Re: [PATCH v7] scripts/config: honor $KBUILD_OUTPUT by default

[Nathan Chancellor <nathan@kernel.org>]

Hi Dmitry,

On 2026-10-06 18:11 +0200, Dmitry Voytik wrote:
> If $KBUILD_OUTPUT is set, use it by default if --file is not passed.
> 
> Fix the issue when the script silently updates a stale .config in
> the root directory, while the user expects ${KBUILD_OUTPUT}/.config
> to be updated.
> Handle properly if the config file is a relative path.
> 
> The problem can be worked around with --file, but this is easy to miss,
> and is inconsistent with how the Makefile and other tools work
> (e.g., scripts/diffconfig).

I was finally able to sit down and look at this a little bit more. I
think we can avoid the use of realpath altogether, which would avoid
most of what Sashiko is complaining about. I tested the following diff
with your examples and they appear to pass without any issues. Please
give it a shot. I think we can drop most of the reproduction and
examples in the commit message. If you want to include them for others,
please put it below the '---' where you have the changelog, as I don't
think it needs to end up in git history.

diff --git a/scripts/config b/scripts/config
index 32428ea909c2..497551538433 100755
--- a/scripts/config
+++ b/scripts/config
@@ -144,6 +144,22 @@ while [[ $# -gt 0 ]]; do
 	fi
 done
 
+# If no '--file' was specified, use KBUILD_OUTPUT as the base if it exists
+if [[ "$FN" = ".config" && -n "$KBUILD_OUTPUT" ]]; then
+	if [[ ! -d "$KBUILD_OUTPUT" ]]; then
+		echo "KBUILD_OUTPUT is set ('$KBUILD_OUTPUT') but does not exist or is not a directory." >&2
+		echo "Create it before running $myname or use '--file' to specify configuration file." >&2
+		exit 1
+	fi
+	FN="$KBUILD_OUTPUT/$FN"
+fi
+# Turn FN into an absolute path if it is relative so that '--refresh' works on
+# the correct file. This does not use realpath, as $FN may not exist yet.
+case "$FN" in
+	/*) ;;
+	*) FN="$PWD/$FN" ;;
+esac
+
 set -- "${CMDS[@]}"
 if [ "$1" = "" ] ; then
 	usage
@@ -200,10 +216,10 @@ while [ "$1" != "" ] ; do
 		;;
 
 	--state|-s)
-		if grep -q "# ${CONFIG_}$ARG is not set" $FN ; then
+		if grep -q "# ${CONFIG_}$ARG is not set" "$FN" ; then
 			echo n
 		else
-			V="$(grep "^${CONFIG_}$ARG=" $FN)"
+			V="$(grep "^${CONFIG_}$ARG=" "$FN")"
 			if [ $? != 0 ] ; then
 				echo undef
 			else
@@ -229,7 +245,7 @@ while [ "$1" != "" ] ; do
 		;;
 
 	--refresh)
-		yes "" | make oldconfig KCONFIG_CONFIG=$FN
+		yes "" | make oldconfig KCONFIG_CONFIG="$FN"
 		;;
 
 	*)

-- 
Cheers,
Nathan