Add future-incompat warning against keywords in cfgs and add raw-idents #14671

Urgau · 2024-10-11T11:41:53Z

What does this PR try to resolve?

This PR tries to address this thread #14649 (comment) in #14649 regarding cfg(true)/cfg(false) (and keywords more generally) which are wrongly accepted¹ as ident.

To address this, this PR does two things:

it introduce a future-incompatibility warning against those (wrongly) accepted keywords as ident
it add parsing for raw-idents (r#true) add suggest-it in the warning

How should we test and review this PR?

This PR should be reviewed commit-by-commit.
Tests are included in preliminary commits.

Additional information

I added a new struct for representing Idents which is rawness aware.
Which implied updating cargo-platform to 0.2.0 due to the API changes.

r? @epage

https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=ccfb9c894dbf14e791c8ae7e4798efd0 ↩

tests/testsuite/cfg.rs

crates/cargo-platform/src/cfg.rs

epage · 2024-11-01T18:55:44Z

@rfcbot fcp merge

This PR adds a future-incompat warning for the use of true and false values in a cfg within Cargo. This is to make room supporting RFC3695 (see #14649) which we verbally confirmed approval for (see rust-lang/rfcs#3695 (comment))

The main focus of this FCP is insta-stabilizing support for raw identifiers (e.g. r#true) in cfgs in Cargo. The future-incompat warning (this PR) and support for true / false (#14649) is implemented in a way that mirrors rustc where true and false are considered keywords and to reference the identifers with those names you need to use raw identifiers.

rfcbot · 2024-11-01T18:55:56Z

Team member @epage has proposed to merge this. The next step is review by the rest of the tagged team members:

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for info about what commands tagged team members can give me.

ehuss · 2024-11-02T21:24:33Z

I'm not quite sure I understand the wording of the error message. Saying cfg(true) is deprecated and will become a hard error in a future doesn't seem correct, since when rust-lang/rust#131204 is stabilized, it will become a supported feature (and thus not deprecated, and will intentionally be supported), right?

Would it be possible to change the wording to be something more like:

warning: the meaning of cfg(true) may change in the future
Cargo used to erroneously allow cfg(true) and cfg(false), but both forms were interpreted as false unless manually overridden with --cfg. In the future these will be built-in defines that will have the corresponding true/false value. It is recommended to avoid using these values until they are properly supported. See rust-lang/rust#131204 for more information.

Urgau · 2024-11-02T23:54:01Z

[..] it will become a supported feature (and thus not deprecated, and will intentionally be supported), right?

Yes, cfg(true) and cfg(false) will have the right semantic after #14649 is stabilized.

Changed the wording as suggest.

rfcbot · 2024-11-15T05:48:35Z

🔔 This is now entering its final comment period, as per the review above. 🔔

rfcbot · 2024-11-25T06:02:08Z

The final comment period, with a disposition to merge, as per the review above, is now complete.

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.

This will be merged soon.

epage

Thanks @Urgau !

weihanglo · 2024-11-26T18:29:18Z

---- test_proc_macro stdout ----
running `/home/runner/work/cargo/cargo/target/debug/cargo test --lib -Zbuild-std -Zpublic-dependency`
thread 'test_proc_macro' panicked at tests/build-std/main.rs:391:10:

---- expected: tests/build-std/main.rs:385:27
++++ actual:   stderr
        1 + [BLOCKING] waiting for file lock on package cache
        2 + [BLOCKING] waiting for file lock on package cache
   1    3 | [COMPILING] foo v0.0.0 ([ROOT]/foo)
   2    4 | [FINISHED] `test` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
   3    5 | [RUNNING] unittests src/lib.rs (target/debug/deps/foo-[HASH])

Hmm… build-std seems to clobber each others after #14850. Let me check how to fix it.

weihanglo · 2024-11-26T18:42:12Z

Got a PR up: #14861

weihanglo · 2024-11-26T19:45:40Z

Re-queuing as #14861 has been merged.

