php bug require_once don't keep file in another file code example

Example 1: php require

// Require a file to be imported or quit if it can't be found
<?php
 require 'somefile.php';
?>
  
// Alternatively: Include a file, if it can't be found: continue.
<?php
include 'vars.php';
?>

Example 2: echo require php

return.php
<?php

$var = 'PHP';

return $var;

?>

noreturn.php
<?php

$var = 'PHP';

?>

testreturns.php
<?php

$foo = include 'return.php';

echo $foo; // prints 'PHP'

$bar = include 'noreturn.php';

echo $bar; // prints 1

?>

//$bar is the value 1 because the include was successful. Notice the difference between the above examples. The first uses return within the included file while the other does not. If the file can't be included, false is returned and E_WARNING is issued.