Re: [PATCH 04/10] configure: protect against escaping venv when running Meson

[Paolo Bonzini]

On Wed, Feb 22, 2023 at 4:04 PM Daniel P. Berrangé <berrange@redhat.com> wrote:
> > So, detect whether a virtual environment is setup, and if the virtual
> > environment does not have Meson, use the meson submodule.  Meson will
> > then run under the virtual environment's Python interpreter.
>
> I fear this could be somewhat confusing to contributors. If I have
> meson in my $PATH, at a sufficient version, it would be surprising
> to find QEMU had been using a different version instead.
>
> I can understand wanting to make it "just work", but should we
> perhaps issue a warning from configure when we're intentionally
> ignoring an otherwise valid meson installation ?

I don't think a warning is needed. First, the exact Meson version
should be pretty much neutral to the rest of the build system, and
QEMU should ship a good one (Meson's .0 releases aren't of the best
quality). Second, after all the user has _not_ specified --meson at
all in this scenario.

FWIW I think --sphinx-build and --meson should go away, and the single
way to invoke Python packages should be through $python. This means
that sphinx-build would have to be installed in $python's search path
or, in the future, installed via pip (same for meson once we decide
that it's okay to remove the bundled copy).

Overall, the result will be much more intuitive even if it may seem to
be a "less standard" setup. Both sphinx-build's and meson's
interpreters influence which interpreter is used during the build, and
it's confusing if it is anything but --python.

Paolo