path: root/eclass/python-multilib-r1.eclass

# Copyright 1999-2013 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2
# $Header: $

# @ECLASS: python-multilib-r1
# @MAINTAINER:
# Nobody
# @AUTHOR:
# Greg Turner <gmt@be-evil.net>
# Based on work of: Michał Górny <mgorny@gentoo.org>
# Based on work of: Krzysztof Pawlik <nelchael@gentoo.org>
# @BLURB: A common, simple eclass for making your head explode.
# @DESCRIPTION:
# A common eclass providing helper functions to build and install
# packages supporting being installed for multiple Python
# implementations.
#
# Please note that python-multilib-r1 will always inherit
# python-multilib-utils-r1, as well. Thus, all the functions defined
# there can be used in the packages using python-multilib-r1, and there
# is no need ever to inherit both.  However, doing so is harmless.
#
# For more information, please see the python-r1 Developer's Guide:
# http://www.gentoo.org/proj/en/Python/python-r1/dev-guide.xml

case "${EAPI:-0}" in
	0|1|2|3)
		die "Unsupported EAPI=${EAPI:-0} (too old) for ${ECLASS}"
		;;
	4|5)
		# EAPI=4 is required for USE default deps on USE_EXPAND flags
		;;
	*)
		die "Unsupported EAPI=${EAPI} (unknown) for ${ECLASS}"
		;;
esac

if [[ ! ${_PYTHON_MULTILIB_R1} ]]; then

if [[ ${_PYTHON_ANY_R1} ]]; then
	die 'python-r1.eclass can not be used with python-any-r1.eclass.'
fi

[[ ${PYTHON_MULTILIB_UTILS_R1} ]] || \
	inherit python-multilib-utils-r1

# @ECLASS-VARIABLE: DISTUTILS_JOBS
# @DEFAULT_UNSET
# @DESCRIPTION:
# The number of parallel jobs to run for distutils-r1 parallel builds.
# If unset, the job-count in ${MAKEOPTS} will be used.
#
# This variable is intended to be set in make.conf.

# @ECLASS-VARIABLE: PYTHON_COMPAT
# @DESCRIPTION:
# This variable contains a list of Python implementations the package
# supports. It must be set before the `inherit' call. It has to be
# an array.
#
# Example:
# @CODE
# PYTHON_COMPAT=( python{2_5,2_6,2_7} )
# @CODE

# @ECLASS-VARIABLE: PYTHON_COMPAT_MULTILIB
# @DEFAULT-UNSET
# @DESCRIPTION:
# This variable is generated from PYTHON_COMPAT and multilib-build
# metadata.  It is simply the Cartesian product of ${PYTHON_COMPAT} and
# _CACHED_MULTILIB_FLAGS from python-multilib-utils-r1.eclass, expressed
# as an array of <python-abi>_<multilib-flag> tuples.  The tuples are
# grouped by python-abi, with the best python-abi entries coming last,
# and wihtin these groups, sorted such that the multilib flags corresponding
# to the best multilib abi are last (except during the depend phase,
# when no ordering guarantees are available).
#
# Aside from the ordering, (which is itself fully invariant during the
# depend ebuild phase), this variable is invariant with respect
# to profile settings and therefore should be suitable for generating
# package-manager-cachable metadata.

_autogen_python_compat_multilib_from_python_compat() {
    debug-print-function ${FUNCNAME} "$@"

	local impl flag
	# exploit PYTHON_NOMULTILIB_ALL_IMPLS best-last ordering & freedom from legacy impls
	for impl in "${_PYTHON_NOMULTILIB_ALL_IMPLS[@]}"; do
		# but skip any impls not in PYTHON_COMPAT
		[[ " ${PYTHON_COMPAT[*]} " == *" ${impl} "* ]] || continue
		# exploit (phase-predicated) CACHED_MULTILIB_FLAGS best-last ordering
		for flag in "${_CACHED_MULTILIB_FLAGS[@]}" ; do
			PYTHON_COMPAT_MULTILIB+=("${impl}_${flag}")
        done
    done
	debug-print "${FUNCNAME}: from PYTHON_COMPAT: ( $(mg-qm "${PYTHON_COMPAT[@]}") )"
    debug-print "${FUNCNAME}: computed PYTHON_COMPAT_MULTILIB: ( $(mg-qm "${PYTHON_COMPAT_MULTILIB[@]}") )"
}

