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Date:   Fri, 16 Jun 2023 10:15:22 -0700
From:   Nathan Chancellor <nathan@kernel.org>
To:     Miguel Ojeda <ojeda@kernel.org>
Cc:     Masahiro Yamada <masahiroy@kernel.org>,
        Wedson Almeida Filho <wedsonaf@gmail.com>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nicolas Schier <nicolas@fjasle.eu>,
        Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
        =?iso-8859-1?Q?Bj=F6rn?= Roy Baron <bjorn3_gh@protonmail.com>,
        Benno Lossin <benno.lossin@proton.me>,
        Alice Ryhl <aliceryhl@google.com>,
        Andreas Hindborg <nmi@metaspace.dk>,
        linux-kbuild@vger.kernel.org, rust-for-linux@vger.kernel.org,
        linux-kernel@vger.kernel.org, patches@lists.linux.dev
Subject: Re: [PATCH v2 09/11] kbuild: rust_is_available: handle failures
 calling `$RUSTC`/`$BINDGEN`
Message-ID: <20230616171522.GH3474164@dev-arch.thelio-3990X>
References: <20230616001631.463536-1-ojeda@kernel.org>
 <20230616001631.463536-10-ojeda@kernel.org>
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On Fri, Jun 16, 2023 at 02:16:29AM +0200, Miguel Ojeda wrote:
> The script already checks if `$RUSTC` and `$BINDGEN` exists via
> `command`, but the environment variables may point to a
> non-executable file, or the programs may fail for some other reason.
> While the script successfully exits with a failure as it should,
> the error given can be quite confusing depending on the shell and
> the behavior of its `command`. For instance, with `dash`:
> 
>     $ RUSTC=./mm BINDGEN=bindgen CC=clang scripts/rust_is_available.sh
>     scripts/rust_is_available.sh: 19: arithmetic expression: expecting primary: "100000 *  + 100 *  + "
> 
> Thus detect failure exit codes when calling `$RUSTC` and `$BINDGEN` and
> print a better message, in a similar way to what we do when extracting
> the `libclang` version found by `bindgen`.
> 
> Link: https://lore.kernel.org/rust-for-linux/CAK7LNAQYk6s11MASRHW6oxtkqF00EJVqhHOP=5rynWt-QDUsXw@mail.gmail.com/
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

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

> ---
>  scripts/rust_is_available.sh | 28 ++++++++++++++++++++++++++--
>  1 file changed, 26 insertions(+), 2 deletions(-)
> 
> diff --git a/scripts/rust_is_available.sh b/scripts/rust_is_available.sh
> index b7e0781fdea9..da8296cd9b8d 100755
> --- a/scripts/rust_is_available.sh
> +++ b/scripts/rust_is_available.sh
> @@ -81,8 +81,20 @@ fi
>  # Check that the Rust compiler version is suitable.
>  #
>  # Non-stable and distributions' versions may have a version suffix, e.g. `-dev`.
> +rust_compiler_output=$( \
> +	LC_ALL=C "$RUSTC" --version 2>/dev/null
> +) || rust_compiler_code=$?
> +if [ -n "$rust_compiler_code" ]; then
> +	echo >&2 "***"
> +	echo >&2 "*** Running '$RUSTC' to check the Rust compiler version failed with"
> +	echo >&2 "*** code $rust_compiler_code. See output and docs below for details:"
> +	echo >&2 "***"
> +	echo >&2 "$rust_compiler_output"
> +	echo >&2 "***"
> +	exit 1
> +fi
>  rust_compiler_version=$( \
> -	LC_ALL=C "$RUSTC" --version 2>/dev/null \
> +	echo "$rust_compiler_output" \
>  		| sed -nE '1s:.*rustc ([0-9]+\.[0-9]+\.[0-9]+).*:\1:p'
>  )
>  rust_compiler_min_version=$($min_tool_version rustc)
> @@ -108,8 +120,20 @@ fi
>  # Check that the Rust bindings generator is suitable.
>  #
>  # Non-stable and distributions' versions may have a version suffix, e.g. `-dev`.
> +rust_bindings_generator_output=$( \
> +	LC_ALL=C "$BINDGEN" --version 2>/dev/null
> +) || rust_bindings_generator_code=$?
> +if [ -n "$rust_bindings_generator_code" ]; then
> +	echo >&2 "***"
> +	echo >&2 "*** Running '$BINDGEN' to check the Rust bindings generator version failed with"
> +	echo >&2 "*** code $rust_bindings_generator_code. See output and docs below for details:"
> +	echo >&2 "***"
> +	echo >&2 "$rust_bindings_generator_output"
> +	echo >&2 "***"
> +	exit 1
> +fi
>  rust_bindings_generator_version=$( \
> -	LC_ALL=C "$BINDGEN" --version 2>/dev/null \
> +	echo "$rust_bindings_generator_output" \
>  		| sed -nE '1s:.*bindgen ([0-9]+\.[0-9]+\.[0-9]+).*:\1:p'
>  )
>  rust_bindings_generator_min_version=$($min_tool_version bindgen)
> -- 
> 2.41.0
>