register_post hook not compatible with PHP 4.x

[ppaquet]

In wp-login.php, the way that the register_post get back errors is not compatible with PHP 4.x ($error is a passed as a copy, not a reference). Because of that, plugins that use that hook like no-disposable-email won't work with PHP 4.x

The plugin should be providing the updated error information using the registration_errors errors filter.

The action does not provide the $errors object explicitly as a reference - if it was it would use do_action_ref_array

The registration_errors filter is there so that a plugin can filter the $errors and return alternative

Possibly $user_login, $user_email should be added to the registration_errors filter as well?

Replying to dd32:

Possibly $user_login, $user_email should be added to the registration_errors filter as well?

See #11237. Closing this as invalid.