Functions.php reverted to new one

You should not change anything in files inside wp-admin and wp-includes folder. All these files gets overwritten when WordPress is updated. The correct functions.php file is in your theme folder. full path to that file: wp-content/themes/YOUR-THEME-FOLDER/functions.php

Why when I instantiate wp_error in a validation method my user registration method stops working?

It seems you need to use $errors = new \WP_Error(); in your code, since WP_Error isn’t part of your namespace. I ran a quick test on my machine, using wp-cli commands: Using new WP_Error(): % wp eval ‘namespace PJ\NS\Test; $x = new WP_Error(); var_dump( $x );’ Fatal error: Uncaught Error: Class ‘PJ\NS\Test\WP_Error’ not found in … Read more

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)