diff --git a/src/cargo/core/compiler/build_context/target_info.rs b/src/cargo/core/compiler/build_context/target_info.rs index e9358bdf93d..f80f45c8f58 100644 --- a/src/cargo/core/compiler/build_context/target_info.rs +++ b/src/cargo/core/compiler/build_context/target_info.rs @@ -55,11 +55,6 @@ pub struct TargetInfo { pub rustflags: Vec, /// Extra flags to pass to `rustdoc`, see [`extra_args`]. pub rustdocflags: Vec, - /// Whether or not rustc (stably) supports the `--check-cfg` flag. - /// - /// Can be removed once the minimum supported rustc version of Cargo is - /// at minimum 1.80.0. - pub support_check_cfg: bool, } /// Kind of each file generated by a Unit, part of `FileType`. @@ -204,13 +199,6 @@ impl TargetInfo { process.arg("--crate-type").arg(crate_type.as_str()); } - let support_check_cfg = rustc - .cached_output( - process.clone().arg("--check-cfg").arg("cfg()"), - extra_fingerprint, - ) - .is_ok(); - process.arg("--print=sysroot"); process.arg("--print=split-debuginfo"); process.arg("--print=crate-name"); // `___` as a delimiter. @@ -322,7 +310,6 @@ impl TargetInfo { )?, cfg, support_split_debuginfo, - support_check_cfg, }); } } diff --git a/src/cargo/core/compiler/build_runner/mod.rs b/src/cargo/core/compiler/build_runner/mod.rs index 7dce02c2fb8..ac99b734c8d 100644 --- a/src/cargo/core/compiler/build_runner/mod.rs +++ b/src/cargo/core/compiler/build_runner/mod.rs @@ -256,9 +256,12 @@ impl<'a, 'gctx> BuildRunner<'a, 'gctx> { args.push(cfg.into()); } - for check_cfg in &output.check_cfgs { - args.push("--check-cfg".into()); - args.push(check_cfg.into()); + if !output.check_cfgs.is_empty() { + args.push("-Zunstable-options".into()); + for check_cfg in &output.check_cfgs { + args.push("--check-cfg".into()); + args.push(check_cfg.into()); + } } for (lt, arg) in &output.linker_args { diff --git a/src/cargo/core/compiler/custom_build.rs b/src/cargo/core/compiler/custom_build.rs index 0e1ca88ea6d..829177f5fbb 100644 --- a/src/cargo/core/compiler/custom_build.rs +++ b/src/cargo/core/compiler/custom_build.rs @@ -408,11 +408,7 @@ fn build_work(build_runner: &mut BuildRunner<'_, '_>, unit: &Unit) -> CargoResul paths::create_dir_all(&script_out_dir)?; let nightly_features_allowed = build_runner.bcx.gctx.nightly_features_allowed; - let extra_check_cfg = build_runner - .bcx - .target_data - .info(unit.kind) - .support_check_cfg; + let extra_check_cfg = build_runner.bcx.gctx.cli_unstable().check_cfg; let targets: Vec = unit.pkg.targets().to_vec(); let msrv = unit.pkg.rust_version().cloned(); // Need a separate copy for the fresh closure. @@ -669,7 +665,9 @@ impl BuildOutput { /// /// * `pkg_descr` --- for error messages /// * `library_name` --- for determining if `RUSTC_BOOTSTRAP` should be allowed - /// * `extra_check_cfg` --- for `--check-cfg` (if supported) + /// * `extra_check_cfg` --- for unstable feature [`-Zcheck-cfg`] + /// + /// [`-Zcheck-cfg`]: https://doc.rust-lang.org/cargo/reference/unstable.html#check-cfg pub fn parse( input: &[u8], // Takes String instead of InternedString so passing `unit.pkg.name()` will give a compile error. @@ -912,8 +910,8 @@ impl BuildOutput { if extra_check_cfg { check_cfgs.push(value.to_string()); } else { - // silently ignoring the instruction because the rustc version - // we are using does not support --check-cfg stably + // silently ignoring the instruction to try to + // minimise MSRV annoyance when stabilizing -Zcheck-cfg } } "rustc-env" => { @@ -1256,11 +1254,7 @@ fn prev_build_output( &unit.pkg.to_string(), &prev_script_out_dir, &script_out_dir, - build_runner - .bcx - .target_data - .info(unit.kind) - .support_check_cfg, + build_runner.bcx.gctx.cli_unstable().check_cfg, build_runner.bcx.gctx.nightly_features_allowed, unit.pkg.targets(), &unit.pkg.rust_version().cloned(), diff --git a/src/cargo/core/compiler/fingerprint/mod.rs b/src/cargo/core/compiler/fingerprint/mod.rs index f22d4a9ed97..f3389b49f58 100644 --- a/src/cargo/core/compiler/fingerprint/mod.rs +++ b/src/cargo/core/compiler/fingerprint/mod.rs @@ -1454,7 +1454,14 @@ fn calculate_normal( // actually affect the output artifact so there's no need to hash it. path: util::hash_u64(path_args(build_runner.bcx.ws, unit).0), features: format!