actions overwrite variables

[tazotodua]

hello.
for example,we have:

add_action('wp_head','my_function');

function my_function($first=false){ 
    var_dump($first); exit;
}

it doesnt show false, instead something empty string is passed from the action... why? I think actions should not touch the arguments of functions..

[swissspidy]

Hey there,

Thanks for your report. This is already being tracked in #14881. See also #14671 for some history.