_gen_python_multilib_deps() {
	local impls=()

	PYTHON_MULTILIB_DEPS=
	local i PYTHON_MULTILIB_PKG_DEP
	for i in "${PYTHON_COMPAT[@]}"; do
		_python_nomultilib_impl_supported "${i}" || continue

		python_export "${i}" PYTHON_MULTILIB_PKG_DEP
		PYTHON_MULTILIB_DEPS+="python_targets_${i}? ( ${PYTHON_MULTILIB_PKG_DEP} ) "

		impls+=( "${i}" )
	done

	if [[ ${#impls[@]} -eq 0 ]]; then
		die "No supported implementation in PYTHON_COMPAT."
	fi

	local flags=( "${impls[@]/#/python_targets_}" )
	debug-print "${FUNCNAME}: NML: flags=(${flags[*]})"
	local optflags=${flags[@]/%/(-)?}

	# A nice QA trick here. Since a python-single-r1 package has to have
	# at least one PYTHON_SINGLE_TARGET enabled (REQUIRED_USE),
	# the following check will always fail on those packages. Therefore,
	# it should prevent developers from mistakenly depending on packages
	# not supporting multiple Python implementations.

	local flags_st=( "${impls[@]/#/-python_single_target_}" )
	debug-print "${FUNCNAME}: NML: flags_st=(${flags_st[*]})"
	optflags+=,${flags_st[@]/%/(-)}
	debug-print "${FUNCNAME}: NML: optflags=(${optflags[*]})"

	IUSE=${flags[*]}
	PYTHON_MULTILIB_REQUIRED_USE="|| ( ${flags[*]} )"
	PYTHON_MULTILIB_USEDEP=${optflags// /,}

	debug-print "${FUNCNAME}: IUSE (NML): \"${IUSE}\""
	debug-print "${FUNCNAME}: PYTHON_MULTILIB_REQUIRED_USE (NML): \"${PYTHON_MULTILIB_REQUIRED_USE}\""
	debug-print "${FUNCNAME}: PYTHON_MULTILIB_USEDEP (NML): \"${PYTHON_MULTILIB_USEDEP}\""

	# 1) well, python-exec would suffice as an RDEP
	# but no point in making this overcomplex, BDEP doesn't hurt anyone
	# 2) python-exec should be built with all targets forced anyway
	# but if new targets were added, we may need to force a rebuild
	PYTHON_MULTILIB_DEPS+="dev-lang/python-exec:=[${PYTHON_MULTILIB_USEDEP}]"

	# multilib-specifc:
	impls=()
	for i in "${PYTHON_COMPAT_MULTILIB[@]}"; do
		_python_multilib_impl_supported "${i}" || continue

		si=$(_python_strip_multilib_impl_abi "${i}")
		uf="abi${i#${si}}"
		i2=$(epythonize "${i}")

		# this will always work during the depend phase but some irrelevant stuff will
		# go missing during the others, due to ABIs disabled in portage.
		# FIXME: probably a pms violation
		if [[ ${i2} ]] ; then
			# The chosen targets need to be in PYTHON_TARGETS and
			# PYTHON_MULTILIB_TARGETS.
			PYTHON_MULTILIB_REQUIRED_USE+=" python_multilib_targets_${i}? (
				python_targets_${si} "
			# the multilib abi should match the python multilib abis
			PYTHON_MULTILIB_REQUIRED_USE+="${uf} )"

			python_export "${i2}" PYTHON_MULTILIB_PKG_DEP
			PYTHON_MULTILIB_DEPS+=" python_multilib_targets_${i}? ( ${PYTHON_MULTILIB_PKG_DEP} ) "
			impls+=( "${i}" )
		fi
	done

	if [[ ${#impls[@]} -eq 0 ]]; then
		die "No supported implementation in PYTHON_COMPAT_MULTILIB."
	fi

	debug-print "${FUNCNAME}: impls=(${impls[*]})"

	flags=( "${impls[@]/#/python_multilib_targets_}" )
	debug-print "${FUNCNAME}: ML: flags=(${flags[*]})"
	optflags=( "${impls[@]/#/python_multilib_mtargets_}" )
	debug-print "${FUNCNAME}: ML: optflags=(${optflags[*]})"

