On Tue, Feb 21, 2023 at 12:37:43PM -0500, John Snow wrote: > On Tue, Feb 21, 2023, 6:03 AM Paolo Bonzini <pbonz...@redhat.com> wrote: > > > On 2/21/23 02:24, 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. > > > > > > As a courtesy, we can make a cursory attempt to locate a suitable Python > > > binary ourselves, looking for the remaining well-known binaries. This > > > also has the added benefit of making configure "just work" more often > > > on various BSD distributions that do not have the concept of a > > > "platform default python". > > > > > > This configure loop will prefer, in order: > > > > > > 1. Whatever is specified in $PYTHON > > > 2. python3 > > > 3. python (Which is usually 2.x, but might be 3.x on some platforms.) > > > 4. python3.11 down through python3.6 > > > > > > Notes: > > > > > > - Python virtual environments provide 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 <js...@redhat.com> > > > --- > > > configure | 34 ++++++++++++++++++++++++++-------- > > > 1 file changed, 26 insertions(+), 8 deletions(-) > > > > > > diff --git a/configure b/configure > > > index cf6db3d5518..6abf5a72078 100755 > > > --- a/configure > > > +++ b/configure > > > @@ -592,20 +592,40 @@ 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 > > > +# Check for $PYTHON, python3, python, then explicitly-versioned > > interpreters. > > > +for binary in "${PYTHON-python3}" ${PYTHON:+python3} python \ > > > + python3.11 python3.10 python3.9 \ > > > + python3.8 python3.7 python3.6 > > > > I think if PYTHON is set we shouldn't look at anything else. > > > > Paolo > > > > PYTHON is one we made up, right?
$PYTHON is explicitly set in all our dockerfiles. We should ensure we honour it and not fallback to anything else when it is set. ie it would be a user error to set it to point to a python that is missing/broken, so the user should expect an error, not fallback to another version. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|