python*-r1.eclass: Commonize PYTHON_COMPAT processing, cache the result

Introduce a common _python_set_impls function in python-utils-r1.eclass
that validates and processes PYTHON_COMPAT, then stores the result in
_PYTHON_SUPPORTED_IMPLS and _PYTHON_UNSUPPORTED_IMPLS variables. Reuse
those variables in all python-r1 suite eclasses, effectively reducing
code duplication and providing cache for repeated implementation support
checks.

1 files changed, 11 insertions, 36 deletions

diff --git a/eclass/python-r1.eclass b/eclass/python-r1.eclass
index fbc39dceaa83..f7a8541f9b7b 100644
--- a/eclass/python-r1.eclass
+++ b/eclass/python-r1.eclass
@@ -82,12 +82,6 @@ inherit multibuild python-utils-r1
 # @CODE
 # PYTHON_COMPAT=( python2_7 python3_{3,4} )
 # @CODE
-if ! declare -p PYTHON_COMPAT &>/dev/null; then
-	die 'PYTHON_COMPAT not declared.'
-fi
-if [[ $(declare -p PYTHON_COMPAT) != "declare -a"* ]]; then
-	die 'PYTHON_COMPAT must be an array.'
-fi
 
 # @ECLASS-VARIABLE: PYTHON_COMPAT_OVERRIDE
 # @INTERNAL
@@ -186,24 +180,17 @@ fi
 # @CODE
 
 _python_set_globals() {
-	local impls=()
-
 	PYTHON_DEPS=
 	local i PYTHON_PKG_DEP
-	for i in "${PYTHON_COMPAT[@]}"; do
-		_python_impl_supported "${i}" || continue
 
+	_python_set_impls
+
+	for i in "${_PYTHON_SUPPORTED_IMPLS[@]}"; do
 		python_export "${i}" PYTHON_PKG_DEP
 		PYTHON_DEPS+="python_targets_${i}? ( ${PYTHON_PKG_DEP} ) "
-
-		impls+=( "${i}" )
 	done
 
-	if [[ ${#impls[@]} -eq 0 ]]; then
-		die "No supported implementation in PYTHON_COMPAT."
-	fi
-
-	local flags=( "${impls[@]/#/python_targets_}" )
+	local flags=( "${_PYTHON_SUPPORTED_IMPLS[@]/#/python_targets_}" )
 	local optflags=${flags[@]/%/(-)?}
 
 	# A nice QA trick here. Since a python-single-r1 package has to have
@@ -212,7 +199,7 @@ _python_set_globals() {
 	# it should prevent developers from mistakenly depending on packages
 	# not supporting multiple Python implementations.
 
-	local flags_st=( "${impls[@]/#/-python_single_target_}" )
+	local flags_st=( "${_PYTHON_SUPPORTED_IMPLS[@]/#/-python_single_target_}" )
 	optflags+=,${flags_st[@]/%/(-)}
 
 	IUSE=${flags[*]}
@@ -246,9 +233,7 @@ _python_validate_useflags() {
 
 	local i
 
-	for i in "${PYTHON_COMPAT[@]}"; do
-		_python_impl_supported "${i}" || continue
-
+	for i in "${_PYTHON_SUPPORTED_IMPLS[@]}"; do
 		use "python_targets_${i}" && return 0
 	done
 
@@ -290,9 +275,7 @@ python_gen_usedep() {
 	local impl pattern
 	local matches=()
 
-	for impl in "${PYTHON_COMPAT[@]}"; do
-		_python_impl_supported "${impl}" || continue
-
+	for impl in "${_PYTHON_SUPPORTED_IMPLS[@]}"; do
 		for pattern; do
 			if [[ ${impl} == ${pattern} ]]; then
 				matches+=(
@@ -333,9 +316,7 @@ python_gen_useflags() {
 	local impl pattern
 	local matches=()
 
-	for impl in "${PYTHON_COMPAT[@]}"; do
-		_python_impl_supported "${impl}" || continue
-
+	for impl in "${_PYTHON_SUPPORTED_IMPLS[@]}"; do
 		for pattern; do
 			if [[ ${impl} == ${pattern} ]]; then
 				matches+=( "python_targets_${impl}" )
@@ -382,9 +363,7 @@ python_gen_cond_dep() {
 	local dep=${1}
 	shift
 
-	for impl in "${PYTHON_COMPAT[@]}"; do
-		_python_impl_supported "${impl}" || continue
-
+	for impl in "${_PYTHON_SUPPORTED_IMPLS[@]}"; do
 		for pattern; do
 			if [[ ${impl} == ${pattern} ]]; then
 				# substitute ${PYTHON_USEDEP} if used
@@ -460,12 +439,8 @@ _python_obtain_impls() {
 
 	MULTIBUILD_VARIANTS=()
 
-	for impl in "${_PYTHON_ALL_IMPLS[@]}"; do
-		if has "${impl}" "${PYTHON_COMPAT[@]}" \
-			&& use "python_targets_${impl}"
-		then
-			MULTIBUILD_VARIANTS+=( "${impl}" )
-		fi
+	for impl in "${_PYTHON_SUPPORTED_IMPLS[@]}"; do
+		use "python_targets_${impl}" && MULTIBUILD_VARIANTS+=( "${impl}" )
 	done
 }