	# QA "trick" multilib edition:
	flags_st=( "${impls[@]/#/-python_multilib_single_targets_}" )
	optflags+=,${flags_st[@]/%/(-)}
	IUSE+=" ${flags[*]}"
	debug-print "${FUNCNAME}: final value: IUSE=\"${IUSE}\""
	# nb: no required use augmentation required since
	# it is sufficient to have only nomultilib impls selected.
	PYTHON_MULTILIB_USEDEP+=",${optflags// /,}"
}

_python_multilib_set_globals() {
	debug-print-function ${FUNCNAME} "$@"
	PYTHON_COMPAT_MULTILIB=()
	_autogen_python_compat_multilib_from_python_compat
	_gen_python_multilib_deps
}
_python_multilib_set_globals

# @ECLASS-VARIABLE:_PYTHON_ACTIVE_MULTILIB_IMPL_CACHE
# @INTERNAL
# @DEFAULT_UNSET
# @DESCRIPTION:
# Once generated, contains a list of all the currently active multilib
# python impls as an array of PYTHON_COMPAT_MULTILIB impl specifiers.
# This list may be empty, for example if there are no corresponding
# multilib impls's for the active DEFAULT_ABI in portage.
#
# Except during the depend ebuild phase, this list will always be ordered
# first by the python abi's and then by the multilib abi's, with the best
# python abi's coming last and the best multilib abis (for a given python
# abi) coming last, such that the very last item, if any, is the most
# preferred multilib python impl available (however, it is possible that
# a no-multilib python impl might be active which is preferred over all
# of the multilib python impl's).

# @FUNCTION: _python_multilib_impl_activate
# @INTERNAL
# @DESCRIPTION:
# Appends a multilib impl to the _PYTHON_ACTIVE_MULTILIB_IMPL_CACHE,
# creating the variable if it does not exist.
_python_multilib_impl_activate() {
	debug-print-function ${FUNCNAME} "$@"
	if ! declare -p _PYTHON_ACTIVE_MULTILIB_IMPL_CACHE &> /dev/null ; then
		_PYHON_ACTIVE_MULTILIB_IMPL_CACHE=()
	fi
	_PYTHON_ACTIVE_MULTILIB_IMPL_CACHE+=("${1}")
}

# @FUNCTION: _python_multilib_cache_active_impls
# @INTERNAL
# @DESCRIPTION:
# Enforce the proper setting of PYTHON_MULTILIB_TARGETS_*, and construct
# the _PYTHON_ACTIVE_{NO,}MULTILIB_IMPL_CACHES if necesary.
_python_multilib_cache_active_impls() {
	debug-print-function ${FUNCNAME} "${@}"

	local nomultilib_impl="${1}" i
	for i in "${PYTHON_COMPAT_MULTILIB[@]}"; do
		[[ $(_python_strip_multilib_impl_abi "${i}") == ${nomultilib_impl} ]] &&
			use_if_iuse "python_multilib_targets_${i}" && \
				_python_multilib_impl_activate "${i}"
	done
	debug-print "${FUNCNAME}: generated: _PYTHON_ACTIVE_MULTILIB_IMPL_CACHE=(${_PYTHON_ACTIVE_MULTILIB_IMPL_CACHE[*]})"
}

# @ECLASS-VARIABLE:_PYTHON_ACTIVE_NOMULTILIB_IMPL_CACHE
# @INTERNAL
# @DEFAULT_UNSET
# @DESCRIPTION:
# Once generated, contains a list of all the currently active nomultilib
# python impls as an array of PYTHON_COMPAT impl specifiers.  Some of these
# may be redundant equivalents to the best-multilib-abi entries in the
# _PYTHON_ACTIVE_MULTILIB_IMPL_CACHE.  When multilib impl's exist for a
# nomultilib impl, the nomultilib imple cache entry may be thought of as
# a hint to use the multilib impl's instead.
#
# This list will always have the best enabled python ABI as the last item.

