eclass/python-single-r1: Sync with gentoo

It's from gentoo commit 1aefe31e9b1d54ce085b18455e8cbf60fc39abd0.

sdk_container/src/third_party/portage-stable/eclass/python-single-r1.eclass

@@ -1,4 +1,4 @@
-# Copyright 1999-2018 Gentoo Foundation
+# Copyright 1999-2021 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 # @ECLASS: python-single-r1.eclass
@@ -7,17 +7,23 @@
 # @AUTHOR:
 # Author: Michał Górny <mgorny@gentoo.org>
 # Based on work of: Krzysztof Pawlik <nelchael@gentoo.org>
-# @SUPPORTED_EAPIS: 5 6 7
+# @SUPPORTED_EAPIS: 6 7 8
+# @PROVIDES: python-utils-r1
 # @BLURB: An eclass for Python packages not installed for multiple implementations.
 # @DESCRIPTION:
 # An extension of the python-r1 eclass suite for packages which
 # don't support being installed for multiple Python implementations.
-# This mostly includes tools embedding Python.
+# This mostly includes tools embedding Python and packages using foreign
+# build systems.
 #
-# This eclass extends the IUSE and REQUIRED_USE set by python-r1
+# This eclass sets correct IUSE.  It also provides PYTHON_DEPS
-# to request the PYTHON_SINGLE_TARGET when the inheriting ebuild
+# and PYTHON_REQUIRED_USE that need to be added to appropriate ebuild
-# can be supported by more than one Python implementation. It also
+# metadata variables.
-# replaces PYTHON_USEDEP and PYTHON_DEPS with a more suitable form.
+#
+# The eclass exports PYTHON_SINGLE_USEDEP that is suitable for depending
+# on other packages using the eclass.  Dependencies on packages using
+# python-r1 should be created via python_gen_cond_dep() function,
+# using PYTHON_USEDEP placeholder.
 #
 # Please note that packages support multiple Python implementations
 # (using python-r1 eclass) can not depend on packages not supporting
@@ -28,15 +34,14 @@
 # in the packages using python-single-r1, and there is no need ever
 # to inherit both.
 #
-# For more information, please see the wiki:
+# For more information, please see the Python Guide:
-# https://wiki.gentoo.org/wiki/Project:Python/python-single-r1
+# https://dev.gentoo.org/~mgorny/python-guide/
 
 case "${EAPI:-0}" in
-	0|1|2|3|4)
+	[0-5])
 		die "Unsupported EAPI=${EAPI:-0} (too old) for ${ECLASS}"
 		;;
-	5|6|7)
+	[6-8])
-		# EAPI=5 is required for sane USE_EXPAND dependencies
 		;;
 	*)
 		die "Unsupported EAPI=${EAPI} (unknown) for ${ECLASS}"
@@ -75,7 +80,8 @@ EXPORT_FUNCTIONS pkg_setup
 # @CODE
 
 # @ECLASS-VARIABLE: PYTHON_COMPAT_OVERRIDE
-# @INTERNAL
+# @USER_VARIABLE
+# @DEFAULT_UNSET
 # @DESCRIPTION:
 # This variable can be used when working with ebuilds to override
 # the in-ebuild PYTHON_COMPAT. It is a string naming the implementation
@@ -84,9 +90,9 @@ EXPORT_FUNCTIONS pkg_setup
 #
 # It should be noted that in order to preserve metadata immutability,
 # PYTHON_COMPAT_OVERRIDE does not affect IUSE nor dependencies.
-# The state of PYTHON_TARGETS and PYTHON_SINGLE_TARGET is ignored,
+# The state of PYTHON_SINGLE_TARGET is ignored, and the implementation
-# and the implementation in PYTHON_COMPAT_OVERRIDE is built instead.
+# in PYTHON_COMPAT_OVERRIDE is built instead.  Dependencies need to be
-# Dependencies need to be satisfied manually.
+# satisfied manually.
 #
 # Example:
 # @CODE
@@ -114,6 +120,7 @@ EXPORT_FUNCTIONS pkg_setup
 # @CODE
 