Update cargo 8 commits in 4c39aaff66862cc0da52fe529aa1990bb8bb9a22..3908f64086a3d7b9af8d87b4da2bd100776c3e61 2024-11-25 16:36:17 +0000 to 2024-11-29 17:32:44 +0000 - chore(deps): update msrv (rust-lang/cargo#14867) - fix(fix): Migrate cargo script manifests across editions (rust-lang/cargo#14864) - feat(toml): Allow adding/removing from cargo scripts (rust-lang/cargo#14857) - Add future-incompat warning against keywords in cfgs and add raw-idents (rust-lang/cargo#14671) - test(build-std): download deps first (rust-lang/cargo#14861) - test(pgo): ensure PGO works (rust-lang/cargo#14859) - git-fetch-with-cli: Set `GIT_DIR` for bare repository compatibility (rust-lang/cargo#14860) - fix(build-std): always link to std when testing proc-macros (rust-lang/cargo#14850)

Update cargo 17 commits in 4c39aaff66862cc0da52fe529aa1990bb8bb9a22..05f54fdc34310f458033af8a63ce1d699fae8bf6 2024-11-25 16:36:17 +0000 to 2024-12-03 03:14:12 +0000 - test(pgo): only run on nightly (rust-lang/cargo#14887) - chore: Bump to 0.86.0; update changelog (rust-lang/cargo#14885) - docs(ref): Finish a sentence on rust-versions (rust-lang/cargo#14884) - chore(deps): update rust crate cargo_metadata to 0.19.0 (rust-lang/cargo#14878) - chore(deps): update rust crate gix to 0.68.0 (rust-lang/cargo#14879) - fix: Remove default registry reference in `info` cmd docs (rust-lang/cargo#14880) - test(pgo): determine test runnability at compile time (rust-lang/cargo#14874) - test: `requires` attribute accepts string literals for cmds (rust-lang/cargo#14875) - chore(deps): update msrv (3 versions) to v1.81 (rust-lang/cargo#14871) - chore(deps): update msrv (rust-lang/cargo#14867) - fix(fix): Migrate cargo script manifests across editions (rust-lang/cargo#14864) - feat(toml): Allow adding/removing from cargo scripts (rust-lang/cargo#14857) - Add future-incompat warning against keywords in cfgs and add raw-idents (rust-lang/cargo#14671) - test(build-std): download deps first (rust-lang/cargo#14861) - test(pgo): ensure PGO works (rust-lang/cargo#14859) - git-fetch-with-cli: Set `GIT_DIR` for bare repository compatibility (rust-lang/cargo#14860) - fix(build-std): always link to std when testing proc-macros (rust-lang/cargo#14850)

