[gentoo-dev] Re: [PATCH] Check for USE_PYTHON <-> PYTHON_TARGETS equiv.

[Mike Gilbert]

On Mon, Nov 5, 2012 at 6:59 AM, Michał Górny <mgorny@g.o> wrote:
> ---
>  gx86/eclass/python-r1.eclass | 66 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 66 insertions(+)
>
> diff --git a/gx86/eclass/python-r1.eclass b/gx86/eclass/python-r1.eclass
> index 0d6ef4c..6d4eb33 100644
> --- a/gx86/eclass/python-r1.eclass
> +++ b/gx86/eclass/python-r1.eclass
> @@ -363,6 +363,70 @@ python_copy_sources() {
>         done
>  }
>
> +# @FUNCTION: _python_check_USE_PYTHON
> +# @INTERNAL
> +# @DESCRIPTION:
> +# Check whether USE_PYTHON and PYTHON_TARGETS are in sync. Output
> +# warnings if they are not.
> +_python_check_USE_PYTHON() {
> +       if [[ ! ${_PYTHON_USE_PYTHON_CHECKED} ]]; then
> +               _PYTHON_USE_PYTHON_CHECKED=1
> +
> +               local USE_PYTHON=${USE_PYTHON}
> +
> +               if [[ ! ${USE_PYTHON} ]]; then
> +                       # default to selected Python2+3
> +                       if has_version app-admin/eselect-python; then
> +                               local py2=$(eselect python show --python2)
> +                               local py3=$(eselect python show --python3)
> +
> +                               USE_PYTHON="${py2#python} ${py3#python}"
> +                       fi
> +               fi
> +
> +               local impl warned
> +               for impl in "${PYTHON_COMPAT[@]}"; do
> +                       local abi
> +                       case "${impl}" in
> +                               python*)
> +                                       abi=${impl#python}
> +                                       ;;
> +                               jython*)
> +                                       abi=${impl#jython}-jython
> +                                       ;;
> +                               pypy*)
> +                                       abi=2.7-pypy-${impl#pypy}
> +                                       ;;
> +                               *)
> +                                       die "Unexpected Python implementation: ${impl}"
> +                                       ;;
> +                       esac
> +
> +                       has "${abi/_/.}" ${USE_PYTHON}
> +                       local has_abi=${?}
> +                       use "python_targets_${impl}"
> +                       local has_impl=${?}
> +
> +                       if [[ ${has_abi} != ${has_impl} ]]; then
> +                               if [[ ! ${warned} ]]; then
> +                                       ewarn "PYTHON_TARGETS <-> USE_PYTHON inconsistency found. This may result"
> +                                       ewarn "in missing modules when trying to use Python packages. Please ensure"
> +                                       ewarn "that the same implementations are listed in both variables."
> +                                       ewarn
> +
> +                                       warned=1
> +                               fi
> +
> +                               if [[ ${has_abi} == 0 ]]; then
> +                                       ewarn "Implementation ${impl} disabled but ${abi/_/.} in USE_PYTHON"
> +                               else
> +                                       ewarn "Implementation ${impl} enabled but ${abi/_/.} not in USE_PYTHON"
> +                               fi
> +                       fi
> +               done
> +       fi
> +}
> +
>  # @FUNCTION: python_foreach_impl
>  # @USAGE: <command> [<args>...]
>  # @DESCRIPTION:
> @@ -376,6 +440,8 @@ python_copy_sources() {
>  python_foreach_impl() {
>         debug-print-function ${FUNCNAME} "${@}"
>
> +       _python_check_USE_PYTHON
> +
>         local impl
>         local bdir=${BUILD_DIR:-${S}}
>
> --
> 1.7.12.4
>

We should not encourage users to set USE_PYTHON if it has not been set
already; the variable is pretty much undocumented, and should probably
stay that way. If USE_PYTHON is unset, we should advise them to update
PYTHON_TARGETS to match their active python2 and python3 versions
(from eselect python).