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Date:   Mon, 12 Dec 2022 10:21:10 -0700
From:   Nathan Chancellor <nathan@kernel.org>
To:     Masahiro Yamada <masahiroy@kernel.org>
Cc:     linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nicolas Schier <nicolas@fjasle.eu>
Subject: Re: [PATCH] kbuild: ensure Make >= 3.82 is used
Message-ID: <Y5djBr9rVhSq8+iK@dev-arch.thelio-3990X>
References: <20221211030352.2622425-1-masahiroy@kernel.org>
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On Sun, Dec 11, 2022 at 12:03:52PM +0900, Masahiro Yamada wrote:
> Documentation/process/changes.rst notes the minimal GNU Make version,
> but it is not checked anywhere.
> 
> We could check $(MAKE_VERSION), but another simple way is to check
> $(.FEATURES) since the feature list always grows although this way
> is not always possible. For example Make 4.0 through 4.2 have the
> same set of $(.FEATURES).
> 
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Reviewed-by: Nathan Chancellor <nathan@kernel.org>

> ---
> 
> Changes in v3:
>   - Check the version in a different way
> 
>  Makefile | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/Makefile b/Makefile
> index 2dda1e9a717a..66dfc5751470 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -11,6 +11,11 @@ NAME = Hurr durr I'ma ninja sloth
>  # Comments in this file are targeted only to the developer, do not
>  # expect to learn how to build the kernel reading this file.
>  
> +# Ensure Make >= 3.82
> +ifeq ($(filter undefine,$(.FEATURES)),)
> +$(error Make $(MAKE_VERSION) is too old)

Would it make sense to state what version is needed, similar to the
Kconfig checks for compiler and binutils?

> +endif
> +
>  $(if $(filter __%, $(MAKECMDGOALS)), \
>  	$(error targets prefixed with '__' are only for internal use))
>  
> -- 
> 2.34.1
>