Classes that have __set() also need __isset() and __unset().

See #27881, #22234.


git-svn-id: https://develop.svn.wordpress.org/trunk@28524 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-error.php

@@ -87,6 +87,28 @@ class WP_Error {
 		return $this->$name = $value;
 	}
 
+	/**
+	 * Make private properties checkable for backwards compatibility
+	 *
+	 * @since 4.0.0
+	 * @param string $name
+	 * @return mixed
+	 */
+	public function __isset( $name ) {
+		return isset( $this->$name );
+	}
+
+	/**
+	 * Make private properties unsetable for backwards compatibility
+	 *
+	 * @since 4.0.0
+	 * @param string $name
+	 * @return mixed
+	 */
+	public function __unset( $name ) {
+		unset( $this->$name );
+	}
+
 	/**
 	 * Retrieve all error codes.
 	 *