Add special `check-cfg` lint config for the `unexpected_cfgs` lint #13913

Urgau · 2024-05-14T20:12:30Z

What does this PR try to resolve?

This PR adds a special check-cfg lint config for the unexpected_cfgs lint, as it was decided by T-cargo (in today's meeting).

The goal of this lint config is to provide a simple and cost-less alternative to the build-script cargo::rustc-check-cfg instruction.

[lints.rust]
unexpected_cfgs = { level = "warn", check-cfg = ['cfg(foo, values("bar"))'] }

How should we test and review this PR?

I recommand reviewing commit by commit; and looking at all the new tests added in check_cfg.rs, I tried making them as exhaustive as I could, many of them are very similar to their non-config counterpart.

Additional information

I didn't add (actually removed from the 1st version of this PR) the possibility to omit the level field if check-cfg is specified, #13913 (comment).

Regarding the implementation, I tried making it is as straight forward as possible, nothing over-engineered or complex.

r? @epage (or @weihanglo maybe)

crates/cargo-util-schemas/src/manifest/mod.rs

src/doc/src/reference/build-scripts.md

src/doc/src/reference/manifest.md

tests/testsuite/check_cfg.rs

tests/testsuite/lints_table.rs

Add special `check-cfg` lint config for the `unexpected_cfgs` lint This PR adds a special `check-cfg` lint config for the `unexpected_cfgs` lint, as it was decided by T-cargo (in today's meeting). The goal of this lint config is to provide a simple and cost-less alternative to the build-script `cargo::rustc-check-cfg` instruction. ```toml [lints.rust] unexpected_cfgs = { check-cfg = ["cfg(foo, values(\"bar\"))"] } ``` Regarding the implementation, everything is as straight forward as possible, nothing over-engineered; I added the possibility to omit the `level` field if a sub-config is specified instead, since it seems useful and was easy to implement. There are many small-ish commit, I recommend reviewing them independently. r? `@epage` (or `@weihanglo` maybe)

Update `unexpected_cfgs` lint for Cargo new `check-cfg` config This PR updates the diagnostics output of the `unexpected_cfgs` lint for Cargo new `check-cfg` config. It's a simple and cost-less alternative to the build-script `cargo::rustc-check-cfg` instruction. ```toml [lints.rust] unexpected_cfgs = { level = "warn", check-cfg = ['cfg(foo, values("bar"))'] } ``` This PR also adds a Cargo specific section regarding check-cfg and Cargo inside rustc's book (motivation is described inside the file, but mainly check-cfg is a rustc feature not a Cargo one, Cargo only enabled the feature, it does not own it; T-cargo even considers the `check-cfg` lint config to be an implementation detail). This PR also updates the links to refer to that sub-page when using Cargo from rustc. As well as updating the lint doc to refer to the check-cfg docs. ~**Not to be merged before rust-lang/cargo#13913 reaches master!**~ (EDIT: merged in rust-lang/rust#125237) `@rustbot` label +F-check-cfg r? `@fmease` *(feel free to roll)* Fixes rust-lang/rust#124800 cc `@epage` `@weihanglo`

[beta-1.79] fix(toml): Don't warn on lints.rust.unexpected_cfgs.check-cfg Beta backports: - #13913 (sort of): removes just the lint warning (in a different way to be minimal) so we reduce warning noise for people using this key on nightly In order to make CI pass, the following PRs are also cherry-picked: - #13865 - #13834 (only `time` due to rust-lang/rust#125319) - #13901 - #13931 - #13920 - #13890 - disable link check (not a cherry pick)

Update `unexpected_cfgs` lint for Cargo new `check-cfg` config This PR updates the diagnostics output of the `unexpected_cfgs` lint for Cargo new `check-cfg` config. It's a simple and cost-less alternative to the build-script `cargo::rustc-check-cfg` instruction. ```toml [lints.rust] unexpected_cfgs = { level = "warn", check-cfg = ['cfg(foo, values("bar"))'] } ``` This PR also adds a Cargo specific section regarding check-cfg and Cargo inside rustc's book (motivation is described inside the file, but mainly check-cfg is a rustc feature not a Cargo one, Cargo only enabled the feature, it does not own it; T-cargo even considers the `check-cfg` lint config to be an implementation detail). This PR also updates the links to refer to that sub-page when using Cargo from rustc. As well as updating the lint doc to refer to the check-cfg docs. ~**Not to be merged before rust-lang/cargo#13913 reaches master!**~ (EDIT: merged in rust-lang/rust#125237) `@rustbot` label +F-check-cfg r? `@fmease` *(feel free to roll)* Fixes rust-lang/rust#124800 cc `@epage` `@weihanglo`

rustbot assigned epage May 14, 2024

rustbot added A-build-execution Area: anything dealing with executing the compiler A-documenting-cargo-itself Area: Cargo's documentation A-manifest Area: Cargo.toml issues S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels May 14, 2024

Urgau force-pushed the check-cfg-lints-sub-config branch 2 times, most recently from 021ba1f to 628542e Compare May 14, 2024 20:27