Restore ability to assign groups

app/services/quick_actions/interpret_service.rb

@@ -85,7 +85,7 @@ module QuickActions
           end
       end
 
-      failed_parse(format(_("Failed to find users for '%{params}'"), params: params)) unless users.size == args.size
+      failed_parse(format(_("Failed to find users for '%{params}'"), params: params)) if users.size < args.size
 
       users
     end

ee/spec/services/quick_actions/interpret_service_spec.rb

@@ -132,6 +132,25 @@ RSpec.describe QuickActions::InterpretService do
           expect(updates[:assignee_ids]).to match_array([user.id, user2.id])
         end
 
+        context 'assign command with a group of users' do
+          let(:group) { create(:group) }
+          let(:project) { create(:project, group: group) }
+          let(:group_members) { create_list(:user, 3) }
+          let(:command) { "/assign #{group.to_reference}" }
+
+          before do
+            group_members.each { group.add_developer(_1) }
+          end
+
+          it 'asssigns all group members' do
+            merge_request.update!(assignee_ids: [user.id])
+
+            _, updates = service.execute(command, merge_request)
+
+            expect(updates[:assignee_ids]).to match_array([user.id] + group_members.map(&:id))
+          end
+        end
+
         context 'assign command with multiple assignees' do
           it 'fetches assignee and populates assignee_ids if content contains /assign' do
             merge_request.update!(assignee_ids: [user.id])