Respect [lints.rust.unexpected_cfgs] lint level

Author: Urgau

src/cargo/core/workspace.rs

@@ -1240,6 +1240,10 @@ impl<'gctx> Workspace<'gctx> {
             .get("cargo")
             .cloned()
             .unwrap_or(manifest::TomlToolLints::default());
+        let rust_lints = toml_lints
+            .get("rust")
+            .cloned()
+            .unwrap_or(manifest::TomlToolLints::default());
 
         let ws_contents = match self.root_maybe() {
             MaybePackage::Package(pkg) => pkg.manifest().contents(),
@@ -1261,7 +1265,7 @@ impl<'gctx> Workspace<'gctx> {
             self.gctx,
         )?;
         check_im_a_teapot(pkg, &path, &cargo_lints, &mut error_count, self.gctx)?;
-        unexpected_target_cfgs(self, pkg, &path, &mut error_count, self.gctx)?;
+        unexpected_target_cfgs(self, pkg, &path, &rust_lints, &mut error_count, self.gctx)?;
         if error_count > 0 {
             Err(crate::util::errors::AlreadyPrintedError::new(anyhow!(
                 "encountered {error_count} errors(s) while running lints"

src/cargo/util/lints.rs

@@ -12,7 +12,7 @@ use std::path::Path;
 use toml_edit::ImDocument;
 
 const LINT_GROUPS: &[LintGroup] = &[TEST_DUMMY_UNSTABLE];
-pub const LINTS: &[Lint] = &[IM_A_TEAPOT, UNKNOWN_LINTS];
+pub const LINTS: &[Lint] = &[IM_A_TEAPOT, UNEXPECTED_CFGS, UNKNOWN_LINTS];
 
 pub fn analyze_cargo_lints_table(
     pkg: &Package,
@@ -608,17 +608,35 @@ fn output_unknown_lints(
     Ok(())
 }
 
+// FIXME: This lint is only used for the Cargo infra, it's actually defined in rustc
+// it-self, which is broken is several ways, as it doesn't take into account
+// `rustc` flags ('via `RUSTFLAGS`), nor the possible `rustc` lints groups, ...
+const UNEXPECTED_CFGS: Lint = Lint {
+    name: "unexpected_cfgs",
+    desc: "lint on unexpected target cfgs",
+    groups: &[],
+    default_level: LintLevel::Warn,
+    edition_lint_opts: None,
+    feature_gate: None,
+    docs: None,
+};
+
 pub fn unexpected_target_cfgs(
     ws: &Workspace<'_>,
     pkg: &Package,
     path: &Path,
+    rust_lints: &TomlToolLints,
     error_count: &mut usize,
     gctx: &GlobalContext,
 ) -> CargoResult<()> {
     let manifest = pkg.manifest();
 
-    // FIXME: We should get the lint level from `[lints.rust.unexpected_cfgs]`
-    let lint_level = LintLevel::Warn;
+    let (lint_level, _lint_reason) =
+        UNEXPECTED_CFGS.level(rust_lints, manifest.edition(), manifest.unstable_features());
+
+    if lint_level == LintLevel::Allow {
+        return Ok(());
+    }
 
     let rustc = gctx.load_global_rustc(Some(ws))?;
     // FIXME: While it doesn't doesn't really matter for `--print=check-cfg`, we should

tests/testsuite/cfg.rs

@@ -1040,14 +1040,7 @@ fn unexpected_cfgs_target_lint_level_allow() {
 
     p.cargo("check -Zcargo-lints -Zcheck-target-cfgs")
         .masquerade_as_nightly_cargo(&["requires -Zcheck-target-cfgs"])
-        // FIXME: We shouldn't warn any target cfgs because of the level="allow"
         .with_stderr_data(str![[r#"
-[WARNING] unexpected `cfg` condition name: foo
- --> Cargo.toml:8:25
-  |
-8 |                 [target."cfg(foo)".dependencies]
-  |                         ----------
-  |
 [LOCKING] 1 package to latest compatible version
 [CHECKING] a v0.0.1 ([ROOT]/foo)
 [FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
@@ -1083,19 +1076,15 @@ fn unexpected_cfgs_target_lint_level_deny() {
     p.cargo("check -Zcargo-lints -Zcheck-target-cfgs")
         .masquerade_as_nightly_cargo(&["requires -Zcheck-target-cfgs"])
         .with_stderr_data(str![[r#"
-[WARNING] unexpected `cfg` condition name: foo
+[ERROR] unexpected `cfg` condition name: foo
  --> Cargo.toml:8:25
   |
 8 |                 [target."cfg(foo)".dependencies]
-  |                         ----------
+  |                         ^^^^^^^^^^
   |
-[LOCKING] 1 package to latest compatible version
-[CHECKING] a v0.0.1 ([ROOT]/foo)
-[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
 
 "#]])
-        // FIXME: this test should fail
-        // .with_status(101)
+        .with_status(101)
         .run();
 }
 
@@ -1128,17 +1117,16 @@ fn unexpected_cfgs_target_cfg_any() {
         .masquerade_as_nightly_cargo(&["requires -Zcheck-target-cfgs"])
         // FIXME: We shouldn't be linting `cfg(foo)` because of the `cfg(any())`
         .with_stderr_data(str![[r#"
-[WARNING] unexpected `cfg` condition name: foo
+[ERROR] unexpected `cfg` condition name: foo
  --> Cargo.toml:8:25
   |
 8 |                 [target."cfg(foo)".dependencies]
-  |                         ----------
+  |                         ^^^^^^^^^^
   |
-[LOCKING] 1 package to latest compatible version
-[CHECKING] a v0.0.1 ([ROOT]/foo)
-[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
 
 "#]])
+        // nor should we error out because of the level="deny"
+        .with_status(101)
         .run();
 }