Only allow multiple reviewers in paid tiers

Issue: https://gitlab.com/gitlab-org/gitlab/-/issues/246905

app/assets/javascripts/sidebar/components/reviewers/uncollapsed_reviewer_list.vue

@@ -75,9 +75,9 @@ export default {
     :root-path="rootPath"
     :issuable-type="issuableType"
   >
-    <div class="ml-2">
-      <span class="author"> {{ user.name }} </span>
-      <span class="username"> {{ username }} </span>
+    <div class="gl-ml-3 gl-line-height-normal">
+      <div class="author">{{ user.name }}</div>
+      <div class="username">{{ username }}</div>
     </div>
   </reviewer-avatar-link>
   <div v-else>

app/helpers/form_helper.rb

@@ -56,7 +56,7 @@ module FormHelper
   end
 
   def reviewers_dropdown_options(issuable_type)
-    {
+    dropdown_data = {
       toggle_class: 'js-reviewer-search js-multiselect js-save-user-data',
       title: 'Request review from',
       filter: true,
@@ -69,13 +69,20 @@ module FormHelper
         project_id: (@target_project || @project)&.id,
         field_name: "#{issuable_type}[reviewer_ids][]",
         default_label: 'Unassigned',
-        'dropdown-header': 'Reviewer(s)',
+        'max-select': 1,
+        'dropdown-header': 'Reviewer',
         multi_select: true,
         'input-meta': 'name',
         'always-show-selectbox': true,
         current_user_info: UserSerializer.new.represent(current_user)
       }
     }
+
+    if merge_request_supports_multiple_reviewers?
+      dropdown_data = multiple_reviewers_dropdown_options(dropdown_data)
+    end
+
+    dropdown_data
   end
 
   # Overwritten
@@ -88,6 +95,11 @@ module FormHelper
     false
   end
 
+  # Overwritten
+  def merge_request_supports_multiple_reviewers?
+    false
+  end
+
   private
 
   def multiple_assignees_dropdown_options(options)
@@ -99,6 +111,16 @@ module FormHelper
 
     new_options
   end
+
+  def multiple_reviewers_dropdown_options(options)
+    new_options = options.dup
+
+    new_options[:title] = _('Select reviewer(s)')
+    new_options[:data][:'dropdown-header'] = _('Reviewer(s)')
+    new_options[:data].delete(:'max-select')
+
+    new_options
+  end
 end
 
 FormHelper.prepend_if_ee('::EE::FormHelper')

ee/app/helpers/ee/form_helper.rb

@@ -9,5 +9,9 @@ module EE
     def merge_request_supports_multiple_assignees?
       @merge_request&.allows_multiple_assignees?
     end
+
+    def merge_request_supports_multiple_reviewers?
+      @merge_request&.allows_multiple_reviewers?
+    end
   end
 end

ee/changelogs/unreleased/246905-only-allow-multiple-reviewers-in-paid-tiers.yml

+---
+title: Only allow multiple reviewers in paid tiers
+merge_request: 44097
+author:
+type: changed

ee/spec/features/merge_request/user_creates_multiple_reviewers_mr_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'Merge request > User creates MR with multiple reviewers' do
+  include_context 'merge request create context'
+
+  before do
+    stub_licensed_features(multiple_merge_request_reviewers: true)
+  end
+
+  it_behaves_like 'multiple reviewers merge request', 'creates', 'Submit merge request'
+end

ee/spec/features/merge_request/user_edits_multiple_reviewers_mr_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'Merge request > User edits MR with multiple reviewers' do
+  include_context 'merge request edit context'
+
+  before do
+    stub_licensed_features(multiple_merge_request_reviewers: true)
+  end
+
+  it_behaves_like 'multiple reviewers merge request', 'updates', 'Save changes'
+end

locale/gitlab.pot

@@ -23168,6 +23168,9 @@ msgstr ""
 msgid "Select required regulatory standard"
 msgstr ""
 
+msgid "Select reviewer(s)"
+msgstr ""
+
 msgid "Select shards to replicate"
 msgstr ""
 

spec/support/shared_examples/features/multiple_reviewers_mr_shared_examples.rb

+# frozen_string_literal: true
+
+RSpec.shared_examples 'multiple reviewers merge request' do |action, save_button_title|
+  it "#{action} a MR with multiple reviewers", :js do
+    find('.js-reviewer-search').click
+    page.within '.dropdown-menu-user' do
+      click_link user.name
+      click_link user2.name
+    end
+
+    # Extra click needed in order to toggle the dropdown
+    find('.js-reviewer-search').click
+
+    expect(all('input[name="merge_request[reviewer_ids][]"]', visible: false).map(&:value))
+      .to match_array([user.id.to_s, user2.id.to_s])
+
+    page.within '.js-reviewer-search' do
+      expect(page).to have_content "#{user2.name} + 1 more"
+    end
+
+    click_button save_button_title
+
+    page.within '.issuable-sidebar' do
+      page.within '.reviewer' do
+        expect(page).to have_content '2 Reviewers'
+
+        click_link 'Edit'
+
+        expect(page).to have_content user.name
+        expect(page).to have_content user2.name
+      end
+    end
+
+    page.within '.dropdown-menu-user' do
+      click_link user.name
+    end
+
+    page.within '.issuable-sidebar' do
+      page.within '.reviewer' do
+        # Closing dropdown to persist
+        click_link 'Edit'
+
+        expect(page).to have_content user2.name
+      end
+    end
+  end
+end