Include public/private dependency status in cargo metadata

fixes rust-lang#14502

This change introduces a new method, `Dependency::serialized` which replaces the direct `Serialize` implementation on `Dependency`.

This matches the pattern used by `Package` with its `Package::serialized`, and enables us to influence the serialization format with unstable flags.

I replaced borrowed types in `SerializedDependency` with owned variants to satisfy the borrow checker.
This matches `SerializedPackage` and shouldn't be an issue since `Dependency` is cheap to copy.

src/bin/cargo/commands/read_manifest.rs

@@ -15,6 +15,7 @@ Deprecated, use `<cyan,bold>cargo metadata --no-deps</>` instead.\
 
 pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
     let ws = args.workspace(gctx)?;
-    gctx.shell().print_json(&ws.current()?.serialized())?;
+    gctx.shell()
+        .print_json(&ws.current()?.serialized(gctx.cli_unstable()))?;
     Ok(())
 }

src/cargo/core/dependency.rs

@@ -9,7 +9,7 @@ use std::sync::Arc;
 use tracing::trace;
 
 use crate::core::compiler::{CompileKind, CompileTarget};
-use crate::core::{PackageId, SourceId, Summary};
+use crate::core::{CliUnstable, PackageId, SourceId, Summary};
 use crate::util::errors::CargoResult;
 use crate::util::interning::InternedString;
 use crate::util::OptVersionReq;
@@ -52,50 +52,32 @@ struct Inner {
 }
 
 #[derive(Serialize)]
-struct SerializedDependency<'a> {
-    name: &'a str,
+pub struct SerializedDependency {
+    name: InternedString,
     source: SourceId,
     req: String,
     kind: DepKind,
-    rename: Option<&'a str>,
+    rename: Option<InternedString>,
 
     optional: bool,
     uses_default_features: bool,
-    features: &'a [InternedString],
+    features: Vec<InternedString>,
     #[serde(skip_serializing_if = "Option::is_none")]
-    artifact: Option<&'a Artifact>,
-    target: Option<&'a Platform>,
+    artifact: Option<Artifact>,
+    target: Option<Platform>,
     /// The registry URL this dependency is from.
     /// If None, then it comes from the default registry (crates.io).
-    registry: Option<&'a str>,
+    registry: Option<String>,
 
     /// The file system path for a local path dependency.
     #[serde(skip_serializing_if = "Option::is_none")]
     path: Option<PathBuf>,
-}
 
-impl ser::Serialize for Dependency {
-    fn serialize<S>(&self, s: S) -> Result<S::Ok, S::Error>
-    where
-        S: ser::Serializer,
-    {
-        let registry_id = self.registry_id();
-        SerializedDependency {
-            name: &*self.package_name(),
-            source: self.source_id(),
-            req: self.version_req().to_string(),
-            kind: self.kind(),
-            optional: self.is_optional(),
-            uses_default_features: self.uses_default_features(),
-            features: self.features(),
-            target: self.platform(),
-            rename: self.explicit_name_in_toml().map(|s| s.as_str()),
-            registry: registry_id.as_ref().map(|sid| sid.url().as_str()),
-            path: self.source_id().local_path(),
-            artifact: self.artifact(),
-        }
-        .serialize(s)
-    }
+    /// `public` flag is unset if `-Zpublic-dependency` is not enabled
+    ///
+    /// Once that feature is stabilized, `public` will not need to be `Option`
+    #[serde(skip_serializing_if = "Option::is_none")]
+    public: Option<bool>,
 }
 
