fix(doc): respect public-dependency when documenting deps

Author: ojuschugh1

src/cargo/core/compiler/unit_dependencies.rs

@@ -637,6 +637,16 @@ fn compute_deps_doc(
     // built. If we're documenting *all* libraries, then we also depend on
     // the documentation of the library being built.
     let mut ret = Vec::new();
+    let is_root = state.ws.is_member(&unit.pkg);
+
+    // Check if public-dependency feature is enabled
+    let public_deps_enabled = state.gctx.cli_unstable().public_dependency
+        || unit
+            .pkg
+            .manifest()
+            .unstable_features()
+            .is_enabled(Feature::public_dependency());
+
     for (id, deps) in state.deps(unit, unit_for) {
         let Some(dep_lib) = calc_artifact_deps(unit, unit_for, id, &deps, state, &mut ret)? else {
             continue;
@@ -657,7 +667,20 @@ fn compute_deps_doc(
             IS_NO_ARTIFACT_DEP,
         )?;
         ret.push(lib_unit_dep);
-        if dep_lib.documented() && state.intent.wants_deps_docs() {
+
+        // Decide whether to document this dependency.
+        // When public-dependency is enabled, only document:
+        // - Direct dependencies of workspace members
+        // - Public dependencies (recursively)
+        // This dramatically speeds up documentation builds by excluding indirect
+        // private dependencies that cannot be used by readers of the docs.
+        let should_doc_dep = if public_deps_enabled && !is_root {
+            state.resolve().is_public_dep(unit.pkg.package_id(), id)
+        } else {
+            true
+        };
+
+        if dep_lib.documented() && state.intent.wants_deps_docs() && should_doc_dep {
             // Document this lib as well.
             let doc_unit_dep = new_unit_dep(
                 state,

tests/testsuite/doc.rs

@@ -4032,14 +4032,11 @@ fn mergeable_info_dep_collision() {
 
 #[cargo_test(nightly, reason = "public-dependency feature is unstable")]
 fn doc_with_public_dependency_transitive() {
-    // Tests recursive public dependency documentation with 2 layers.
+    // Tests recursive public dependency documentation with 2 layers
     // foo -> bar (direct) -> baz (public) -> qux (public)
-    //
-    // Before the fix: all transitive deps are documented regardless of
-    // public/private markers, so foo, bar, baz, and qux all get docs.
-    // After the fix: only direct deps and their public deps recursively
-    // are documented, so the same set applies here since the whole chain
-    // is public.
+    // foo and bar should be documented (direct deps)
+    // baz should be documented (public dep of direct dep bar)
+    // qux should be documented (public dep of public dep baz)
 
     Package::new("qux", "0.0.1")
         .file("src/lib.rs", "pub fn qux() {}")
@@ -4100,8 +4097,6 @@ fn doc_with_public_dependency_transitive() {
         )
         .run();
 
-    // All four are documented: the whole chain is public so behavior is
-    // the same before and after the fix.
     assert!(p.root().join("target/doc/foo/index.html").is_file());
     assert!(p.root().join("target/doc/bar/index.html").is_file());
     assert!(p.root().join("target/doc/baz/index.html").is_file());
@@ -4110,12 +4105,9 @@ fn doc_with_public_dependency_transitive() {
 
 #[cargo_test(nightly, reason = "public-dependency feature is unstable")]
 fn doc_direct_deps_always_documented() {
-    // Direct dependencies should always be documented regardless of the
-    // public flag on them.
-    // foo -> bar (public = true), baz (public = false)
-    //
-    // Both bar and baz are direct deps of foo, so both get documented
-    // both before and after the fix.
+    // Direct dependencies should always be documented regardless of public flag
+    // foo -> bar (public=true), baz (public=false)
+    // Both bar and baz should be documented since they are direct deps
 
     Package::new("bar", "0.0.1")
         .file("src/lib.rs", "pub fn bar() {}")
@@ -4166,20 +4158,16 @@ fn doc_direct_deps_always_documented() {
         )
         .run();
 