Pkgsrc changes relative to rust184: * patch reorganization to deal with new version of upstream vendored crates, checksum updates. Version 1.85.0 (2025-02-20) ========================== Language -------- - [The 2024 Edition is now stable.] (rust-lang/rust#133349) See [the edition guide] (https://doc.rust-lang.org/nightly/edition-guide/rust-2024/index.html) for more details. - [Stabilize async closures] (rust-lang/rust#132706) See [RFC 3668] (https://rust-lang.github.io/rfcs/3668-async-closures.html) for more details. - [Stabilize `#[diagnostic::do_not_recommend]`] (rust-lang/rust#132056) - [Add `unpredictable_function_pointer_comparisons` lint to warn against function pointer comparisons] (rust-lang/rust#118833) - [Lint on combining `#[no_mangle]` and `#[export_name]` attributes.] (rust-lang/rust#131558) Compiler -------- - [The unstable flag `-Zpolymorphize` has been removed] (rust-lang/rust#133883), see rust-lang/compiler-team#810 for some background. Platform Support ---------------- - [Promote `powerpc64le-unknown-linux-musl` to tier 2 with host tools] (rust-lang/rust#133801) Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. Libraries --------- - [Panics in the standard library now have a leading `library/` in their path] (rust-lang/rust#132390) - [`std::env::home_dir()` on Windows now ignores the non-standard `$HOME` environment variable] (rust-lang/rust#132515) It will be un-deprecated in a subsequent release. - [Add `AsyncFn*` to the prelude in all editions.] (rust-lang/rust#132611) Stabilized APIs --------------- - [`BuildHasherDefault::new`] (https://doc.rust-lang.org/stable/std/hash/struct.BuildHasherDefault.html#method.new) - [`ptr::fn_addr_eq`] (https://doc.rust-lang.org/std/ptr/fn.fn_addr_eq.html) - [`io::ErrorKind::QuotaExceeded`] (https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.QuotaExceeded) - [`io::ErrorKind::CrossesDevices`] (https://doc.rust-lang.org/stable/std/io/enum.ErrorKind.html#variant.CrossesDevices) - [`{float}::midpoint`] (https://doc.rust-lang.org/core/primitive.f32.html#method.midpoint) - [Unsigned `{integer}::midpoint`] (https://doc.rust-lang.org/std/primitive.u64.html#method.midpoint) - [`NonZeroU*::midpoint`] (https://doc.rust-lang.org/std/num/type.NonZeroU32.html#method.midpoint) - [impl `std::iter::Extend` for tuples with arity 1 through 12] (https://doc.rust-lang.org/stable/std/iter/trait.Extend.html#impl-Extend%3C(A,)%3E-for-(EA,)) - [`FromIterator<(A, ...)>` for tuples with arity 1 through 12] (https://doc.rust-lang.org/stable/std/iter/trait.FromIterator.html#impl-FromIterator%3C(EA,)%3E-for-(A,)) - [`std::task::Waker::noop`] (https://doc.rust-lang.org/stable/std/task/struct.Waker.html#method.noop) These APIs are now stable in const contexts: - [`mem::size_of_val`] (https://doc.rust-lang.org/stable/std/mem/fn.size_of_val.html) - [`mem::align_of_val`] (https://doc.rust-lang.org/stable/std/mem/fn.align_of_val.html) - [`Layout::for_value`] (https://doc.rust-lang.org/stable/std/alloc/struct.Layout.html#method.for_value) - [`Layout::align_to`] (https://doc.rust-lang.org/stable/std/alloc/struct.Layout.html#method.align_to) - [`Layout::pad_to_align`] (https://doc.rust-lang.org/stable/std/alloc/struct.Layout.html#method.pad_to_align) - [`Layout::extend`] (https://doc.rust-lang.org/stable/std/alloc/struct.Layout.html#method.extend) - [`Layout::array`] (https://doc.rust-lang.org/stable/std/alloc/struct.Layout.html#method.array) - [`std::mem::swap`] (https://doc.rust-lang.org/stable/std/mem/fn.swap.html) - [`std::ptr::swap`] (https://doc.rust-lang.org/stable/std/ptr/fn.swap.html) - [`NonNull::new`] (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.new) - [`HashMap::with_hasher`] (https://doc.rust-lang.org/stable/std/collections/struct.HashMap.html#method.with_hasher) - [`HashSet::with_hasher`] (https://doc.rust-lang.org/stable/std/collections/struct.HashSet.html#method.with_hasher) - [`BuildHasherDefault::new`] (https://doc.rust-lang.org/stable/std/hash/struct.BuildHasherDefault.html#method.new) - [`<float>::recip`] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.recip) - [`<float>::to_degrees`] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.to_degrees) - [`<float>::to_radians`] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.to_radians) - [`<float>::max`] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.max) - [`<float>::min`] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.min) - [`<float>::clamp`] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.clamp) - [`<float>::abs`] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.abs) - [`<float>::signum`] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.signum) - [`<float>::copysign`] (https://doc.rust-lang.org/stable/std/primitive.f32.html#method.copysign) - [`MaybeUninit::write`] (https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.write) Cargo ----- - [Add future-incompatibility warning against keywords in cfgs and add raw-idents] (rust-lang/cargo#14671) - [Stabilize higher precedence trailing flags] (rust-lang/cargo#14900) - [Pass `CARGO_CFG_FEATURE` to build scripts] (rust-lang/cargo#14902) Rustdoc ----- - [Doc comment on impl blocks shows the first line, even when the impl block is collapsed] (rust-lang/rust#132155) Compatibility Notes ------------------- - [`rustc` no longer treats the `test` cfg as a well known check-cfg] (rust-lang/rust#131729), instead it is up to the build systems and users of `--check-cfg`[^check-cfg] to set it as a well known cfg using `--check-cfg=cfg(test)`. This is done to enable build systems like Cargo to set it conditionally, as not all source files are suitable for unit tests. [Cargo (for now) unconditionally sets the `test` cfg as a well known cfg] (rust-lang/cargo#14963). [^check-cfg]: https://doc.rust-lang.org/nightly/rustc/check-cfg.html - [Disable potentially incorrect type inference if there are trivial and non-trivial where-clauses] (rust-lang/rust#132325) - `std::env::home_dir()` has been deprecated for years, because it can give surprising results in some Windows configurations if the `HOME` environment variable is set (which is not the normal configuration on Windows). We had previously avoided changing its behavior, out of concern for compatibility with code depending on this non-standard configuration. Given how long this function has been deprecated, we're now fixing its behavior as a bugfix. A subsequent release will remove the deprecation for this function. - [Make `core::ffi::c_char` signedness more closely match that of the platform-default `char`] (rust-lang/rust#132975) This changed `c_char` from an `i8` to `u8` or vice versa on many Tier 2 and 3 targets (mostly Arm and RISC-V embedded targets). The new definition may result in compilation failures but fixes compatibility issues with C. The `libc` crate matches this change as of its 0.2.169 release. - [When compiling a nested `macro_rules` macro from an external crate, the content of the inner `macro_rules` is now built with the edition of the external crate, not the local crate.] (rust-lang/rust#133274) - [Increase `sparcv9-sun-solaris` and `x86_64-pc-solaris` Solaris baseline to 11.4.] (rust-lang/rust#133293) - [Show `abi_unsupported_vector_types` lint in future breakage reports] (rust-lang/rust#133374) - [Error if multiple super-trait instantiations of `dyn Trait` need associated types to be specified but only one is provided] (rust-lang/rust#133392) - [Change `powerpc64-ibm-aix` default `codemodel` to large] (rust-lang/rust#133811) Internal Changes ---------------- These changes do not affect any public interfaces of Rust, but they represent significant improvements to the performance or internals of rustc and related tools. - [Build `x86_64-unknown-linux-gnu` with LTO for C/C++ code (e.g., `jemalloc`)] (rust-lang/rust#134690)

