Lock award emojis when issuable is locked

We should not allow award emojis to be toggled when an issuable is
locked

app/policies/issuable_policy.rb

@@ -24,5 +24,6 @@ class IssuablePolicy < BasePolicy
     prevent :create_note
     prevent :admin_note
     prevent :resolve_note
+    prevent :award_emoji
   end
 end

changelogs/unreleased/29957-locked_issues_no_reaction.yml

+---
+title: Disallow awarding emojis to locked Issuables for users that are not member
+  of the project
+merge_request: 40150
+author:
+type: changed

spec/features/issues/user_interacts_with_awards_spec.rb

@@ -184,6 +184,31 @@ RSpec.describe 'User interacts with awards' do
         wait_for_requests
       end
 
+      context 'when the issue is locked' do
+        before do
+          create(:award_emoji, awardable: issue, name: '100')
+          issue.update!(discussion_locked: true)
+
+          visit project_issue_path(project, issue)
+          wait_for_requests
+        end
+
+        it 'hides the add award button' do
+          page.within('.awards') do
+            expect(page).not_to have_css('.js-add-award')
+          end
+        end
+
+        it 'does not allow toggling existing emoji' do
+          page.within('.awards') do
+            find('gl-emoji[data-name="100"]').click
+          end
+          wait_for_requests
+
+          expect(issue.reload.award_emoji.size).to eq(1)
+        end
+      end
+
       it 'adds award to issue' do
         first('.js-emoji-btn').click
 

spec/policies/issuable_policy_spec.rb

@@ -40,8 +40,8 @@ RSpec.describe IssuablePolicy, models: true do
       let(:issue) { create(:issue, project: project, discussion_locked: true) }
 
       context 'when the user is not a project member' do
-        it 'can not create a note' do
-          expect(policies).to be_disallowed(:create_note)
+        it 'can not create a note nor award emojis' do
+          expect(policies).to be_disallowed(:create_note, :award_emoji)
         end
       end
 
@@ -50,8 +50,8 @@ RSpec.describe IssuablePolicy, models: true do
           project.add_guest(user)
         end
 
-        it 'can create a note' do
-          expect(policies).to be_allowed(:create_note)
+        it 'can create a note and award emojis' do
+          expect(policies).to be_allowed(:create_note, :award_emoji)
         end
       end
     end