Add includeSubepics argument to issue filters in GraphQL

Filtering issues already allowed epicId. If includeSubepics
is true, issues associated with the specified epicId or any
of its children will be returned.

Changelog: added
EE: true

doc/api/graphql/reference/index.md

@@ -10305,6 +10305,7 @@ four standard [pagination arguments](#connection-pagination-arguments):
 | <a id="groupissuesepicid"></a>`epicId` | [`String`](#string) | ID of an epic associated with the issues, "none" and "any" values are supported. |
 | <a id="groupissuesiid"></a>`iid` | [`String`](#string) | IID of the issue. For example, "1". |
 | <a id="groupissuesiids"></a>`iids` | [`[String!]`](#string) | List of IIDs of issues. For example, `["1", "2"]`. |
+| <a id="groupissuesincludesubepics"></a>`includeSubepics` | [`Boolean`](#boolean) | Whether to include subepics when filtering issues by epicId. |
 | <a id="groupissuesincludesubgroups"></a>`includeSubgroups` | [`Boolean`](#boolean) | Include issues belonging to subgroups. |
 | <a id="groupissuesiterationid"></a>`iterationId` | [`[ID]`](#id) | List of iteration Global IDs applied to the issue. |
 | <a id="groupissuesiterationwildcardid"></a>`iterationWildcardId` | [`IterationWildcardId`](#iterationwildcardid) | Filter by iteration ID wildcard. |
@@ -12740,6 +12741,7 @@ Returns [`Issue`](#issue).
 | <a id="projectissueepicid"></a>`epicId` | [`String`](#string) | ID of an epic associated with the issues, "none" and "any" values are supported. |
 | <a id="projectissueiid"></a>`iid` | [`String`](#string) | IID of the issue. For example, "1". |
 | <a id="projectissueiids"></a>`iids` | [`[String!]`](#string) | List of IIDs of issues. For example, `["1", "2"]`. |
+| <a id="projectissueincludesubepics"></a>`includeSubepics` | [`Boolean`](#boolean) | Whether to include subepics when filtering issues by epicId. |
 | <a id="projectissueiterationid"></a>`iterationId` | [`[ID]`](#id) | List of iteration Global IDs applied to the issue. |
 | <a id="projectissueiterationwildcardid"></a>`iterationWildcardId` | [`IterationWildcardId`](#iterationwildcardid) | Filter by iteration ID wildcard. |
 | <a id="projectissuelabelname"></a>`labelName` | [`[String]`](#string) | Labels applied to this issue. |
@@ -12810,6 +12812,7 @@ four standard [pagination arguments](#connection-pagination-arguments):
 | <a id="projectissuesepicid"></a>`epicId` | [`String`](#string) | ID of an epic associated with the issues, "none" and "any" values are supported. |
 | <a id="projectissuesiid"></a>`iid` | [`String`](#string) | IID of the issue. For example, "1". |
 | <a id="projectissuesiids"></a>`iids` | [`[String!]`](#string) | List of IIDs of issues. For example, `["1", "2"]`. |
+| <a id="projectissuesincludesubepics"></a>`includeSubepics` | [`Boolean`](#boolean) | Whether to include subepics when filtering issues by epicId. |
 | <a id="projectissuesiterationid"></a>`iterationId` | [`[ID]`](#id) | List of iteration Global IDs applied to the issue. |
 | <a id="projectissuesiterationwildcardid"></a>`iterationWildcardId` | [`IterationWildcardId`](#iterationwildcardid) | Filter by iteration ID wildcard. |
 | <a id="projectissueslabelname"></a>`labelName` | [`[String]`](#string) | Labels applied to this issue. |

ee/app/graphql/ee/resolvers/issues_resolver.rb

@@ -16,6 +16,9 @@ module EE
         argument :epic_id, GraphQL::Types::String,
                  required: false,
                  description: 'ID of an epic associated with the issues, "none" and "any" values are supported.'
+        argument :include_subepics, GraphQL::Types::Boolean,
+                 required: false,
+                 description: 'Whether to include subepics when filtering issues by epicId.'
         argument :weight, GraphQL::Types::String,
                  required: false,
                  description: 'Weight applied to the issue, "none" and "any" values are supported.'

ee/spec/graphql/ee/resolvers/issues_resolver_spec.rb

@@ -12,7 +12,7 @@ RSpec.describe Resolvers::IssuesResolver do
   context "with a project" do
     describe '#resolve' do
       let_it_be(:epic1) { create :epic, group: group }
-      let_it_be(:epic2) { create :epic, group: group }
+      let_it_be(:epic2) { create :epic, group: group, parent: epic1 }
 
       let_it_be(:iteration1) { create(:iteration, group: group, start_date: 2.weeks.ago, due_date: 1.week.ago) }
       let_it_be(:current_iteration) { create(:iteration, group: group, start_date: Date.yesterday, due_date: 1.day.from_now) }
@@ -134,6 +134,10 @@ RSpec.describe Resolvers::IssuesResolver do
         it 'returns issues with any epic when epic_id is specific' do
           expect(resolve_issues(epic_id: epic1.id.to_s)).to contain_exactly(issue1)
         end
+
+        it 'includes issues associated with subepics when specified' do
+          expect(resolve_issues(epic_id: epic1.id.to_s, include_subepics: true)).to contain_exactly(issue1, issue2)
+        end
       end
 
       describe 'filter by weight' do