Add "Allow merge trains" setting (CE)ce-9186-add-merge-train-setting

This commit adds the "Allow merge trains" options to the project merge
request settings page.  This option is only visible in EE.  This option
is also hidden behind the "merge_trains" feature flag.

2 files changed, 20 insertions, 0 deletions

diff --git a/app/assets/javascripts/pages/projects/edit/index.js b/app/assets/javascripts/pages/projects/edit/index.js
index 92ed6a652d7..ecf38d87aac 100644
--- a/app/assets/javascripts/pages/projects/edit/index.js
+++ b/app/assets/javascripts/pages/projects/edit/index.js
@@ -7,6 +7,7 @@ import dirtySubmitFactory from '~/dirty_submit/dirty_submit_factory';
 import initAvatarPicker from '~/avatar_picker';
 import initProjectLoadingSpinner from '../shared/save_project_loader';
 import initProjectPermissionsSettings from '../shared/permissions';
+import initMergeOptionsCheckboxSync from './init_merge_options_checkbox_sync';
 
 document.addEventListener('DOMContentLoaded', () => {
   initAvatarPicker();
@@ -17,6 +18,7 @@ document.addEventListener('DOMContentLoaded', () => {
   initProjectLoadingSpinner();
   initProjectPermissionsSettings();
   setupProjectEdit();
+  initMergeOptionsCheckboxSync();
 
   dirtySubmitFactory(
     document.querySelectorAll(
diff --git a/app/assets/javascripts/pages/projects/edit/init_merge_options_checkbox_sync.js b/app/assets/javascripts/pages/projects/edit/init_merge_options_checkbox_sync.js
new file mode 100644
index 00000000000..19fbf10bbf6
--- /dev/null
+++ b/app/assets/javascripts/pages/projects/edit/init_merge_options_checkbox_sync.js
@@ -0,0 +1,18 @@
+export default () => {
+  const mergePipelinesCheckbox = document.querySelector('.js-merge-options-merge-pipelines');
+  const mergeTrainsCheckbox = document.querySelector('.js-merge-options-merge-trains');
+
+  if (mergePipelinesCheckbox && mergeTrainsCheckbox) {
+    mergePipelinesCheckbox.addEventListener('change', event => {
+      if (!event.target.checked && mergeTrainsCheckbox.checked) {
+        mergeTrainsCheckbox.click();
+      }
+    });
+
+    mergeTrainsCheckbox.addEventListener('change', event => {
+      if (event.target.checked && !mergePipelinesCheckbox.checked) {
+        mergePipelinesCheckbox.click();
+      }
+    });
+  }
+};