1.2.1324. Use DateTimeImmutable Class

The DateTimeImmutable class is the immutable version of the Datetime class.

While DateTime may be modified, DateTimeImmutable cannot be modified : it needs to be cloned instead. Any modification to such an object will return a new and distinct object. This prevents alterations that are hard to track.

<?php
// Example extracted from Derick Rethans' article (link below)

function formatNextMondayFromNow( DateTime $dt )
{
        return $dt->modify( 'next monday' )->format( 'Y-m-d' );
}

$d = new DateTime();                          //2014-02-17
echo formatNextMondayFromNow( $d ), "\n";
echo $d->format( 'Y-m-d' ), "\n";             //2014-02-17
?>

See also What’s all this ‘immutable date’ stuff, anyway?, DateTimeImmutable, The DateTime class and The DateTimeImmutable class.

1.2.1324.1. Suggestions

• Always use DateTimeImmutable when manipulating dates.

1.2.1324.2. Specs

Short name	Php/UseDateTimeImmutable
Rulesets	All, Suggestions
Exakat since	1.8.7
PHP Version	All
Severity	Minor
Time To Fix	Quick (30 mins)
Precision	Very high
Features	immutable, date
Available in	Entreprise Edition, Exakat Cloud