python-single-r1.eclass: Revert "Remove unused PYTHON_TARGETS"

Pushed too many commits.

Signed-off-by: Michał Górny <[email protected]>

eclass/python-single-r1.eclass

@@ -89,9 +89,9 @@ 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_SINGLE_TARGET is ignored, and the implementation
-# in PYTHON_COMPAT_OVERRIDE is built instead. Dependencies need to be
-# satisfied manually.
+# The state of PYTHON_TARGETS and PYTHON_SINGLE_TARGET is ignored,
+# and the implementation in PYTHON_COMPAT_OVERRIDE is built instead.
+# Dependencies need to be satisfied manually.
 #
 # Example:
 # @CODE
@@ -178,8 +178,10 @@ EXPORT_FUNCTIONS pkg_setup
 
 # @ECLASS-VARIABLE: PYTHON_REQUIRED_USE
 # @DESCRIPTION:
-# This is an eclass-generated required-use expression which ensures
-# that exactly one PYTHON_SINGLE_TARGET value has been enabled.
+# This is an eclass-generated required-use expression which ensures the following
+# when more than one python implementation is possible:
+# 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.
@@ -191,20 +193,23 @@ 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 flags_mt=( "${_PYTHON_SUPPORTED_IMPLS[@]/#/python_targets_}" )
  local flags=( "${_PYTHON_SUPPORTED_IMPLS[@]/#/python_single_target_}" )
 
  if [[ ${#_PYTHON_SUPPORTED_IMPLS[@]} -eq 1 ]]; then
  # if only one implementation is supported, use IUSE defaults
  # to avoid requesting the user to enable it
- IUSE="+${flags[0]}"
+ IUSE="+${flags_mt[0]} +${flags[0]}"
  else
- IUSE="${flags[*]}"
+ IUSE="${flags_mt[*]} ${flags[*]}"
  fi
 
  local requse="^^ ( ${flags[*]} )"
@@ -213,6 +218,11 @@ _python_single_set_globals() {
 
  local deps= i PYTHON_PKG_DEP
  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
  # 1) well, python-exec would suffice as an RDEP
  # but no point in making this overcomplex, BDEP doesn't hurt anyone
@@ -480,6 +490,15 @@ python_setup() {
  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 "${impl}" EPYTHON PYTHON
  python_wrapper_setup
  fi
@@ -492,7 +511,7 @@ python_setup() {
  eerror
  eerror "${_PYTHON_SUPPORTED_IMPLS[@]}"
  echo
- die "No supported Python implementation in PYTHON_SINGLE_TARGET."
+ die "No supported Python implementation in PYTHON_SINGLE_TARGET/PYTHON_TARGETS."
  fi
 }