Use specific check-cfg args if provided for each unit

Author: Urgau

src/cargo/core/compiler/build_context/target_info.rs

@@ -76,6 +76,45 @@ pub enum ExpectedValues<T> {
 }
 
 impl CheckCfg {
+    pub fn new(
+        gctx: &GlobalContext,
+        rustc: &Rustc,
+        extra_args: Option<&[String]>,
+    ) -> CargoResult<CheckCfg> {
+        let mut process = rustc.workspace_process();
+
+        apply_env_config(gctx, &mut process)?;
+        process
+            .arg("-")
+            .arg("--print=check-cfg")
+            .arg("--check-cfg=cfg()")
+            .arg("-Zunstable-options")
+            .env_remove("RUSTC_LOG");
+
+        if let Some(extra_args) = extra_args {
+            process.args(extra_args);
+        }
+
+        // Removes `FD_CLOEXEC` set by `jobserver::Client` to pass jobserver
+        // as environment variables specify.
+        if let Some(client) = gctx.jobserver_from_env() {
+            process.inherit_jobserver(client);
+        }
+
+        let (output, _error) = rustc
+            .cached_output(&process, 0)
+            .with_context(|| "failed to run `rustc` to learn about check-cfg information")?;
+
+        let lines = output.lines();
+        let mut check_cfg = CheckCfg::default();
+        check_cfg.exhaustive = true;
+
+        Ok(lines.fold(check_cfg, |mut check_cfg, line| {
+            check_cfg.process_line(line);
+            check_cfg
+        }))
+    }
+
     fn process_line(&mut self, line: &str) {
         if line == "any()=any()" || line == "any()" {
             self.exhaustive = false;
@@ -945,7 +984,7 @@ pub struct RustcTargetData<'gctx> {
     /// Information about the target platform that we're building for.
     target_info: HashMap<CompileTarget, TargetInfo>,
 
-    /// `--print=cfg`
+    /// `--print=check-cfg`
     check_cfg: Option<CheckCfg>,
 }
 
@@ -994,32 +1033,7 @@ impl<'gctx> RustcTargetData<'gctx> {
         };
 
         let check_cfg = if gctx.cli_unstable().check_target_cfgs {
-            let mut process = rustc.workspace_process();
-
-            apply_env_config(gctx, &mut process)?;
-            process
-                .arg("-")
-                .arg("--print=check-cfg")
-                .arg("--check-cfg=cfg()")
-                .arg("-Zunstable-options")
-                .env_remove("RUSTC_LOG");
-
-            // Removes `FD_CLOEXEC` set by `jobserver::Client` to pass jobserver
-            // as environment variables specify.
-            if let Some(client) = gctx.jobserver_from_env() {
-                process.inherit_jobserver(client);
-            }
-
-            let (output, _error) = rustc
-                .cached_output(&process, 0)
-                .with_context(|| "failed to run `rustc` to learn about check-cfg information")?;
-
-            let lines = output.lines();
-
-            Some(lines.fold(CheckCfg::default(), |mut check_cfg, line| {
-                check_cfg.process_line(line);
-                check_cfg
-            }))
+            Some(CheckCfg::new(gctx, &rustc, None)?)
         } else {
             None
         };

src/cargo/ops/cargo_compile/mod.rs

@@ -57,7 +57,7 @@ use crate::ops;
 use crate::ops::resolve::WorkspaceResolve;
 use crate::util::context::GlobalContext;
 use crate::util::interning::InternedString;
-use crate::util::{CargoResult, StableHasher};
+use crate::util::{CargoResult, Rustc, StableHasher};
 
 mod compile_filter;
 use cargo_platform::{Cfg, CfgExpr, Platform};
@@ -501,6 +501,14 @@ pub fn create_bcx<'a, 'gctx>(
                     continue;
                 }
 
