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Date:   Sat, 29 Jul 2023 21:41:51 +0000
To:     linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org
From:   Rahul Rameshbabu <sergeantsagara@protonmail.com>
Cc:     Rahul Rameshbabu <sergeantsagara@protonmail.com>,
        Masahiro Yamada <masahiroy@kernel.org>
Subject: [PATCH] scripts: merge_config: Add flag to prevent unsetting config option
Message-ID: <20230729214138.79902-1-sergeantsagara@protonmail.com>
Feedback-ID: 26003777:user:proton
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Overriding a previously defined entry for a config option with 'is not set'
may be undesirable in some fragment configuration setups. Provide a flag to
change the behavior, so 'is not set' is not overridden when a previous
value for the same config option already exists.

Cc: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Rahul Rameshbabu <sergeantsagara@protonmail.com>
---
 scripts/kconfig/merge_config.sh | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/scripts/kconfig/merge_config.sh b/scripts/kconfig/merge_config=
.sh
index 902eb429b9db..bbe235f2df70 100755
--- a/scripts/kconfig/merge_config.sh
+++ b/scripts/kconfig/merge_config.sh
@@ -30,6 +30,7 @@ usage() {
 =09echo "  -O    dir to put generated output files.  Consider setting \$KC=
ONFIG_CONFIG instead."
 =09echo "  -s    strict mode. Fail if the fragment redefines any value."
 =09echo "  -Q    disable warning messages for overridden options."
+=09echo "  -N    not set entries in fragments will not override options."
 =09echo
 =09echo "Used prefix: '$CONFIG_PREFIX'. You can redefine it with \$CONFIG_=
 environment variable."
 }
@@ -42,6 +43,7 @@ OUTPUT=3D.
 STRICT=3Dfalse
 CONFIG_PREFIX=3D${CONFIG_-CONFIG_}
 WARNOVERRIDE=3Decho
+OVERRIDENOTSET=3Dtrue
=20
 while true; do
 =09case $1 in
@@ -89,6 +91,11 @@ while true; do
 =09=09shift
 =09=09continue
 =09=09;;
+=09"-N")
+=09=09OVERRIDENOTSET=3Dfalse
+=09=09shift
+=09=09continue
+=09=09;;
 =09*)
 =09=09break
 =09=09;;
@@ -143,13 +150,20 @@ for ORIG_MERGE_FILE in $MERGE_LIST ; do
 =09=09grep -q -w $CFG $TMP_FILE || continue
 =09=09PREV_VAL=3D$(grep -w $CFG $TMP_FILE)
 =09=09NEW_VAL=3D$(grep -w $CFG $MERGE_FILE)
-=09=09BUILTIN_FLAG=3Dfalse
-=09=09if [ "$BUILTIN" =3D "true" ] && [ "${NEW_VAL#CONFIG_*=3D}" =3D "m" ]=
 && [ "${PREV_VAL#CONFIG_*=3D}" =3D "y" ]; then
+=09=09NO_OVERRIDE_FLAG=3Dfalse
+=09=09if [ "$OVERRIDENOTSET" =3D "false" ] && [ "${NEW_VAL#\# CONFIG_* }" =
=3D "is not set" ] &&
+=09=09=09   [ "$PREV_VAL" !=3D "" ] && [ "${PREV_VAL#\# CONFIG_* }" !=3D "=
is not set" ]; then
+=09=09=09${WARNOVERRIDE} Previous  value: $PREV_VAL
+=09=09=09${WARNOVERRIDE} New value:       $NEW_VAL
+=09=09=09${WARNOVERRIDE} -N passed, will not unset option
+=09=09=09${WARNOVERRIDE}
+=09=09=09NO_OVERRIDE_FLAG=3Dtrue
+=09=09elif [ "$BUILTIN" =3D "true" ] && [ "${NEW_VAL#CONFIG_*=3D}" =3D "m"=
 ] && [ "${PREV_VAL#CONFIG_*=3D}" =3D "y" ]; then
 =09=09=09${WARNOVERRIDE} Previous  value: $PREV_VAL
 =09=09=09${WARNOVERRIDE} New value:       $NEW_VAL
 =09=09=09${WARNOVERRIDE} -y passed, will not demote y to m
 =09=09=09${WARNOVERRIDE}
-=09=09=09BUILTIN_FLAG=3Dtrue
+=09=09=09NO_OVERRIDE_FLAG=3Dtrue
 =09=09elif [ "x$PREV_VAL" !=3D "x$NEW_VAL" ] ; then
 =09=09=09${WARNOVERRIDE} Value of $CFG is redefined by fragment $ORIG_MERG=
E_FILE:
 =09=09=09${WARNOVERRIDE} Previous  value: $PREV_VAL
@@ -161,7 +175,7 @@ for ORIG_MERGE_FILE in $MERGE_LIST ; do
 =09=09elif [ "$WARNREDUN" =3D "true" ]; then
 =09=09=09${WARNOVERRIDE} Value of $CFG is redundant by fragment $ORIG_MERG=
E_FILE:
 =09=09fi
-=09=09if [ "$BUILTIN_FLAG" =3D "false" ]; then
+=09=09if [ "$NO_OVERRIDE_FLAG" =3D "false" ]; then
 =09=09=09sed -i "/$CFG[ =3D]/d" $TMP_FILE
 =09=09else
 =09=09=09sed -i "/$CFG[ =3D]/d" $MERGE_FILE
--=20
2.40.1