PHP foreach没有引用错过元素

Question

I tend to find that when using foreach stuctures without using references, some elements of the array are missing.

$array = array();

/* ... */

$array[] = 1;
$array[] = 2;
$array[] = 3;

/* ... */

print_r($array); /* print_r always shows all elements */

foreach ($array as $element) { /* missing elements */ }
foreach ($array as &$element) { /* does a fine job */ }

I have had three independent occurrences of this in my code. The fix is easy (add &), but it sounds like a bug either in PHP or in my setup...

Are more people experiencing this? What is the problem?

PHP 5.4.12

---

EDIT

Case:

$a = array();
$a[] = 1;
$a[] = 2;
$a[] = 3;

foreach ($a as &$e)
{
    echo $e;
}

echo '<br>';

foreach ($a as $e)
{
    echo $e;
}

Output:

123
122

Answer 1

Just confirmed.

<?php
  $x[]=1;
  $x[]=2;
  $x[]=3;
  $x[]=4;
  foreach($x as $y) {
    var_dump($y);
  }
?>

int(1) int(2) int(3) int(4)