-    // Both direct deps are documented regardless of their public flag.
+    // Both direct deps should be documented
     assert!(p.root().join("target/doc/foo/index.html").is_file());
     assert!(p.root().join("target/doc/bar/index.html").is_file());
     assert!(p.root().join("target/doc/baz/index.html").is_file());
 }
 
 #[cargo_test(nightly, reason = "public-dependency feature is unstable")]
 fn doc_with_private_dependency() {
-    // foo -> bar (direct) -> baz (private dep of bar)
-    //
-    // Before the fix: baz is documented because cargo docs all transitive
-    // deps unconditionally, even when -Zpublic-dependency is active.
-    // After the fix: baz is NOT documented because it is a private
-    // transitive dep that callers of foo cannot use.
+    // foo -> bar (any) -> baz (private)
+    // Only foo and bar documented, not baz (transitive private dep)
 
     Package::new("baz", "0.0.1")
         .file("src/lib.rs", "pub fn baz() {}")
@@ -4196,7 +4184,7 @@ fn doc_with_private_dependency() {
             "Cargo.toml",
             r#"
                 cargo-features = ["public-dependency"]
-
+                
                 [package]
                 name = "foo"
                 version = "0.0.1"
@@ -4218,7 +4206,6 @@ fn doc_with_private_dependency() {
 [DOWNLOADING] crates ...
 [DOWNLOADED] baz v0.0.1 (registry `dummy-registry`)
 [DOWNLOADED] bar v0.0.1 (registry `dummy-registry`)
-[DOCUMENTING] baz v0.0.1
 [CHECKING] baz v0.0.1
 [DOCUMENTING] bar v0.0.1
 [CHECKING] bar v0.0.1
@@ -4233,19 +4220,12 @@ fn doc_with_private_dependency() {
 
     assert!(p.root().join("target/doc/foo/index.html").is_file());
     assert!(p.root().join("target/doc/bar/index.html").is_file());
-    // Before the fix baz is documented even though it is a private dep.
-    assert!(p.root().join("target/doc/baz/index.html").is_file());
+    assert!(!p.root().join("target/doc/baz/index.html").is_file());
 }
 
 #[cargo_test(nightly, reason = "public-dependency feature is unstable")]
 fn doc_mixed_public_private_deps() {
-    // foo -> pub_dep (public), priv_dep (private), priv_dep_with_dep (default)
-    //     priv_dep_with_dep -> transitive
-    //
-    // Before the fix: transitive is documented because cargo docs every
-    // reachable dep regardless of public/private markers.
-    // After the fix: transitive is NOT documented because it is only
-    // reachable through a private dependency chain.
+    // Tests mixed public and private dependencies
 
     Package::new("pub_dep", "0.0.1")
         .file("src/lib.rs", "pub fn pub_dep() {}")
@@ -4269,7 +4249,7 @@ fn doc_mixed_public_private_deps() {
             "Cargo.toml",
             r#"
                 cargo-features = ["public-dependency"]
-
+                
                 [package]
                 name = "foo"
                 version = "0.0.1"
@@ -4288,7 +4268,7 @@ fn doc_mixed_public_private_deps() {
         .masquerade_as_nightly_cargo(&["public-dependency"])
         .run();
 
-    // All direct deps are documented.
+    // Direct deps documented, transitive private deps not documented
     assert!(p.root().join("target/doc/foo/index.html").is_file());
     assert!(p.root().join("target/doc/pub_dep/index.html").is_file());
     assert!(p.root().join("target/doc/priv_dep/index.html").is_file());
@@ -4297,7 +4277,7 @@ fn doc_mixed_public_private_deps() {
             .join("target/doc/priv_dep_with_dep/index.html")
             .is_file()
     );
-    // Before the fix transitive is also documented even though it is an
-    // indirect private dep.
-    assert!(p.root().join("target/doc/transitive/index.html").is_file());
+
+    // transitive should NOT be documented
+    assert!(!p.root().join("target/doc/transitive/index.html").is_file());
 }