Empty arrays aren't converted to Collections

[ropi-bc]

✏️ Describe the bug
While creating an instance of a DTO that has a collection, if the source had an empty array, the returning property will be an empty array, instead of an empty Collection, resulting in the error message: TestDTO::__construct(): Argument #1 ($items) must be of type Illuminate\Support\Collection, array given.

Line causing the issue

↪️ To Reproduce

class TestDTO extends Data
{
    public function __construct(
        /** @var Collection<int, string> $items */
        public readonly Collection $items
    ) {
    }
}

it('Empty array should return Collection too', function () {
    // Throws the above mentioned error
    $result = TestDTO::from(['items' => []]);
    expect($result->items)->toBeEmpty();
});

✅ Expected behavior
I expect the test to complete, and the expectations to be satisfied.

🖥️ Versions

Laravel: 11.4
Laravel Data: 4.5.0
PHP: 8.3

[inxilpro]

We're running into the same issue. It looks like when the Enumerable cast was removed in #686 it broke casting empty arrays to empty collections. In the short term, we're able to add #[WithCast(EnumerableCast::class)] to force it, but the class is marked as deprecated and it seems like that's not a great long-term solution.

The main problem is that if you're relying on Laravel-Data within another package, you can't rely on cast_and_transform_iterables to be enabled, but now you also can't rely on the Enumerable cast to be enabled either.

The easiest solution, as far as I can tell, is to re-enable the Enumerable cast for now (until the next major version release), and add a comment next to the cast_and_transform_iterables config explaining that the cast should be disabled if that feature is turned on.

[rubenvanassche]

The issue here is not that we've removed Enumerable but a bug in the new implementation, it should be cast into a Collection and not be kept as an array.

Fixed in next release (108e660)

[ropi-bc]

Thank you, this is great news!