Change Wordpress User Login & Registration Error messages to avoid User Enumeration

gistfile1.txt

<?php

add_filter('woocommerce_process_registration_errors', 'clario_override_registration_error_messages', 999,4);

// woocommerce_process_registration_errors fires before the username and email already exist check (so in a sense it is too early),
// however once these checks happen, the code immediate throws an error and returns so no later hooks are available to handle 
// changing the error messages
function clario_override_registration_error_messages($errors,$username, $password, $email) {

    if ( username_exists( $username ) ) {
        $errors->add( 'username_exists', __( 'An account with this email or username already exists. Please try another or reset your password.', 'woocommerce' ) );
    }

    if ( email_exists( $email ) ) {
        $errors->add( 'email_exists', __( 'An account with this email or username already exists. Please try another or reset your password.', 'woocommerce' ) );
    }

    return $errors;
}

// many resources say use the login_errors hook for this but it only gives you access to the error message and not the error codes.
// you would have to parse the message and be relying on it not changing in future for any level of granular control. wp_login_failed
// gives you access to the whole error object and works for both WooCommerce my account login and wp-admin login
add_action( 'wp_login_failed', 'clario_override_login_error_messages', 10, 2 );

function clario_override_login_error_messages( $username, $error ) {
    // error_log(print_r($error,true));    error_log(print_r($error->get_error_codes(),true));

    // put whichever errors you like in here!
    $mmx_errors = [
        'invalid_username' => 'Incorrect credentials, please check your login details and try again.',
        'incorrect_password' => 'Incorrect credentials, please check your login details and try again.',
        'invalid_email' => 'Incorrect credentials, please check your login details and try again.',
    ];

    $codes = $error->get_error_codes();

    foreach ($codes as $code) {
        if (array_key_exists($code,$mmx_errors)) {
            // error_log(print_r('key exists... change error',true));
            $error->remove($code);
            $error->add($code,$mmx_errors[$code]);
        
        }
    }

}