Support public dependency configuration with workspace deps

This commit updates the processing of `workspace = true` dependencies in
the `[dependencies]` section to process the `public` field. Previously
this field was ignored and didn't get plumbed through as configured.

src/cargo/util/toml/mod.rs

@@ -2080,6 +2080,7 @@ pub struct TomlWorkspaceDependency {
     #[serde(rename = "default_features")]
     default_features2: Option<bool>,
     optional: Option<bool>,
+    public: Option<bool>,
     /// This is here to provide a way to see the "unused manifest keys" when deserializing
     #[serde(skip_serializing)]
     #[serde(flatten)]
@@ -2114,11 +2115,12 @@ impl TomlWorkspaceDependency {
                     if let Some(false) = self.default_features.or(self.default_features2) {
                         default_features_msg(name, None, cx);
                     }
-                    if self.optional.is_some() || self.features.is_some() {
+                    if self.optional.is_some() || self.features.is_some() || self.public.is_some() {
                         TomlDependency::Detailed(DetailedTomlDependency {
                             version: Some(s),
                             optional: self.optional,
                             features: self.features.clone(),
+                            public: self.public,
                             ..Default::default()
                         })
                     } else {
@@ -2150,6 +2152,11 @@ impl TomlWorkspaceDependency {
                         }
                         _ => {}
                     }
+                    // Inherit the workspace configuration for `public` unless
+                    // it's explicitly specified for this dependency.
+                    if let Some(public) = self.public {
+                        d.public = Some(public);
+                    }
                     d.add_features(self.features.clone());
                     d.update_optional(self.optional);
                     TomlDependency::Detailed(d)

tests/testsuite/pub_priv.rs

@@ -197,3 +197,52 @@ Caused by:
         )
         .run()
 }
+
+#[cargo_test(nightly, reason = "exported_private_dependencies lint is unstable")]
+fn workspace_dep_made_public() {
+    Package::new("foo1", "0.1.0")
+        .file("src/lib.rs", "pub struct FromFoo;")
+        .publish();
+    Package::new("foo2", "0.1.0")
+        .file("src/lib.rs", "pub struct FromFoo;")
+        .publish();
+    Package::new("foo3", "0.1.0")
+        .file("src/lib.rs", "pub struct FromFoo;")
+        .publish();
+
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                cargo-features = ["public-dependency"]
+
+                [package]
+                name = "foo"
+                version = "0.0.1"
+
+                [workspace.dependencies]
+                foo1 = "0.1.0"
+                foo2 = { version = "0.1.0", public = true }
+                foo3 = { version = "0.1.0", public = false }
+
+                [dependencies]
+                foo1 = { workspace = true, public = true }
+                foo2 = { workspace = true }
+                foo3 = { workspace = true, public = true }
+            "#,
+        )
+        .file(
+            "src/lib.rs",
+            "
+                #![deny(exported_private_dependencies)]
+                pub fn use_priv1(_: foo1::FromFoo) {}
+                pub fn use_priv2(_: foo2::FromFoo) {}
+                pub fn use_priv3(_: foo3::FromFoo) {}
+            ",
+        )
+        .build();
+
+    p.cargo("check")
+        .masquerade_as_nightly_cargo(&["public-dependency"])
+        .run()
+}