Incorrect version for pypi packages

[jameshilliard]

It appears the latest version for pypi packages is being pulled from a sorted list of all available versions rather than the explicit default version specified in the pypi json api.

This is mostly a problem for projects that upload alpha releases to pypi.

As you can see here the latest version in release-monitoring doesn't match the version in pypi.

[Zlopez]

It will be probably good to use explicit default version instead of sorted list.

[Zlopez]

The best approach here will be to detect pre-release versions and add a check if user wants to be notified about the new version or not. Hopefully implementing #753 should help.

[z3ntu]

As anitya now supports the concept of stable vs pre-release versions the "pre-release" pypi tag should be taken into account. For example this package: https://pypi.org/project/rdflib/#history where anitya currently thinks 6.0.2a0 is the latest even though it was the release candidate for 6.0.2 proper and is marked pre-release and as such shouldn't be considered to be the stable version.

[Zlopez]

@z3ntu The Anitya doesn't look at the backend for the pre-release information, but rather on the version scheme, which also does the sorting. The version scheme is implemented according to the documentation. If this is not sorted correctly, try different version scheme for the project.

From what I remember python encourages projects to use Semantic versioning, if they don't there isn't much we can do about it. If Pypi has something special, please fill a request for this to be implemented together with the link on the documentation for this versioning system.

[z3ntu]

With the semantic version scheme selected in anitya 6.0.2 is now the latest. But this 'a0' suffix seems be a one-off weirdness, whatever the maintainer was thinking.