From 7a2027652b8f443a9247dbb85ef0e988bbddb3ab Mon Sep 17 00:00:00 2001
From: Valeri Karpov <val@karpov.io>
Date: Mon, 7 Oct 2019 14:59:34 -0400
Subject: [PATCH] fix(schema): handle `required: null` and `required:
 undefined` as `required: false`

Fix #8219
---
 lib/schematype.js | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/lib/schematype.js b/lib/schematype.js
index 2cd0caf0858..fbce0e0dce6 100644
--- a/lib/schematype.js
+++ b/lib/schematype.js
@@ -798,6 +798,17 @@ const handleIsAsync = util.deprecate(function handleIsAsync() {},
 
 SchemaType.prototype.required = function(required, message) {
   let customOptions = {};
+
+  if (arguments.length > 0 && required == null) {
+    this.validators = this.validators.filter(function(v) {
+      return v.validator !== this.requiredValidator;
+    }, this);
+
+    this.isRequired = false;
+    delete this.originalRequiredValue;
+    return this;
+  }
+
   if (typeof required === 'object') {
     customOptions = required;
     message = customOptions.message || message;