Fixing Bug #249

src/DataTransferObject.php

@@ -26,7 +26,7 @@ public function __construct(...$args)
         $class = new DataTransferObjectClass($this);
 
         foreach ($class->getProperties() as $property) {
-            $property->setValue(Arr::get($args, $property->name) ?? $this->{$property->name} ?? null);
+            $property->setValue(Arr::get($args, $property->name, $property->getDefaultValue()));
 
             $args = Arr::forget($args, $property->name);
         }

src/Reflection/DataTransferObjectProperty.php

@@ -69,6 +69,11 @@ public function getValue(): mixed
         return $this->reflectionProperty->getValue($this->dataTransferObject);
     }
 
+    public function getDefaultValue(): mixed
+    {
+        return $this->reflectionProperty->getDefaultValue();
+    }
+
     private function resolveCaster(): ?Caster
     {
         $attributes = $this->reflectionProperty->getAttributes(CastWith::class);

tests/MapFromTest.php

@@ -76,4 +76,30 @@ public function dto_can_have_mapped_and_regular_properties()
         $this->assertEquals('2021-01-01', $dto->date);
         $this->assertEquals('News', $dto->categoryName);
     }
+
+    /** @test */
+    public function mapped_from_works_with_default_values()
+    {
+        $data = [
+            'title' => 'Hello world',
+        ];
+
+        $dto = new class ($data) extends DataTransferObject {
+            public string $title;
+
+            #[MapFrom('desc')]
+            public string $description = 'Test Text';
+
+            #[MapFrom('is_public')]
+            public bool $isPublic = false;
+
+            #[MapFrom('random_int')]
+            public int $randomInt = 42;
+        };
+
+        $this->assertEquals('Hello world', $dto->title);
+        $this->assertEquals('Test Text', $dto->description);
+        $this->assertFalse($dto->isPublic);
+        $this->assertEquals(42, $dto->randomInt);
+    }
 }