orklah/psalm-insane-comparison

Detects possible insane comparison ("string" == 0) to help migrate to PHP8

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Type:psalm-plugin

v1.0.3 2021-01-12 17:01 UTC

This package is auto-updated.

Last update: 2021-09-13 00:37:06 UTC


README

A Psalm plugin to detect code susceptible to change behaviour with the introduction of PHP RFC: Saner string to number comparisons

Installation:

$ composer require --dev orklah/psalm-insane-comparison
$ vendor/bin/psalm-plugin enable orklah/psalm-insane-comparison

Usage:

Run your usual Psalm command:

$ vendor/bin/psalm

Explanation:

Before PHP8, comparison between a non-empty-string and the literal int 0 resulted in true. This is no longer the case with the PHP RFC: Saner string to number comparisons.

$a = 'banana';
$b = 0;
if($a == $b){
    echo 'PHP 7 will display this';
}
else{
    echo 'PHP 8 will display this instead';
}

This plugin helps identify those case to check them before migrating.

You can solve this issue in a lot of ways:

  • use strict equality:
$a = 'banana';
$b = 0;
if($a === $b){
    echo 'This is impossible';
}
else{
    echo 'PHP 7 and 8 will both display this';
}
  • use a cast to make both operands the same type:
$a = 'banana';
$b = 0;
if((int)$a == $b){
    echo 'PHP 7 and 8 will both display this';
}
else{
    echo 'This is impossible';
}
$a = 'banana';
$b = 0;
if($a == (string)$b){
    echo 'This is impossible';
}
else{
    echo 'PHP 7 and 8 will both display this';
}
  • Make psalm understand you're working with positive-ints when the int operand is not a literal:
$a = 'banana';
/** @var positive-int $b */
if($a == $b){
    echo 'This is impossible';
}
else{
    echo 'PHP 7 and 8 will both display this';
}
  • Make psalm understand you're working with numeric-strings when the string operand is not a literal:
/** @var numeric-string $a */
$b = 0;
if($a == $b){
    echo 'PHP 7 and 8 will both display this depending on the value of $a';
}
else{
    echo 'PHP 7 and 8 will both display this depending on the value of $a';
}