feat: A callback for reporting unexpected enum values

Author: autaut03

README.md

@@ -137,9 +137,9 @@ to use in order of priority:
 
 ```php
 (new SerializerBuilder())
-	->addMapperLast(new TestMapper()) // then this one
-	->addFactoryLast(new TestFactory()) // and this one last
-	->addFactory(new TestFactory()) // attempted first
+	->addMapperLast(new TestMapper()) // #2 - then this one
+	->addFactoryLast(new TestFactory()) // #3 - and this one last
+	->addFactory(new TestFactory()) // #1 - attempted first
 ```
 
 A factory has the following signature:
@@ -205,11 +205,11 @@ methods: `serialize` and `deserialize`. They do exactly what they're called.
 
 ## Naming of keys
 
-By default serializer preserves the naming of keys, but this is easily customizable (in order of priority):
+By default, serializer preserves the naming of keys, but this is easily customizable (in order of priority):
 
 - specify a custom property name using the `#[SerializedName]` attribute
 - specify a custom naming strategy per class using the `#[SerializedName]` attribute
-- specify a custom global naming strategy (use one of the built in or write your own)
+- specify a custom global (default) naming strategy (use one of the built-in or write your own)
 
 Here's an example:
 
@@ -235,7 +235,7 @@ class Item2 {
 ```
 
 Out of the box, strategies for `snake_case`, `camelCase` and `PascalCase` are provided,
-but you it's trivial to implement your own:
+but it's trivial to implement your own:
 
 ```php
 class PrefixedNaming implements NamingStrategy {
@@ -255,7 +255,7 @@ class SiftTrackData {}
 
 ## Required, nullable, optional and default values
 
-By default if a property is missing in serialized payload:
+By default, if a property is missing in serialized payload:
 
