Trying to Access Array Offset on Null

Why This Happens

This warning was introduced in PHP 7.4 to replace the silent null behavior of earlier versions. It triggers when you use bracket notation like $var['key'] on a variable that is null. This typically happens when a function returns null instead of an array, or when a database query finds no results.

The Problem

$config = parse_ini_file('missing-config.ini'); // Returns false on failure
echo $config['database_host'];

The Fix

$config = parse_ini_file('config.ini');
if ($config === false) {
    throw new RuntimeException('Failed to load config file');
}
echo $config['database_host'];

Step-by-Step Fix

1. 1

   Find the null variable

   Check the line number in the warning and identify which variable is null by using var_dump() before the access.

2. 2

   Trace the data source

   Find where the variable is assigned. Check if the source function can return null or false, such as database queries, file operations, or API calls.

3. 3

   Add validation

   Check for null before accessing the array offset, use the null coalescing operator ?? for defaults, or handle the error case explicitly.