fix(model): add version to save() filter if pushing to a nested array

Fix #11108

Author: vkarpov15

lib/model.js

@@ -589,18 +589,18 @@ function operand(self, where, delta, data, val, op) {
   // editing the correct array element.
   // only increment the version if an array position changes.
   // modifying elements of an array is ok if position does not change.
-  if (op === '$push' || op === '$addToSet' || op === '$pullAll' || op === '$pull') {
+  if (/\.\d+\.|\.\d+$/.test(data.path)) {
+    // now handling $set, $unset
+    // subpath of array
+    self.$__.version = VERSION_WHERE;
+  } else if (op === '$push' || op === '$addToSet' || op === '$pullAll' || op === '$pull') {
     self.$__.version = VERSION_INC;
   } else if (/^\$p/.test(op)) {
     // potentially changing array positions
     increment.call(self);
   } else if (Array.isArray(val)) {
     // $set an array
     increment.call(self);
-  } else if (/\.\d+\.|\.\d+$/.test(data.path)) {
-    // now handling $set, $unset
-    // subpath of array
-    self.$__.version = VERSION_WHERE;
   }
 }
 

test/versioning.test.js

@@ -651,4 +651,23 @@ describe('versioning', function() {
     assert.ok(err);
     assert.equal(err.name, 'VersionError');
   });
+
+  it('adds version to filter if pushing to a nested array (gh-11108)', async function() {
+    const Test = db.model('Test', Schema({ comments: [{ likedBy: [String] }] }));
+    const entry = await Test.create({
+      comments: [{ likedBy: ['Friends', 'Family'] }]
+    });
+
+    const post1 = await Test.findById(entry._id).exec();
+    const post2 = await Test.findById(entry._id).exec();
+
+    post1.comments = [{ likedBy: ['test'] }];
+    await post1.save();
+
+    const comment = post2.comments[0];
+    comment.likedBy.push('Some User');
+
+    const err = await post2.save().then(() => null, err => err);
+    assert.equal(err.name, 'VersionError');
+  });
 });