+                let specific_check_cfg =
+                    get_specific_check_cfg_for_unit(gctx, &target_data.rustc, unit)?;
+                let check_cfg = specific_check_cfg.as_ref().unwrap_or(check_cfg);
+
+                if !check_cfg.exhaustive {
+                    continue;
+                }
+
                 for dep in unit.pkg.summary().dependencies() {
                     let Some(platform) = dep.platform() else {
                         continue;
@@ -587,6 +595,20 @@ where `<compatible-ver>` is the latest version supporting rustc {rustc_version}"
     Ok(bcx)
 }
 
+fn get_specific_check_cfg_for_unit<'a>(
+    gctx: &GlobalContext,
+    rustc: &Rustc,
+    unit: &Unit,
+) -> CargoResult<Option<CheckCfg>> {
+    let lint_rustflags = unit.pkg.manifest().lint_rustflags();
+
+    if lint_rustflags.iter().any(|a| a == "--check-cfg") {
+        Ok(Some(CheckCfg::new(gctx, rustc, Some(lint_rustflags))?))
+    } else {
+        Ok(None)
+    }
+}
+
 fn warn_on_unexpected_cfgs(
     gctx: &GlobalContext,
     check_cfg: &CheckCfg,

tests/testsuite/cfg.rs

@@ -585,6 +585,92 @@ fn unexpected_cfgs_target() {
         .run();
 }
 
+#[cargo_test(nightly, reason = "--print=check-cfg is unstable in rustc")]
+fn unexpected_cfgs_target_with_lint() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "a"
+                version = "0.0.1"
+                edition = "2015"
+                authors = []
+
+                [target."cfg(foo)".dependencies] # should not warn here
+                b = { path = 'b' }
+
+                [target.'cfg(foo = "foo")'.dependencies] # should not warn here
+                b = { path = 'b' }
+
+                [target."cfg(bar)".dependencies]
+                b = { path = 'b' }
+
+                [lints.rust.unexpected_cfgs]
+                level = "warn"
+                check-cfg = ['cfg(foo, values(none(), "foo"))'] # because of this line
+            "#,
+        )
+        .file(
+            ".cargo/config.toml",
+            r#"
+                [target."cfg(foo)"] # but it doesn't have an effect here
+            "#,
+        )
+        .file("src/lib.rs", "")
+        .file("b/Cargo.toml", &basic_manifest("b", "0.0.1"))
+        .file("b/src/lib.rs", "")
+        .build();
+
+    p.cargo("check -Zcheck-target-cfgs")
+        .masquerade_as_nightly_cargo(&["requires -Zcheck-target-cfgs"])
+        .with_stderr_data(str![[r#"
+[LOCKING] 1 package to latest compatible version
+[WARNING] unexpected `cfg` condition name: `foo` in `[target.'cfg(foo)']`
+[WARNING] [ROOT]/foo/Cargo.toml: unexpected `cfg` condition name: `bar` in `[target.'cfg(bar)'.dependencies]`
+[CHECKING] a v0.0.1 ([ROOT]/foo)
+[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
+
+"#]])
+        .run();
+}
+
+#[cargo_test(nightly, reason = "--print=check-cfg is unstable in rustc")]
+fn unexpected_cfgs_target_cfg_any() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "a"
+                version = "0.0.1"
+                edition = "2015"
+                authors = []
+
+                [target."cfg(foo)".dependencies]
+                b = { path = 'b' }
+
+                [lints.rust.unexpected_cfgs]
+                level = "deny"
+                check-cfg = ["cfg(any())"]
+            "#,
+        )
+        .file("src/lib.rs", "")
+        .file("b/Cargo.toml", &basic_manifest("b", "0.0.1"))
+        .file("b/src/lib.rs", "")
+        .build();
+
+    p.cargo("check -Zcheck-target-cfgs")
+        .masquerade_as_nightly_cargo(&["requires -Zcheck-target-cfgs"])
+        .with_stderr_data(str![[r#"
+[LOCKING] 1 package to latest compatible version
+[CHECKING] a v0.0.1 ([ROOT]/foo)
+[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
+
+"#]])
+        .run();
+}
+
 #[cargo_test]
 fn no_unexpected_cfgs_target() {
     let p = project()