1.2.786. No Append On Source¶
Do not append new elements to an array in a foreach loop. Since PHP 7.0, the array is still used as a source, and will be augmented, and used again.
Thanks to Frederic Bouchery for the reminder.
<?php
// Relying on the initial copy
$a = [1];
$initial = $a;
foreach($initial as $v) {
$a[] = $v + 1;
}
// Keep new results aside
$a = [1];
$tmp = [];
foreach($a as $v) {
$tmp[] = $v + 1;
}
$a = array_merge($a, $tmp);
unset($tmp);
// Example, courtesy of Frederic Bouchery
// This is an infinite loop
$a = [1];
foreach($a as $v) {
$a[] = $v + 1;
}
?>
See also foreach and What will this code return? #PHP.
1.2.786.1. Suggestions¶
Use a copy of the source, to avoid modifying it during the loop
Store the new values in a separate storage
1.2.786.2. Specs¶
Short name |
Structures/NoAppendOnSource |
Rulesets |
|
Exakat since |
1.8.2 |
PHP Version |
All |
Severity |
Minor |
Time To Fix |
Quick (30 mins) |
Precision |
Very high |
Features |
class |
Available in |