scripts: merge_config: add strict mode to fail upon any redefinition

When merging configuration fragments, it might be of interest to
identify mismatches (redefinitions) programmatically. Hence add the
option -s (strict mode) to instruct merge_config.sh to bail out in
case any redefinition has been detected.

With strict mode, warnings are emitted as before, but the script
terminates with rc=1. If -y is set to define "builtin having
precedence over modules", fragments are still allowed to set =m (while
the base config has =y). Strict mode will tolerate that as demotions
from =y to =m are ignored when setting -y.

Signed-off-by: Matthias Maennich <maennich@google.com>
Reviewed-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

diff --git a/scripts/kconfig/merge_config.sh b/scripts/kconfig/merge_config.sh
index 63c8565206a451c4c3e800148b209b0e98d47432..e5b46980c22ae7cb40c603e7f469e1d204d1829e 100755 (executable)
--- a/scripts/kconfig/merge_config.sh
+++ b/scripts/kconfig/merge_config.sh
@@ -28,6 +28,7 @@ usage() {
        echo "  -r    list redundant entries when merging fragments"
        echo "  -y    make builtin have precedence over modules"
        echo "  -O    dir to put generated output files.  Consider setting \$KCONFIG_CONFIG instead."
+       echo "  -s    strict mode. Fail if the fragment redefines any value."
        echo
        echo "Used prefix: '$CONFIG_PREFIX'. You can redefine it with \$CONFIG_ environment variable."
 }
@@ -37,6 +38,7 @@ ALLTARGET=alldefconfig
 WARNREDUN=false
 BUILTIN=false
 OUTPUT=.
+STRICT=false
 CONFIG_PREFIX=${CONFIG_-CONFIG_}
 
 while true; do
@@ -75,6 +77,11 @@ while true; do
                shift 2
                continue
                ;;
+       "-s")
+               STRICT=true
+               shift
+               continue
+               ;;
        *)
                break
                ;;
@@ -141,6 +148,9 @@ for ORIG_MERGE_FILE in $MERGE_LIST ; do
                        echo Previous  value: $PREV_VAL
                        echo New value:       $NEW_VAL
                        echo
+                       if [ "$STRICT" = "true" ]; then
+                               STRICT_MODE_VIOLATED=true
+                       fi
                elif [ "$WARNREDUN" = "true" ]; then
                        echo Value of $CFG is redundant by fragment $ORIG_MERGE_FILE:
                fi
@@ -153,6 +163,11 @@ for ORIG_MERGE_FILE in $MERGE_LIST ; do
        cat $MERGE_FILE >> $TMP_FILE
 done
 
+if [ "$STRICT_MODE_VIOLATED" = "true" ]; then
+       echo "The fragment redefined a value and strict mode had been passed."
+       exit 1
+fi
+
 if [ "$RUNMAKE" = "false" ]; then
        cp -T -- "$TMP_FILE" "$KCONFIG_CONFIG"
        echo "#"