("{:?}", unit.features), - declared_features: format!("{declared_features:?}"), + // Note we curently only populate `declared_features` when `-Zcheck-cfg` + // is passed since it's the only user-facing toggle that will make this + // fingerprint relevant. + declared_features: if build_runner.bcx.gctx.cli_unstable().check_cfg { + format!("{declared_features:?}") + } else { + "".to_string() + }, deps, local: Mutex::new(local), memoized_hash: Mutex::new(None), diff --git a/src/cargo/core/compiler/mod.rs b/src/cargo/core/compiler/mod.rs index f30368e0fbe..3b0510ac94f 100644 --- a/src/cargo/core/compiler/mod.rs +++ b/src/cargo/core/compiler/mod.rs @@ -1310,13 +1310,11 @@ fn trim_paths_args( } /// Generates the `--check-cfg` arguments for the `unit`. +/// See unstable feature [`check-cfg`]. +/// +/// [`check-cfg`]: https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#check-cfg fn check_cfg_args(build_runner: &BuildRunner<'_, '_>, unit: &Unit) -> Vec { - if build_runner - .bcx - .target_data - .info(unit.kind) - .support_check_cfg - { + if build_runner.bcx.gctx.cli_unstable().check_cfg { // The routine below generates the --check-cfg arguments. Our goals here are to // enable the checking of conditionals and pass the list of declared features. // @@ -1354,6 +1352,7 @@ fn check_cfg_args(build_runner: &BuildRunner<'_, '_>, unit: &Unit) -> Vec> = ("Enable Cargo to compile the standard library itself as part of a crate graph compilation"), build_std_features: Option> = ("Configure features enabled for the standard library itself when building the standard library"), cargo_lints: bool = ("Enable the `[lints.cargo]` table"), + check_cfg: bool = ("Enable compile-time checking of `cfg` names/values/features"), codegen_backend: bool = ("Enable the `codegen-backend` option in profiles in .cargo/config.toml file"), config_include: bool = ("Enable the `include` key in config files"), direct_minimal_versions: bool = ("Resolve minimal dependency versions instead of maximum (direct dependencies only)"), @@ -859,9 +860,6 @@ const STABILIZED_REGISTRY_AUTH: &str = const STABILIZED_LINTS: &str = "The `[lints]` table is now always available."; -const STABILIZED_CHECK_CFG: &str = - "Compile-time checking of conditional (a.k.a. `-Zcheck-cfg`) is now always enabled."; - fn deserialize_build_std<'de, D>(deserializer: D) -> Result>, D::Error> where D: serde::Deserializer<'de>, @@ -1116,7 +1114,6 @@ impl CliUnstable { "credential-process" => stabilized_warn(k, "1.74", STABILIZED_CREDENTIAL_PROCESS), "lints" => stabilized_warn(k, "1.74", STABILIZED_LINTS), "registry-auth" => stabilized_warn(k, "1.74", STABILIZED_REGISTRY_AUTH), - "check-cfg" => stabilized_warn(k, "1.80", STABILIZED_CHECK_CFG), // Unstable features // Sorted alphabetically: @@ -1130,6 +1127,9 @@ impl CliUnstable { } "build-std-features" => self.build_std_features = Some(parse_features(v)), "cargo-lints" => self.cargo_lints = parse_empty(k, v)?, + "check-cfg" => { + self.check_cfg = parse_empty(k, v)?; + } "codegen-backend" => self.codegen_backend = parse_empty(k, v)?, "config-include" => self.config_include = parse_empty(k, v)?, "direct-minimal-versions" => self.direct_minimal_versions = parse_empty(k, v)?, diff --git a/src/cargo/util/context/target.rs b/src/cargo/util/context/target.rs index 6d7e7fde9b9..dab4af2c72f 100644 --- a/src/cargo/util/context/target.rs +++ b/src/cargo/util/context/target.rs @@ -120,7 +120,7 @@ fn load_config_table(gctx: &GlobalContext, prefix: &str) -> CargoResult parse_links_overrides(&target_key, links.val)?, + Some(links) => parse_links_overrides(&target_key, links.val, gctx)?, None => BTreeMap::new(), }; Ok(TargetConfig { @@ -135,6 +135,7 @@ fn load_config_table(gctx: &GlobalContext, prefix: &str) -> CargoResult, + gctx: &GlobalContext, ) -> CargoResult> { let mut links_overrides = BTreeMap::new(); @@ -203,8 +204,13 @@ fn