Expose discussion and notes count

Exposes `userDiscussionsCount` & `userNotesCount`
props in Group Epics query.

doc/api/graphql/reference/gitlab_schema.graphql

@@ -1802,6 +1802,16 @@ type BoardEpic implements CurrentUserTodos & Noteable {
   """
   upvotes: Int!
 
+  """
+  Number of user discussions in the epic
+  """
+  userDiscussionsCount: Int!
+
+  """
+  Number of user notes of the epic
+  """
+  userNotesCount: Int!
+
   """
   Permissions for the current user on the resource
   """
@@ -7245,6 +7255,16 @@ type Epic implements CurrentUserTodos & Noteable {
   """
   upvotes: Int!
 
+  """
+  Number of user discussions in the epic
+  """
+  userDiscussionsCount: Int!
+
+  """
+  Number of user notes of the epic
+  """
+  userNotesCount: Int!
+
   """
   Permissions for the current user on the resource
   """

doc/api/graphql/reference/gitlab_schema.json

@@ -4753,6 +4753,42 @@
               "isDeprecated": false,
               "deprecationReason": null
             },
+            {
+              "name": "userDiscussionsCount",
+              "description": "Number of user discussions in the epic",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "NON_NULL",
+                "name": null,
+                "ofType": {
+                  "kind": "SCALAR",
+                  "name": "Int",
+                  "ofType": null
+                }
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
+            {
+              "name": "userNotesCount",
+              "description": "Number of user notes of the epic",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "NON_NULL",
+                "name": null,
+                "ofType": {
+                  "kind": "SCALAR",
+                  "name": "Int",
+                  "ofType": null
+                }
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
             {
               "name": "userPermissions",
               "description": "Permissions for the current user on the resource",
@@ -20045,6 +20081,42 @@
               "isDeprecated": false,
               "deprecationReason": null
             },
+            {
+              "name": "userDiscussionsCount",
+              "description": "Number of user discussions in the epic",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "NON_NULL",
+                "name": null,
+                "ofType": {
+                  "kind": "SCALAR",
+                  "name": "Int",
+                  "ofType": null
+                }
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
+            {
+              "name": "userNotesCount",
+              "description": "Number of user notes of the epic",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "NON_NULL",
+                "name": null,
+                "ofType": {
+                  "kind": "SCALAR",
+                  "name": "Int",
+                  "ofType": null
+                }
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
             {
               "name": "userPermissions",
               "description": "Permissions for the current user on the resource",

doc/api/graphql/reference/index.md

@@ -290,6 +290,8 @@ Represents an epic on an issue board.
 | `title` | String | Title of the epic |
 | `updatedAt` | Time | Timestamp of when the epic was updated |
 | `upvotes` | Int! | Number of upvotes the epic has received |
+| `userDiscussionsCount` | Int! | Number of user discussions in the epic |
+| `userNotesCount` | Int! | Number of user notes of the epic |
 | `userPermissions` | EpicPermissions! | Permissions for the current user on the resource |
 | `userPreferences` | BoardEpicUserPreferences | User preferences for the epic on the issue board |
 | `webPath` | String! | Web path of the epic |
@@ -1189,6 +1191,8 @@ Represents an epic.
 | `title` | String | Title of the epic |
 | `updatedAt` | Time | Timestamp of when the epic was updated |
 | `upvotes` | Int! | Number of upvotes the epic has received |
+| `userDiscussionsCount` | Int! | Number of user discussions in the epic |
+| `userNotesCount` | Int! | Number of user notes of the epic |
 | `userPermissions` | EpicPermissions! | Permissions for the current user on the resource |
 | `webPath` | String! | Web path of the epic |
 | `webUrl` | String! | Web URL of the epic |

ee/app/graphql/types/epic_type.rb

@@ -66,6 +66,11 @@ module Types
     field :downvotes, GraphQL::INT_TYPE, null: false,
           description: 'Number of downvotes the epic has received'
 
