Re: [PATCH v3 1/8] meson: stop discovering native version of Python

From: Justin Tobler <jltobler@gmail.com>
Date: Jul 9, 2025, 21:36 UTC
Message-ID: <mku4cmu4tgib637ptpile5nch72cr55565o6oyaxjklc756j4c@63zony3qdzio>
In-Reply-To: <xmqqikk1pfiz.fsf@gitster.g>

On 25/07/09 08:09AM, Junio C Hamano wrote:

Show 18 quoted lines

> Patrick Steinhardt <ps@pks.im> writes:
> > -python = import('python').find_installation('python3', required: get_option('python'))
> > -target_python = find_program('python3', native: false, required: python.found())
> > -if python.found()
> > +# Python is not used for our build system, but exclusively for git-p4.
> > +# Consequently we only need to determine whether Python is available for the
> > +# build target.
> > +target_python = find_program('python3', native: false, required: get_option('python'))
> > +if target_python.found()
> >    build_options_config.set('NO_PYTHON', '')
> >  else
> >    libgit_c_args += '-DNO_PYTHON'
> 
> We ask explicitly for Python 3 here.
> 
> Does find_program() have some magic to deal with installations where
> Python3 is simply called /usr/bin/python (and worse yet, not as a
> symbolic link to /usr/bin/python3)?

My understanding is that find_program() won't do anything in this case. I would imagine if the target host has Python3 in a non-standard location, there would probably need to be a cross-file that defines it.

Show 12 quoted lines

> I found
> 
>     "Since 0.50.0 if the "python3" program is requested and it is
>     not found in the system, Meson will return its current
>     interpreter",
> 
> which I suspect refers to the path to python3 used during the build
> and is not what we want, at
> 
> https://mesonbuild.com/Reference-manual_functions.html#find_program
> 
> which got me a bit worried.

As you mentioned, I think this is only relevant for Python scipts executed at build time.

-Justin