parse_links_overrides( output.cfgs.extend(list.iter().map(|v| v.0.clone())); } "rustc-check-cfg" => { - let list = value.list(key)?; - output.check_cfgs.extend(list.iter().map(|v| v.0.clone())); + if gctx.cli_unstable().check_cfg { + let list = value.list(key)?; + output.check_cfgs.extend(list.iter().map(|v| v.0.clone())); + } else { + // silently ignoring the instruction to try to + // minimise MSRV annoyance when stabilizing -Zcheck-cfg + } } "rustc-env" => { for (name, val) in value.table(key)?.0 { diff --git a/src/doc/src/reference/build-script-examples.md b/src/doc/src/reference/build-script-examples.md index e5bdaa3c19b..f9c1d1e9e31 100644 --- a/src/doc/src/reference/build-script-examples.md +++ b/src/doc/src/reference/build-script-examples.md @@ -456,9 +456,6 @@ values](https://github.com/sfackler/rust-openssl/blob/dc72a8e2c429e46c275e528b61 ```rust,ignore // (portion of build.rs) -println!("cargo::rustc-check-cfg=cfg(ossl101,ossl102)"); -println!("cargo::rustc-check-cfg=cfg(ossl110,ossl110g,ossl111)"); - if let Ok(version) = env::var("DEP_OPENSSL_VERSION_NUMBER") { let version = u64::from_str_radix(&version, 16).unwrap(); diff --git a/src/doc/src/reference/build-scripts.md b/src/doc/src/reference/build-scripts.md index ee2416817b5..dc74fea95e3 100644 --- a/src/doc/src/reference/build-scripts.md +++ b/src/doc/src/reference/build-scripts.md @@ -130,8 +130,6 @@ one detailed below. compiler. * [`cargo::rustc-cfg=KEY[="VALUE"]`](#rustc-cfg) --- Enables compile-time `cfg` settings. -* [`cargo::rustc-check-cfg=CHECK_CFG`](#rustc-check-cfg) -- Register custom `cfg`s as - expected for compile-time checking of configs. * [`cargo::rustc-env=VAR=VALUE`](#rustc-env) --- Sets an environment variable. * [`cargo::rustc-cdylib-link-arg=FLAG`](#rustc-cdylib-link-arg) --- Passes custom flags to a linker for cdylib crates. @@ -235,10 +233,7 @@ equivalent to using [`rustc-link-lib`](#rustc-link-lib) and The `rustc-cfg` instruction tells Cargo to pass the given value to the [`--cfg` flag][option-cfg] to the compiler. This may be used for compile-time -detection of features to enable [conditional compilation]. Custom cfgs -must either be expected using the [`cargo::rustc-check-cfg`](#rustc-check-cfg) -instruction or usage will need to allow the [`unexpected_cfgs`][unexpected-cfgs] -lint to avoid unexpected cfgs warnings. +detection of features to enable [conditional compilation]. Note that this does *not* affect Cargo's dependency resolution. This cannot be used to enable an optional dependency, or enable other Cargo features. @@ -254,41 +249,6 @@ identifier, the value should be a string. [cargo features]: features.md [conditional compilation]: ../../reference/conditional-compilation.md [option-cfg]: ../../rustc/command-line-arguments.md#option-cfg -[unexpected-cfgs]: ../../rustc/lints/listing/warn-by-default.md#unexpected-cfgs - -### `cargo::rustc-check-cfg=CHECK_CFG` {#rustc-check-cfg} - -Add to the list of expected config names and values that is used when checking -the _reachable_ cfg expressions. - -For details on the syntax of `CHECK_CFG`, see `rustc` [`--check-cfg` flag][option-check-cfg]. -See also the [`unexpected_cfgs`][unexpected-cfgs] lint. - -The instruction can be used like this: - -```rust,no_run -// build.rs -println!("cargo::rustc-check-cfg=cfg(foo, values(\"bar\"))"); -``` - -Note that all possible cfgs should be defined, regardless of which cfgs are -currently enabled. This includes all possible values of a given cfg name. - -It is recommended to group the `cargo::rustc-check-cfg` and -[`cargo::rustc-cfg`][option-cfg] instructions as closely as possible in order to -avoid typos, missing check-cfg, stalled cfgs... - -#### Example of using `cargo::rustc-check-cfg` and `cargo::rustc-cfg` together - -```rust,no_run -// build.rs -println!("cargo::rustc-check-cfg=cfg(foo, values(\"bar\"))"); -if foo_bar_condition { - println!