Fix regression in package.yml metadata.owner key

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "codeowners"
-version = "0.3.0"
+version = "0.3.1"
 edition = "2024"
 
 [profile.release]

src/project.rs

@@ -111,6 +111,7 @@ pub mod deserializers {
     #[derive(Deserialize)]
     pub struct RubyPackage {
         pub owner: Option<String>,
+        pub metadata: Option<Metadata>,
     }
 
     #[derive(Deserialize)]

src/project_builder.rs

@@ -309,7 +309,17 @@ fn ruby_package_owner(path: &Path) -> Result<Option<String>, Error> {
     let file = File::open(path).change_context(Error::Io)?;
     let deserializer: deserializers::RubyPackage = serde_yaml::from_reader(file).change_context(Error::SerdeYaml)?;
 
-    Ok(deserializer.owner)
+    let top_level_owner = deserializer.owner;
+    let metadata_owner = deserializer.metadata.and_then(|metadata| metadata.owner);
+
+    // Error if both are present to avoid ambiguity
+    match (top_level_owner.as_ref(), metadata_owner.as_ref()) {
+        (Some(_), Some(_)) => Err(error_stack::report!(Error::Io).attach_printable(format!(
+            "Package at {} has both 'owner' and 'metadata.owner' defined. Please use only one.",
+            path.display()
+        ))),
+        _ => Ok(top_level_owner.or(metadata_owner)),
+    }
 }
 
 fn javascript_package_owner(path: &Path) -> Result<Option<String>, Error> {
@@ -334,4 +344,44 @@ mod tests {
     fn test_glob_match() {
         assert!(glob_match(OWNED_GLOB, "script/.eslintrc.js"));
     }
+
+    #[test]
+    fn test_ruby_package_owner_top_level() {
+        let yaml = "owner: TeamA\n";
+        let temp_file = tempfile::NamedTempFile::new().unwrap();
+        std::fs::write(temp_file.path(), yaml).unwrap();
+
+        let owner = ruby_package_owner(temp_file.path()).unwrap();
+        assert_eq!(owner, Some("TeamA".to_string()));
+    }
+
+    #[test]
+    fn test_ruby_package_owner_metadata() {
+        let yaml = "metadata:\n  owner: TeamB\n";
+        let temp_file = tempfile::NamedTempFile::new().unwrap();
+        std::fs::write(temp_file.path(), yaml).unwrap();
+
+        let owner = ruby_package_owner(temp_file.path()).unwrap();
+        assert_eq!(owner, Some("TeamB".to_string()));
+    }
+
+    #[test]
+    fn test_ruby_package_owner_errors_when_both_present() {
+        let yaml = "owner: TeamA\nmetadata:\n  owner: TeamB\n";
+        let temp_file = tempfile::NamedTempFile::new().unwrap();
+        std::fs::write(temp_file.path(), yaml).unwrap();
+
+        let result = ruby_package_owner(temp_file.path());
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_ruby_package_owner_no_owner() {
+        let yaml = "name: my_package\n";
+        let temp_file = tempfile::NamedTempFile::new().unwrap();
+        std::fs::write(temp_file.path(), yaml).unwrap();
+
+        let owner = ruby_package_owner(temp_file.path()).unwrap();
+        assert_eq!(owner, None);
+    }
 }