Create feature flag for unsigned alert in IDE

This allows local instance admins to toggle
this particular behavior off while we work on
the [holistic solution][1].

[1]: https://gitlab.com/gitlab-org/gitlab/-/issues/19185

app/assets/javascripts/ide/stores/getters.js

@@ -208,7 +208,7 @@ export const canPushCodeStatus = (state, getters) => {
     PUSH_RULE_REJECT_UNSIGNED_COMMITS
   ];
 
-  if (rejectUnsignedCommits) {
+  if (window.gon?.features?.rejectUnsignedCommitsByGitlab && rejectUnsignedCommits) {
     return {
       isAllowed: false,
       message: MSG_CANNOT_PUSH_UNSIGNED,

app/controllers/ide_controller.rb

@@ -10,6 +10,7 @@ class IdeController < ApplicationController
   before_action do
     push_frontend_feature_flag(:build_service_proxy)
     push_frontend_feature_flag(:schema_linting)
+    push_frontend_feature_flag(:reject_unsigned_commits_by_gitlab, default_enabled: :yaml)
     define_index_vars
   end
 

config/feature_flags/development/reject_unsigned_commits_by_gitlab.yml

+---
+name: reject_unsigned_commits_by_gitlab
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/58453
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/326775
+milestone: '13.11'
+type: development
+group: group::editor
+default_enabled: true

ee/spec/features/ide/user_opens_ide_spec.rb

@@ -3,6 +3,7 @@
 require 'spec_helper'
 
 RSpec.describe 'EE user opens IDE', :js do
+  using RSpec::Parameterized::TableSyntax
   include WebIdeSpecHelpers
 
   let_it_be(:unsigned_commits_warning) { 'This project does not accept unsigned commits.' }
@@ -16,25 +17,39 @@ RSpec.describe 'EE user opens IDE', :js do
     sign_in(user)
   end
 
-  context 'default' do
-    before do
+  shared_examples 'no warning' do
+    it 'does not show warning' do
       ide_visit(project)
-    end
 
-    it 'does not show warning' do
       expect(page).not_to have_text(unsigned_commits_warning)
     end
   end
 
+  shared_examples 'has warning' do
+    it 'shows warning' do
+      ide_visit(project)
+
+      expect(page).to have_text(unsigned_commits_warning)
+    end
+  end
+
+  context 'no push rules' do
+    it_behaves_like 'no warning'
+  end
+
   context 'when has reject_unsigned_commit push rule' do
     before do
       create(:push_rule, project: project, reject_unsigned_commits: true)
-
-      ide_visit(project)
     end
 
-    it 'shows warning' do
-      expect(page).to have_text(unsigned_commits_warning)
+    it_behaves_like 'has warning'
+
+    context 'and feature flag off' do
+      before do
+        stub_feature_flags(reject_unsigned_commits_by_gitlab: false)
+      end
+
+      it_behaves_like 'no warning'
     end
   end
 end

spec/frontend/ide/stores/getters_spec.js

@@ -24,12 +24,22 @@ const TEST_FORK_PATH = '/test/fork/path';
 describe('IDE store getters', () => {
   let localState;
   let localStore;
+  let origGon;
 
   beforeEach(() => {
+    origGon = window.gon;
+
+    // Feature flag is defaulted to on in prod
+    window.gon = { features: { rejectUnsignedCommitsByGitlab: true } };
+
     localStore = createStore();
     localState = localStore.state;
   });
 
+  afterEach(() => {
+    window.gon = origGon;
+  });
+
   describe('activeFile', () => {
     it('returns the current active file', () => {
       localState.openFiles.push(file());
@@ -500,9 +510,25 @@ describe('IDE store getters', () => {
           },
         },
       ],
+      [
+        'when can push code, but cannot push unsigned commits, with reject_unsigned_commits_by_gitlab feature off',
+        {
+          input: {
+            pushCode: true,
+            rejectUnsignedCommits: true,
+            features: { rejectUnsignedCommitsByGitlab: false },
+          },
+          output: {
+            isAllowed: true,
+            message: '',
+            messageShort: '',
+          },
+        },
+      ],
     ])('%s', (testName, { input, output }) => {
-      const { forkInfo, rejectUnsignedCommits, pushCode } = input;
+      const { forkInfo, rejectUnsignedCommits, pushCode, features = {} } = input;
 
+      Object.assign(window.gon.features, features);
       localState.links = { forkInfo };
       localState.projects[TEST_PROJECT_ID] = {
         pushRules: {