Hello!
Current situation ================= Without specifying USE_PYTHON in /etc/make.conf ebuilds based on the python eclass will install packages for no more ABIs than the two active versions on the 2.x and 3.x lines. To give an example: with Python 2.6, 2.7 and 3.1 installed and 2.7 set as the active 2.x Python version I would get files installed for python 2.7 and 3.1, but not 2.6. Is that a sane default? Especially when a new slot of Python arrives at the Gentoo tree, you run into situations with two slots of Python 2.x installed. To have packages functioning with both, you would need a custom USE_PYTHON line like USE_PYTHON="2.6 2.7" - otherwise one of these slots' Python will be very limited. This problem is made worse by the fact that USE_PYTHON has almost no documentation. This bug shows well, that the current behavior is a surprising troublemaker: https://bugs.gentoo.org/show_bug.cgi?id=347153 Proposed new situation ====================== If I have a version of Python installed, it should be usable well. So USE_PYTHON is derived from the list of all available Python slots. Excluded are ABIs restricted by an ebuild, say by a line like RESTRICT_PYTHON_ABIS="3.*" for software that does not build with Python 3.x. Proposed code ============= I would love to just pass a patch here - I have two files to diff between - but (due to the algorithm diff works with) the patch is much less clear as the relevant excerpt itself. If you want a patch or the file version get my modified python.eclass file from here: http://hartwork.org/public/python.eclass So now comes the excerpt (with tabs converted to double spaces just for this mail). The code is meant to fill variable PYTHON_ABIS with content like "2.6 2.7" in case of no USE_PYTHON line around. ======================================================================= debug-print 'USE_PYTHON not specified in make.conf, deriving default' # - include all installed ABIs # - but exclude those restricted by the ebuild local PYTHON_ABI restricted_ABI restricted_ABIs support_ABI python_versions restricted_ABIs="${RESTRICT_PYTHON_ABIS// /$'\n'}" python_versions=("${_cpython2_supported_ab...@]}" "${_cpython3_supported_ab...@]}") for PYTHON_ABI in ${python_versio...@]} ; do # ABI available? local interpreter="${EPREFIX}"/usr/bin/python${PYTHON_ABI} if [[ ! -x "${interpreter}" ]]; then debug-print "Disabling ABI ${PYTHON_ABI} (interpreter ${interpreter} missing)" continue fi # ABI restricted by ebuild? support_ABI="1" while read restricted_ABI; do if [[ "${PYTHON_ABI}" == ${restricted_ABI} ]]; then support_ABI="0" break fi done <<< "${restricted_ABIs}" if [[ "${support_ABI}" != "1" ]]; then debug-print "Disabling ABI ${PYTHON_ABI} (due to restrictions from the ebuild)" continue fi debug-print "Enabling ABI ${PYTHON_ABI}" export PYTHON_ABIS+="${PYTHON_ABIS:+ }${PYTHON_ABI}" done export PYTHON_ABIS="${PYTHON_ABIS% }" debug-print "PYTHON_ABIS now is '${PYTHON_ABIS}'" ======================================================================= Please review the proposal and above code. Thanks in advance. ECLASS_DEBUG_OUTPUT=on may be of use when testing. Best, Sebastian