# @FUNCTION: _python_nomultilib_impl_activate
# @INTERNAL
# @DESCRIPTION:
# Appends a nomultilib impl to the _PYTHON_ACTIVE_NOMULTILIB_IMPL_CACHE,
# creating the variable if it does not exist.  Then calls
# _python_multilib_cache_active_impls in order to cache any corresponding
# multilib impls.
_python_nomultilib_impl_activate() {
	debug-print-function ${fUNCNAME} "$@"
	declare -p _PYTHON_ACTIVE_NOMULTILIB_IMPL_CACHE &> /dev/null || \
		_PYHON_ACTIVE_NOMULTILIB_IMPL_CACHE=()
	_PYTHON_ACTIVE_NOMULTILIB_IMPL_CACHE+=("${1}")
	_python_multilib_cache_active_impls "${1}"
}

# @FUNCTION: _python_cache_active_impls
# @INTERNAL
# @DESCRIPTION:
# Enforce and remember the proper setting of PYTHON_TARGETS.
_python_cache_active_impls() {
	debug-print-function ${FUNCNAME} "${@}"

	if declare -p _PYTHON_ACTIVE_NOMULTILIB_IMPL_CACHE &> /dev/null ; then
		debug-print "${FUNCNAME}: already generated"
		return 0
	fi

	declare -p PYTHON_COMPAT &> /dev/null || \
		die "Somebody forgot to define PYTHON_COMPAT before inheriting a python-multilib-r1 framework eclass."

	local i found=
	# exploit PYTHON_NOMULTILIB_ALL_IMPLS's best-last ordering & guaranteed content validity
	for i in "${_PYTHON_NOMULTILIB_ALL_IMPLS[@]}"; do
		# ... but skip any impls not in PYTHON_COMPAT
		[[ " ${PYTHON_COMPAT[*]} " == *" ${i} "* ]] || continue

		# if the corresponding use-flag is on, we are building it.
		if use_if_iuse "python_targets_${i}" ; then
			# ... so cache the impl and any corresponding multilib impls now.
			_python_nomultilib_impl_activate "${i}"
			found=1
		fi
	done

	if [[ ${found} ]] ; then
		debug-print "${FUNCNAME}: generated _PYTHON_ACTIVE_NOMULTILIB_IMPL_CACHE: ($(
			mg-qm "${_PYTHON_ACTIVE_NOMULTILIB_IMPL_CACHE[@]}"))"
		debug-print "${FUNCNAME}: generated _PYTHON_ACTIVE_MULTILIB_IMPL_CACHE: ($(
			mg-qm "${_PYTHON_ACTIVE_MULTILIB_IMPL_CACHE[@]}"))"
		return 0
	fi

	eerror "No Python implementation selected for the build. Please add one"
	eerror "of the following values to your PYTHON_TARGETS (in make.conf):"
	eerror
	eerror "${PYTHON_COMPAT[@]}"
	echo
	die "No supported Python implementation in PYTHON_TARGETS."
}

# @FUNCTION: python_gen_useflags
# @USAGE: <pattern> [...]
# @DESCRIPTION:
# Output a list of USE flags for Python implementations which
# are both in PYTHON_COMPAT and match any of the patterns passed
# as parameters to the function.
#
# Example:
# @CODE
# PYTHON_COMPAT=( python{2_7,3_2} )
# REQUIRED_USE="doc? ( || ( $(python_gen_useflags 'python2*') ) )"
# @CODE
#
# Would be equivalent to:
# @CODE
# REQUIRED_USE="doc? ( || ( python_targets_python2_7
#                           python_targets_python2_7_x86_32
#                           python_targets_python2_7_x86_64
#                           python_targets_python2_7_x86_x32
#                           python_targets_python2_7_mips_n32
#                           python_targets_python2_7_mips_n64
#                           python_targets_python2_7_mips_o32 ) )"
# @CODE
python_gen_useflags() {
	debug-print-function ${FUNCNAME} "${@}"

	local impl pattern
	local matches=()

	for impl in "${PYTHON_COMPAT[@]}"; do
		_python_nomultilib_impl_supported "${impl}" || continue
		for pattern; do
			if [[ ${impl} == ${pattern} ]]; then
				matches+=( "python_targets_${impl}" )
				break
			fi
		done
	done
	for impl in "${PYTHON_COMPAT_MULTILIB[@]}"; do
		_python_multilib_impl_support "${impl}" || continue
		for pattern; do
			if [[ ${impl} == ${pattern} ]]; then
				matches+=( "python_multilib_targets_${impl}" )
				break
			fi
		done
	done