 #[derive(PartialEq, Eq, Hash, Ord, PartialOrd, Clone, Debug, Copy)]
@@ -130,6 +112,30 @@ impl ser::Serialize for DepKind {
 }
 
 impl Dependency {
+    pub fn serialized(&self, unstable_flags: &CliUnstable) -> SerializedDependency {
+        SerializedDependency {
+            name: self.package_name(),
+            source: self.source_id(),
+            req: self.version_req().to_string(),
+            kind: self.kind(),
+            optional: self.is_optional(),
+            uses_default_features: self.uses_default_features(),
+            features: self.features().to_vec(),
+            target: self.inner.platform.clone(),
+            rename: self.explicit_name_in_toml(),
+            registry: self
+                .registry_id()
+                .as_ref()
+                .map(|sid| sid.url().as_str().to_owned()),
+            path: self.source_id().local_path(),
+            artifact: self.inner.artifact.clone(),
+
+            public: unstable_flags
+                .public_dependency
+                .then_some(self.inner.public),
+        }
+    }
+
     /// Attempt to create a `Dependency` from an entry in the manifest.
     pub fn parse(
         name: impl Into<InternedString>,

src/cargo/core/mod.rs

@@ -1,4 +1,4 @@
-pub use self::dependency::Dependency;
+pub use self::dependency::{Dependency, SerializedDependency};
 pub use self::features::{CliUnstable, Edition, Feature, Features};
 pub use self::manifest::{EitherManifest, VirtualManifest};
 pub use self::manifest::{Manifest, Target, TargetKind};

src/cargo/core/package.rs

@@ -22,7 +22,10 @@ use crate::core::compiler::{CompileKind, RustcTargetData};
 use crate::core::dependency::DepKind;
 use crate::core::resolver::features::ForceAllTargets;
 use crate::core::resolver::{HasDevUnits, Resolve};
-use crate::core::{Dependency, Manifest, PackageId, PackageIdSpec, SourceId, Target};
+use crate::core::{
+    CliUnstable, Dependency, Manifest, PackageId, PackageIdSpec, SerializedDependency, SourceId,
+    Target,
+};
 use crate::core::{Summary, Workspace};
 use crate::sources::source::{MaybePackage, SourceMap};
 use crate::util::cache_lock::{CacheLock, CacheLockMode};
@@ -73,7 +76,7 @@ pub struct SerializedPackage {
     license_file: Option<String>,
     description: Option<String>,
     source: SourceId,
-    dependencies: Vec<Dependency>,
+    dependencies: Vec<SerializedDependency>,
     targets: Vec<Target>,
     features: BTreeMap<InternedString, Vec<InternedString>>,
     manifest_path: PathBuf,
@@ -188,7 +191,7 @@ impl Package {
         self.targets().iter().any(|t| t.is_example() || t.is_bin())
     }
 
-    pub fn serialized(&self) -> SerializedPackage {
+    pub fn serialized(&self, unstable_flags: &CliUnstable) -> SerializedPackage {
         let summary = self.manifest().summary();
         let package_id = summary.package_id();
         let manmeta = self.manifest().metadata();
@@ -224,7 +227,11 @@ impl Package {
             license_file: manmeta.license_file.clone(),
             description: manmeta.description.clone(),
             source: summary.source_id(),
-            dependencies: summary.dependencies().to_vec(),
+            dependencies: summary
+                .dependencies()
+                .iter()
+                .map(|dep| dep.clone().serialized(unstable_flags))
+                .collect(),
             targets,
             features,
             manifest_path: self.manifest_path().to_path_buf(),

src/cargo/ops/cargo_output_metadata.rs

@@ -33,7 +33,10 @@ pub fn output_metadata(ws: &Workspace<'_>, opt: &OutputMetadataOptions) -> Cargo
         );
     }
     let (packages, resolve) = if opt.no_deps {
-        let packages = ws.members().map(|pkg| pkg.serialized()).collect();
+        let packages = ws
+            .members()
+            .map(|pkg| pkg.serialized(ws.gctx().cli_unstable()))
+            .collect();
         (packages, None)
     } else {
         let (packages, resolve) = build_resolve_graph(ws, opt)?;
@@ -178,7 +181,7 @@ fn build_resolve_graph(
     let actual_packages = package_map
         .into_iter()
         .filter_map(|(pkg_id, pkg)| node_map.get(&pkg_id).map(|_| pkg))
-        .map(|pkg| pkg.serialized())
+        .map(|pkg| pkg.serialized(ws.gctx().cli_unstable()))
         .collect();
 
     let mr = MetadataResolve {