Add Event type to GraphQL and events to epics

  - Add EventType to GraphQL
  - Add events connection to epics

app/graphql/types/event_action_enum.rb

+# frozen_string_literal: true
+
+module Types
+  class EventActionEnum < BaseEnum
+    graphql_name 'EventAction'
+    description 'Event action'
+
+    ::Event.actions.keys.each do |target_type|
+      value target_type.upcase, value: target_type, description: "#{target_type.titleize} action"
+    end
+  end
+end

app/graphql/types/event_type.rb

+# frozen_string_literal: true
+
+module Types
+  class EventType < BaseObject
+    graphql_name 'Event'
+    description 'Representing an event'
+
+    present_using EventPresenter
+
+    authorize :read_event
+
+    field :id, GraphQL::ID_TYPE,
+          description: 'ID of the event.',
+          null: false
+
+    field :author, Types::UserType,
+          description: 'Author of this event.',
+          null: false
+
+    field :action, Types::EventActionEnum,
+          description: 'Action of the event.',
+          null: false
+
+    field :created_at, Types::TimeType,
+          description: 'When this event was created.',
+          null: false
+
+    field :updated_at, Types::TimeType,
+          description: 'When this event was updated.',
+          null: false
+
+    def author
+      Gitlab::Graphql::Loaders::BatchModelLoader.new(User, object.author_id).find
+    end
+  end
+end

app/graphql/types/eventable_type.rb

+# frozen_string_literal: true
+
+module Types
+  module EventableType
+    include Types::BaseInterface
+
+    field :events, Types::EventType.connection_type, null: true, description: 'A list of events associated with the object.'
+  end
+end

app/policies/event_policy.rb

+# frozen_string_literal: true
+
+class EventPolicy < BasePolicy # rubocop:disable Gitlab/NamespacedClass
+  condition(:visible_to_user) do
+    subject.visible_to_user?(user)
+  end
+
+  rule { visible_to_user }.enable :read_event
+end

doc/api/graphql/reference/gitlab_schema.graphql

@@ -1639,7 +1639,7 @@ type BoardEdge {
 """
 Represents an epic on an issue board
 """
-type BoardEpic implements CurrentUserTodos & Noteable {
+type BoardEpic implements CurrentUserTodos & Eventable & Noteable {
   """
   Author of the epic.
   """
@@ -1878,6 +1878,31 @@ type BoardEpic implements CurrentUserTodos & Noteable {
   """
   dueDateIsFixed: Boolean
 
+  """
+  A list of events associated with the object.
+  """
+  events(
+    """
+    Returns the elements in the list that come after the specified cursor.
+    """
+    after: String
+
+    """
+    Returns the elements in the list that come before the specified cursor.
+    """
+    before: String
+
+    """
+    Returns the first _n_ elements from the list.
+    """
+    first: Int
+
+    """
+    Returns the last _n_ elements from the list.
+    """
+    last: Int
+  ): EventConnection
+
   """
   Group to which the epic belongs.
   """
@@ -8682,7 +8707,7 @@ type EnvironmentsCanaryIngressUpdatePayload {
 """
 Represents an epic
 """
-type Epic implements CurrentUserTodos & Noteable {
+type Epic implements CurrentUserTodos & Eventable & Noteable {
   """
   Author of the epic.
   """
@@ -8921,6 +8946,31 @@ type Epic implements CurrentUserTodos & Noteable {
   """
   dueDateIsFixed: Boolean
 
+  """
+  A list of events associated with the object.
+  """
+  events(
+    """
+    Returns the elements in the list that come after the specified cursor.
+    """
+    after: String
+
+    """
+    Returns the elements in the list that come before the specified cursor.
+    """
+    before: String
+
+    """
+    Returns the first _n_ elements from the list.
+    """
+    first: Int
+
+    """
+    Returns the last _n_ elements from the list.
+    """
+    last: Int
+  ): EventConnection
+
   """
   Group to which the epic belongs.
   """
@@ -10251,6 +10301,168 @@ enum EpicWildcardId {
   NONE
 }
 
