Get ancestors of an Epic using GraphQL

- Add ancestors field to EpicType
- Update schema and documentation
- Add EpicsAncestorsResolver
- Add child_id param to EpicsFinder

Changelog: added
EE: true

doc/api/graphql/reference/index.md

@@ -7317,6 +7317,38 @@ Represents an epic on an issue board.
 
 #### Fields with arguments
 
+##### `BoardEpic.ancestors`
+
+Ancestors (parents) of the epic.
+
+Returns [`EpicConnection`](#epicconnection).
+
+This field returns a [connection](#connections). It accepts the
+four standard [pagination arguments](#connection-pagination-arguments):
+`before: String`, `after: String`, `first: Int`, `last: Int`.
+
+###### Arguments
+
+| Name | Type | Description |
+| ---- | ---- | ----------- |
+| <a id="boardepicancestorsauthorusername"></a>`authorUsername` | [`String`](#string) | Filter epics by author. |
+| <a id="boardepicancestorsconfidential"></a>`confidential` | [`Boolean`](#boolean) | Filter epics by given confidentiality. |
+| <a id="boardepicancestorsenddate"></a>`endDate` **{warning-solid}** | [`Time`](#time) | **Deprecated** in 13.5. Use timeframe.end. |
+| <a id="boardepicancestorsiid"></a>`iid` | [`ID`](#id) | IID of the epic, e.g., "1". |
+| <a id="boardepicancestorsiidstartswith"></a>`iidStartsWith` | [`String`](#string) | Filter epics by IID for autocomplete. |
+| <a id="boardepicancestorsiids"></a>`iids` | [`[ID!]`](#id) | List of IIDs of epics, e.g., [1, 2]. |
+| <a id="boardepicancestorsincludeancestorgroups"></a>`includeAncestorGroups` | [`Boolean`](#boolean) | Include epics from ancestor groups. |
+| <a id="boardepicancestorsincludedescendantgroups"></a>`includeDescendantGroups` | [`Boolean`](#boolean) | Include epics from descendant groups. |
+| <a id="boardepicancestorslabelname"></a>`labelName` | [`[String!]`](#string) | Filter epics by labels. |
+| <a id="boardepicancestorsmilestonetitle"></a>`milestoneTitle` | [`String`](#string) | Filter epics by milestone title, computed from epic's issues. |
+| <a id="boardepicancestorsmyreactionemoji"></a>`myReactionEmoji` | [`String`](#string) | Filter by reaction emoji applied by the current user. |
+| <a id="boardepicancestorsnot"></a>`not` | [`NegatedEpicFilterInput`](#negatedepicfilterinput) | Negated epic arguments. |
+| <a id="boardepicancestorssearch"></a>`search` | [`String`](#string) | Search query for epic title or description. |
+| <a id="boardepicancestorssort"></a>`sort` | [`EpicSort`](#epicsort) | List epics by sort order. |
+| <a id="boardepicancestorsstartdate"></a>`startDate` **{warning-solid}** | [`Time`](#time) | **Deprecated** in 13.5. Use timeframe.start. |
+| <a id="boardepicancestorsstate"></a>`state` | [`EpicState`](#epicstate) | Filter epics by state. |
+| <a id="boardepicancestorstimeframe"></a>`timeframe` | [`Timeframe`](#timeframe) | List items overlapping the given timeframe. |
+
 ##### `BoardEpic.children`
 
 Children (sub-epics) of the epic.
@@ -8475,6 +8507,38 @@ Represents an epic.
 