 # @ECLASS-VARIABLE: PYTHON_DEPS
+# @OUTPUT_VARIABLE
 # @DESCRIPTION:
 # This is an eclass-generated Python dependency string for all
 # implementations listed in PYTHON_COMPAT.
@@ -124,42 +131,60 @@ EXPORT_FUNCTIONS pkg_setup
 # @CODE
 # RDEPEND="${PYTHON_DEPS}
 #	dev-foo/mydep"
-# DEPEND="${RDEPEND}"
+# BDEPEND="${PYTHON_DEPS}"
 # @CODE
 #
 # Example value:
 # @CODE
 # dev-lang/python-exec:=
 # python_single_target_python2_7? ( dev-lang/python:2.7[gdbm] )
-# python_single_target_pypy? ( virtual/pypy[gdbm] )
+# python_single_target_pypy? ( dev-python/pypy[gdbm] )
 # @CODE
 
-# @ECLASS-VARIABLE: PYTHON_USEDEP
+# @ECLASS-VARIABLE: PYTHON_SINGLE_USEDEP
+# @OUTPUT_VARIABLE
 # @DESCRIPTION:
 # This is an eclass-generated USE-dependency string which can be used to
-# depend on another Python package being built for the same Python
+# depend on another python-single-r1 package being built for the same
-# implementations.
+# Python implementations.
 #
-# The generate USE-flag list is compatible with packages using python-r1,
+# If you need to depend on a multi-impl (python-r1) package, use
-# python-single-r1 and python-distutils-ng eclasses. It must not be used
+# python_gen_cond_dep with PYTHON_USEDEP placeholder instead.
-# on packages using python.eclass.
 #
 # Example use:
 # @CODE
-# RDEPEND="dev-python/foo[${PYTHON_USEDEP}]"
+# RDEPEND="dev-python/foo[${PYTHON_SINGLE_USEDEP}]"
 # @CODE
 #
 # Example value:
 # @CODE
-# python_targets_python2_7(-)?,python_single_target_python3_4(+)?
+# python_single_target_python3_4(-)?
+# @CODE
+
+# @ECLASS-VARIABLE: PYTHON_USEDEP
+# @OUTPUT_VARIABLE
+# @DESCRIPTION:
+# This is a placeholder variable supported by python_gen_cond_dep,
+# in order to depend on python-r1 packages built for the same Python
+# implementations.
+#
+# Example use:
+# @CODE
+# RDEPEND="$(python_gen_cond_dep '
+#     dev-python/foo[${PYTHON_USEDEP}]
+#   ')"
+# @CODE
+#
+# Example value:
+# @CODE
+# python_targets_python3_4(-)
 # @CODE
 
 # @ECLASS-VARIABLE: PYTHON_REQUIRED_USE
+# @OUTPUT_VARIABLE
 # @DESCRIPTION:
-# This is an eclass-generated required-use expression which ensures the following
+# This is an eclass-generated required-use expression which ensures
-# when more than one python implementation is possible:
+# that exactly one PYTHON_SINGLE_TARGET value has been enabled.
-# 1. Exactly one PYTHON_SINGLE_TARGET value has been enabled.
-# 2. The selected PYTHON_SINGLE_TARGET value is enabled in PYTHON_TARGETS.
 #
 # This expression should be utilized in an ebuild by including it in
 # REQUIRED_USE, optionally behind a use flag.
@@ -171,65 +196,38 @@ EXPORT_FUNCTIONS pkg_setup
 #
 # Example value:
 # @CODE
-# python_single_target_python2_7? ( python_targets_python2_7 )
-# python_single_target_python3_3? ( python_targets_python3_3 )
 # ^^ ( python_single_target_python2_7 python_single_target_python3_3 )
 # @CODE
 
 _python_single_set_globals() {
 	_python_set_impls
 
-	local i PYTHON_PKG_DEP
-
-	local flags_mt=( "${_PYTHON_SUPPORTED_IMPLS[@]/#/python_targets_}" )
 	local flags=( "${_PYTHON_SUPPORTED_IMPLS[@]/#/python_single_target_}" )
-	local unflags=( "${_PYTHON_UNSUPPORTED_IMPLS[@]/#/-python_single_target_}" )
 
