Fix duplicate item in protected branch/tag dropdown

Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/42157
Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/41989

1 files changed, 11 insertions, 1 deletions

diff --git a/app/assets/javascripts/create_item_dropdown.js b/app/assets/javascripts/create_item_dropdown.js
index c3eceb285f5..488db023ee7 100644
--- a/app/assets/javascripts/create_item_dropdown.js
+++ b/app/assets/javascripts/create_item_dropdown.js
@@ -65,7 +65,17 @@ export default class CreateItemDropdown {
 
   getData(term, callback) {
     this.getDataOption(term, (data = []) => {
-      callback(data.concat(this.selectedItem || []));
+      // Ensure the selected item isn't already in the data to avoid duplicates
+      const alreadyHasSelectedItem = this.selectedItem && data.some(item =>
+        item.id === this.selectedItem.id,
+      );
+
+      let uniqueData = data;
+      if (!alreadyHasSelectedItem) {
+        uniqueData = data.concat(this.selectedItem || []);
+      }
+
+      callback(uniqueData);
     });
   }