throw error after all saves are done

lib/model.js

@@ -2878,24 +2878,34 @@ Model.create = async function create(doc, options) {
     }
     return res;
   } else {
+    let firstError = null;
     res = await Promise.all(args.map(async doc => {
       const Model = this.discriminators && doc[discriminatorKey] != null ?
         this.discriminators[doc[discriminatorKey]] || getDiscriminatorByValue(this.discriminators, doc[discriminatorKey]) :
         this;
       if (Model == null) {
         throw new MongooseError(`Discriminator "${doc[discriminatorKey]}" not ` +
-          `found for model "${this.modelName}"`);
+            `found for model "${this.modelName}"`);
       }
-      let toSave = doc;
+      try {
+        let toSave = doc;
 
-      if (!(toSave instanceof Model)) {
-        toSave = new Model(toSave);
-      }
+        if (!(toSave instanceof Model)) {
+          toSave = new Model(toSave);
+        }
 
-      await toSave.$save(options);
+        await toSave.$save(options);
 
-      return toSave;
+        return toSave;
+      } catch (err) {
+        if (!firstError) {
+          firstError = err;
+        }
+      }
     }));
+    if (firstError) {
+      throw firstError;
+    }
   }
 
 

test/model.create.test.js

@@ -197,6 +197,20 @@ describe('model', function() {
         const docs = await Test.find();
         assert.equal(docs.length, 5);
       });
+      it('should throw an error only after all the documents have finished saving gh-4628', async function() {
+        const testSchema = new Schema({ name: { type: String, unique: true } });
+
+
+        const Test = db.model('gh4628Test', testSchema);
+        await Test.init();
+        const data = [];
+        for (let i = 0; i < 11; i++) {
+          data.push({ name: 'Test' + Math.abs(i - 4) });
+        }
+        await Test.create(data, { ordered: false }).catch(err => err);
+        const docs = await Test.find();
+        assert.equal(docs.length, 7); // docs 1,2,3,4 should not go through 11-4 == 7
+      });
     });
   });
 });