Array Unpacking with String Keys in PHP 8.1

PHP 8.1 adds array unpacking with string keys, a feature that was unavailable in earlier versions because the language lacked a clear rule for merging duplicate keys.

The RFC resolves this by adopting array_merge semantics, where later values overwrite earlier ones when keys collide.

Example:

<code>$array1 = ["a" => 1];
$array2 = ["b" => 2];
$array = ["a" => 0, ...$array1, ...$array2];
var_dump($array); // ["a" => 1, "b" => 2]
</code>

The resulting array shows that the string‑key unpacking works as expected, merging the arrays and keeping the last occurrence of each key.

For the full specification see the RFC at https://wiki.php.net/rfc/array_unpacking_string_keys and related articles on other PHP 8.1 features.