Add `issuableDatesUpdated` subscription to GraphQL API

Changelog: added

Updating start or due date in an Issue or WorkItem will now
trigger a relatime update so you can fetch the updated dates

app/graphql/graphql_triggers.rb

@@ -16,4 +16,8 @@ def self.issuable_title_updated(issuable)
   def self.issuable_labels_updated(issuable)
     GitlabSchema.subscriptions.trigger('issuableLabelsUpdated', { issuable_id: issuable.to_gid }, issuable)
   end
+
+  def self.issuable_dates_updated(issuable)
+    GitlabSchema.subscriptions.trigger('issuableDatesUpdated', { issuable_id: issuable.to_gid }, issuable)
+  end
 end

app/graphql/types/subscription_type.rb

@@ -15,5 +15,8 @@ class SubscriptionType < ::Types::BaseObject
 
     field :issuable_labels_updated, subscription: Subscriptions::IssuableUpdated, null: true,
                                     description: 'Triggered when the labels of an issuable are updated.'
+
+    field :issuable_dates_updated, subscription: Subscriptions::IssuableUpdated, null: true,
+                                   description: 'Triggered when the due date or start date of an issuable is updated.'
   end
 end

app/services/issues/update_service.rb

@@ -70,6 +70,7 @@ def handle_changes(issue, options)
       handle_severity_change(issue, old_severity)
       handle_escalation_status_change(issue)
       handle_issue_type_change(issue)
+      handle_date_changes(issue)
     end
 
     def handle_assignee_changes(issue, old_assignees)
@@ -116,6 +117,12 @@ def move_issue_to_new_project(issue)
 
     attr_reader :spam_params
 
+    def handle_date_changes(issue)
+      return unless issue.previous_changes.slice('due_date', 'start_date').any?
+
+      GraphqlTriggers.issuable_dates_updated(issue)
+    end
+
     def clone_issue(issue)
       target_project = params.delete(:target_clone_project)
       with_notes = params.delete(:clone_with_notes)

spec/graphql/graphql_triggers_spec.rb

@@ -47,4 +47,18 @@
       GraphqlTriggers.issuable_labels_updated(issue)
     end
   end
+
+  describe '.issuable_dates_updated' do
+    it 'triggers the issuableDatesUpdated subscription' do
+      work_item = create(:work_item)
+
+      expect(GitlabSchema.subscriptions).to receive(:trigger).with(
+        'issuableDatesUpdated',
+        { issuable_id: work_item.to_gid },
+        work_item
+      ).and_call_original
+
+      GraphqlTriggers.issuable_dates_updated(work_item)
+    end
+  end
 end

spec/graphql/types/subscription_type_spec.rb

@@ -9,6 +9,7 @@
       issue_crm_contacts_updated
       issuable_title_updated
       issuable_labels_updated
+      issuable_dates_updated
     ]
 
     expect(described_class).to have_graphql_fields(*expected_fields).only

spec/services/issues/update_service_spec.rb

@@ -988,6 +988,52 @@ def update_issue(opts)
       end
     end
 
+    context 'updating dates' do
+      subject(:result) { described_class.new(project: project, current_user: user, params: params).execute(issue) }
+
+      let(:updated_date) { 1.week.from_now.to_date }
+
+      shared_examples 'issue update service that triggers date updates' do
+        it 'triggers graphql date updated subscription' do
+          expect(GraphqlTriggers).to receive(:issuable_dates_updated).with(issue).and_call_original
+
+          result
+        end
+      end
+
+      shared_examples 'issue update service that does not trigger date updates' do
+        it 'does not trigger date updated subscriptions' do
+          expect(GraphqlTriggers).not_to receive(:issuable_dates_updated)
+
+          result
+        end
+      end
+
+      context 'when due_date is updated' do
+        let(:params) { { due_date: updated_date } }
+
+        it_behaves_like 'issue update service that triggers date updates'
+      end
+
+      context 'when start_date is updated' do
+        let(:params) { { start_date: updated_date } }
+
+        it_behaves_like 'issue update service that triggers date updates'
+      end
+
+      context 'when no date is updated' do
+        let(:params) { { title: 'should not trigger date updates' } }
+
+        it_behaves_like 'issue update service that does not trigger date updates'
+      end
+
+      context 'when update is not successful but date is provided' do
+        let(:params) { { title: '', due_date: updated_date } }
+
+        it_behaves_like 'issue update service that does not trigger date updates'
+      end
+    end
+
     context 'updating asssignee_id' do
       it 'does not update assignee when assignee_id is invalid' do
         update_issue(assignee_ids: [-1])

spec/services/work_items/update_service_spec.rb

@@ -36,6 +36,14 @@
       stub_spam_services
     end
 
+    shared_examples 'update service that triggers graphql dates updated subscription' do
+      it 'triggers graphql subscription issueableDatesUpdated' do
+        expect(GraphqlTriggers).to receive(:issuable_dates_updated).with(work_item).and_call_original
+
+        update_work_item
+      end
+    end
+
     context 'when title is changed' do
       let(:opts) { { title: 'changed' } }
 
@@ -187,6 +195,32 @@
         end
       end
 
+      context 'for start and due date widget' do
+        let(:updated_date) { 1.week.from_now.to_date }
+
+        context 'when due_date is updated' do
+          let(:widget_params) { { start_and_due_date_widget: { due_date: updated_date } } }
+
+          it_behaves_like 'update service that triggers graphql dates updated subscription'
+        end
+
+        context 'when start_date is updated' do
+          let(:widget_params) { { start_and_due_date_widget: { start_date: updated_date } } }
+
+          it_behaves_like 'update service that triggers graphql dates updated subscription'
+        end
+
+        context 'when no date param is updated' do
+          let(:opts) { { title: 'should not trigger' } }
+
+          it 'does not trigger date updated subscription' do
+            expect(GraphqlTriggers).not_to receive(:issuable_dates_updated)
+
+            update_work_item
+          end
+        end
+      end
+
       context 'for the hierarchy widget' do
         let(:opts) { { title: 'changed' } }
         let_it_be(:child_work_item) { create(:work_item, :task, project: project) }