?
            (?P<pre_n>[0-9]+)?
        )?
        (?P<post>                                         # post release
            (?:-(?P<post_n1>[0-9]+))
            |
            (?:
                [-_\.]?
                (?P<post_l>post|rev|r)
                [-_\.]?
                (?P<post_n2>[0-9]+)?
            )
        )?
        (?P<dev>                                          # dev release
            [-_\.]?
            (?P<dev_l>dev)
            [-_\.]?
            (?P<dev_n>[0-9]+)?
        )?
    )
    (?:\+(?P<local>[a-z0-9]+(?:[-_\.][a-z0-9]+)*))?       # local version
"""