cmake.eclass: mv _CMAKE_MINREQVER_UNSUPPORTED detection to src_prepare

- _cmake_minverreq-lt(): New function for reusability of regex
- Optimise #1: Reuse existing loop over CMakeLists.txt files
- Optimise #2: If _CMAKE_MINREQVER_UNSUPPORTED is already set, then no
  further run of _cmake_minverreq-lt is necessary since we currently throw
  away the info on affected files
- Relegate "CMake 4 detected; ..." to be a non-QA Notice, it is just an
  addendum

Signed-off-by: Andreas Sturmlechner <asturm@gentoo.org>

1 files changed, 43 insertions, 29 deletions

diff --git a/eclass/cmake.eclass b/eclass/cmake.eclass
index 47f96227d3e..0ad1ca821be 100644
--- a/eclass/cmake.eclass
+++ b/eclass/cmake.eclass
@@ -126,7 +126,8 @@ fi
 # @ECLASS_VARIABLE: _CMAKE_MINREQVER_UNSUPPORTED
 # @DEFAULT_UNSET
 # @DESCRIPTION:
-# Is set to true if an unsupported cmake_minimum_required value was detected.
+# Internal status set by _cmake_minreqver-lt(); is true if an unsupported
+# cmake_minimum_required value was detected.
 
 # @ECLASS_VARIABLE: CMAKE_QA_SRC_DIR_READONLY
 # @USER_VARIABLE
@@ -243,6 +244,25 @@ _cmake_check_build_dir() {
 	mkdir -p "${BUILD_DIR}" || die
 }
 
+# @FUNCTION: _cmake_minreqver-lt
+# @USAGE: <lt-version> <path>
+# @INTERNAL
+# @DESCRIPTION:
+# Internal function for detecting occurrence of lower-than-specified
+# <lt-version> in cmake_minimum_required of a given CMake file <path>.
+# Returns 0 if the regex matched (a lower-than-specified version found).
+_cmake_minreqver-lt() {
+	local ver chk=1
+	ver=$(sed -ne "/cmake_minimum_required/I{s/.*\(\.\.\.*\|\s\)\([0-9.]*\)\([)]\|\s\).*$/\2/p;q}" \
+		"${2}" 2>/dev/null \
+	)
+	if [[ -n ${ver} ]] && ver_test "${ver}" -lt "${1}"; then
+		_CMAKE_MINREQVER_UNSUPPORTED=true
+		chk=0
+	fi
+	return ${chk}
+}
+
 # @FUNCTION: _cmake_modify-cmakelists
 # @INTERNAL
 # @DESCRIPTION:
@@ -254,9 +274,9 @@ _cmake_modify-cmakelists() {
 	# Only edit the files once
 	grep -qs "<<< Gentoo configuration >>>" "${CMAKE_USE_DIR}"/CMakeLists.txt && return 0
 
-	# Comment out all set (<some_should_be_user_defined_variable> value)
 	local file
 	while read -d '' -r file ; do
+		# Comment out all set (<some_should_be_user_defined_variable> value)
 		sed \
 			-e '/^[[:space:]]*set[[:space:]]*([[:space:]]*CMAKE_BUILD_TYPE\([[:space:]].*)\|)\)/I{s/^/#_cmake_modify_IGNORE /g}' \
 			-e '/^[[:space:]]*set[[:space:]]*([[:space:]]*CMAKE_\(COLOR_MAKEFILE\|INSTALL_PREFIX\|VERBOSE_MAKEFILE\)[[:space:]].*)/I{s/^/#_cmake_modify_IGNORE /g}' \
@@ -269,7 +289,11 @@ _cmake_modify-cmakelists() {
 				einfo "${mod_line:22:99}"
 			done
 		fi
-	done < <(find "${CMAKE_USE_DIR}" -type f -iname "CMakeLists.txt" -print0)
+		# Detect unsupported minimum CMake versions unless CMAKE_QA_COMPAT_SKIP is set
+		if [[ -z ${_CMAKE_MINREQVER_UNSUPPORTED} ]] && ! [[ ${CMAKE_QA_COMPAT_SKIP} ]]; then
+			_cmake_minreqver-lt "3.5" "${file}"
+		fi
+	done < <(find "${CMAKE_USE_DIR}" -type f -iname "CMakeLists.txt" -print0 || die)
 