	echo "${matches[*]}"
}

# @FUNCTION: python_gen_cond_dep
# @USAGE: <dependency> <pattern> [...]
# @DESCRIPTION:
# Output a list of <dependency>-ies made conditional to USE flags
# of Python implementations which are both in PYTHON_COMPAT and match
# any of the patterns passed as the remaining parameters.
#
# Please note that USE constraints on the package itself need to be enforced
# separately. Therefore, the dependency usually needs to use
# some front-end usedep generator as well as this one.
#
# Example:
# @CODE
# PYTHON_COMPAT=( python{2_5,2_6,2_7} )
# RDEPEND="$(python_gen_cond_dep dev-python/unittest2 python2_5 python2_7_x86-x32)"
# @CODE
#
# It will cause the variable to look like:
# @CODE
# RDEPEND="python_targets_python2_5? ( dev-python/unittest2 )
#	python_targets_python2_7? ( dev-python/unittest2[abi_x86_x32(-)?] )"
# @CODE
python_gen_cond_dep() {
	debug-print-function ${FUNCNAME} "${@}"

	local impl pattern
	local matches=()

	local dep=${1}
	shift

	for impl in "${PYTHON_COMPAT[@]}"; do
		_python_nomultilib_impl_supported "${impl}" || continue

		for pattern; do
			if [[ ${impl} == ${pattern} ]]; then
				matches+=( "python_targets_${impl}? ( ${dep} )" )
				break
			fi
		done
	done

	for impl in "${PYTHON_COMPAT_MULTILIB[@]}"; do
		_python_multilib_impl_supported "${impl}" || continue

		for pattern; do
			if [[ ${impl} == ${pattern} ]]; then
				matches+=( "python_multilib_targets_${impl}? ( ${dep}[abi_${impl}(-)?] )" )
				break
			fi
		done
	done
	echo ${matches[@]}
}

# @ECLASS-VARIABLE: BUILD_DIR
# @DESCRIPTION:
# The current build directory. In global scope, it is supposed to
# contain an initial build directory; if unset, it defaults to ${S}.
#
# In functions run by python_foreach_impl(), the BUILD_DIR is locally
# set to an implementation-specific build directory. That path is
# created through appending a hyphen and the implementation name
# to the final component of the initial BUILD_DIR.
#
# Example value:
# @CODE
# ${WORKDIR}/foo-1.3-python2_6
# @CODE

# @FUNCTION: python_copy_sources
# @DESCRIPTION:
# Create a single copy of the package sources for each enabled Python
# implementation.
#
# The sources are always copied from initial BUILD_DIR (or S if unset)
# to implementation-specific build directory matching BUILD_DIR used by
# python_foreach_abi().
python_copy_sources() {
	debug-print-function ${FUNCNAME} "${@}"

	local MULTIBUILD_VARIANTS
	_python_obtain_impls

	multibuild_copy_sources
}

# @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() {
	debug-print-function ${FUNCNAME} "${@}"

	if [[ ! ${_PYTHON_USE_PYTHON_CHECKED} ]]; then
		_PYTHON_USE_PYTHON_CHECKED=1

		# python-exec has profile-forced flags.
		if [[ ${CATEGORY}/${PN} == dev-lang/python-exec ]]; then
			return
		fi

		_try_eselect() {
			# The eselect solution will work only with one py2 & py3.

			local impl py2 py3 dis_py2 dis_py3
			for impl in "${PYTHON_COMPAT[@]}"; do
				_python_nomultilib_impl_supported "${impl}" || continue

				if use "python_targets_${impl}"; then
					case "${impl}" in
						python2_*)
							if [[ ${py2+1} ]]; then
								debug-print "${FUNCNAME}: -> more than one py2: ${py2} ${impl}"
								return 1
							fi
							py2=${impl/_/.}
							;;
						python3_*)
							if [[ ${py3+1} ]]; then
								debug-print "${FUNCNAME}: -> more than one py3: ${py3} ${impl}"
								return 1
							fi
							py3=${impl/_/.}
							;;
						*)
							return 1
							;;
					esac
				else
					case "${impl}" in
						python2_*)
							dis_py2=1
							;;
						python3_*)
							dis_py3=1
							;;
					esac
				fi
			done

