fix(update): handle subdocument pre('validate') errors in update validation

Fix #7187

Author: vkarpov15

lib/document.js

@@ -1932,9 +1932,11 @@ Document.prototype.validate = function(options, callback) {
     options = null;
   }
 
-  return utils.promiseOrCallback(callback, cb => this.$__validate(options, function(error) {
-    cb(error);
-  }), this.constructor.events);
+  return utils.promiseOrCallback(callback, cb => {
+    this.$__validate(options, function(error) {
+      cb(error);
+    });
+  }, this.constructor.events);
 };
 
 /*!

lib/helpers/updateValidators.js

@@ -136,6 +136,9 @@ module.exports = function(query, schema, castedDoc, options, callback) {
                     _err.path = updates[i] + '.' + key;
                     validationErrors.push(_err);
                   }
+                } else {
+                  err.path = updates[i];
+                  validationErrors.push(err);
                 }
               }
               callback(null);