 #### Fields with arguments
 
+##### `Epic.ancestors`
+
+Ancestors (parents) of the epic.
+
+Returns [`EpicConnection`](#epicconnection).
+
+This field returns a [connection](#connections). It accepts the
+four standard [pagination arguments](#connection-pagination-arguments):
+`before: String`, `after: String`, `first: Int`, `last: Int`.
+
+###### Arguments
+
+| Name | Type | Description |
+| ---- | ---- | ----------- |
+| <a id="epicancestorsauthorusername"></a>`authorUsername` | [`String`](#string) | Filter epics by author. |
+| <a id="epicancestorsconfidential"></a>`confidential` | [`Boolean`](#boolean) | Filter epics by given confidentiality. |
+| <a id="epicancestorsenddate"></a>`endDate` **{warning-solid}** | [`Time`](#time) | **Deprecated** in 13.5. Use timeframe.end. |
+| <a id="epicancestorsiid"></a>`iid` | [`ID`](#id) | IID of the epic, e.g., "1". |
+| <a id="epicancestorsiidstartswith"></a>`iidStartsWith` | [`String`](#string) | Filter epics by IID for autocomplete. |
+| <a id="epicancestorsiids"></a>`iids` | [`[ID!]`](#id) | List of IIDs of epics, e.g., [1, 2]. |
+| <a id="epicancestorsincludeancestorgroups"></a>`includeAncestorGroups` | [`Boolean`](#boolean) | Include epics from ancestor groups. |
+| <a id="epicancestorsincludedescendantgroups"></a>`includeDescendantGroups` | [`Boolean`](#boolean) | Include epics from descendant groups. |
+| <a id="epicancestorslabelname"></a>`labelName` | [`[String!]`](#string) | Filter epics by labels. |
+| <a id="epicancestorsmilestonetitle"></a>`milestoneTitle` | [`String`](#string) | Filter epics by milestone title, computed from epic's issues. |
+| <a id="epicancestorsmyreactionemoji"></a>`myReactionEmoji` | [`String`](#string) | Filter by reaction emoji applied by the current user. |
+| <a id="epicancestorsnot"></a>`not` | [`NegatedEpicFilterInput`](#negatedepicfilterinput) | Negated epic arguments. |
+| <a id="epicancestorssearch"></a>`search` | [`String`](#string) | Search query for epic title or description. |
+| <a id="epicancestorssort"></a>`sort` | [`EpicSort`](#epicsort) | List epics by sort order. |
+| <a id="epicancestorsstartdate"></a>`startDate` **{warning-solid}** | [`Time`](#time) | **Deprecated** in 13.5. Use timeframe.start. |
+| <a id="epicancestorsstate"></a>`state` | [`EpicState`](#epicstate) | Filter epics by state. |
+| <a id="epicancestorstimeframe"></a>`timeframe` | [`Timeframe`](#timeframe) | List items overlapping the given timeframe. |
+
 ##### `Epic.children`
 
 Children (sub-epics) of the epic.

ee/app/finders/epics_finder.rb

@@ -10,6 +10,7 @@
 #   state: 'open' or 'closed' or 'all'
 #   group_id: integer
 #   parent_id: integer
+#   child_id: integer
 #   author_id: integer
 #   author_username: string
 #   label_name: string
@@ -127,6 +128,7 @@ class EpicsFinder < IssuableFinder
     items = by_state(items)
     items = by_label(items)
     items = by_parent(items)
+    items = by_child(items)
     items = by_iids(items)
     items = by_my_reaction_emoji(items)
     items = by_confidential(items)
@@ -194,6 +196,10 @@ class EpicsFinder < IssuableFinder
     params[:parent_id].present?
   end
 
+  def child_id?
+    params[:child_id].present?
+  end
+
   # rubocop: disable CodeReuse/ActiveRecord
   def by_parent(items)
     return items unless parent_id?
@@ -202,6 +208,15 @@ class EpicsFinder < IssuableFinder
   end
   # rubocop: enable CodeReuse/ActiveRecord
 
+  # rubocop: disable CodeReuse/ActiveRecord
+  def by_child(items)
+    return items unless child_id?
+
+    ancestor_ids = Epic.find(params[:child_id]).ancestors.select(:id)
+    items.where(id: ancestor_ids)
+  end
+  # rubocop: enable CodeReuse/ActiveRecord
+
   def with_confidentiality_access_check(epics, groups)
     return epics if can_read_all_epics_in_related_groups?(groups)
 

ee/app/graphql/resolvers/epic_ancestors_resolver.rb

+# frozen_string_literal: true
+
+module Resolvers
+  class EpicAncestorsResolver < EpicsResolver
+    type Types::EpicType, null: true
+
+    argument :include_ancestor_groups, GraphQL::BOOLEAN_TYPE,
+             required: false,
+             description: 'Include epics from ancestor groups.',
+             default_value: true
+
+    private
+
+    def set_relative_param(args)
+      args[:child_id] = parent.id if parent
+
+      args
+    end
+  end
+end

ee/app/graphql/resolvers/epics_resolver.rb

@@ -102,10 +102,15 @@ module Resolvers
     def transform_args(args)
       transformed               = args.dup
       transformed[:group_id]    = group
-      transformed[:parent_id]   = parent.id if parent
       transformed[:iids]      ||= [args[:iid]].compact
 
