1.2.372. Don’t Mix ++

++ operators, pre and post, have two distinct behaviors, and should be used separately.

When mixed in a larger expression, they are difficult to read, and may lead to unwanted behaviors.

<?php

    // Clear and defined behavior
    $i++;
    $a[$i] = $i;

    // The index is also incremented, as it is used AFTP the incrementation
    // With $i = 2; $a is array(3 => 3)
    $a[$i] = ++$i;

    // $i is actually modified twice
    $i = --$i + 1;
?>

See also EXP30-C. Do not depend on the order of evaluation for side effects.

1.2.372.1. Connex PHP features

• readability

1.2.372.1.1. Suggestions

• Extract the increment from the expression, and put it on a separate line.

1.2.372.1.2. Specs

Short name	Structures/DontMixPlusPlus
Rulesets	All, Analyze, Changed Behavior
Exakat since	1.3.2
PHP Version	All
Severity	Minor
Time To Fix	Instant (5 mins)
Precision	High
Examples	Contao, Typo3
Available in	Entreprise Edition, Exakat Cloud