Add "members_count" and "parent_id" data on namespaces API

app/models/group.rb

@@ -222,6 +222,12 @@ class Group < Namespace
     User.where(id: members_with_parents.select(:user_id))
   end
+  def users_with_descendants
+    members_with_descendants = GroupMember.non_request.where(source_id: descendants.pluck(:id).push(id))
+
+    User.where(id: members_with_descendants.select(:user_id))
+  end
+
   def max_member_access_for_user(user)
     return GroupMember::OWNER if user.admin?

changelogs/unreleased/add-members-count-and-parent-id-data-on-namespaces-api.yml

+---
+title: Add "members_count" and "parent_id" data on namespaces API
+merge_request:
+author:

doc/api/namespaces.md

@@ -29,18 +29,27 @@ Example response:
   {
     "id": 1,
     "path": "user1",
-    "kind": "user"
+    "kind": "user",
+    "full_path": "user1",
+    "parent_id": "null",
+    "members_count": "null"
   },
   {
     "id": 2,
     "path": "group1",
-    "kind": "group"
+    "kind": "group",
+    "full_path": "group1",
+    "parent_id": "null",
+    "members_count": 2
+
   },
   {
     "id": 3,
     "path": "bar",
     "kind": "group",
     "full_path": "foo/bar",
+    "parent_id": "9",
+    "members_count": 5
   }
 ]
 ```
@@ -72,6 +81,8 @@ Example response:
     "path": "twitter",
     "kind": "group",
     "full_path": "twitter",
+    "parent_id": "null",
+    "members_count": 2
   }
 ]
 ```

lib/api/entities.rb

@@ -444,7 +444,11 @@ module API
     end
     class Namespace < Grape::Entity
-      expose :id, :name, :path, :kind, :full_path
+      expose :id, :name, :path, :kind, :full_path, :parent_id
+
+      expose :members_count do |namespace, _|
+        namespace.users_with_descendants.count if namespace.kind == 'group'
+      end
     end
     class MemberAccess < Grape::Entity

spec/models/namespace_spec.rb

@@ -323,6 +323,25 @@ describe Namespace, models: true do
     end
   end
+  describe '#users_with_descendants', :nested_groups do
+    let(:user_a) { create(:user) }
+    let(:user_b) { create(:user) }
+
+    let(:group) { create(:group) }
+    let(:nested_group) { create(:group, parent: group) }
+    let(:deep_nested_group) { create(:group, parent: nested_group) }
+
+    it 'returns member users on every nest level without duplication' do
+      group.add_developer(user_a)
+      nested_group.add_developer(user_b)
+      deep_nested_group.add_developer(user_a)
+
+      expect(group.users_with_descendants).to contain_exactly(user_a, user_b)
+      expect(nested_group.users_with_descendants).to contain_exactly(user_a, user_b)
+      expect(deep_nested_group.users_with_descendants).to contain_exactly(user_a)
+    end
+  end
+
   describe '#user_ids_for_project_authorizations' do
     it 'returns the user IDs for which to refresh authorizations' do
       expect(namespace.user_ids_for_project_authorizations)

spec/requests/api/namespaces_spec.rb

@@ -15,6 +15,14 @@ describe API::Namespaces do
     end
     context "when authenticated as admin" do
+      it "returns correct attributes" do
+        get api("/namespaces", admin)
+
+        expect(response).to have_http_status(200)
+        expect(response).to include_pagination_headers
+        expect(json_response.first).to include('id', 'name', 'path', 'full_path', 'parent_id', 'members_count')
+      end
+
       it "admin: returns an array of all namespaces" do
         get api("/namespaces", admin)
@@ -37,6 +45,14 @@ describe API::Namespaces do
     end
     context "when authenticated as a regular user" do
+      it "returns correct attributes" do
+        get api("/namespaces", user)
+
+        expect(response).to have_http_status(200)
+        expect(response).to include_pagination_headers
+        expect(json_response.first).to include('id', 'name', 'path', 'full_path', 'parent_id', 'members_count')
+      end
+
       it "user: returns an array of namespaces" do
         get api("/namespaces", user)