Solve issue where an iterable cast wont cast its container if empty

src/DataPipes/CastPropertiesDataPipe.php

@@ -146,10 +146,6 @@ protected function castIterable(
         array $properties,
         CreationContext $creationContext
     ): iterable {
-        if (empty($values)) {
-            return $values;
-        }
-
         if ($values instanceof Enumerable) {
             $values = $values->all();
         }
@@ -179,6 +175,10 @@ protected function castIterableItems(
         array $properties,
         CreationContext $creationContext
     ): array {
+        if(empty($values)) {
+            return $values;
+        }
+
         /** @var ?IterableItemCast $cast */
         $cast = $this->findCastForIterableItems($property, $values, $properties, $creationContext);
 

tests/CreationTest.php

@@ -1087,6 +1087,34 @@ public function __invoke(SimpleData $data)
         ->toEqual(['a', 'collection']);
 })->skip(fn () => config('data.features.cast_and_transform_iterables') === false);
 
+it('will cast an empty iterables list into the correct type', function () {
+    $dataClass = new class () extends Data {
+        public EloquentCollection $collection;
+
+        public CustomCollection $customCollection;
+
+        public array $array;
+    };
+
+    $data = $dataClass::from([
+        'collection' => [],
+        'customCollection' => [],
+        'array' => collect([]),
+    ]);
+
+    expect($data->collection)
+        ->toBeInstanceOf(EloquentCollection::class)
+        ->toEqual(new EloquentCollection([]));
+
+    expect($data->customCollection)
+        ->toBeInstanceOf(CustomCollection::class)
+        ->toEqual(new CustomCollection([]));
+
+    expect($data->array)
+        ->toBeArray()
+        ->toEqual([]);
+})->skip(fn () => config('data.features.cast_and_transform_iterables') === false);
+
 it('will cast iterables into default types', function () {
     $dataClass = new class () extends Data {
         /** @var array<int, string> */

tests/DataTest.php

@@ -1,6 +1,7 @@
 <?php
 
 use Illuminate\Contracts\Support\Responsable;
+use Illuminate\Support\Collection;
 use Illuminate\Validation\ValidationException;
 use Spatie\LaravelData\Concerns\AppendableData;
 use Spatie\LaravelData\Concerns\BaseData;
@@ -78,3 +79,18 @@ public static function fromString(string $string): static
         'validate',
     ]);
 });
+
+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();
+});