fix(schema): support setting _id option to false after instantiat…

…ing schema

Fix #9390

lib/schema.js

@@ -1656,6 +1656,16 @@ Schema.prototype.set = function(key, value, _tags) {
       this.options[key] = value;
       this._userProvidedOptions[key] = this.options[key];
       break;
+    case '_id':
+      this.options[key] = value;
+      this._userProvidedOptions[key] = this.options[key];
+
+      if (value && !this.paths['_id']) {
+        addAutoId(this);
+      } else if (!value && this.paths['_id'] != null && this.paths['_id'].auto) {
+        this.remove('_id');
+      }
+      break;
     default:
       this.options[key] = value;
       this._userProvidedOptions[key] = this.options[key];