-      transformed
+      set_relative_param(transformed)
+    end
+
+    def set_relative_param(args)
+      args[:parent_id] = parent.id if parent
+
+      args
     end
 
     # `resolver_object` refers to the object we're currently querying on, and is usually a `Group`

ee/app/graphql/types/epic_type.rb

@@ -149,6 +149,12 @@ module Types
           null: true,
           description: 'A list of award emojis associated with the epic.'
 
+    field :ancestors, Types::EpicType.connection_type,
+          null: true,
+          complexity: 5,
+          resolver: ::Resolvers::EpicAncestorsResolver,
+          description: 'Ancestors (parents) of the epic.'
+
     def has_children?
       Gitlab::Graphql::Aggregations::Epics::LazyEpicAggregate.new(context, object.id, COUNT) do |node, _aggregate_object|
         node.children.any?

ee/spec/finders/epics_finder_spec.rb

@@ -9,8 +9,8 @@ RSpec.describe EpicsFinder do
   let_it_be(:another_group) { create(:group) }
   let_it_be(:reference_time) { Time.parse('2020-09-15 01:00') } # Arbitrary time used for time/date range filters
   let_it_be(:epic1) { create(:epic, :opened, group: group, title: 'This is awesome epic', created_at: 1.week.before(reference_time), end_date: 10.days.before(reference_time)) }
-  let_it_be(:epic2) { create(:epic, :opened, group: group, created_at: 4.days.before(reference_time), author: user, start_date: 2.days.before(reference_time), end_date: 3.days.since(reference_time)) }
-  let_it_be(:epic3) { create(:epic, :closed, group: group, description: 'not so awesome', start_date: 5.days.before(reference_time), end_date: 3.days.before(reference_time)) }
+  let_it_be(:epic2) { create(:epic, :opened, group: group, created_at: 4.days.before(reference_time), author: user, start_date: 2.days.before(reference_time), end_date: 3.days.since(reference_time), parent: epic1) }
+  let_it_be(:epic3) { create(:epic, :closed, group: group, description: 'not so awesome', start_date: 5.days.before(reference_time), end_date: 3.days.before(reference_time), parent: epic2) }
   let_it_be(:epic4) { create(:epic, :closed, group: another_group) }
 
   describe '#execute' do
@@ -258,20 +258,21 @@ RSpec.describe EpicsFinder do
         end
 
         context 'by parent' do
-          before do
-            epic2.update!(parent: epic1)
-            epic3.update!(parent: epic2)
-          end
-
           it 'returns direct children of the parent' do
-            params = {
-              parent_id: epic1.id
-            }
+            params = { parent_id: epic1.id }
 
             expect(epics(params)).to contain_exactly(epic2)
           end
         end
 
+        context 'by child' do
+          it 'returns ancestors of the child epic' do
+            params = { child_id: epic3.id }
+
+            expect(epics(params)).to contain_exactly(epic1, epic2)
+          end
+        end
+
         context 'by confidential' do
           let_it_be(:confidential_epic) { create(:epic, :confidential, group: group) }
 

