Re: [PATCH] build: make sure build fails when running kconfig fails

[Anthony PERARD <anthony.perard@xxxxxxxxx>]

On Tue, Feb 20, 2024 at 09:43:56AM +0100, Jan Beulich wrote:
> Because of using "-include", failure to (re)build auto.conf (with
> auto.conf.cmd produced as a secondary target) won't stop make from
> continuing the build. Arrange for it being possible to drop the - from
> Rules.mk, requiring that the include be skipped for tools-only targets.
> Note that relying on the inclusion in those cases wouldn't be correct
> anyway, as it might be a stale file (yet to be rebuilt) which would be
> included, while during initial build, the file would be absent
> altogether.
> 
> Fixes: 8d4c17a90b0a ("xen/build: silence make warnings about missing 
> auto.conf*")
> Reported-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

Just to make sure, this patch is a workaround to a harmless bug in older
version of GNU Make which print spurious error messages, and said bug as
been fixed in GNU Make 4.2, right? Bug report:

    bug #102: Make prints an incorrect error for missing includes
    https://savannah.gnu.org/bugs/?func=detailitem&item_id=102

> --- a/xen/Makefile
> +++ b/xen/Makefile
> @@ -375,6 +375,7 @@ $(KCONFIG_CONFIG): tools_fixdep
>  # This exploits the 'multi-target pattern rule' trick.
>  # The syncconfig should be executed only once to make all the targets.
>  include/config/%.conf include/config/%.conf.cmd: $(KCONFIG_CONFIG)
> +     $(Q)rm -f include/config/$*.conf

Maybe this should say "include/config/auto.conf" instead of using "$*".
"syncconfig" is going to generate "auto.conf" and not "$*.conf". And it
would make easier to find the "rm" command via "grep".

>       $(Q)$(MAKE) $(build)=tools/kconfig syncconfig
>  

Thanks,

-- 
Anthony PERARD