			# The eselect solution won't work if the disabled Python version
			# is installed.
			if [[ ! ${py2+1} && ${dis_py2} ]]; then
				debug-print "${FUNCNAME}: -> all py2 versions disabled"
				if ! has python2_7 "${PYTHON_COMPAT[@]}"; then
					debug-print "${FUNCNAME}: ---> package does not support 2.7"
					return 0
				fi
				if has_version '=dev-lang/python-2*'; then
					debug-print "${FUNCNAME}: ---> but =python-2* installed!"
					return 1
				fi
			fi
			if [[ ! ${py3+1} && ${dis_py3} ]]; then
				debug-print "${FUNCNAME}: -> all py3 versions disabled"
				if ! has python3_2 "${PYTHON_COMPAT[@]}"; then
					debug-print "${FUNCNAME}: ---> package does not support 3.2"
					return 0
				fi
				if has_version '=dev-lang/python-3*'; then
					debug-print "${FUNCNAME}: ---> but =python-3* installed!"
					return 1
				fi
			fi

			local warned

			# Now check whether the correct implementations are active.
			if [[ ${py2+1} ]]; then
				local sel_py2=$(eselect python show --python2)

				debug-print "${FUNCNAME}: -> py2 built: ${py2}, active: ${sel_py2}"
				if [[ ${py2} != ${sel_py2} ]]; then
					ewarn "Building package for ${py2} only while ${sel_py2} is active."
					ewarn "Please consider switching the active Python 2 interpreter:"
					ewarn
					ewarn "	eselect python set --python2 ${py2}"
					warned=1
				fi
			fi

			if [[ ${py3+1} ]]; then
				local sel_py3=$(eselect python show --python3)

				debug-print "${FUNCNAME}: -> py3 built: ${py3}, active: ${sel_py3}"
				if [[ ${py3} != ${sel_py3} ]]; then
					[[ ${warned} ]] && ewarn
					ewarn "Building package for ${py3} only while ${sel_py3} is active."
					ewarn "Please consider switching the active Python 3 interpreter:"
					ewarn
					ewarn "	eselect python set --python3 ${py3}"
					warned=1
				fi
			fi

			if [[ ${warned} ]]; then
				ewarn
				ewarn "Please note that after switching the active Python interpreter,"
				ewarn "you may need to run 'python-updater' to rebuild affected packages."
				ewarn
				ewarn "For more information on PYTHON_TARGETS and python.eclass"
				ewarn "compatibility, please see the relevant Wiki article [1]."
				ewarn
				ewarn "[1] https://wiki.gentoo.org/wiki/Project:Python/PYTHON_TARGETS"
			fi
		}

		# If user has no USE_PYTHON, try to avoid it.
		if [[ ! ${USE_PYTHON} ]]; then
			debug-print "${FUNCNAME}: trying eselect solution ..."
			_try_eselect && return
		fi

		debug-print "${FUNCNAME}: trying USE_PYTHON solution ..."
		debug-print "${FUNCNAME}: -> USE_PYTHON=${USE_PYTHON}"

		local impl old=${USE_PYTHON} new=() removed=()

		for impl in "${PYTHON_COMPAT[@]}"; do
			_python_nomultilib_impl_supported "${impl}" || continue

			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: ${impl}"
					;;
			esac
			abi=${abi/_/.}

			has "${abi}" ${USE_PYTHON}
			local has_abi=${?}
			use "python_targets_${impl}"
			local has_impl=${?}

			# 0 = has, 1 = does not have
			if [[ ${has_abi} == 0 && ${has_impl} == 1 ]]; then
				debug-print "${FUNCNAME}: ---> remove ${abi}"
				# remove from USE_PYTHON
				old=${old/${abi}/}
				removed+=( ${abi} )
			elif [[ ${has_abi} == 1 && ${has_impl} == 0 ]]; then
				debug-print "${FUNCNAME}: ---> add ${abi}"
				# add to USE_PYTHON
				new+=( ${abi} )
			fi
		done

		if [[ ${removed[@]} || ${new[@]} ]]; then
			old=( ${old} )

			debug-print "${FUNCNAME}: -> old: ${old[@]}"
			debug-print "${FUNCNAME}: -> new: ${new[@]}"
			debug-print "${FUNCNAME}: -> removed: ${removed[@]}"