rustbot assigned epage Oct 11, 2024

rustbot added A-build-scripts Area: build.rs scripts A-cfg-expr Area: Platform cfg expressions A-manifest Area: Cargo.toml issues S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Oct 11, 2024

Urgau mentioned this pull request Oct 11, 2024

Implement RFC3695: Allow boolean literals as cfg predicates #14649

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Urgau added 6 commits November 25, 2024 21:51

Bump cargo-platform to 0.2.0 in preparation for cfg(<true/false>)

80dde85

Add preliminary test for keywords in cfgs

ac10b55

Add future-incompatibility warning against some keyword-as-ident

4946828

Add preliminary test for raw-idents in cfgs

3c3bfb0

Add support for raw-idents in cfgs

9450706

Adjust future-incompatibility cfg keyword with raw-idents in cfgs

e2028d4

Urgau force-pushed the cfg-keyword-and-raw-idents branch from 363c9b7 to e2028d4 Compare November 25, 2024 21:02

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Merged via the queue into rust-lang:master with commit 10c255a Nov 26, 2024
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weihanglo mentioned this pull request Nov 29, 2024

Update cargo rust-lang/rust#133654

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weihanglo mentioned this pull request Dec 3, 2024

Update cargo rust-lang/rust#133825

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Add future-incompat warning against keywords in cfgs and add raw-idents #14671

Add future-incompat warning against keywords in cfgs and add raw-idents #14671

Urgau commented Oct 11, 2024

epage commented Nov 1, 2024

rfcbot commented Nov 1, 2024 •

edited by weihanglo

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ehuss commented Nov 2, 2024

Urgau commented Nov 2, 2024

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weihanglo commented Nov 26, 2024

weihanglo commented Nov 26, 2024

Add future-incompat warning against keywords in cfgs and add raw-idents #14671

Add future-incompat warning against keywords in cfgs and add raw-idents #14671

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Urgau commented Oct 11, 2024

What does this PR try to resolve?

How should we test and review this PR?

Additional information

Footnotes

epage commented Nov 1, 2024

rfcbot commented Nov 1, 2024 • edited by weihanglo Loading

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rfcbot commented Nov 1, 2024 •

edited by weihanglo

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