Hello!

Closes rectorphp/rector#9289

Motivation

Converting ArrayDimFetch (for objects that implement ArrayAccess) can be very dangerous if the isset(), unset, and assignment operations are not accounted for. If the object is used in any of the following scenarios:

$object['key'] = 42;
isset($object['key']);
unset($object['key']);

this rule would update them to the following and the application will be in a broken state:

$object->get('key') = 42;
isset($object->get('key'));
unset($object->get('key'));

Implementation

This rule properly handles all of the above situations (including when isset and unset have multiple arguments). The ArrayDimFetchToMethodCall class has been updated to accept methods for the other operations:

class ArrayDimFetchToMethodCall
{
    public function __construct(
        private readonly ObjectType $objectType,
        private readonly string $method,
        // Optional methods for set, exists, and unset operations
        // if null, then these operations will not be transformed
        private readonly ?string $setMethod = null,
        private readonly ?string $existsMethod = null,
        private readonly ?string $unsetMethod = null,
    ) {
    }
}

The other methods are nullable by default. If null, then that particular operation is skipped.

CC: @peterfox

Thanks!