 	# NOTE Append some useful summary here
 	cat >> "${CMAKE_USE_DIR}"/CMakeLists.txt <<- _EOF_ || die
@@ -329,6 +353,20 @@ cmake_src_prepare() {
 	# Remove dangerous things.
 	_cmake_modify-cmakelists
 
+	if [[ ${_CMAKE_MINREQVER_UNSUPPORTED} ]]; then
+		eqawarn "QA Notice: Compatibility with CMake < 3.5 has been removed from CMake 4,"
+		eqawarn "${CATEGORY}/${PN} will fail to build w/o a fix."
+		eqawarn "See also tracker bug #951350; check existing bug or file a new one for"
+		eqawarn "this package, and take it upstream."
+		if has_version -b ">=dev-build/cmake-4"; then
+			eqawarn "CMake 4 detected; building with -DCMAKE_POLICY_VERSION_MINIMUM=3.5"
+			eqawarn "This is merely a workaround and *not* a permanent fix."
+		fi
+		if [[ ${EAPI} == 7 ]]; then
+			eqawarn "QA Notice: EAPI=7 detected; this package is now a prime last-rites target."
+		fi
+	fi
+
 	if [[ ${EAPI} == 7 ]]; then
 		popd > /dev/null || die
 	fi
@@ -377,19 +415,6 @@ cmake_src_configure() {
 	# Fix xdg collision with sandbox
 	xdg_environment_reset
 
-	local file ver
-	if ! [[ ${CMAKE_QA_COMPAT_SKIP} ]]; then
-		while read -d '' -r file ; do
-			ver=$(sed -ne "/cmake_minimum_required/I{s/.*\(\.\.\.*\|\s\)\([0-9.]*\)\([)]\|\s\).*$/\2/p;q}" \
-				"${file}" 2>/dev/null \
-			)
-
-			if [[ -n $ver ]] && ver_test $ver -lt "3.5"; then
-				_CMAKE_MINREQVER_UNSUPPORTED=true
-			fi
-		done < <(find "${CMAKE_USE_DIR}" -type f -iname "CMakeLists.txt" -print0)
-	fi
-
 	# Prepare Gentoo override rules (set valid compiler, append CPPFLAGS etc.)
 	local build_rules=${BUILD_DIR}/gentoo_rules.cmake
 
@@ -571,19 +596,8 @@ cmake_src_configure() {
 		cmakeargs+=( -C "${CMAKE_EXTRA_CACHE_FILE}" )
 	fi
 
-	if [[ ${_CMAKE_MINREQVER_UNSUPPORTED} ]]; then
-		eqawarn "QA Notice: Compatibility with CMake < 3.5 has been removed from CMake 4,"
-		eqawarn "${CATEGORY}/${PN} will fail to build w/o a fix."
-		eqawarn "See also tracker bug #951350; check existing bug or file a new one for"
-		eqawarn "this package, and take it upstream."
-		if has_version -b ">=dev-build/cmake-4"; then
-			eqawarn "QA Notice: CMake 4 detected; building with -DCMAKE_POLICY_VERSION_MINIMUM=3.5"
-			eqawarn "This is merely a workaround and *not* a permanent fix."
-			cmakeargs+=( -DCMAKE_POLICY_VERSION_MINIMUM=3.5 )
-		fi
-		if [[ ${EAPI} == 7 ]]; then
-			eqawarn "QA Notice: EAPI=7 detected; this package is now a prime last-rites target."
-		fi
+	if [[ ${_CMAKE_MINREQVER_UNSUPPORTED} ]] && has_version -b ">=dev-build/cmake-4"; then
+		cmakeargs+=( -DCMAKE_POLICY_VERSION_MINIMUM=3.5 )
 	fi
 
 	pushd "${BUILD_DIR}" > /dev/null || die