ee/spec/graphql/resolvers/epic_ancestors_resolver_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Resolvers::EpicAncestorsResolver do
+  include GraphqlHelpers
+
+  let_it_be_with_refind(:group) { create(:group, :private) }
+  let_it_be(:current_user) { create(:user) }
+  let_it_be(:epic1) { create(:epic, group: group) }
+  let_it_be(:epic2) { create(:epic, group: group, parent: epic1) }
+  let_it_be_with_reload(:base_epic) { create(:epic, group: group, parent: epic2) }
+  let_it_be(:confidential_epic1) { create(:epic, :confidential, group: group) }
+  let_it_be(:confidential_epic2) { create(:epic, :confidential, group: group, parent: confidential_epic1) }
+  let_it_be_with_reload(:confidential_epic) { create(:epic, :confidential, group: group, parent: confidential_epic2) }
+
+  let(:args) { { include_ancestor_groups: true } }
+
+  before do
+    stub_licensed_features(epics: true)
+  end
+
+  describe '#resolve' do
+    it 'returns nothing when feature disabled' do
+      stub_licensed_features(epics: false)
+
+      expect(resolve_ancestors(base_epic, args)).to be_empty
+    end
+
+    it 'does not return ancestor epics when user has no access to group epics' do
+      expect(resolve_ancestors(base_epic, args)).to be_empty
+    end
+
+    context 'when user has access to the group epics' do
+      before do
+        group.add_developer(current_user)
+      end
+
+      it 'returns non confidential ancestor epics' do
+        expect(resolve_ancestors(base_epic, args)).to contain_exactly(epic1, epic2)
+      end
+
+      it 'returns confidential ancestors' do
+        expect(resolve_ancestors(confidential_epic, args))
+          .to contain_exactly(confidential_epic1, confidential_epic2)
+      end
+
+      context 'with subgroups' do
+        let_it_be(:sub_group) { create(:group, :private, parent: group) }
+        let_it_be(:epic3)    { create(:epic, group: sub_group, parent: epic2) }
+        let_it_be(:epic4)    { create(:epic, group: sub_group, parent: epic3) }
+
+        before do
+          sub_group.add_developer(current_user)
+        end
+
+        it 'returns all ancestors' do
+          expect(resolve_ancestors(epic4, args)).to contain_exactly(epic1, epic2, epic3)
+        end
+
+        it 'does not return parent group epics when include_ancestor_groups is false' do
+          expect(resolve_ancestors(epic4, { include_ancestor_groups: false }))
+            .to contain_exactly(epic3)
+        end
+      end
+    end
+
+    context 'when user is a guest' do
+      before do
+        group.add_guest(current_user)
+      end
+
+      it 'returns non confidential ancestor epics' do
+        expect(resolve_ancestors(base_epic, args)).to contain_exactly(epic1, epic2)
+      end
+
+      it 'does not return confidential epics' do
+        expect(resolve_ancestors(confidential_epic, args)).to be_empty
+      end
+    end
+  end
+
+  def resolve_ancestors(object, args = {}, context = { current_user: current_user })
+    resolve(described_class, obj: object, args: args, ctx: context)
+  end
+end

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 events
+      award_emoji events ancestors
     ]
   end
 

ee/spec/requests/api/graphql/group/epic/epic_ancestors_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'Getting ancestors of an epic' do
+  include GraphqlHelpers
+
+  let_it_be(:user) { create(:user) }
+  let_it_be(:parent_group) { create(:group, :private) }
+  let_it_be(:group) { create(:group, :private, parent: parent_group) }
+  let_it_be(:ancestor_a) { create(:epic, group: parent_group) }
+  let_it_be(:ancestor_b) { create(:epic, group: group, parent: ancestor_a) }
+  let_it_be(:epic) { create(:epic, group: group, parent: ancestor_b) }
+
+  let(:epics_data) { graphql_data['group']['epics']['edges'] }
+
+  let(:epic_node) do
+    <<~NODE
+      edges {
+        node {
+          id
+          iid
+          ancestors {
+            edges {
+              node {
+                iid
+              }
+            }
+          }
+        }
+      }
+    NODE
+  end
+
+  def query(params = {})
+    graphql_query_for(
+      "group", { "fullPath" => group.full_path },
+      ['epicsEnabled', query_graphql_field("epics", params, epic_node)]
+    )
+  end
+
+  def epic_node_array(extract_attribute = nil)
+    node_array(epics_data, extract_attribute)
+  end
+
+  context 'when epics are enabled' do
+    before do
+      stub_licensed_features(epics: true)
+      group.add_developer(user)
+    end
+
+    it 'finds ancestors from group' do
+      post_graphql(query(iid: epic.iid), current_user: user)
+
+      expect(epic_node_array('ancestors'))
+        .to include({ 'edges' => [{ 'node' => { 'iid' => ancestor_b.iid.to_s } }] })
+    end
+
+    context 'when user has access to the parent group epics' do
+      before do
+        parent_group.add_developer(user)
+      end
+
+      it 'finds ancestors from group and parent group' do
+        post_graphql(query(iid: epic.iid), current_user: user)
+
+        expect(epic_node_array('ancestors')).to include(
+          { 'edges' =>
+            [{ 'node' => { 'iid' => ancestor_b.iid.to_s } },
+             { 'node' => { 'iid' => ancestor_a.iid.to_s } }] }
+        )
+      end
+    end
+  end
+
+  context 'when epics are disabled' do
+    before do
+      group.add_developer(user)
+      stub_licensed_features(epics: false)
+    end
+
+    it 'does not find the epic ancestors' do
+      post_graphql(query(iid: epic.iid), current_user: user)
+
+      expect(response).to have_gitlab_http_status(:success)
+      expect(graphql_errors).to be_nil
+      expect(epic_node_array('ancestors')).to be_empty
+    end
+  end
+end