-	local optflags=${flags_mt[@]/%/(-)?},${unflags[@]/%/(-)}
-
-	IUSE="${flags_mt[*]}"
-
-	local deps requse usedep
 	if [[ ${#_PYTHON_SUPPORTED_IMPLS[@]} -eq 1 ]]; then
-		# There is only one supported implementation; set IUSE and other
+		# if only one implementation is supported, use IUSE defaults
-		# variables without PYTHON_SINGLE_TARGET.
+		# to avoid requesting the user to enable it
-		requse=${flags_mt[*]}
+		IUSE="+${flags[0]}"
-		python_export "${_PYTHON_SUPPORTED_IMPLS[0]}" PYTHON_PKG_DEP
-		deps="${flags_mt[*]}? ( ${PYTHON_PKG_DEP} ) "
-		# Force on the python_single_target_* flag for this impl, so
-		# that any dependencies that inherit python-single-r1 and
-		# happen to have multiple implementations will still need
-		# to bound by the implementation used by this package.
-		optflags+=,${flags[0]/%/(+)}
 	else
-		# Multiple supported implementations; honor PYTHON_SINGLE_TARGET.
+		IUSE="${flags[*]}"
-		IUSE+=" ${flags[*]}"
-		requse="^^ ( ${flags[*]} )"
-		# Ensure deps honor the same python_single_target_* flag as is set
-		# on this package.
-		optflags+=,${flags[@]/%/(+)?}
-
-		for i in "${_PYTHON_SUPPORTED_IMPLS[@]}"; do
-			# The chosen targets need to be in PYTHON_TARGETS as well.
-			# This is in order to enforce correct dependencies on packages
-			# supporting multiple implementations.
-			requse+=" python_single_target_${i}? ( python_targets_${i} )"
-
-			python_export "${i}" PYTHON_PKG_DEP
-			deps+="python_single_target_${i}? ( ${PYTHON_PKG_DEP} ) "
-		done
 	fi
-	usedep=${optflags// /,}
 
-	# 1) well, python-exec would suffice as an RDEP
+	local requse="^^ ( ${flags[*]} )"
-	# but no point in making this overcomplex, BDEP doesn't hurt anyone
+	local single_flags="${flags[@]/%/(-)?}"
-	# 2) python-exec should be built with all targets forced anyway
+	local single_usedep=${single_flags// /,}
-	# but if new targets were added, we may need to force a rebuild
+
-	if [[ ${_PYTHON_WANT_PYTHON_EXEC2} == 0 ]]; then
+	local deps= i PYTHON_PKG_DEP
-		die "python-exec:0 is no longer supported, please fix your ebuild to work with python-exec:2"
+	for i in "${_PYTHON_SUPPORTED_IMPLS[@]}"; do
-	else
+		_python_export "${i}" PYTHON_PKG_DEP
-		deps+=">=dev-lang/python-exec-2:=[${usedep}]"
+		# 1) well, python-exec would suffice as an RDEP
-	fi
+		# 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
+		deps+="python_single_target_${i}? (
+			${PYTHON_PKG_DEP}
+			>=dev-lang/python-exec-2:=[python_targets_${i}]
+		) "
+	done
 
 	if [[ ${PYTHON_DEPS+1} ]]; then
 		if [[ ${PYTHON_DEPS} != "${deps}" ]]; then
@@ -247,17 +245,19 @@ _python_single_set_globals() {
 			die "PYTHON_REQUIRED_USE integrity check failed"
 		fi
 
-		if [[ ${PYTHON_USEDEP} != "${usedep}" ]]; then
+		if [[ ${PYTHON_SINGLE_USEDEP} != "${single_usedep}" ]]; then
-			eerror "PYTHON_USEDEP have changed between inherits!"
+			eerror "PYTHON_SINGLE_USEDEP have changed between inherits!"
-			eerror "Before: ${PYTHON_USEDEP}"
+			eerror "Before: ${PYTHON_SINGLE_USEDEP}"
-			eerror "Now   : ${usedep}"
+			eerror "Now   : ${single_usedep}"
-			die "PYTHON_USEDEP integrity check failed"
+			die "PYTHON_SINGLE_USEDEP integrity check failed"
 		fi
 	else
 		PYTHON_DEPS=${deps}
 		PYTHON_REQUIRED_USE=${requse}
-		PYTHON_USEDEP=${usedep}
+		PYTHON_USEDEP='%PYTHON_USEDEP-NEEDS-TO-BE-USED-IN-PYTHON_GEN_COND_DEP%'
-		readonly PYTHON_DEPS PYTHON_REQUIRED_USE PYTHON_USEDEP
+		PYTHON_SINGLE_USEDEP=${single_usedep}
+		readonly PYTHON_DEPS PYTHON_REQUIRED_USE PYTHON_SINGLE_USEDEP \
+			PYTHON_USEDEP
 	fi
 }
 _python_single_set_globals
@@ -265,43 +265,30 @@ unset -f _python_single_set_globals
 