+"""
+Representing an event
+"""
+type Event {
+  """
+  Action of the event.
+  """
+  action: EventAction!
+
+  """
+  Author of this event.
+  """
+  author: User!
+
+  """
+  When this event was created.
+  """
+  createdAt: Time!
+
+  """
+  ID of the event.
+  """
+  id: ID!
+
+  """
+  When this event was updated.
+  """
+  updatedAt: Time!
+}
+
+"""
+Event action
+"""
+enum EventAction {
+  """
+  Approved action
+  """
+  APPROVED
+
+  """
+  Archived action
+  """
+  ARCHIVED
+
+  """
+  Closed action
+  """
+  CLOSED
+
+  """
+  Commented action
+  """
+  COMMENTED
+
+  """
+  Created action
+  """
+  CREATED
+
+  """
+  Destroyed action
+  """
+  DESTROYED
+
+  """
+  Expired action
+  """
+  EXPIRED
+
+  """
+  Joined action
+  """
+  JOINED
+
+  """
+  Left action
+  """
+  LEFT
+
+  """
+  Merged action
+  """
+  MERGED
+
+  """
+  Pushed action
+  """
+  PUSHED
+
+  """
+  Reopened action
+  """
+  REOPENED
+
+  """
+  Updated action
+  """
+  UPDATED
+}
+
+"""
+The connection type for Event.
+"""
+type EventConnection {
+  """
+  A list of edges.
+  """
+  edges: [EventEdge]
+
+  """
+  A list of nodes.
+  """
+  nodes: [Event]
+
+  """
+  Information to aid in pagination.
+  """
+  pageInfo: PageInfo!
+}
+
+"""
+An edge in a connection.
+"""
+type EventEdge {
+  """
+  A cursor for use in pagination.
+  """
+  cursor: String!
+
+  """
+  The item at the end of the edge.
+  """
+  node: Event
+}
+
+interface Eventable {
+  """
+  A list of events associated with the object.
+  """
+  events(
+    """
+    Returns the elements in the list that come after the specified cursor.
+    """
+    after: String
+
+    """
+    Returns the elements in the list that come before the specified cursor.
+    """
+    before: String
+
+    """
+    Returns the first _n_ elements from the list.
+    """
+    first: Int
+
+    """
+    Returns the last _n_ elements from the list.
+    """
+    last: Int
+  ): EventConnection
+}
+
 """
 Autogenerated input type of ExportRequirements
 """

doc/api/graphql/reference/index.md

@@ -309,6 +309,7 @@ Represents an epic on an issue board.
 | `dueDateFixed` | Time | Fixed due date of the epic. |
 | `dueDateFromMilestones` | Time | Inherited due date of the epic from milestones. |
 | `dueDateIsFixed` | Boolean | Indicates if the due date has been manually set. |
+| `events` | EventConnection | A list of events associated with the object. |
 | `group` | Group! | Group to which the epic belongs. |
 | `hasChildren` | Boolean! | Indicates if the epic has children. |
 | `hasIssues` | Boolean! | Indicates if the epic has direct issues. |
@@ -1467,6 +1468,7 @@ Represents an epic.
 | `dueDateFixed` | Time | Fixed due date of the epic. |
 | `dueDateFromMilestones` | Time | Inherited due date of the epic from milestones. |
 | `dueDateIsFixed` | Boolean | Indicates if the due date has been manually set. |
+| `events` | EventConnection | A list of events associated with the object. |
 | `group` | Group! | Group to which the epic belongs. |
 | `hasChildren` | Boolean! | Indicates if the epic has children. |
 | `hasIssues` | Boolean! | Indicates if the epic has direct issues. |
@@ -1678,6 +1680,18 @@ Autogenerated return type of EpicTreeReorder.
 | `clientMutationId` | String | A unique identifier for the client performing the mutation. |
 | `errors` | String! => Array | Errors encountered during execution of the mutation. |
 
+### Event
+
+Representing an event.
+
+| Field | Type | Description |
+| ----- | ---- | ----------- |
+| `action` | EventAction! | Action of the event. |
+| `author` | User! | Author of this event. |
+| `createdAt` | Time! | When this event was created. |
+| `id` | ID! | ID of the event. |
+| `updatedAt` | Time! | When this event was updated. |
+
 ### ExportRequirementsPayload
 
 Autogenerated return type of ExportRequirements.
@@ -4879,6 +4893,26 @@ Epic ID wildcard values.
 | `ANY` | Any epic is assigned |
 | `NONE` | No epic is assigned |
 
