feat: null to Traversable or ArrayAccess is now handled & returns empty.

CHANGELOG.md

@@ -24,6 +24,7 @@
 * feat(`PresetMappingFactory`): Add `fromObjectCache()` and `fromObjectCacheReversed()`.
 * chore: Simplify remembering mapper.
 * refactor: Deprecate serializer context.
+* feat: null to `Traversable` or `ArrayAccess` is now handled & returns empty.
 
 ## 1.0.0
 

psalm.xml

@@ -52,6 +52,8 @@
                 <file name="tests/Fixtures/UninitializedProperty/ObjectWithUninitializedProperty.php" />
                 <file name="tests/Fixtures/UninitializedPropertyDto/FinalObjectWithUninitializedPropertyDto.php" />
                 <file name="tests/Fixtures/UninitializedPropertyDto/ObjectWithUninitializedPropertyDto.php" />
+                <file name="tests/Fixtures/ArrayLikeDto/ObjectWithNotNullArrayAccessPropertyDto.php" />
+                <file name="tests/Fixtures/ArrayLikeDto/ObjectWithNotNullTraversablePropertyDto.php" />
             </errorLevel>
         </MissingConstructor>
         <ArgumentTypeCoercion>

src/Transformer/Implementation/TraversableToArrayAccessTransformer.php

@@ -51,6 +51,10 @@ public function transform(
         ?Type $targetType,
         Context $context
     ): mixed {
+        if ($source === null) {
+            $source = [];
+        }
+
         if ($targetType === null) {
             throw new InvalidArgumentException('Target type must not be null.', context: $context);
         }
@@ -221,6 +225,7 @@ public function getSupportedTransformation(): iterable
         $sourceTypes = [
             TypeFactory::objectOfClass(\Traversable::class),
             TypeFactory::array(),
+            TypeFactory::null(),
         ];
 
         $targetTypes = [

src/Transformer/Implementation/TraversableToTraversableTransformer.php

@@ -44,6 +44,10 @@ public function transform(
         ?Type $targetType,
         Context $context
     ): mixed {
+        if ($source === null) {
+            $source = [];
+        }
+
         if ($targetType === null) {
             throw new InvalidArgumentException('Target type must not be null.', context: $context);
         }
@@ -103,6 +107,7 @@ public function getSupportedTransformation(): iterable
         $sourceTypes = [
             TypeFactory::objectOfClass(\Traversable::class),
             TypeFactory::array(),
+            TypeFactory::null(),
         ];
 
         $targetTypes = [

tests/Fixtures/ArrayLike/ObjectWithNullCollectionProperty.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of rekalogika/mapper package.
+ *
+ * (c) Priyadi Iman Nurcahyo <https://rekalogika.dev>
+ *
+ * For the full copyright and license information, please view the LICENSE file
+ * that was distributed with this source code.
+ */
+
+namespace Rekalogika\Mapper\Tests\Fixtures\ArrayLike;
+
+use Doctrine\Common\Collections\Collection;
+use Rekalogika\Mapper\Tests\Fixtures\Scalar\ObjectWithScalarProperties;
+
+class ObjectWithNullCollectionProperty
+{
+    /**
+     * @var null|Collection<int,ObjectWithScalarProperties>
+     */
+    public ?Collection $property = null;
+}

tests/Fixtures/ArrayLikeDto/ObjectWithNotNullArrayAccessPropertyDto.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of rekalogika/mapper package.
+ *
+ * (c) Priyadi Iman Nurcahyo <https://rekalogika.dev>
+ *
+ * For the full copyright and license information, please view the LICENSE file
+ * that was distributed with this source code.
+ */
+
+namespace Rekalogika\Mapper\Tests\Fixtures\ArrayLikeDto;
+
+use Rekalogika\Mapper\Tests\Fixtures\ScalarDto\ObjectWithScalarPropertiesDto;
+
+class ObjectWithNotNullArrayAccessPropertyDto
+{
+    /**
+     * @var \ArrayAccess<int,ObjectWithScalarPropertiesDto>
+     */
+    public \ArrayAccess $property;
+}

tests/Fixtures/ArrayLikeDto/ObjectWithNotNullTraversablePropertyDto.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of rekalogika/mapper package.
+ *
+ * (c) Priyadi Iman Nurcahyo <https://rekalogika.dev>
+ *
+ * For the full copyright and license information, please view the LICENSE file
+ * that was distributed with this source code.
+ */
+
+namespace Rekalogika\Mapper\Tests\Fixtures\ArrayLikeDto;
+
+use Rekalogika\Mapper\Tests\Fixtures\ScalarDto\ObjectWithScalarPropertiesDto;
+
+class ObjectWithNotNullTraversablePropertyDto
+{
+    /**
+     * @var \Traversable<int,ObjectWithScalarPropertiesDto>
+     */
+    public \Traversable $property;
+}

