Patch packaging to support PEP 703 (--disable-gil)

[colesbury]

This applies pypa/packaging#728 as a stopgap measure to support the free-threaded builds of CPython. That PR is already merged upstream, but a full upgrade of the packaging library is more complicated due to removal of legacy versions and version specifiers.

See #12634

[notatallshaw]

I believe vendor patches should be put here: https://github.com/pypa/pip/tree/main/tools/vendoring/patches

I'm not familiar with the mechanism of how they get applied though.

[notatallshaw]

Also, you should be aware of the policy in case you're not already: https://pip.readthedocs.io/en/stable/development/vendoring-policy/ https://pip.pypa.io/en/stable/development/vendoring-policy/

[pfmoore]

Also, you should be aware of the policy in case you're not already: https://pip.readthedocs.io/en/stable/development/vendoring-policy/

The official link is https://pip.pypa.io/en/stable/development/vendoring-policy/ (I think you're quoting the docs from a fork).

[colesbury]

Thanks for the pointers. A relevant line from the policy is:

Vendored libraries MUST not be modified except as required to successfully vendor them.

I'm not sure what counts as "successfully vendor", but I think a reasonable interpretation would be that a library is not successfully vendored if it prevents pip from working correctly in the free-threaded 3.13 build.

#12300 is clearly a better long term solution -- this is only intended as a stopgap measure. I would like feedback on whether you think this worthwhile.

[pfmoore]

I think it's reasonable to consider doing this. Having said that, the plan is for the upgrade of packaging to be completed for the 24.1 release, so I'd advise that we don't merge this until we know for certain whether that's going to be possible.

[pradyunsg]

Closing this out since #12300 has merged.