Thanks for the report @mkoeppe. That's a bug indeed. The gitversion.py script should check for a file containing the needed git hash (as was done with if fs.exists('_version_meson.py') before gh-24196). Building from an sdist should work when git is not installed.

@stefanv can you please have a look at this?

While #24511, the sage build of 1.26b1 should not be hitting this. Are you building from the sdist or from a github archive?

Building from the sdist from PyPI. I've just added #24511 as a patch. Tests running at https://github.com/mkoeppe/sage/actions/runs/5954216252, I'll report back when finished

I confirm that this fixes the problem. Thanks for the quick fix @mattip

Thanks for handling it, @mattip

Note that the idea is to always generate the version and distribute it as part of the sdist. That way, the git hash should never be empty.

So if the version is not in the sdist, I guess we should reopen this and figure out why it is missing.

It is present, Stefan's comment was only clarifying. I just checked it when working on the next fix (gh-24515), version.py is part of the sdist.

The meson.add_dist_script call takes care of this. It should be robust.

Weird. @mkoeppe how did the sage build not find it? What is the command you are using to build NumPy 1.26b1?

@mattip Just using python3 -m pip wheel.

Does the above command go via setuptools? When I run:

python3 -m build -s

it invokes Meson and builds the sdist that contains version.py.

No, python3 -m pip wheel does not invoke setuptools. It runs the build system declared in pyproject.toml

The problem here was simply that gitversion.py is unconditionally triggered right at the top of meson.build, and the git_hash = '' for when git is not installed was in the wrong place. It was fixed with Matti's one-line patch, and nothing else was wrong.

That makes sense. Thanks for the explanation.

Thanks for checking that; I wasn't able to look at the time, but that sets my mind at ease.