("cargo::rustc-cfg=foo=\"bar\""); -} -``` - -[option-check-cfg]: ../../rustc/command-line-arguments.md#option-check-cfg ### `cargo::rustc-env=VAR=VALUE` {#rustc-env} diff --git a/src/doc/src/reference/unstable.md b/src/doc/src/reference/unstable.md index d1ee3f9f09d..472ae88b99f 100644 --- a/src/doc/src/reference/unstable.md +++ b/src/doc/src/reference/unstable.md @@ -83,6 +83,7 @@ For the latest nightly, see the [nightly version] of this page. * [build-std-features](#build-std-features) --- Sets features to use with the standard library. * [binary-dep-depinfo](#binary-dep-depinfo) --- Causes the dep-info file to track binary dependencies. * [panic-abort-tests](#panic-abort-tests) --- Allows running tests with the "abort" panic strategy. + * [check-cfg](#check-cfg) --- Compile-time validation of `cfg` expressions. * [host-config](#host-config) --- Allows setting `[target]`-like configuration settings for host build targets. * [target-applies-to-host](#target-applies-to-host) --- Alters whether certain flags will be passed to host build targets. * [gc](#gc) --- Global cache garbage collection. @@ -1153,6 +1154,44 @@ You can use the flag like this: cargo rustdoc -Z unstable-options --output-format json ``` +## check-cfg + +* RFC: [#3013](https://github.com/rust-lang/rfcs/pull/3013) +* Tracking Issue: [#10554](https://github.com/rust-lang/cargo/issues/10554) + +`-Z check-cfg` command line enables compile time checking of Cargo features as well as `rustc` +well known names and values in `#[cfg]`, `cfg!`, `#[link]` and `#[cfg_attr]` with the `rustc` +and `rustdoc` unstable `--check-cfg` command line. + +You can use the flag like this: + +``` +cargo check -Z unstable-options -Z check-cfg +``` + +### `cargo::rustc-check-cfg=CHECK_CFG` + +The `rustc-check-cfg` instruction tells Cargo to pass the given value to the +`--check-cfg` flag to the compiler. This may be used for compile-time +detection of unexpected conditional compilation name and/or values. + +This can only be used in combination with `-Zcheck-cfg` otherwise it is ignored +with a warning. + +If you want to integrate with Cargo features, only use `-Zcheck-cfg` instead of +trying to do it manually with this option. + +You can use the instruction like this: + +```rust,no_run +// build.rs +println!("cargo::rustc-check-cfg=cfg(foo, bar)"); +``` + +``` +cargo check -Z unstable-options -Z check-cfg +``` + ## codegen-backend The `codegen-backend` feature makes it possible to select the codegen backend used by rustc using a profile. @@ -1759,11 +1798,3 @@ The `-Z registry-auth` feature has been stabilized in the 1.74 release with the requirement that a credential-provider is configured. See [Registry Authentication](registry-authentication.md) documentation for details. - -## check-cfg - -The `-Z check-cfg` feature has been stabilized in the 1.80 release by making it the -default behavior. - -See the [build script documentation](build-scripts.md#rustc-check-cfg) for informations -about specifying custom cfgs. diff --git a/tests/testsuite/build_script.rs b/tests/testsuite/build_script.rs index 18ba76c44dd..d8fed645aec 100644 --- a/tests/testsuite/build_script.rs +++ b/tests/testsuite/build_script.rs @@ -2609,10 +2609,7 @@ fn cfg_test() { ) .file( "build.rs", - r#"fn main() { - println!("cargo::rustc-cfg=foo"); - println!("cargo::rustc-check-cfg=cfg(foo)"); - }"#, + r#"fn main() { println!("cargo::rustc-cfg=foo"); }"#, ) .file( "src/lib.rs", @@ -2717,9 +2714,6 @@ fn cfg_override_test() { authors = [] build = "build.rs" links = "a" - - [lints.rust] - unexpected_cfgs = "allow" # bc of override, stable/nightly, tests "#, ) .file("build.rs", "") @@ -5596,10 +5590,9 @@ fn build_script_rerun_when_target_rustflags_change() { use std::env; fn main() { - println!("cargo::rustc-check-cfg=cfg(enable)"); if let Ok(rustflags) = env::var("CARGO_ENCODED_RUSTFLAGS") { if !rustflags.is_empty() { - println!("cargo::rustc-cfg=enable"); + println!("cargo::rustc-cfg=enable") } } } diff --git a/tests/testsuite/cargo/z_help/stdout.term.svg b/tests/testsuite/cargo/z_help/stdout.term.svg index c453ebc0b25..cde7a959502 100644 --- a/tests/testsuite/cargo/z_help/stdout.term.svg +++ b/tests/testsuite/cargo/z_help/stdout.term.svg @@ -1,4 +1,4 @@ - +