Allow casters to parse null values and provide default or Injected values

src/Fixtures/ClassWithDefaultValueProvidingCaster.php

@@ -0,0 +1,14 @@
+<?php
+
+declare(strict_types=1);
+
+namespace EventSauce\ObjectHydrator\Fixtures;
+
+class ClassWithDefaultValueProvidingCaster
+{
+    public function __construct(
+        #[DefaultValueProvidingCaster]
+        public string $valueProvidedFromCaster,
+    ) {
+    }
+}

src/Fixtures/DefaultValueProvidingCaster.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace EventSauce\ObjectHydrator\Fixtures;
+
+use Attribute;
+use EventSauce\ObjectHydrator\ObjectMapper;
+use EventSauce\ObjectHydrator\PropertyCaster;
+
+#[Attribute(Attribute::TARGET_PARAMETER)]
+final class DefaultValueProvidingCaster implements PropertyCaster
+{
+    public function cast(mixed $value, ObjectMapper $hydrator): mixed
+    {
+        return 'some_default_value';
+    }
+}

src/ObjectHydrationTestCase.php

@@ -15,6 +15,7 @@
 use EventSauce\ObjectHydrator\Fixtures\ClassThatUsesMutipleCastersWithoutOptions;
 use EventSauce\ObjectHydrator\Fixtures\ClassWithCamelCaseProperty;
 use EventSauce\ObjectHydrator\Fixtures\ClassWithComplexTypeThatIsMapped;
+use EventSauce\ObjectHydrator\Fixtures\ClassWithDefaultValueProvidingCaster;
 use EventSauce\ObjectHydrator\Fixtures\ClassWithDocblockAndArrayFollowingScalar;
 use EventSauce\ObjectHydrator\Fixtures\ClassWithDefaultValue;
 use EventSauce\ObjectHydrator\Fixtures\ClassWithDocblockArrayVariants;
@@ -466,6 +467,17 @@ public function hydrating_a_class_with_a_nullable_property_defaults_to_null(): v
         self::assertNull($object->defaultsToNull);
     }
 
+    /** @test */
+    public function hydrating_a_class_with_a_default_value_providing_caster(): void
+    {
+        $hydrator = $this->createObjectHydrator();
+
+        $object = $hydrator->hydrateObject(ClassWithDefaultValueProvidingCaster::class, []);
+
+        self::assertInstanceOf(ClassWithDefaultValueProvidingCaster::class, $object);
+        self::assertEquals('some_default_value', $object->valueProvidedFromCaster);
+    }
+
     /**
      * @test
      */

src/ObjectMapperCodeGenerator.php

@@ -245,11 +245,6 @@ private function dumpClassHydrator(string $className, ClassHydrationDefinition $
                 $body .= <<<CODE
 
             \$value = \$payload['$from'] ?? null;
-
-            if (\$value === null) {
-$isNullBody
-            }
-
 CODE;
             } else {
                 $collectKeys = '';
@@ -295,15 +290,20 @@ private function dumpClassHydrator(string $className, ClassHydrationDefinition $
             }
 
             \$value = \${$casterName}->cast(\$value, \$this);
+CODE;
+                }
+            }
 
+            if(isset($isNullBody)){
+                $body .= <<<CODE
             if (\$value === null) {
                 $isNullBody
             }
-
 CODE;
-                }
             }
 
+
+
             if ($definition->isBackedEnum()) {
                 $body .= <<<CODE
 

src/ObjectMapperUsingReflection.php

@@ -98,26 +98,13 @@ public function hydrateObject(string $className, array $payload): object
                 $property = $definition->accessorName;
                 $value = $this->extractPayloadViaMap($payload, $keys);
 
-                // same code as two sections below
-                if ($value === null) {
-                    if ($definition->hasDefaultValue) {
-                        continue;
-                    } elseif ($definition->nullable) {
-                        $properties[$property] = null;
-                    } else {
-                        $missingFields[] = implode('.', end($keys));
-                    }
-                    continue;
-                }
-
                 foreach ($definition->casters as [$caster, $options]) {
                     $key = $className . '-' . $caster . '-' . json_encode($options);
                     /** @var PropertyCaster $propertyCaster */
                     $propertyCaster = $this->casterInstances[$key] ??= new $caster(...$options);
                     $value = $propertyCaster->cast($value, $this);
                 }
 
-                // same code as two sections above
                 if ($value === null) {
                     if ($definition->hasDefaultValue) {
                         continue;

src/PropertyCasters/CastToDateTimeImmutable.php

@@ -23,6 +23,10 @@ public function __construct(private ?string $format = null, private ?string $tim
 
     public function cast(mixed $value, ObjectMapper $hydrator): mixed
     {
+        if($value === null){
+            return null;
+        }
+
         $timeZone = $this->timeZone ? new DateTimeZone($this->timeZone) : $this->timeZone;
 
         if ($this->format !== null) {