1.2.639. Logical Mistakes¶
Avoid logical mistakes within long expressions.
Sometimes, the logic is not what it seems. It is important to check the actual impact of every part of the logical expression. Do not hesitate to make a table with all possible cases. If those cases are too numerous, it may be time to rethink the whole expression.
Inspired by an article from Andrey Karpov.
<?php
// Always true
if ($a != 1 || $a != 2) { }
// $a == 1 is useless
if ($a == 1 || $a != 2) {}
// Always false
if ($a == 1 && $a == 2) {}
// $a != 2 is useless
if ($a == 1 && $a != 2) {}
?>
See also Logical Expressions in C/C++. Mistakes Made by Professionals.
1.2.639.1. Suggestions¶
Change the expressions for them to have a real meaning
1.2.639.2. Specs¶
Short name |
Structures/LogicalMistakes |
Rulesets |
|
Exakat since |
0.8.4 |
PHP Version |
All |
Severity |
Critical |
Time To Fix |
Quick (30 mins) |
Precision |
High |
Examples |
|
Available in |