register_tick_function() not work in external file

+ php main.php | grep f2 || echo "f2 function not appear"
f2 function not appear

Why?

Here are some details

+ ls -1
f2.php
main.php



+ cat main.php 
<?php
declare(ticks=1);
require 'f2.php'; // external file

register_tick_function(
    function () {
        debug_print_backtrace();
        echo "\n";
    }
);

function f1() {
    f2();
}

f1();



+ cat f2.php 
<?php
declare(ticks=1);
function f2() {}



+ php main.php 
#0 /tmp/tmp.UFjE757TrJ/main.php(9): {closure}()

#0 /tmp/tmp.UFjE757TrJ/main.php(13): {closure}()
#1 /tmp/tmp.UFjE757TrJ/main.php(16): f1()

#0 /tmp/tmp.UFjE757TrJ/main.php(16): {closure}()

Start by running the reported php main.php | grep f2 || echo "f2 function not appear" reproduction and inspect main.php together with the externally required f2.php. Compare the tick callbacks around the f2() call and determine whether the missing callback is expected or indicates a runtime bug; document the confirmed behavior and add a focused regression test if appropriate.