 if [[ ! ${_PYTHON_SINGLE_R1} ]]; then
 
-# @FUNCTION: python_gen_usedep
+# @FUNCTION: _python_gen_usedep
-# @USAGE: <pattern> [...]
+# @USAGE: [<pattern>...]
+# @INTERNAL
 # @DESCRIPTION:
 # Output a USE dependency string for Python implementations which
 # are both in PYTHON_COMPAT and match any of the patterns passed
 # as parameters to the function.
 #
-# The patterns can be either fnmatch-style patterns (matched via bash
+# The patterns are fnmatch-style patterns (matched via bash
-# == operator against PYTHON_COMPAT values) or '-2' / '-3' to indicate
+# == operator against PYTHON_COMPAT values).  Remember to escape
-# appropriately all enabled Python 2/3 implementations (alike
+# or quote the fnmatch patterns to prevent accidental shell filename
-# python_is_python3). Remember to escape or quote the fnmatch patterns
+# expansion.
-# to prevent accidental shell filename expansion.
 #
-# When all implementations are requested, please use ${PYTHON_USEDEP}
+# This is an internal function used to implement python_gen_cond_dep.
-# instead. Please also remember to set an appropriate REQUIRED_USE
+_python_gen_usedep() {
-# to avoid ineffective USE flags.
-#
-# Example:
-# @CODE
-# PYTHON_COMPAT=( python{2_7,3_4} )
-# DEPEND="doc? ( dev-python/epydoc[$(python_gen_usedep 'python2*')] )"
-# @CODE
-#
-# It will cause the dependency to look like:
-# @CODE
-# DEPEND="doc? ( dev-python/epydoc[python_targets_python2_7(-)?,...] )"
-# @CODE
-python_gen_usedep() {
 	debug-print-function ${FUNCNAME} "${@}"
 
 	local impl matches=()
 
+	_python_verify_patterns "${@}"
 	for impl in "${_PYTHON_SUPPORTED_IMPLS[@]}"; do
 		if _python_impl_matches "${impl}" "${@}"; then
 			matches+=(
-				"python_targets_${impl}(-)?"
+				"python_single_target_${impl}(-)?"
-				"python_single_target_${impl}(+)?"
 			)
 		fi
 	done
@@ -313,17 +300,16 @@ python_gen_usedep() {
 }
 
 # @FUNCTION: python_gen_useflags
-# @USAGE: <pattern> [...]
+# @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.
 #
-# The patterns can be either fnmatch-style patterns (matched via bash
+# The patterns are fnmatch-style patterns (matched via bash
-# == operator against PYTHON_COMPAT values) or '-2' / '-3' to indicate
+# == operator against PYTHON_COMPAT values).  Remember to escape
-# appropriately all enabled Python 2/3 implementations (alike
+# or quote the fnmatch patterns to prevent accidental shell filename
-# python_is_python3). Remember to escape or quote the fnmatch patterns
+# expansion.
-# to prevent accidental shell filename expansion.
 #
 # Example:
 # @CODE
@@ -338,17 +324,12 @@ python_gen_usedep() {
 python_gen_useflags() {
 	debug-print-function ${FUNCNAME} "${@}"
 
-	local flag_prefix impl matches=()
+	local impl matches=()
-
-	if [[ ${#_PYTHON_SUPPORTED_IMPLS[@]} -eq 1 ]]; then
-		flag_prefix=python_targets
-	else
-		flag_prefix=python_single_target
-	fi
 
+	_python_verify_patterns "${@}"
 	for impl in "${_PYTHON_SUPPORTED_IMPLS[@]}"; do
 		if _python_impl_matches "${impl}" "${@}"; then
-			matches+=( "${flag_prefix}_${impl}" )
+			matches+=( "python_single_target_${impl}" )
 		fi
 	done
 
