Re: [RFC PATCH v3 00/20] configure: create a python venv and ensure meson, sphinx

[Paolo Bonzini <pbonzini@redhat.com>]

On 4/24/23 22:02, John Snow wrote:
> Some important points as a pre-emptive "FAQ":
> 
> - This venv is unconditionally created and lives at {build_dir}/pyvenv.
> 
> - The python interpreter used by this venv is always the one identified
>    by configure. (Which in turn is always the one specified by --python
>    or $PYTHON)
> 
> -*almost*  all python scripts in qemu.git executed as part of the build
>    system, meson, sphinx, avocado tests, vm tests or CI are always
>    executed within this venv.
> 
>    (iotests are not yet integrated; I plan to tackle this separately as a
>    follow-up in order to have a more tightly focused scope on that
>    series.)
> 
> - It remains possible to build and test fully offline.
>    (In most cases, you just need meson and sphinx from your distro's repo.)
> 
> - Distribution packaged 'meson' and 'sphinx' are still utilized whenever
>    possible as the highest preference.
> 
> - Vendored versions of e.g. 'meson' are always preferred to PyPI
>    versions for speed, repeatability and ensuring tarball builds work
>    as-is offline.
> 
>    (Sphinx will not be vendored, just like it already isn't.)
> 
> - Missing dependencies, when possible, are fetched and installed
>    on-demand automatically to make developer environments "just work".
> 
> - Works for Python 3.7 and up, on Fedora, OpenSuSE, Red Hat, CentOS,
>    Alpine, Debian, Ubuntu, NetBSD, OpenBSD, and hopefully everywhere
> 
> - No new dependencies (...for most platforms. Debian and NetBSD get an
>    asterisk.)
> 
> - The meson git submodule is unused after this series and can be removed.

Thanks, this looks pretty good.  Some changes I'd make for the non-RFC 
version:

- I think we should just check in the meson wheel (which also removes 
the need for patch 12, so it can be done in its stead) and remove the 
submodule

- The verbosity of mkvenv.py can be tuned down and most prints replaced 
with logger.info() or logger.debug()

- While I agree with keeping patch 18 separate, I would move it earlier 
so that patch 19 can be squashed into patch 14

- I am ambivalent about keeping --enable/--disable-pypi in the first 
committed patchset, but in any case I would move patches 16 and 20 
before patch 15

Paolo