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

@@ -7,13 +7,20 @@ require 'spec_helper'
 RSpec.describe 'Epics through GroupQuery' do
   include GraphqlHelpers
 
-  let(:user)        { create(:user) }
+  let(:epics_data) { graphql_data['group']['epics']['edges'] }
+  let(:epic_data) { graphql_data['group']['epic'] }
+
+  let_it_be(:user) { create(:user) }
   let_it_be(:group) { create(:group) }
-  let(:project)     { create(:project, :public, group: group) }
-  let(:label)       { create(:label) }
-  let(:epic)        { create(:labeled_epic, group: group, labels: [label]) }
-  let(:epics_data)  { graphql_data['group']['epics']['edges'] }
-  let(:epic_data)   { graphql_data['group']['epic'] }
+  let_it_be(:project) { create(:project, :public, group: group) }
+  let_it_be(:label) { create(:label) }
+  let_it_be_with_reload(:epic) do
+    create(:labeled_epic, group: group,
+      state: :closed, created_at: 3.days.ago,
+      updated_at: 2.days.ago, start_date: 2.days.ago,
+      end_date: 4.days.ago, labels: [label]
+    )
+  end
 
   # similar to GET /groups/:id/epics
   describe 'Get list of epics from a group' do
@@ -44,8 +51,6 @@ RSpec.describe 'Epics through GroupQuery' do
     context 'when the request is correct' do
       before do
         stub_licensed_features(epics: true)
-        epic && group.reload
-
         post_graphql(query, current_user: user)
       end
 
@@ -61,7 +66,6 @@ RSpec.describe 'Epics through GroupQuery' do
 
     context 'with multiple epics' do
       let_it_be(:user2) { create(:user) }
-      let_it_be(:epic)  { create(:epic, group: group, state: :closed, created_at: 3.days.ago, updated_at: 2.days.ago, start_date: 2.days.ago, end_date: 4.days.ago) }
       let_it_be(:epic2) { create(:epic, author: user2, group: group, title: 'foo', description: 'bar', created_at: 2.days.ago, updated_at: 3.days.ago, start_date: 3.days.ago, end_date: 3.days.ago ) }
 
       before do
@@ -164,7 +168,7 @@ RSpec.describe 'Epics through GroupQuery' do
       end
 
       context 'query performance' do
-        let!(:child_epic) { create(:epic, group: group, parent: epic2) }
+        let_it_be(:child_epic) { create(:epic, group: group, parent: create(:epic, group: group)) }
         let(:epic_node) do
           <<~NODE
             edges {
@@ -177,16 +181,12 @@ RSpec.describe 'Epics through GroupQuery' do
           NODE
         end
 
-        before do
-          group.reload
-        end
-
         it 'avoids n+1 queries when loading parent field' do
           # warm up
-          post_graphql(query({ iids: [epic.iid] }), current_user: user)
+          post_graphql(query({ iids: [child_epic.iid] }), current_user: user)
 
           control_count = ActiveRecord::QueryRecorder.new(skip_cached: false) do
-            post_graphql(query({ iids: [epic.iid] }), current_user: user)
+            post_graphql(query({ iids: [child_epic.iid] }), current_user: user)
           end.count
 
           epics_with_parent = create_list(:epic, 3, group: group) do |epic|
@@ -194,10 +194,10 @@ RSpec.describe 'Epics through GroupQuery' do
           end
           group.reload
 
-          # Added +5 to control_count due to an existing N+1 with licenses
+          # Threshold of 3 due to an existing N+1 with licenses
           expect do
             post_graphql(query({ iids: epics_with_parent.pluck(:iid) }), current_user: user)
-          end.not_to exceed_all_query_limit(control_count + 5)
+          end.not_to exceed_query_limit(control_count).with_threshold(3)
         end
       end