fix(cargo-lints): Don't always inherit workspace lints

src/cargo/core/workspace.rs

@@ -1147,11 +1147,26 @@ impl<'gctx> Workspace<'gctx> {
     }
 
     pub fn emit_warnings(&self) -> CargoResult<()> {
+        let ws_lints = self
+            .root_maybe()
+            .workspace_config()
+            .inheritable()
+            .and_then(|i| i.lints().ok())
+            .unwrap_or_default();
+
+        let ws_cargo_lints = ws_lints
+            .get("cargo")
+            .cloned()
+            .unwrap_or_default()
+            .into_iter()
+            .map(|(k, v)| (k.replace('-', "_"), v))
+            .collect();
+
         for (path, maybe_pkg) in &self.packages.packages {
             let path = path.join("Cargo.toml");
             if let MaybePackage::Package(pkg) = maybe_pkg {
                 if self.gctx.cli_unstable().cargo_lints {
-                    self.emit_lints(pkg, &path)?
+                    self.emit_lints(pkg, &path, &ws_cargo_lints)?
                 }
             }
             let warnings = match maybe_pkg {
@@ -1179,22 +1194,12 @@ impl<'gctx> Workspace<'gctx> {
         Ok(())
     }
 
-    pub fn emit_lints(&self, pkg: &Package, path: &Path) -> CargoResult<()> {
-        let ws_lints = self
-            .root_maybe()
-            .workspace_config()
-            .inheritable()
-            .and_then(|i| i.lints().ok())
-            .unwrap_or_default();
-
-        let ws_cargo_lints = ws_lints
-            .get("cargo")
-            .cloned()
-            .unwrap_or_default()
-            .into_iter()
-            .map(|(k, v)| (k.replace('-', "_"), v))
-            .collect();
-
+    pub fn emit_lints(
+        &self,
+        pkg: &Package,
+        path: &Path,
+        ws_cargo_lints: &manifest::TomlToolLints,
+    ) -> CargoResult<()> {
         let mut error_count = 0;
         let toml_lints = pkg
             .manifest()
@@ -1212,27 +1217,37 @@ impl<'gctx> Workspace<'gctx> {
             .map(|(name, lint)| (name.replace('-', "_"), lint))
             .collect();
 
+        // We should only be using workspace lints if the `[lints]` table is
+        // present in the manifest, and `workspace` is set to `true`
+        let ws_cargo_lints = pkg
+            .manifest()
+            .resolved_toml()
+            .lints
+            .as_ref()
+            .is_some_and(|l| l.workspace)
+            .then(|| ws_cargo_lints);
+
         check_im_a_teapot(
             pkg,
             &path,
             &normalized_lints,
-            &ws_cargo_lints,
+            ws_cargo_lints,
             &mut error_count,
             self.gctx,
         )?;
         check_implicit_features(
             pkg,
             &path,
             &normalized_lints,
-            &ws_cargo_lints,
+            ws_cargo_lints,
             &mut error_count,
             self.gctx,
         )?;
         unused_dependencies(
             pkg,
             &path,
             &normalized_lints,
-            &ws_cargo_lints,
+            ws_cargo_lints,
             &mut error_count,
             self.gctx,
         )?;

src/cargo/util/lints.rs

@@ -88,7 +88,7 @@ impl Lint {
     pub fn level(
         &self,
         pkg_lints: &TomlToolLints,
-        ws_lints: &TomlToolLints,
+        ws_lints: Option<&TomlToolLints>,
         edition: Edition,
     ) -> (LintLevel, LintLevelReason) {
         self.groups
@@ -188,7 +188,7 @@ fn level_priority(
     default_level: LintLevel,
     edition_lint_opts: Option<(Edition, LintLevel)>,
     pkg_lints: &TomlToolLints,
-    ws_lints: &TomlToolLints,
+    ws_lints: Option<&TomlToolLints>,
     edition: Edition,
 ) -> (LintLevel, LintLevelReason, i8) {
     let (unspecified_level, reason) = if let Some(level) = edition_lint_opts
@@ -211,7 +211,7 @@ fn level_priority(
             LintLevelReason::Package,
             defined_level.priority(),
         )
-    } else if let Some(defined_level) = ws_lints.get(name) {
+    } else if let Some(defined_level) = ws_lints.and_then(|l| l.get(name)) {
         (
             defined_level.level().into(),
             LintLevelReason::Workspace,
@@ -234,7 +234,7 @@ pub fn check_im_a_teapot(
     pkg: &Package,
     path: &Path,
     pkg_lints: &TomlToolLints,
-    ws_lints: &TomlToolLints,
+    ws_lints: Option<&TomlToolLints>,
     error_count: &mut usize,
     gctx: &GlobalContext,
 ) -> CargoResult<()> {
@@ -306,7 +306,7 @@ pub fn check_implicit_features(
     pkg: &Package,
     path: &Path,
     pkg_lints: &TomlToolLints,
-    ws_lints: &TomlToolLints,
+    ws_lints: Option<&TomlToolLints>,
     error_count: &mut usize,
     gctx: &GlobalContext,
 ) -> CargoResult<()> {
@@ -390,7 +390,7 @@ pub fn unused_dependencies(
     pkg: &Package,
     path: &Path,
     pkg_lints: &TomlToolLints,
-    ws_lints: &TomlToolLints,
+    ws_lints: Option<&TomlToolLints>,
     error_count: &mut usize,
     gctx: &GlobalContext,
 ) -> CargoResult<()> {

tests/testsuite/lints_table.rs

@@ -982,3 +982,43 @@ error: `im_a_teapot` is specified
         )
         .run();
 }
+
+#[cargo_test]
+fn dont_always_inherit_workspace_lints() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+[workspace]
+members = ["foo"]
+
+[workspace.lints.cargo]
+im-a-teapot = "warn"
+"#,
+        )
+        .file(
+            "foo/Cargo.toml",
+            r#"
+cargo-features = ["test-dummy-unstable"]
+
+[package]
+name = "foo"
+version = "0.0.1"
+edition = "2015"
+authors = []
+im-a-teapot = true
+"#,
+        )
+        .file("foo/src/lib.rs", "")
+        .build();
+
+    p.cargo("check -Zcargo-lints")
+        .masquerade_as_nightly_cargo(&["cargo-lints"])
+        .with_stderr(
+            "\
+[CHECKING] foo v0.0.1 ([CWD]/foo)
+[FINISHED] [..]
+",
+        )
+        .run();
+}