[PATCH] rust: kconfig: Don't require RUST_IS_AVAILABLE for rustc-option

[PATCH] rust: kconfig: Don't require RUST_IS_AVAILABLE for rustc-option

[Matthew Maurer]

The final version of this macro does not fail in the absence of an
invokable `$(RUSTC)`, so we don't need to be careful not to invoke it.

Link: https://lore.kernel.org/all/CAGSQo01mQfcU1EiW53be1hcts0c1p-HQAab_HBk6VcVmhq3n2Q@mail.gmail.com/
Signed-off-by: Matthew Maurer <mmaurer@google.com>
---
 scripts/Kconfig.include | 2 --
 1 file changed, 2 deletions(-)

diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include
index 33193ca6e8030e659d6b321acaea1acd42c387a4..7d9a0b4f66a9667b2cdc9d7e87c582487476f311 100644
--- a/scripts/Kconfig.include
+++ b/scripts/Kconfig.include
@@ -70,8 +70,6 @@ rustc-llvm-version := $(shell,$(srctree)/scripts/rustc-llvm-version.sh $(RUSTC))
 
 # $(rustc-option,<flag>)
 # Return y if the Rust compiler supports <flag>, n otherwise
-# Calls to this should be guarded so that they are not evaluated if
-# CONFIG_RUST_IS_AVAILABLE is not set.
 # If you are testing for unstable features, consider testing RUSTC_VERSION
 # instead, as features may have different completeness while available.
 rustc-option = $(success,trap "rm -rf .tmp_$$" EXIT; mkdir .tmp_$$; $(RUSTC) $(1) --crate-type=rlib /dev/null --out-dir=.tmp_$$ -o .tmp_$$/tmp.rlib)

---
base-commit: 76eeb9b8de9880ca38696b2fb56ac45ac0a25c6c
change-id: 20250909-docrem-149a48521128

Best regards,
-- 
Matthew Maurer <mmaurer@google.com>

Re: [PATCH] rust: kconfig: Don't require RUST_IS_AVAILABLE for rustc-option

[Nathan Chancellor]

On Tue, 09 Sep 2025 18:14:20 +0000, Matthew Maurer wrote:
> The final version of this macro does not fail in the absence of an
> invokable `$(RUSTC)`, so we don't need to be careful not to invoke it.
> 
> 

Applied to

  https://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux.git kbuild-next

Thanks!

[1/1] rust: kconfig: Don't require RUST_IS_AVAILABLE for rustc-option
      https://git.kernel.org/kbuild/c/f2445d6f264c6

Please look out for regression or issue reports or other follow up
comments, as they may result in the patch/series getting dropped or
reverted. Patches applied to an "unstable" branch are accepted pending
wider testing in -next and any post-commit review; they will generally
be moved to the main branch in a week if no issues are found.

Best regards,
-- 
Nathan Chancellor <nathan@kernel.org>

Re: [PATCH] rust: kconfig: Don't require RUST_IS_AVAILABLE for rustc-option

[Masahiro Yamada]

On Wed, Feb 4, 2026 at 9:16 AM Nathan Chancellor <nathan@kernel.org> wrote:
>
> On Tue, 09 Sep 2025 18:14:20 +0000, Matthew Maurer wrote:
> > The final version of this macro does not fail in the absence of an
> > invokable `$(RUSTC)`, so we don't need to be careful not to invoke it.
> >
> >
>
> Applied to
>
>   https://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux.git kbuild-next
>
> Thanks!
>
> [1/1] rust: kconfig: Don't require RUST_IS_AVAILABLE for rustc-option
>       https://git.kernel.org/kbuild/c/f2445d6f264c6
>
> Please look out for regression or issue reports or other follow up
> comments, as they may result in the patch/series getting dropped or
> reverted. Patches applied to an "unstable" branch are accepted pending
> wider testing in -next and any post-commit review; they will generally
> be moved to the main branch in a week if no issues are found.
>
> Best regards,
> --
> Nathan Chancellor <nathan@kernel.org>
>
>

Removing this comment is correct, but please note
the commit description is not accurate.

Kconfig evaluates all $(shell ...) macros before deciding the
value of RUSAT_IS_AVAILABLE.
You cannot prevent Kconfig from evaluating $(shell ...).
The author of c42297438aee7 did not read
Documentation/kbuild/kconfig-macro-language.rst



--
Best Regards

Masahiro Yamada

Re: [PATCH] rust: kconfig: Don't require RUST_IS_AVAILABLE for rustc-option

[Nathan Chancellor]

On Wed, Feb 04, 2026 at 04:17:26PM +0900, Masahiro Yamada wrote:
> On Wed, Feb 4, 2026 at 9:16 AM Nathan Chancellor <nathan@kernel.org> wrote:
> >
> > On Tue, 09 Sep 2025 18:14:20 +0000, Matthew Maurer wrote:
> > > The final version of this macro does not fail in the absence of an
> > > invokable `$(RUSTC)`, so we don't need to be careful not to invoke it.
> > >
> > >
> >
> > Applied to
> >
> >   https://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux.git kbuild-next
> >
> > Thanks!
> >
> > [1/1] rust: kconfig: Don't require RUST_IS_AVAILABLE for rustc-option
> >       https://git.kernel.org/kbuild/c/f2445d6f264c6
> >
> > Please look out for regression or issue reports or other follow up
> > comments, as they may result in the patch/series getting dropped or
> > reverted. Patches applied to an "unstable" branch are accepted pending
> > wider testing in -next and any post-commit review; they will generally
> > be moved to the main branch in a week if no issues are found.
> >
> > Best regards,
> > --
> > Nathan Chancellor <nathan@kernel.org>
> >
> >
> 
> Removing this comment is correct, but please note
> the commit description is not accurate.
> 
> Kconfig evaluates all $(shell ...) macros before deciding the
> value of RUSAT_IS_AVAILABLE.
> You cannot prevent Kconfig from evaluating $(shell ...).
> The author of c42297438aee7 did not read
> Documentation/kbuild/kconfig-macro-language.rst

Ugh, yes, sorry, I should have caught that too because I just recently
looked at this in another thread :(

  https://lore.kernel.org/20260129232535.GD844102@ax162/

I'd rather not rebase at this point but I appreciate you clarifying this
for the record.

Cheers,
Nathan