1.2.973. Php 7 Indirect Expression¶
This rule reports variable indirect expressions, that are interpreted differently in PHP 5 and PHP 7.
They should be checked, as they will behave differently between these PHP versions.
<?php
// Ambiguous expression :
$b = $$foo['bar']['baz'];
echo $b;
$foo = array('bar' => array('baz' => 'bat'));
$bat = 'PHP 5.6';
// In PHP 5, the expression above means :
$b = ${$foo['bar']['baz']};
$b = 'PHP 5.6';
$foo = 'a';
$a = array('bar' => array('baz' => 'bat'));
// In PHP 7, the expression above means :
$b = ($$foo)['bar']['baz'];
$b = 'bat';
?>
See also Changes to variable handling.
1.2.973.1. Suggestions¶
Avoid using complex expressions, mixing $$, [0] and -> in the same expression
Add curly braces {} to ensure that the precedence is the same between PHP 5 and 7. For example,
$$vbecomes${$v}
1.2.973.2. Specs¶
Short name |
Variables/Php7IndirectExpression |
Rulesets |
All, Changed Behavior, CompatibilityPHP53, CompatibilityPHP54, CompatibilityPHP55, CompatibilityPHP56, CompatibilityPHP70 |
Exakat since |
0.8.4 |
PHP Version |
With PHP 7.0 and more recent |
Severity |
Major |
Time To Fix |
Slow (1 hour) |
Precision |
Very high |
Available in |