python*-r1.eclass: Check for invalid impl patterns

Check for invalid implementation patterns passed to python_gen*
functions, python_setup, etc.  Currently the functions silently ignore
pattern mismatches which is fine for patterns matching historical
implementations but also hides errors in patterns.

After this change, each pattern must match at least one current or
historical implementation.  If no match is found, the function dies
indicating developer's mistake.

Signed-off-by: Michał Górny <mgorny@gentoo.org>

1 files changed, 34 insertions, 0 deletions

diff --git a/eclass/python-utils-r1.eclass b/eclass/python-utils-r1.eclass
index 9bad72a77e98..87cb662c64fd 100644
--- a/eclass/python-utils-r1.eclass
+++ b/eclass/python-utils-r1.eclass
@@ -45,6 +45,18 @@ _PYTHON_ALL_IMPLS=(
 )
 readonly _PYTHON_ALL_IMPLS
 
+# @ECLASS-VARIABLE: _PYTHON_HISTORICAL_IMPLS
+# @INTERNAL
+# @DESCRIPTION:
+# All historical Python implementations that are no longer supported.
+_PYTHON_HISTORICAL_IMPLS=(
+	jython2_7
+	pypy pypy1_{8,9} pypy2_0
+	python2_{5,6}
+	python3_{1,2,3,4,5}
+)
+readonly _PYTHON_HISTORICAL_IMPLS
+
 # @ECLASS-VARIABLE: PYTHON_COMPAT_NO_STRICT
 # @INTERNAL
 # @DESCRIPTION:
@@ -89,6 +101,28 @@ _python_impl_supported() {
 	esac
 }
 
+# @FUNCTION: _python_verify_patterns
+# @USAGE: <pattern>...
+# @INTERNAL
+# @DESCRIPTION:
+# Verify whether the patterns passed to the eclass function are correct
+# (i.e. can match any valid implementation).  Dies on wrong pattern.
+_python_verify_patterns() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	local impl pattern
+	for pattern; do
+		[[ ${pattern} == -[23] ]] && continue
+
+		for impl in "${_PYTHON_ALL_IMPLS[@]}" "${_PYTHON_HISTORICAL_IMPLS[@]}"
+		do
+			[[ ${impl} == ${pattern/./_} ]] && continue 2
+		done
+
+		die "Invalid implementation pattern: ${pattern}"
+	done
+}
+
 # @FUNCTION: _python_set_impls
 # @INTERNAL
 # @DESCRIPTION: