fix MatchSpec roundtrip parsing

[wolfv]

We have an issue in mamba where the MatchSpec looses some information through the representation.

If you parse libblas=*=*mkl, the repr of that is libblas=[build=*mkl]
When parsing libblas=[build=*mkl] one hits a assert because the version is empty.

I believe it would be better to have libblas=*[build=*mkl] and I attached a fix for this.

[cla-bot]

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[jjhelmus]

@cla-bot check

[cla-bot]

The cla-bot has been summoned, and re-checked this pull request!

[mcg1969]

Thanks!

[mcg1969]

Seems like it is failing here

[mcg1969]

flake is complaining about the extra blank here :-(

[jezdez]

@wolfv Hey Wolf, I'm not sure if this is current or not, could you let me know if this is still an issue?

[wolfv]

@jezdez yes, this is still an issue, I just checked.

Also, there is another issue I've been hitting before in micromamba. When requesting a spec from the command line like so numpy=1.23 it means "loose 1.23" requirement, and is equal to numpy 1.23.*.
However, when requesting numpy=1.23=*123, the first single-equals is translated into a double equals, e.g. numpy==1.23=*123. However, the double-equals signifies a strong pin so that numpy==1.23.0 which is a lot less flexible.

>>> a = MatchSpec("numpy=1.23=*123")
>>> a.__str__()
'numpy==1.23=*123'
>>> a.conda_build_form()
'numpy 1.23 123'

[github-actions]

Hi there, thank you for your contribution!

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed automatically if no further activity occurs.

If you would like this pull request to remain open please:

1. Rebase and verify the changes still work
2. Leave a comment with the current status

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Thanks!

[github-actions]

Hi there, thank you for your contribution!

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed automatically if no further activity occurs.

If you would like this pull request to remain open please:

1. Rebase and verify the changes still work
2. Leave a comment with the current status

NOTE: If this pull request was closed prematurely, please leave a comment.

Thanks!