			if [[ ${USE_PYTHON} ]]; then
				ewarn "It seems that your USE_PYTHON setting lists different Python"
				ewarn "implementations than your PYTHON_TARGETS variable. Please consider"
				ewarn "using the following value instead:"
				ewarn
				ewarn "	USE_PYTHON='\033[35m${old[@]}${new[@]+ \033[1m${new[@]}}\033[0m'"

				if [[ ${removed[@]} ]]; then
					ewarn
					ewarn "(removed \033[31m${removed[@]}\033[0m)"
				fi
			else
				ewarn "It seems that you need to set USE_PYTHON to make sure that legacy"
				ewarn "packages will be built with respect to PYTHON_TARGETS correctly:"
				ewarn
				ewarn "	USE_PYTHON='\033[35;1m${new[@]}\033[0m'"
			fi

			ewarn
			ewarn "Please note that after changing the USE_PYTHON variable, you may need"
			ewarn "to run 'python-updater' to rebuild affected packages."
			ewarn
			ewarn "For more information on PYTHON_TARGETS and python.eclass"
			ewarn "compatibility, please see the relevant Wiki article [1]."
			ewarn
			ewarn "[1] https://wiki.gentoo.org/wiki/Project:Python/PYTHON_TARGETS"
		fi
	fi
}

# @FUNCTION: _python_obtain_impls
# @INTERNAL
# @DESCRIPTION:
# Set up the enabled implementation list.
_python_obtain_impls() {
	debug-print-function ${FUNCNAME} "${@}"
	if [[ ${PYTHON_COMPAT_OVERRIDE} ]]; then
		if [[ ! ${_PYTHON_COMPAT_OVERRIDE_WARNED} ]]; then
			ewarn "WARNING: PYTHON_COMPAT_OVERRIDE in effect. The following Python"
			ewarn "implementations will be enabled:"
			ewarn
			ewarn "	${PYTHON_COMPAT_OVERRIDE}"
			ewarn
			ewarn "Dependencies won't be satisfied, and PYTHON_TARGETS will be ignored."
			_PYTHON_COMPAT_OVERRIDE_WARNED=1
		fi

		MULTIBUILD_VARIANTS=( ${PYTHON_COMPAT_OVERRIDE} )
		return
	fi

	_python_cache_active_impls
	_python_check_USE_PYTHON

	MULTIBUILD_VARIANTS=()

	local impl ml_impl best_ml_abi=$(multilib_get_native_abi)
	for impl in "${_PYTHON_ACTIVE_NOMULTILIB_IMPL_CACHE}" ; do
		for ml_impl in "${_PYTHON_ACTIVE_MULTILIB_IMPL_CACHE}" ; do
			if [[ $(_python_strip_multilib_impl_abi ${ml_impl}) == ${impl} ]] ; then
				if [[ $(_python_impl_abi ${ml_impl}) == ${best_ml_abi} ]] ; then
					MULTIBUILD_VARIANTS+=("${impl}")
				else
					MULTIBUILD_VARIANTS+=("${ml_impl}")
				fi
				continue 2
			fi
		done
		# no multilib version so the no-multilib version is to be treated as a variant.
		MULTIBUILD_VARAINTS+=("${impl}")
	done
	debug-print "${FUNCNAME}: result: MULTIBUILD_VARAINTS=($(mg-qm "${MULTIBUILD_VARIANTS[@]}"))"
}

# @FUNCTION: _python_multibuild_wrapper
# @USAGE: <command> [<args>...]
# @INTERNAL
# @DESCRIPTION:
# Calls python_multilib_automagic_wrapper for the
# selected MULTIBUILD_VARIANT.
_python_multibuild_wrapper() {
	debug-print-function ${FUNCNAME} "$(mg-qm "${@}")"
	python_multilib_automagic_wrapper "${MULTIBUILD_VARIANT}" "${@}"
}