+### EventAction
+
+Event action.
+
+| Value | Description |
+| ----- | ----------- |
+| `APPROVED` | Approved action |
+| `ARCHIVED` | Archived action |
+| `CLOSED` | Closed action |
+| `COMMENTED` | Commented action |
+| `CREATED` | Created action |
+| `DESTROYED` | Destroyed action |
+| `EXPIRED` | Expired action |
+| `JOINED` | Joined action |
+| `LEFT` | Left action |
+| `MERGED` | Merged action |
+| `PUSHED` | Pushed action |
+| `REOPENED` | Reopened action |
+| `UPDATED` | Updated action |
+
 ### GroupMemberRelation
 
 Group member relation.

ee/app/graphql/resolvers/epics_resolver.rb

@@ -78,7 +78,8 @@ module Resolvers
 
     def preloads
       {
-        parent: [:parent]
+        parent: [:parent],
+        events: { events: [:target] }
       }
     end
 

ee/app/graphql/types/epic_type.rb

@@ -15,6 +15,7 @@ module Types
 
     implements(Types::Notes::NoteableType)
     implements(Types::CurrentUserTodos)
+    implements(Types::EventableType)
 
     field :id, GraphQL::ID_TYPE, null: false,
           description: 'ID of the epic.'

ee/changelogs/unreleased/georgekoltsov-add-events-to-epics-graphql.yml

+---
+title: Add Event type to GraphQL and events to epics
+merge_request: 53152
+author:
+type: changed

ee/spec/graphql/types/epic_type_spec.rb

@@ -13,7 +13,7 @@ RSpec.describe GitlabSchema.types['Epic'] do
       notes discussions relative_position subscribed participants
       descendant_counts descendant_weight_sum upvotes downvotes
       user_notes_count user_discussions_count health_status current_user_todos
-      award_emoji
+      award_emoji events
     ]
   end
 

ee/spec/policies/event_policy_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe EventPolicy do
+  let(:user) { create(:user) }
+  let(:event) { create(:event, :created, target: create(:epic, group: group)) }
+
+  subject { described_class.new(user, event) }
+
+  before do
+    stub_licensed_features(epics: true)
+  end
+
+  context 'when the user cannot read the epic' do
+    let(:group) { create(:group, :private) }
+
+    it { expect_disallowed(:read_event) }
+  end
+
+  context 'when the user can read the epic' do
+    let(:group) { create(:group, :public) }
+
+    it { expect_allowed(:read_event) }
+  end
+end

ee/spec/requests/api/graphql/epics/epic_resolver_spec.rb

@@ -83,6 +83,49 @@ RSpec.describe 'getting epics information' do
     end
   end
 
+  context 'query for epics with events' do
+    let_it_be(:epic) { create(:epic, group: group) }
+
+    it 'can lookahead to prevent N+1 queries' do
+      create_list(:event, 10, :created, target: epic, group: group)
+
+      control_count = ActiveRecord::QueryRecorder.new(skip_cached: false) do
+        query_epics_with_events(1)
+      end.count
+
+      events = graphql_dig_at(graphql_data, :group, :epics, :nodes, :events, :nodes)
+      expect(events.count).to eq(1)
+
+      expect do
+        query_epics_with_events(10)
+      end.not_to exceed_all_query_limit(control_count)
+
+      data = graphql_data(fresh_response_data)
+      events = graphql_dig_at(data, :group, :epics, :nodes, :events, :nodes)
+      expect(events.count).to eq(10)
+    end
+  end
+
+  def query_epics_with_events(number)
+    epics_field = <<~NODE
+      epics {
+        nodes {
+          id
+          events(first: #{number}) {
+            nodes {
+              id
+            }
+          }
+        }
+      }
+    NODE
+
+    post_graphql(
+      graphql_query_for('group', { 'fullPath' => group.full_path }, epics_field),
+      current_user: user
+    )
+  end
+
   def epics_query(group, field, value)
     epics_query_by_hash(group, field => value)
   end

spec/graphql/types/event_type_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Types::EventType do
+  specify { expect(described_class.graphql_name).to eq('Event') }
+
+  specify { expect(described_class).to require_graphql_authorizations(:read_event) }
+
+  specify { expect(described_class).to have_graphql_fields(:id, :author, :action, :created_at, :updated_at) }
+end

spec/graphql/types/eventable_type_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Types::EventableType do
+  it 'exposes events field' do
+    expect(described_class).to have_graphql_fields(:events)
+  end
+end