+    field :user_notes_count, GraphQL::INT_TYPE, null: false,
+          description: 'Number of user notes of the epic'
+    field :user_discussions_count, GraphQL::INT_TYPE, null: false,
+          description: 'Number of user discussions in the epic'
+
     field :closed_at, Types::TimeType, null: true,
           description: 'Timestamp of when the epic was closed'
     field :created_at, Types::TimeType, null: true,
@@ -144,6 +149,26 @@ module Types
         Epics::DescendantCountService.new(epic, ctx[:current_user])
       end
 
+    def user_notes_count
+      BatchLoader::GraphQL.for(object.id).batch(key: :epic_user_notes_count) do |ids, loader, args|
+        counts = Note.count_for_collection(ids, 'Epic').index_by(&:noteable_id)
+
+        ids.each do |id|
+          loader.call(id, counts[id]&.count || 0)
+        end
+      end
+    end
+
+    def user_discussions_count
+      BatchLoader::GraphQL.for(object.id).batch(key: :epic_user_discussions_count) do |ids, loader, args|
+        counts = Note.count_for_collection(ids, 'Epic', 'COUNT(DISTINCT discussion_id) as count').index_by(&:noteable_id)
+
+        ids.each do |id|
+          loader.call(id, counts[id]&.count || 0)
+        end
+      end
+    end
+
     def has_children?
       Gitlab::Graphql::Aggregations::Epics::LazyEpicAggregate.new(context, object.id, COUNT) do |node, _aggregate_object|
         node.children.any?

ee/changelogs/unreleased/kp-expose-discussion-notes-count-in-epics-graphql.yml

+---
+title: Expose discussion and notes count in Epic query
+merge_request: 47409
+author:
+type: added

ee/spec/graphql/types/epic_type_spec.rb

@@ -11,8 +11,8 @@ RSpec.describe GitlabSchema.types['Epic'] do
       closed_at created_at updated_at children has_children has_issues has_parent
       web_path web_url relation_path reference issues user_permissions
       notes discussions relative_position subscribed participants
-      descendant_counts descendant_weight_sum upvotes downvotes health_status
-      current_user_todos
+      descendant_counts descendant_weight_sum upvotes downvotes
+      user_notes_count user_discussions_count health_status current_user_todos
     ]
   end
 

ee/spec/requests/api/graphql/group/epics_spec.rb

@@ -206,6 +206,47 @@ RSpec.describe 'Epics through GroupQuery' do
     end
   end
 
+  describe 'N+1 query checks' do
+    let(:epic_a) { create(:epic, group: group) }
+    let(:epic_b) { create(:epic, group: group) }
+    let(:epics) { [epic_a, epic_b] }
+    let(:extra_iid_for_second_query) { epic_b.iid.to_s }
+    let(:search_params) { { iids: [epic_a.iid.to_s] } }
+
+    def execute_query
+      query = graphql_query_for(
+        :group,
+        { full_path: group.full_path },
+        query_graphql_field(:epics, search_params, [
+          query_graphql_field(:nodes, nil, requested_fields)
+        ])
+      )
+      post_graphql(query, current_user: user)
+    end
+
+    context 'when requesting `user_notes_count`' do
+      let(:requested_fields) { [:user_notes_count] }
+
+      before do
+        create_list(:note_on_epic, 2, noteable: epic_a)
+        create(:note_on_epic, noteable: epic_b)
+      end
+
+      include_examples 'N+1 query check'
+    end
+
+    context 'when requesting `user_discussions_count`' do
+      let(:requested_fields) { [:user_discussions_count] }
+
+      before do
+        create_list(:note_on_epic, 2, noteable: epic_a)
+        create(:note_on_epic, noteable: epic_b)
+      end
+
+      include_examples 'N+1 query check'
+    end
+  end
+
   def expect_array_response(items)
     expect(response).to have_gitlab_http_status(:success)
     expect(epics_data).to be_an Array