Support sort RELATIVE_POSITION_ASC for issues

in GraphQL

app/graphql/types/issue_sort_enum.rb

@@ -8,6 +8,7 @@ module Types
 
     value 'DUE_DATE_ASC', 'Due date by ascending order', value: 'due_date_asc'
     value 'DUE_DATE_DESC', 'Due date by descending order', value: 'due_date_desc'
+    value 'RELATIVE_POSITION_ASC', 'Relative position by ascending order', value: 'relative_position_asc'
   end
   # rubocop: enable Graphql/AuthorizeTypes
 end

changelogs/unreleased/29713-graphql-add-issue-relative-position-sort-2.yml

+---
+title: 'Graphql query for issues can now be sorted by relative_position'
+merge_request: 19713
+author:
+type: added

doc/api/graphql/reference/gitlab_schema.graphql

@@ -2772,6 +2772,11 @@ enum IssueSort {
   """
   DUE_DATE_DESC
 
+  """
+  Relative position by ascending order
+  """
+  RELATIVE_POSITION_ASC
+
   """
   Created at ascending order
   """

doc/api/graphql/reference/gitlab_schema.json

@@ -13631,6 +13631,12 @@
               "description": "Due date by descending order",
               "isDeprecated": false,
               "deprecationReason": null
+            },
+            {
+              "name": "RELATIVE_POSITION_ASC",
+              "description": "Relative position by ascending order",
+              "isDeprecated": false,
+              "deprecationReason": null
             }
           ],
           "possibleTypes": null

spec/graphql/resolvers/issues_resolver_spec.rb

@@ -99,6 +99,19 @@ describe Resolvers::IssuesResolver do
             expect(resolve_issues(sort: :due_date_desc)).to eq [due_issue1, due_issue3, due_issue4, due_issue2]
           end
         end
+
+        context 'when sorting by relative position' do
+          let(:project) { create(:project) }
+
+          let!(:relative_issue1) { create(:issue, project: project, relative_position: 2000) }
+          let!(:relative_issue2) { create(:issue, project: project, relative_position: nil) }
+          let!(:relative_issue3) { create(:issue, project: project, relative_position: 1000) }
+          let!(:relative_issue4) { create(:issue, project: project, relative_position: nil) }
+
+          it 'sorts issues ascending' do
+            expect(resolve_issues(sort: :relative_position_asc)).to eq [relative_issue3, relative_issue1, relative_issue4, relative_issue2]
+          end
+        end
       end
 
       it 'returns issues user can see' do

spec/graphql/types/issue_sort_enum_spec.rb

@@ -8,6 +8,6 @@ describe GitlabSchema.types['IssueSort'] do
   it_behaves_like 'common sort values'
 
   it 'exposes all the existing issue sort values' do
-    expect(described_class.values.keys).to include(*%w[DUE_DATE_ASC DUE_DATE_DESC])
+    expect(described_class.values.keys).to include(*%w[DUE_DATE_ASC DUE_DATE_DESC RELATIVE_POSITION_ASC])
   end
 end

spec/requests/api/graphql/project/issues_spec.rb

@@ -200,6 +200,52 @@ describe 'getting an issue list for a project' do
         end
       end
     end
+
+    context 'when sorting by relative position' do
+      let(:sort_project) { create(:project, :public) }
+
+      let!(:relative_issue1) { create(:issue, project: sort_project, relative_position: 2000) }
+      let!(:relative_issue2) { create(:issue, project: sort_project, relative_position: nil) }
+      let!(:relative_issue3) { create(:issue, project: sort_project, relative_position: 1000) }
+      let!(:relative_issue4) { create(:issue, project: sort_project, relative_position: nil) }
+      let!(:relative_issue5) { create(:issue, project: sort_project, relative_position: 500) }
+
+      let(:params) { 'sort: RELATIVE_POSITION_ASC' }
+
+      def query(issue_params = params)
+        graphql_query_for(
+          'project',
+          { 'fullPath' => sort_project.full_path },
+          "issues(#{issue_params}) { pageInfo { endCursor} edges { node { iid dueDate } } }"
+        )
+      end
+
+      before do
+        post_graphql(query, current_user: current_user)
+      end
+
+      it_behaves_like 'a working graphql query'
+
+      context 'when ascending' do
+        it 'sorts issues' do
+          expect(grab_iids).to eq [relative_issue5.iid, relative_issue3.iid, relative_issue1.iid, relative_issue4.iid, relative_issue2.iid]
+        end
+
+        context 'when paginating' do
+          let(:params) { 'sort: RELATIVE_POSITION_ASC, first: 2' }
+
+          it 'sorts issues' do
+            expect(grab_iids).to eq [relative_issue5.iid, relative_issue3.iid]
+
+            cursored_query = query("sort: RELATIVE_POSITION_ASC, after: \"#{end_cursor}\"")
+            post_graphql(cursored_query, current_user: current_user)
+            response_data = JSON.parse(response.body)['data']['project']['issues']['edges']
+
+            expect(grab_iids(response_data)).to eq [relative_issue1.iid, relative_issue4.iid, relative_issue2.iid]
+          end
+        end
+      end
+    end
   end
 
   def grab_iids(data = issues_data)