`restore_xxx_handler()` does silently return even if there is no handler to restore

[mvorisek]

Description

The following code:

repro: https://3v4l.org/DDulh

<?php

restore_error_handler();
restore_error_handler();
restore_error_handler();

restore_exception_handler();
restore_exception_handler();
restore_exception_handler();

Resulted in this output:

But I expected this output instead:

php warning for each restore_xxx_handler() call if there is no handler to restore

The warnings are important to be inform the developer the operation is probably not wanted (ie. handler was never added).

PHP Version

any

Operating System

any