Using null as the key parameter for array_key_exists() is deprecated, use an empty string instead

Description

null cannot be used as an array index anymore, since PHP 8.5. It is deprecated. As such, there is no point anymore to in passing such values to the first argument of array_key_exists(), and this is also deprecated.

Example

<?php

$array = [null => 1];
var_dump(array_key_exists(null, $array));

?>

Solutions

• Use the coalesce operator ?? to turn the null into another value, such as empty string.

• Replace the null value by the empty string.

Related Error Messages

• Using null as an array offset is deprecated, use an empty string instead

Changed Behavior

This error may appear following an evolution in behavior, in previous versions. See NullAsArrayOffset, NullWithArrayKeyExists.