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Auto merge of #125219 - Urgau:check-cfg-cargo-config, r=fmease

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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 https://github.com/rust-lang/cargo/pull/13913 reaches master!**~ (EDIT: merged in https://github.com/rust-lang/rust/pull/125237)

`@rustbot` label +F-check-cfg
r? `@fmease` *(feel free to roll)*
Fixes https://github.com/rust-lang/rust/issues/124800
cc `@epage` `@weihanglo`
This commit is contained in:
bors 2024-05-20 20:14:09 +00:00
commit b92758a9ae
9 changed files with 210 additions and 58 deletions
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50
compiler/rustc_lint/src/context/diagnostics/check_cfg.rs
View file

@ -41,6 +41,24 @@ fn check_cfg_expected_note(
note
}
enum EscapeQuotes {
Yes,
No,
}
fn to_check_cfg_arg(name: Symbol, value: Option<Symbol>, quotes: EscapeQuotes) -> String {
if let Some(value) = value {
let value = str::escape_debug(value.as_str()).to_string();
let values = match quotes {
EscapeQuotes::Yes => format!("\\\"{}\\\"", value.replace("\"", "\\\\\\\\\"")),
EscapeQuotes::No => format!("\"{value}\""),
};
format!("cfg({name}, values({values}))")
} else {
format!("cfg({name})")
}
}
pub(super) fn unexpected_cfg_name(
sess: &Session,
diag: &mut Diag<'_, ()>,
@ -155,20 +173,18 @@ pub(super) fn unexpected_cfg_name(
}
}
let inst = if let Some((value, _value_span)) = value {
let pre = if is_from_cargo { "\\" } else { "" };
format!("cfg({name}, values({pre}\"{value}{pre}\"))")
} else {
format!("cfg({name})")
};
let inst = |escape_quotes| to_check_cfg_arg(name, value.map(|(v, _s)| v), escape_quotes);
if is_from_cargo {
if !is_feature_cfg {
diag.help(format!("consider using a Cargo feature instead or adding `println!(\"cargo::rustc-check-cfg={inst}\");` to the top of the `build.rs`"));
diag.help(format!("consider using a Cargo feature instead"));
diag.help(format!("or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:\n [lints.rust]\n unexpected_cfgs = {{ level = \"warn\", check-cfg = ['{}'] }}", inst(EscapeQuotes::No)));
diag.help(format!("or consider adding `println!(\"cargo::rustc-check-cfg={}\");` to the top of the `build.rs`", inst(EscapeQuotes::Yes)));
}
diag.note("see <https://doc.rust-lang.org/nightly/cargo/reference/build-scripts.html#rustc-check-cfg> for more information about checking conditional configuration");
diag.note("see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration");
} else {
diag.help(format!("to expect this configuration use `--check-cfg={inst}`"));
let inst = inst(EscapeQuotes::No);
diag.help(format!("to expect this configuration use `--check-cfg={inst}`",));
diag.note("see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration");
}
}
@ -251,12 +267,7 @@ pub(super) fn unexpected_cfg_value(
// do it if they want, but should not encourage them.
let is_cfg_a_well_know_name = sess.psess.check_config.well_known_names.contains(&name);
let inst = if let Some((value, _value_span)) = value {
let pre = if is_from_cargo { "\\" } else { "" };
format!("cfg({name}, values({pre}\"{value}{pre}\"))")
} else {
format!("cfg({name})")
};
let inst = |escape_quotes| to_check_cfg_arg(name, value.map(|(v, _s)| v), escape_quotes);
if is_from_cargo {
if name == sym::feature {
@ -266,12 +277,15 @@ pub(super) fn unexpected_cfg_value(
diag.help("consider defining some features in `Cargo.toml`");
}
} else if !is_cfg_a_well_know_name {
diag.help(format!("consider using a Cargo feature instead or adding `println!(\"cargo::rustc-check-cfg={inst}\");` to the top of the `build.rs`"));
diag.help(format!("consider using a Cargo feature instead"));
diag.help(format!("or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:\n [lints.rust]\n unexpected_cfgs = {{ level = \"warn\", check-cfg = ['{}'] }}", inst(EscapeQuotes::No)));
diag.help(format!("or consider adding `println!(\"cargo::rustc-check-cfg={}\");` to the top of the `build.rs`", inst(EscapeQuotes::Yes)));
}
diag.note("see <https://doc.rust-lang.org/nightly/cargo/reference/build-scripts.html#rustc-check-cfg> for more information about checking conditional configuration");
diag.note("see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration");
} else {
if !is_cfg_a_well_know_name {
diag.help(format!("to expect this configuration use `--check-cfg={inst}`"));
let inst = inst(EscapeQuotes::No);
diag.help(format!("to expect this configuration use `--check-cfg={inst}`",));
}
diag.note("see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration");
}