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Message-ID: <51e0fd1d-4d8f-8ef6-f910-6fb1a92755d0@gmail.com>
Date:   Fri, 16 Jun 2023 11:06:46 -0300
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Subject: Re: [PATCH v2 05/11] kbuild: rust_is_available: add check for
 `bindgen` invocation
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To:     Miguel Ojeda <ojeda@kernel.org>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Wedson Almeida Filho <wedsonaf@gmail.com>,
        Alex Gaynor <alex.gaynor@gmail.com>
Cc:     Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nicolas Schier <nicolas@fjasle.eu>,
        Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
        =?UTF-8?Q?Bj=c3=b6rn_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,
        =?UTF-8?Q?Fran=c3=a7ois_Valenduc?= <francoisvalenduc@gmail.com>,
        Alexandru Radovici <msg4alex@gmail.com>,
        Matthew Leach <dev@mattleach.net>
References: <20230616001631.463536-1-ojeda@kernel.org>
 <20230616001631.463536-6-ojeda@kernel.org>
From:   Martin Rodriguez Reboredo <yakoyoku@gmail.com>
In-Reply-To: <20230616001631.463536-6-ojeda@kernel.org>
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On 6/15/23 21:16, Miguel Ojeda wrote:
> `scripts/rust_is_available.sh` calls `bindgen` with a special
> header in order to check whether the `libclang` version in use
> is suitable.
> 
> However, the invocation itself may fail if, for instance, `bindgen`
> cannot locate `libclang`. This is fine for Kconfig (since the
> script will still fail and therefore disable Rust as it should),
> but it is pretty confusing for users of the `rustavailable` target
> given the error will be unrelated:
> 
>      ./scripts/rust_is_available.sh: 21: arithmetic expression: expecting primary: "100000 *  + 100 *  + "
>      make: *** [Makefile:1816: rustavailable] Error 2
> 
> Instead, run the `bindgen` invocation independently in a previous
> step, saving its output and return code. If it fails, then show
> the user a proper error message. Otherwise, continue as usual
> with the saved output.
> 
> Since the previous patch we show a reference to the docs, and
> the docs now explain how `bindgen` looks for `libclang`,
> thus the error message can leverage the documentation, avoiding
> duplication here (and making users aware of the setup guide in
> the documentation).
> 
> Reported-by: Nick Desaulniers <ndesaulniers@google.com>
> Link: https://lore.kernel.org/rust-for-linux/CAKwvOdm5JT4wbdQQYuW+RT07rCi6whGBM2iUAyg8A1CmLXG6Nw@mail.gmail.com/
> Reported-by: François Valenduc <francoisvalenduc@gmail.com>
> Closes: https://github.com/Rust-for-Linux/linux/issues/934
> Reported-by: Alexandru Radovici <msg4alex@gmail.com>
> Closes: https://github.com/Rust-for-Linux/linux/pull/921
> Reported-by: Matthew Leach <dev@mattleach.net>
> Closes: https://lore.kernel.org/rust-for-linux/20230507084116.1099067-1-dev@mattleach.net/
> Fixes: 78521f3399ab ("scripts: add `rust_is_available.sh`")
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
> [...]

Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>