Add workspace metadata field.

src/lib.rs

@@ -120,6 +120,11 @@ impl std::fmt::Display for PackageId {
     }
 }
 
+// Helpers for default metadata fields
+fn is_null(value: &serde_json::Value) -> bool {
+    matches!(value, serde_json::Value::Null)
+}
+
 #[derive(Clone, Serialize, Deserialize, Debug)]
 /// Starting point for metadata returned by `cargo metadata`
 pub struct Metadata {
@@ -133,6 +138,9 @@ pub struct Metadata {
     pub workspace_root: PathBuf,
     /// Build directory
     pub target_directory: PathBuf,
+    /// The workspace-level metadata object. Null if non-existent.
+    #[serde(rename = "metadata", default, skip_serializing_if = "is_null")]
+    pub workspace_metadata: serde_json::Value,
     version: usize,
     #[doc(hidden)]
     #[serde(skip)]
@@ -305,7 +313,7 @@ pub struct Package {
     /// }
     ///
     /// ```
-    #[serde(default)]
+    #[serde(default, skip_serializing_if = "is_null")]
     pub metadata: serde_json::Value,
     /// The name of a native library the package is linking to.
     pub links: Option<String>,

tests/all/Cargo.toml

@@ -49,3 +49,6 @@ edition = '2015'
 [[bin]]
 name = "reqfeat"
 required-features = ["feat2"]
+
+[metadata.testobject]
+myvalue = "abc"

tests/test_samples.rs

@@ -112,6 +112,7 @@ fn old_minimal() {
     );
     assert!(meta.resolve.is_none());
     assert_eq!(meta.workspace_root, PathBuf::from("/foo"));
+    assert_eq!(meta.workspace_metadata, serde_json::Value::Null);
     assert_eq!(meta.target_directory, PathBuf::from("/foo/target"));
 }
 
@@ -140,6 +141,16 @@ fn cargo_version() -> semver::Version {
     ver
 }
 
+#[derive(serde::Deserialize, PartialEq, Eq, Debug)]
+struct WorkspaceMetadata {
+    testobject: TestObject,
+}
+
+#[derive(serde::Deserialize, PartialEq, Eq, Debug)]
+struct TestObject {
+    myvalue: String,
+}
+
 #[test]
 fn all_the_fields() {
     // All the fields currently generated as of 1.47. This tries to exercise as
@@ -165,6 +176,14 @@ fn all_the_fields() {
         meta.workspace_root.file_name().unwrap(),
         PathBuf::from("all")
     );
+    assert_eq!(
+        serde_json::from_value::<WorkspaceMetadata>(meta.workspace_metadata).unwrap(),
+        WorkspaceMetadata {
+            testobject: TestObject {
+                myvalue: "abc".to_string()
+            }
+        }
+    );
     assert_eq!(meta.workspace_members.len(), 1);
     assert!(meta.workspace_members[0].to_string().starts_with("all"));