Python RPM dependency generator does not support PEP 508?

[Michel Alexandre Salim]

Hi all,

Davide recently updated python-fixit, and the new version introduced an
ungated requirement on 'importlib-resources', which is only needed on
Python 3.6 and below; this caused an FTI as nothing satisfies that
dependency:

https://bugzilla.redhat.com/show_bug.cgi?id=2021229

To our surprise, patching requirements.txt to have

importlib-resources>=5.1.2; python_version <= '3.6'

per PEP 508 (which is a fix we can upstream) does not actually work.

cf: https://www.python.org/dev/peps/pep-0508/#examples

We're working around it by patching out this line completely, which
does work as expected, but:

1. should we support this conditional
2. where should we file this RFE?

Thanks,

[Ben Beasley]

I know this pattern works in general, because I maintain several Python 
packages in which it is used.

I tried modifying python-fixit to patch requirements.txt as you 
described. I confirmed the line appeared in the “prepped” source as you 
have written. Then I built it with mock and installed it into a Rawhide 
chroot without difficulty.

My best guess is that there was a mix-up in which RPM version you were 
trying to install—something that’s probably happened to all of us. 
Perhaps you built it in Rawhide and didn’t use --enablerepo=local when 
testing the installation?

Anyway, if you can reproduce the problem again, please consider doing so 
in a PR against your package, so that others can check out the PR and 
examine the exact spec file that is not working.

A side note: since, for example, Python 3.6.1 is not “<= '3.6'”, I think 
this conditional would be better written as “< '3.7'” instead.

On 11/11/21 18:46, Michel Alexandre Salim wrote:
> Hi all,
>
> Davide recently updated python-fixit, and the new version introduced an
> ungated requirement on 'importlib-resources', which is only needed on
> Python 3.6 and below; this caused an FTI as nothing satisfies that
> dependency:
>
> https://bugzilla.redhat.com/show_bug.cgi?id=2021229
>
> To our surprise, patching requirements.txt to have
>
> importlib-resources>=5.1.2; python_version <= '3.6'
>
> per PEP 508 (which is a fix we can upstream) does not actually work.
>
> cf: https://www.python.org/dev/peps/pep-0508/#examples
>
> We're working around it by patching out this line completely, which
> does work as expected, but:
> should we support this conditional
> where should we file this RFE?
>
> Thanks,
>
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[Michel Alexandre Salim]

On Fri, 2021-11-12 at 10:24 -0500, Ben Beasley wrote:
> I know this pattern works in general, because I maintain several Python
> packages in which it is used.
>
> I tried modifying python-fixit to patch requirements.txt as you 
> described. I confirmed the line appeared in the “prepped” source as you
> have written. Then I built it with mock and installed it into a Rawhide
> chroot without difficulty.
>
> My best guess is that there was a mix-up in which RPM version you were 
> trying to install—something that’s probably happened to all of us. 
> Perhaps you built it in Rawhide and didn’t use --enablerepo=local when 
> testing the installation?

Ah, that's likely what happened. And indeed, < '3.7' is better. Thanks!

Now we have something we can upstream, while just yanking out that line
likely won't fly:

https://github.com/Instagram/Fixit/pull/206

Best regards,