static-test: Check for Makefile.dep touching CFLAGS

maribu · maribu · commit 407b88fc94b9 · 2025-12-22T10:56:04.000+01:00
The `Makefile.dep` are intended for dependency tracking only. Modifying
CFLAGS as part of the dependency resolution process is just wrong.

This extends the build system sanity check to prevent this kind of
bug from sneaking in again.
diff --git a/dist/tools/buildsystem_sanity_check/check.sh b/dist/tools/buildsystem_sanity_check/check.sh
@@ -402,6 +402,18 @@ check_pinned_docker_version_is_up_to_date() {
     fi
 }
 
+check_if_cflags_are_touched_at_right_place() {
+    for file in $(git -C "${RIOTBASE}" grep -lE 'CFLAGS[\t ]*\+='); do
+        case $file in
+        */Makefile.dep)
+            # CFLAGS may not be touched in `Makefile.dep`
+            git -C "${RIOTBASE}" grep -nE 'CFLAGS[\t ]*\+=' "$file" \
+                | error_with_message  "A Makefile.dep is for dependency modelling only. Modify CFLAGS in a Makefile.include, in an app's Makefile, or (if only relevant to a single module/package) in the module's/package's Makefile"
+            ;;
+        esac
+    done
+}
+
 error_on_input() {
     ! grep ''
 }
@@ -425,6 +437,7 @@ all_checks() {
     check_stderr_null
     check_tests_application_path
     check_pinned_docker_version_is_up_to_date
+    check_if_cflags_are_touched_at_right_place
 }
 
 if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