tests/IntegrationTest/TraversableToArrayAccessMappingTest.php

@@ -20,6 +20,7 @@
 use Rekalogika\Mapper\Tests\Fixtures\ArrayLike\ObjectWithArrayProperty;
 use Rekalogika\Mapper\Tests\Fixtures\ArrayLike\ObjectWithArrayPropertyWithStringKey;
 use Rekalogika\Mapper\Tests\Fixtures\ArrayLike\ObjectWithCollectionProperty;
+use Rekalogika\Mapper\Tests\Fixtures\ArrayLike\ObjectWithNullCollectionProperty;
 use Rekalogika\Mapper\Tests\Fixtures\ArrayLike\ObjectWithSplObjectStorageProperty;
 use Rekalogika\Mapper\Tests\Fixtures\ArrayLike\ObjectWithTraversableProperties;
 use Rekalogika\Mapper\Tests\Fixtures\ArrayLikeDto\ObjectWithArrayAccessPropertyDto;
@@ -30,6 +31,7 @@
 use Rekalogika\Mapper\Tests\Fixtures\ArrayLikeDto\ObjectWithArrayPropertyWithCompatibleHintDto;
 use Rekalogika\Mapper\Tests\Fixtures\ArrayLikeDto\ObjectWithArrayPropertyWithoutTypeHintDto;
 use Rekalogika\Mapper\Tests\Fixtures\ArrayLikeDto\ObjectWithCollectionPropertyDto;
+use Rekalogika\Mapper\Tests\Fixtures\ArrayLikeDto\ObjectWithNotNullArrayAccessPropertyDto;
 use Rekalogika\Mapper\Tests\Fixtures\Scalar\ObjectWithScalarProperties;
 use Rekalogika\Mapper\Tests\Fixtures\ScalarDto\ObjectWithScalarPropertiesDto;
 use Rekalogika\Mapper\Transformer\Model\HashTable;
@@ -177,6 +179,20 @@ public function testCollectionToArrayAccessDto(): void
         $this->assertEquals(1.1, $result->property[1]?->d);
     }
 
+    public function testNullToNotNullArrayAccessDto(): void
+    {
+        $source = new ObjectWithNullCollectionProperty();
+
+        $result = $this->mapper->map($source, ObjectWithNotNullArrayAccessPropertyDto::class);
+
+        $this->assertInstanceOf(ObjectWithNotNullArrayAccessPropertyDto::class, $result);
+
+        $property = $result->property;
+        $this->assertInstanceOf(LazyArray::class, $property);
+        // @phpstan-ignore-next-line
+        $this->assertInstanceOf(\ArrayAccess::class, $property);
+    }
+
     public function testArrayToArrayInterfaceDto(): void
     {
         $source = new ObjectWithArrayProperty();

tests/IntegrationTest/TraversableToTraversableMappingTest.php

@@ -17,7 +17,9 @@
 use Rekalogika\Mapper\Tests\Fixtures\ArrayLike\ObjectWithArrayProperty;
 use Rekalogika\Mapper\Tests\Fixtures\ArrayLike\ObjectWithLazyDoctrineCollectionProperty;
 use Rekalogika\Mapper\Tests\Fixtures\ArrayLike\ObjectWithLazyDoctrineCollectionWithPresetCountableProperty;
+use Rekalogika\Mapper\Tests\Fixtures\ArrayLike\ObjectWithNullCollectionProperty;
 use Rekalogika\Mapper\Tests\Fixtures\ArrayLike\ObjectWithTraversableProperties;
+use Rekalogika\Mapper\Tests\Fixtures\ArrayLikeDto\ObjectWithNotNullTraversablePropertyDto;
 use Rekalogika\Mapper\Tests\Fixtures\ArrayLikeDto\ObjectWithTraversablePropertyDto;
 use Rekalogika\Mapper\Tests\Fixtures\ArrayLikeDto\ObjectWithTraversablePropertyWithoutTypeHintDto;
 use Rekalogika\Mapper\Tests\Fixtures\Scalar\ObjectWithScalarProperties;
@@ -121,4 +123,15 @@ public function testArrayToTraversableWithoutTypehint(): void
             $this->assertEquals(1.1, $item->d);
         }
     }
+
+    public function testNullToNotNullTraversableDto(): void
+    {
+        $source = new ObjectWithNullCollectionProperty();
+        $result = $this->mapper->map($source, ObjectWithNotNullTraversablePropertyDto::class);
+
+        $this->assertInstanceOf(\Traversable::class, $result->property);
+
+        $arrayResult = iterator_to_array($result->property);
+        $this->assertEmpty($arrayResult);
+    }
 }