Introduce a check for USE_PYTHON & PYTHON_TARGETS compatibility.

2 files changed, 203 insertions, 2 deletions

diff --git a/eclass/ChangeLog b/eclass/ChangeLog
index bfc50089a1e3..2478d1953435 100644
--- a/eclass/ChangeLog
+++ b/eclass/ChangeLog
@@ -1,6 +1,9 @@
 # ChangeLog for eclass directory
 # Copyright 1999-2012 Gentoo Foundation; Distributed under the GPL v2
-# $Header: /var/cvsroot/gentoo-x86/eclass/ChangeLog,v 1.512 2012/11/19 20:35:16 slyfox Exp $
+# $Header: /var/cvsroot/gentoo-x86/eclass/ChangeLog,v 1.513 2012/11/19 21:38:33 mgorny Exp $
+
+  19 Nov 2012; Michał Górny <mgorny@gentoo.org> python-r1.eclass:
+  Introduce a check for USE_PYTHON & PYTHON_TARGETS compatibility.
 
   19 Nov 2012; Sergei Trofimovich <slyfox@gentoo.org> haskell-cabal.eclass:
   Added new helper function 'cabal_chdeps' and and debug variable
diff --git a/eclass/python-r1.eclass b/eclass/python-r1.eclass
index 0d6ef4c86211..a08e0a0523be 100644
--- a/eclass/python-r1.eclass
+++ b/eclass/python-r1.eclass
@@ -1,6 +1,6 @@
 # Copyright 1999-2012 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
-# $Header: /var/cvsroot/gentoo-x86/eclass/python-r1.eclass,v 1.17 2012/11/04 15:16:34 mgorny Exp $
+# $Header: /var/cvsroot/gentoo-x86/eclass/python-r1.eclass,v 1.18 2012/11/19 21:38:33 mgorny Exp $
 
 # @ECLASS: python-r1
 # @MAINTAINER:
@@ -363,6 +363,202 @@ 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() {
+	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-python/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 "${PYTHON_COMPAT[@]}"; do
+				if use "python_targets_${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_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_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.eclass compatibility, please see"
+				ewarn "the appropriate python-r1 User's Guide chapter [1]."
+				ewarn
+				ewarn "[1] http://www.gentoo.org/proj/en/Python/python-r1/user-guide.xml#doc_chap2"
+			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 "${PYTHON_COMPAT[@]}"; do
+			local abi
+			case "${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.eclass compatibility, please see"
+			ewarn "the appropriate python-r1 User's Guide chapter [1]."
+			ewarn
+			ewarn "[1] http://www.gentoo.org/proj/en/Python/python-r1/user-guide.xml#doc_chap2"
+		fi
+	fi
+}
+
 # @FUNCTION: python_foreach_impl
 # @USAGE: <command> [<args>...]
 # @DESCRIPTION:
@@ -376,6 +572,8 @@ python_copy_sources() {
 python_foreach_impl() {
 	debug-print-function ${FUNCNAME} "${@}"
 
+	_python_check_USE_PYTHON
+
 	local impl
 	local bdir=${BUILD_DIR:-${S}}