@@ -356,22 +337,21 @@ python_gen_useflags() {
 }
 
 # @FUNCTION: python_gen_cond_dep
-# @USAGE: <dependency> <pattern> [...]
+# @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.
 #
-# The patterns can be either fnmatch-style patterns (matched via bash
+# The patterns are fnmatch-style patterns (matched via bash
-# == operator against PYTHON_COMPAT values) or '-2' / '-3' to indicate
+# == operator against PYTHON_COMPAT values).  Remember to escape
-# appropriately all enabled Python 2/3 implementations (alike
+# or quote the fnmatch patterns to prevent accidental shell filename
-# python_is_python3). Remember to escape or quote the fnmatch patterns
+# expansion.
-# to prevent accidental shell filename expansion.
 #
 # In order to enforce USE constraints on the packages, verbatim
-# '${PYTHON_USEDEP}' (quoted!) may be placed in the dependency
+# '${PYTHON_SINGLE_USEDEP}' and '${PYTHON_USEDEP}' (quoted!) may
-# specification. It will get expanded within the function into a proper
+# be placed in the dependency specification. It will get expanded within
-# USE dependency string.
+# the function into a proper USE dependency string.
 #
 # Example:
 # @CODE
@@ -390,28 +370,32 @@ python_gen_useflags() {
 python_gen_cond_dep() {
 	debug-print-function ${FUNCNAME} "${@}"
 
-	local flag_prefix impl matches=()
+	local impl matches=()
-
-	if [[ ${#_PYTHON_SUPPORTED_IMPLS[@]} -eq 1 ]]; then
-		flag_prefix=python_targets
-	else
-		flag_prefix=python_single_target
-	fi
 
 	local dep=${1}
 	shift
 
+	_python_verify_patterns "${@}"
 	for impl in "${_PYTHON_SUPPORTED_IMPLS[@]}"; do
 		if _python_impl_matches "${impl}" "${@}"; then
-			# substitute ${PYTHON_USEDEP} if used
+			# substitute ${PYTHON_SINGLE_USEDEP} if used
-			# (since python_gen_usedep() will not return ${PYTHON_USEDEP}
+			# (since python_gen_usedep() will not return
-			#  the code is run at most once)
+			#  ${PYTHON_SINGLE_USEDEP}, the code is run at most once)
-			if [[ ${dep} == *'${PYTHON_USEDEP}'* ]]; then
+			if [[ ${dep} == *'${PYTHON_SINGLE_USEDEP}'* ]]; then
-				local usedep=$(python_gen_usedep "${@}")
+				local usedep=$(_python_gen_usedep "${@}")
-				dep=${dep//\$\{PYTHON_USEDEP\}/${usedep}}
+				dep=${dep//\$\{PYTHON_SINGLE_USEDEP\}/${usedep}}
+			fi
+			local multi_usedep="python_targets_${impl}(-)"
+
+			if [[ ${EAPI} != [67] ]]; then
+				if [[ ${dep} == *\$\{PYTHON_MULTI_USEDEP\}* ]]; then
+					die "Replace PYTHON_MULTI_USEDEP with PYTHON_USEDEP in EAPI ${EAPI}"
+				fi
 			fi
 
-			matches+=( "${flag_prefix}_${impl}? ( ${dep} )" )
+			local subdep=${dep//\$\{PYTHON_MULTI_USEDEP\}/${multi_usedep}}
+			matches+=( "python_single_target_${impl}? (
+				${subdep//\$\{PYTHON_USEDEP\}/${multi_usedep}} )" )
 		fi
 	done
 
@@ -427,11 +411,10 @@ python_gen_cond_dep() {
 # patterns are passed, the output dependencies will be generated only
 # for the implementations matching them.
 #
-# The patterns can be either fnmatch-style patterns (matched via bash
+# The patterns are fnmatch-style patterns (matched via bash
-# == operator against PYTHON_COMPAT values) or '-2' / '-3' to indicate
+# == operator against PYTHON_COMPAT values).  Remember to escape
-# appropriately all enabled Python 2/3 implementations (alike
+# or quote the fnmatch patterns to prevent accidental shell filename
-# python_is_python3). Remember to escape or quote the fnmatch patterns
+# expansion.
-# to prevent accidental shell filename expansion.
 #
 # Use this function when you need to request different USE flags
 # on the Python interpreter depending on package's USE flags. If you
@@ -455,24 +438,18 @@ python_gen_cond_dep() {
 python_gen_impl_dep() {
 	debug-print-function ${FUNCNAME} "${@}"
 
-	local impl pattern
+	local impl
 	local matches=()
 
-	if [[ ${#_PYTHON_SUPPORTED_IMPLS[@]} -eq 1 ]]; then
-		flag_prefix=python_targets
-	else
-		flag_prefix=python_single_target
-	fi
-
 	local PYTHON_REQ_USE=${1}
 	shift
 
