On 2/10/23 01:31, John Snow wrote:
> At the moment, we look for just "python3" and "python", which is good
> enough almost all of the time. But ... if you are on a platform that
> uses an older Python by default and only offers a newer Python as an
> option, you'll have to specify --python=/usr/bin/foo every time.
>
> We can be kind and instead make a cursory attempt to locate a suitable
> Python binary ourselves, looking for the remaining well-known binaries.
>
> This configure loop will prefer, in order:
>
> 1. Whatever is specified in $PYTHON
> 2. python3
> 3. python
> 4. python3.11 down through python3.6
>
> Notes:
>
> - Python virtual environment provides binaries for "python3", "python",
> and whichever version you used to create the venv,
> e.g. "python3.8". If configure is invoked from inside of a venv, this
> configure loop will not "break out" of that venv unless that venv is
> created using an explicitly non-suitable version of Python that we
> cannot use.
>
> - In the event that no suitable python is found, the first python found
> is the version used to generate the human-readable error message.
>
> - The error message isn't printed right away to allow later
> configuration code to pick up an explicitly configured python.
>
> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
> configure | 33 +++++++++++++++++++++++++--------
> 1 file changed, 25 insertions(+), 8 deletions(-)
>
> diff --git a/configure b/configure
> index 64960c6000f..ea8c973d13b 100755
> --- a/configure
> +++ b/configure
> @@ -592,20 +592,39 @@ esac
>
> : ${make=${MAKE-make}}
>
> -# We prefer python 3.x. A bare 'python' is traditionally
> -# python 2.x, but some distros have it as python 3.x, so
> -# we check that too
> +
> +check_py_version() {
> + # We require python >= 3.6.
> + # NB: a True python conditional creates a non-zero return code (Failure)
> + "$1" -c 'import sys; sys.exit(sys.version_info < (3,6))'
> +}
> +
> python=
> +first_python=
> explicit_python=no
> -for binary in "${PYTHON-python3}" python
> +# A bare 'python' is traditionally python 2.x, but some distros
> +# have it as python 3.x, so check in both places.
> +for binary in "${PYTHON-python3}" python python3.{11..6}
This is not available in e.g. dash, so we need to use {11,10,9,8,7,6}.
Just a nit, I can fix it myself.
What platforms use dash by default?
Did I not see a failure because nothing that uses dash iterated that far down in the list?
Anyway, you've got my blessing to change it, of course.
PS, while you're here, how does this new loop interfere with your "custom python specified" flag for meson? I think meson uses the version of python *it* detects and not the configure script identified one, right? Does that mean that e.g. the qapi generator gets run with the system default/meson version and not the config version?
Do I need to adjust this loop to consider more binaries as "explicitly specified"?
(PPS: English needs "paraphrasing quotes" as punctuation. Maybe like double quotes except they're wiggly.)
--js