diff --git a/configure b/configure index a1912463c9..0e41c5e36c 100755 --- a/configure +++ b/configure @@ -592,20 +592,43 @@ 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 -python= -explicit_python=no -for binary in "${PYTHON-python3}" python -do - if has "$binary" - then - python=$(command -v "$binary") - break - fi -done +check_py_version() { + # We require python >= 3.6. + # NB: a True python conditional creates a non-zero return code (Failure) + "$1" -c 'import sys; sys.exit(sys.version_info < (3,6))' +} + +python= +first_python= +if test -z "${PYTHON}"; then + explicit_python=no + # 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 python3 python python3.11 python3.10 python3.9 python3.8 python3.7 python3.6; do + if has "$binary"; then + python=$(command -v "$binary") + if check_py_version "$python"; then + # This one is good. + first_python= + break + else + first_python=$python + fi + fi + done +else + # Same as above, but only check the environment variable. + has "${PYTHON}" || error_exit "The PYTHON environment variable does not point to an executable" + python=$(command -v "$PYTHON") + explicit_python=yes + if check_py_version "$python"; then + # This one is good. + first_python= + else + first_python=$first_python + fi +fi # Check for ancillary tools used in testing genisoimage= @@ -1030,16 +1053,22 @@ rm -f ./*/config-devices.mak.d if test -z "$python" then - error_exit "Python not found. Use --python=/path/to/python" + # If first_python is set, there was a binary somewhere even though + # it was not suitable. Use it for the error message. + if test -n "$first_python"; then + error_exit "Cannot use '$first_python', Python >= 3.6 is required." \ + "Use --python=/path/to/python to specify a supported Python." + else + error_exit "Python not found. Use --python=/path/to/python" + fi fi + if ! has "$make" then error_exit "GNU make ($make) not found" fi -# Note that if the Python conditional here evaluates True we will exit -# with status 1 which is a shell 'false' value. -if ! $python -c 'import sys; sys.exit(sys.version_info < (3,6))'; then +if ! check_py_version "$python"; then error_exit "Cannot use '$python', Python >= 3.6 is required." \ "Use --python=/path/to/python to specify a supported Python." fi