Users: when passing a `WP_User` instance to `wp_update_user()`, ensure that the user password is not accidentally double-hashed. This is terrifying.

Adds unit tests.

Props tbcorr, salcode.
Fixes #28435.

Built from https://develop.svn.wordpress.org/trunk@35116


git-svn-id: http://core.svn.wordpress.org/trunk@35081 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/user-functions.php

@@ -1602,7 +1602,7 @@ function wp_update_user($userdata) {
 	// Escape data pulled from DB.
 	$user = add_magic_quotes( $user );
 
-	if ( ! empty($userdata['user_pass']) ) {
+	if ( ! empty( $userdata['user_pass'] ) && $userdata['user_pass'] !== $user_obj->user_pass ) {
 		// If password is changing, hash it now
 		$plaintext_pass = $userdata['user_pass'];
 		$userdata['user_pass'] = wp_hash_password( $userdata['user_pass'] );

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.4-alpha-35115';
+$wp_version = '4.4-alpha-35116';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.