fix(model): only warn on custom _id index if index only has _id key

Fix #6650
Automattic · Jul 4, 2018 · ff08b9c · ff08b9c
1 parent 2decc5b
commit ff08b9c
Showing 1 changed file with 4 additions and 3 deletions.
diff --git a/lib/model.js b/lib/model.js
@@ -1205,11 +1205,12 @@ function _ensureIndexes(model, options, callback) {
   };
 
   for (const index of indexes) {
-    if (index[0]._id != null) {
-      const err = new Error('Cannot specify a custom index on `_id`, ' +
+    const keys = Object.keys(index[0]);
+    if (keys.length === 1 && keys[0] === '_id') {
+      console.warn('mongoose: Cannot specify a custom index on `_id` for ' +
+        'model name "' + model.modelName + '", ' +
         'MongoDB does not allow overwriting the default `_id` index. See ' +
         'http://bit.ly/mongodb-id-index');
-      return done(err);
     }
   }