Re: [PATCH] kconfig: merge_config: use an empty file as initfile

[Masahiro Yamada]

On Fri, Mar 28, 2025 at 11:29 PM Daniel Gomez <da.gomez@xxxxxxxxxx> wrote:
>
> From: Daniel Gomez <da.gomez@xxxxxxxxxxx>
>
> The scripts/kconfig/merge_config.sh script requires an existing
> $INITFILE (or the $1 argument) as a base file for merging Kconfig
> fragments. However, an empty $INITFILE can serve as an initial starting
> point, later referenced by the KCONFIG_ALLCONFIG Makefile variable
> if -m is not used. This variable can point to any configuration file
> containing preset config symbols (the merged output) as stated in
> Documentation/kbuild/kconfig.rst. When -m is used $INITFILE will
> contain just the merge output requiring the user to run make (i.e.
> KCONFIG_ALLCONFIG=<$INITFILE> make <allnoconfig/alldefconfig> or make
> olddefconfig).
>
> Instead of failing when `$INITFILE` is missing, create an empty file and
> use it as the starting point for merges.
>
> Signed-off-by: Daniel Gomez <da.gomez@xxxxxxxxxxx>
> ---


You still could do 'touch .config' in advance, but
I do not have a strong option.

Applied to linux-kbuild. Thanks.

I quoted $INITFILE in order to fix a shellcheck warning.



diff --git a/scripts/kconfig/merge_config.sh b/scripts/kconfig/merge_config.sh
index ad35a60de350..79c09b378be8 100755
--- a/scripts/kconfig/merge_config.sh
+++ b/scripts/kconfig/merge_config.sh
@@ -113,7 +113,7 @@ shift;

 if [ ! -r "$INITFILE" ]; then
        echo "The base file '$INITFILE' does not exist. Creating one..." >&2
-       touch $INITFILE
+       touch "$INITFILE"
 fi

 MERGE_LIST=$*




> Commit b9fe99c5b994 ("kbuild: mergeconfig: move an error check
> to merge_config.sh") moves the check for .config to exist from
> scripts/kconfig/Makefile to the scripts/kconfig/merge_config.sh.
> But this is no longer necessary.
>
> This avoid having to run a make <target> to create a first .config file.
> Workflow:
>
> ./scripts/kconfig/merge_config.sh \
> -m .config \
> <fragment list>
>
> make olddefconfig
>
> Here the logs with upstream scripts/kconfig/merge_config.sh (to show
> .config is created with tinyconfig).
>
> make tinyconfig V=1
> {..}
> make -f ./scripts/Makefile.build obj=scripts/kconfig tinyconfig
> KCONFIG_ALLCONFIG=kernel/configs/tiny-base.config make -f ./Makefile allnoconfig
> make -f ./scripts/Makefile.build obj=scripts/basic
> make -f ./scripts/Makefile.build obj=scripts/kconfig allnoconfig
> scripts/kconfig/conf  --allnoconfig Kconfig
>
> configuration written to .config
>
> make -f ./Makefile tiny.config
> make -f ./scripts/Makefile.build obj=scripts/basic
> make -f ./scripts/Makefile.build obj=scripts/kconfig tiny.config
> cmd_merge_fragments tiny.config
>   ./scripts/kconfig/merge_config.sh -m .config
> ./kernel/configs/tiny.config ./arch/x86/configs/tiny.config
> Using .config as base
> Merging ./kernel/configs/tiny.config
> Value of CONFIG_CC_OPTIMIZE_FOR_SIZE is redefined by fragment
> ./kernel/configs/tiny.config:
> Previous value: # CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
> New value: CONFIG_CC_OPTIMIZE_FOR_SIZE=y
>
> Value of CONFIG_KERNEL_XZ is redefined by fragment
> ./kernel/configs/tiny.config:
> Previous value: # CONFIG_KERNEL_XZ is not set
> New value: CONFIG_KERNEL_XZ=y
>
> Value of CONFIG_SLUB_TINY is redefined by fragment
> ./kernel/configs/tiny.config:
> Previous value: # CONFIG_SLUB_TINY is not set
> New value: CONFIG_SLUB_TINY=y
>
> Merging ./arch/x86/configs/tiny.config
> Value of CONFIG_UNWINDER_GUESS is redefined by fragment
> ./arch/x86/configs/tiny.config:
> Previous value: # CONFIG_UNWINDER_GUESS is not set
> New value: CONFIG_UNWINDER_GUESS=y
>
> merged configuration written to .config (needs make)
>
> make -f ./Makefile olddefconfig
> make -f ./scripts/Makefile.build obj=scripts/basic
> make -f ./scripts/Makefile.build obj=scripts/kconfig olddefconfig
> scripts/kconfig/conf  --olddefconfig Kconfig
>
> configuration written to .config
> ---
>  scripts/kconfig/merge_config.sh | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/scripts/kconfig/merge_config.sh b/scripts/kconfig/merge_config.sh
> index 0b7952471c18f6882b8978f839f3170bb41fb01f..ad35a60de350ae1c5b60d39bf752115d27276f52 100755
> --- a/scripts/kconfig/merge_config.sh
> +++ b/scripts/kconfig/merge_config.sh
> @@ -112,8 +112,8 @@ INITFILE=$1
>  shift;
>
>  if [ ! -r "$INITFILE" ]; then
> -       echo "The base file '$INITFILE' does not exist.  Exit." >&2
> -       exit 1
> +       echo "The base file '$INITFILE' does not exist. Creating one..." >&2
> +       touch $INITFILE
>  fi
>
>  MERGE_LIST=$*
>
> ---
> base-commit: e21edb1638e82460f126a6e49bcdd958d452929c
> change-id: 20250328-fix-merge-config-87fe109017e9
>
> Best regards,
> --
> Daniel Gomez <da.gomez@xxxxxxxxxxx>
>


-- 
Best Regards
Masahiro Yamada