I can't reproduce this warning (which we treat as a hard error) locally:

/home/runner/work/packaging.python.org/packaging.python.org/source/tutorials/installing-packages.rst:376: WARNING: undefined label: 'pip:install_--no-binary'

The failing label definitely exists: https://pip.pypa.io/en/latest/cli/pip_install/#install-no-binary

Edit: now it reproduces, but I can't think of a reason this would suddenly fail. Sigh.

Oh hmm, this is because pip's RTD is pointing to latest instead of stable, and latest (which is for a development release) doesn't have --no-binary labeled seemingly.

Compare stable where it's documented at that anchor:

• https://pip.pypa.io/en/stable/cli/pip_install/#install-no-binary

And release where it isn't:

• https://pip.pypa.io/en/latest/cli/pip_install/#install-no-binary

So, I think there are two things here:

1. Should pip's default RTD site be stable, instead of latest? This would stop ReST ref churn between releases, which cause problems here. But I don't have a strong sense there.
2. I think that link to --no-binary was unintentionally removed, unless pip actually is fully removing --no-binary in the upcoming 26 release.

CC @ichard26 for opinions on the above 🙂

(One thing that's confusing me about this is that I can't find that --no-binary argument documentation anywhere on pip's main branch. It's not present in pip_install.rst and none of the recent changes look relevant.)

@woodruffw this almost certainly due to this PR: pypa/pip#13769. Thanks for the catch, I will take a look before releasing.

Thanks a ton! I'm glad it served as a backstop here 🙂

@ichard26 is a hero and has already fixed it in pypa/pip#13778, https://pip.pypa.io/en/latest/cli/pip_install/#install-no-binary is now available again.

When I get a moment I will look at the history of pip's default RTD site and see if it needs changing or if there is a known reason for it to point to latest.