# @FUNCTION: python_foreach_impl
# @USAGE: <command> [<args>...]
# @DESCRIPTION:
# Run the given command for each of the enabled Python implementations.
# If additional parameters are passed, they will be passed through
# to the command.
#
# The function will return 0 status if all invocations succeed.
# Otherwise, the return code from first failing invocation will
# be returned.
#
# For each command being run, EPYTHON, PYTHON, BUILD_DIR, and a fuck-ton
# of other variables and settings are exported to the command environment.
# See python_multilib_automagic_wrapper in python-multilib-utils-r1 for
# the gory details.
python_foreach_impl() {
	debug-print-function ${FUNCNAME} "$(mg-qm "${@}")"

	local MULTIBUILD_VARIANTS
	_python_obtain_impls

	multibuild_foreach_variant _python_multibuild_wrapper "${@}"
}

# @FUNCTION: python_parallel_foreach_impl
# @USAGE: <command> [<args>...]
# @DESCRIPTION:
# Run the given command for each of the enabled Python implementations.
# If additional parameters are passed, they will be passed through
# to the command.
#
# The function will return 0 status if all invocations succeed.
# Otherwise, the return code from first failing invocation will
# be returned.
#
# For each command being run, EPYTHON, PYTHON, BUILD_DIR, and a fuck-ton
# of other variables and settings are exported to the command environment.
# See python_multilib_automagic_wrapper in python-multilib-utils-r1 for
# the gory details.
#
# Multiple invocations of the command will be run in parallel, up to
# DISTUTILS_JOBS (defaulting to '-j' option argument from MAKEOPTS).
python_parallel_foreach_impl() {
	debug-print-function ${FUNCNAME} "$(mg-qm "${@}")"

	local MULTIBUILD_JOBS=${MULTIBUILD_JOBS:-${DISTUTILS_JOBS}}
	local MULTIBUILD_VARIANTS
	_python_obtain_impls
	multibuild_parallel_foreach_variant _python_multibuild_wrapper "${@}"
}

# @FUNCTION: python_setup
# @DESCRIPTION:
# Find the best (most preferred) Python implementation enabled
# and set the Python build environment up for it.
#
# This function needs to be used when Python is being called outside
# of python_foreach_impl calls (e.g. for shared processes like doc
# building). python_foreach_impl sets up the build environment itself.
python_setup() {
	debug-print-function ${FUNCNAME} "${@}"

	python_export_best
	python_wrapper_setup
}

# @FUNCTION: python_export_best
# @USAGE: [<variable>...]
# @DESCRIPTION:
# Find the best (most preferred) Python implementation enabled
# and export given variables for it. If no variables are provided,
# EPYTHON & PYTHON will be exported.
python_export_best() {
	debug-print-function ${FUNCNAME} "${@}"

	[[ ${#} -gt 0 ]] || set -- EPYTHON PYTHON

	local best MULTIBUILD_VARIANTS
	_python_obtain_impls

	_python_set_best() {
		best=${MULTIBUILD_VARIANT}
	}
	multibuild_for_best_variant _python_set_best

	debug-print "${FUNCNAME}: Best implementation is: ${best}"
	python_export "${best}" "${@}"
	python_wrapper_setup
}

# @FUNCTION: python_replicate_script
# @USAGE: <path>...
# @DESCRIPTION:
# Copy the given script to variants for all enabled Python
# implementations, then replace it with a symlink to the wrapper.
#
# All specified files must start with a 'python' shebang. A file not
# having a matching shebang will be refused.
python_replicate_script() {
	debug-print-function ${FUNCNAME} "${@}"

	_python_replicate_script() {
		if _python_want_python_exec2; then
			local PYTHON_SCRIPTDIR
			python_export PYTHON_SCRIPTDIR

			(
				exeinto "${PYTHON_SCRIPTDIR#${EPREFIX}}"
				doexe "${files[@]}"
			)

			python_rewrite_shebang_multilib "${EPYTHON}" \
				"${files[@]/*\//${D%/}/${PYTHON_SCRIPTDIR}/}"
		else
			local f
			for f in "${files[@]}"; do
				cp -p "${f}" "${f}-${EPYTHON}" || die
			done

			python_rewrite_shebang_multilib "${EPYTHON}" \
				"${files[@]/%/-${EPYTHON}}"
		fi
	}

	local files=( "${@}" )
	python_foreach_impl _python_replicate_script

	# install the wrappers
	local f
	for f; do
		_python_ln_rel "${ED%/}$(_python_get_wrapper_path)" "${f}" || die
	done
}

_PYTHON_MULTILIB_R1=1
fi