-	local patterns=( "${@-*}" )
+	_python_verify_patterns "${@}"
 	for impl in "${_PYTHON_SUPPORTED_IMPLS[@]}"; do
-		if _python_impl_matches "${impl}" "${patterns[@]}"; then
+		if _python_impl_matches "${impl}" "${@}"; then
 			local PYTHON_PKG_DEP
-			python_export "${impl}" PYTHON_PKG_DEP
+			_python_export "${impl}" PYTHON_PKG_DEP
-			matches+=( "${flag_prefix}_${impl}? ( ${PYTHON_PKG_DEP} )" )
+			matches+=( "python_single_target_${impl}? ( ${PYTHON_PKG_DEP} )" )
 		fi
 	done
 
@@ -500,57 +477,38 @@ python_setup() {
 		ewarn
 		ewarn "Dependencies won't be satisfied, and PYTHON_SINGLE_TARGET flags will be ignored."
 
-		python_export "${impls[0]}" EPYTHON PYTHON
+		_python_export "${impls[0]}" EPYTHON PYTHON
-		python_wrapper_setup
+		_python_wrapper_setup
+		einfo "Using ${EPYTHON} to build"
 		return
 	fi
 
-	if [[ ${#_PYTHON_SUPPORTED_IMPLS[@]} -eq 1 ]]; then
+	local impl
-		if use "python_targets_${_PYTHON_SUPPORTED_IMPLS[0]}"; then
+	for impl in "${_PYTHON_SUPPORTED_IMPLS[@]}"; do
-			# Only one supported implementation, enable it explicitly
+		if use "python_single_target_${impl}"; then
-			python_export "${_PYTHON_SUPPORTED_IMPLS[0]}" EPYTHON PYTHON
+			if [[ ${EPYTHON} ]]; then
-			python_wrapper_setup
+				eerror "Your PYTHON_SINGLE_TARGET setting lists more than a single Python"
-		fi
+				eerror "implementation. Please set it to just one value. If you need"
-	else
+				eerror "to override the value for a single package, please use package.env"
-		local impl
+				eerror "or an equivalent solution (man 5 portage)."
-		for impl in "${_PYTHON_SUPPORTED_IMPLS[@]}"; do
+				echo
-			if use "python_single_target_${impl}"; then
+				die "More than one implementation in PYTHON_SINGLE_TARGET."
-				if [[ ${EPYTHON} ]]; then
-					eerror "Your PYTHON_SINGLE_TARGET setting lists more than a single Python"
-					eerror "implementation. Please set it to just one value. If you need"
-					eerror "to override the value for a single package, please use package.env"
-					eerror "or an equivalent solution (man 5 portage)."
-					echo
-					die "More than one implementation in PYTHON_SINGLE_TARGET."
-				fi
-
-				if ! use "python_targets_${impl}"; then
-					eerror "The implementation chosen as PYTHON_SINGLE_TARGET must be added"
-					eerror "to PYTHON_TARGETS as well. This is in order to ensure that"
-					eerror "dependencies are satisfied correctly. We're sorry"
-					eerror "for the inconvenience."
-					echo
-					die "Build target (${impl}) not in PYTHON_TARGETS."
-				fi
-
-				python_export "${impl}" EPYTHON PYTHON
-				python_wrapper_setup
 			fi
-		done
+
-	fi
+			_python_export "${impl}" EPYTHON PYTHON
+			_python_wrapper_setup
+			einfo "Using ${EPYTHON} to build"
+		fi
+	done
 
 	if [[ ! ${EPYTHON} ]]; then
 		eerror "No Python implementation selected for the build. Please set"
-		if [[ ${#_PYTHON_SUPPORTED_IMPLS[@]} -eq 1 ]]; then
+		eerror "the PYTHON_SINGLE_TARGET variable in your make.conf to one"
-			eerror "the PYTHON_TARGETS variable in your make.conf to include one"
-		else
-			eerror "the PYTHON_SINGLE_TARGET variable in your make.conf to one"
-		fi
 		eerror "of the following values:"
 		eerror
 		eerror "${_PYTHON_SUPPORTED_IMPLS[@]}"
 		echo
-		die "No supported Python implementation in PYTHON_SINGLE_TARGET/PYTHON_TARGETS."
+		die "No supported Python implementation in PYTHON_SINGLE_TARGET."
 	fi
 }