 - nullable properties are just set to null
 - properties with a default value - use the default value
@@ -319,6 +319,51 @@ $adapter->serialize(
 );
 ```
 
+## Use default value for unexpected
+
+There are situations where you're deserializing data from a third party that doesn't have an API documentation
+or one that can't keep a backwards compatibility promise. One such case is when a third party uses an enum
+and you expect that new enum values might get added in the future by them. For example, imagine this structure:
+
+```php
+enum CardType: string 
+{
+	case CLUBS = 'clubs';
+	case DIAMONDS = 'diamonds';
+	case HEARTS = 'hearts'; 
+	case SPADES = 'spades';	
+}
+
+readonly class Card {
+	public function __construct(
+		public CardType $type,
+		public string $value,
+	) {}
+}
+```
+
+If you get an unexpected value for `type`, you'll get an exception:
+
+```php
+// UnexpectedEnumValueException: Expected one of [clubs, diamonds, hearts, spades], but got 'joker'
+$adapter->deserialize('{"type": "joker"}');
+```
+
+So if you suspect that might happen, add a default value you wish to use (anything) and 
+a `#[UseDefaultForUnexpected]` attribute:
+
+```php
+readonly class Card {
+	public function __construct(
+		#[UseDefaultForUnexpected]
+		public CardType $type = null,
+		// Can be any other valid default value
+		#[UseDefaultForUnexpected]
+		public CardType $type2 = CardType::SPADES,
+	) {}
+}
+```
+
 ## Error handling
 
 This is expected to be used with client-provided data, so good error descriptions is a must.
@@ -369,9 +414,9 @@ There are some alternatives to this, but all of them will lack at least one of t
 
 - doesn't rely on inheritance, hence allows serializing third-party classes
 - parses existing PHPDoc information instead of duplicating it through attributes
-- supports generic types which are extremely useful for wrapper types
+- supports generic types which are quite useful for wrapper types
 - allows simple extension through mappers and complex stuff through type adapters
 - produces developer-friendly error messages for invalid data
-- correctly handles optional (missing keys) and `null` values as separate concepts
+- correctly handles optional (missing keys) and `null` values as separate concerns
 - simple to extend with additional formats
-- simple internal structure: no node tree, no value wrappers, no PHP parsing, no inherent limitations
+- simple internal structure: no node tree, no value/JSON wrappers, no custom reflection / PHP parsing, no inherent limitations

src/SerializerBuilder.php

@@ -9,6 +9,7 @@
 use GoodPhp\Serialization\Serializer\Registry\Cache\MemoizingTypeAdapterRegistry;
 use GoodPhp\Serialization\Serializer\Registry\Factory\FactoryTypeAdapterRegistryBuilder;
 use GoodPhp\Serialization\Serializer\TypeAdapterRegistrySerializer;
+use GoodPhp\Serialization\TypeAdapter\Exception\UnexpectedValueException;
 use GoodPhp\Serialization\TypeAdapter\Json\FromPrimitiveJsonTypeAdapterFactory;
 use GoodPhp\Serialization\TypeAdapter\Primitive\BuiltIn\ArrayMapper;
 use GoodPhp\Serialization\TypeAdapter\Primitive\BuiltIn\BackedEnumMapper;
@@ -19,6 +20,7 @@
 use GoodPhp\Serialization\TypeAdapter\Primitive\ClassProperties\Naming\BuiltInNamingStrategy;
 use GoodPhp\Serialization\TypeAdapter\Primitive\ClassProperties\Naming\NamingStrategy;
 use GoodPhp\Serialization\TypeAdapter\Primitive\ClassProperties\Naming\SerializedNameAttributeNamingStrategy;
+use GoodPhp\Serialization\TypeAdapter\Primitive\ClassProperties\Property\BoundClassProperty;
 use GoodPhp\Serialization\TypeAdapter\Primitive\ClassProperties\Property\BoundClassPropertyFactory;
 use GoodPhp\Serialization\TypeAdapter\Primitive\ClassProperties\Property\DefaultBoundClassPropertyFactory;
 use GoodPhp\Serialization\TypeAdapter\Primitive\Illuminate\CollectionMapper;
@@ -44,6 +46,9 @@ final class SerializerBuilder
 
 	private ?MapperMethodFactory $mapperMethodFactory = null;
 
+	/** @var callable(BoundClassProperty<object>, UnexpectedValueException): void|null */
+	private mixed $reportUnexpectedDefault = null;
+
 	public function withReflector(Reflector $reflector): self
 	{
 		Assert::null($this->reflector, 'You must set the reflector before adding any mappers or factories.');
@@ -126,6 +131,19 @@ public function addMapperLast(object $adapter): self
 		return $that;
 	}
 
+	/**
+	 * Define a callback for cases where a default value is substituted when using #[UseDefaultForUnexpected]
+	 *
+	 * @param callable(BoundClassProperty<object>, UnexpectedValueException): void|null $callback
+	 */
+	public function reportUnexpectedDefault(?callable $callback): self
+	{
+		$that = clone $this;
+		$that->reportUnexpectedDefault = $callback;
+
+		return $that;
+	}
+
 	public function build(): Serializer
 	{
 		$typeAdapterRegistryBuilder = $this->typeAdapterRegistryBuilder()
@@ -139,7 +157,9 @@ public function build(): Serializer
 			->addFactoryLast(new ClassPropertiesPrimitiveTypeAdapterFactory(
 				new SerializedNameAttributeNamingStrategy($this->namingStrategy ?? BuiltInNamingStrategy::PRESERVING),
 				$this->hydrator ?? new ConstructorHydrator(),
-				$this->boundClassPropertyFactory ?? new DefaultBoundClassPropertyFactory(),
+				$this->boundClassPropertyFactory ?? new DefaultBoundClassPropertyFactory(
+					$this->reportUnexpectedDefault,
+				),
 			))
 			->addFactoryLast(new FromPrimitiveJsonTypeAdapterFactory());
 

src/TypeAdapter/Primitive/ClassProperties/Property/DefaultBoundClassProperty.php

@@ -26,8 +26,9 @@
 final class DefaultBoundClassProperty implements BoundClassProperty
 {
 	/**
-	 * @param PropertyReflection<T, HasProperties<T>> $property
-	 * @param TypeAdapter<mixed, mixed>               $typeAdapter
+	 * @param PropertyReflection<T, HasProperties<T>>                                   $property
+	 * @param TypeAdapter<mixed, mixed>                                                 $typeAdapter
+	 * @param callable(BoundClassProperty<object>, UnexpectedValueException): void|null $reportUnexpectedDefault
 	 */
 	public function __construct(
 		private readonly PropertyReflection $property,
@@ -37,6 +38,7 @@ public function __construct(
 		private readonly bool $hasDefaultValue,
 		private readonly bool $nullable,
 		private readonly bool $useDefaultForUnexpected,
+		private readonly mixed $reportUnexpectedDefault = null,
 	) {
 		if ($this->useDefaultForUnexpected) {
 			Assert::true($this->hasDefaultValue, 'When using #[UseDefaultForUnexpected], the property must have a default value.');
@@ -92,6 +94,10 @@ public function deserialize(array $data): array
 			];
 		} catch (UnexpectedValueException $e) {
 			if ($this->useDefaultForUnexpected) {
+				if ($this->reportUnexpectedDefault !== null) {
+					($this->reportUnexpectedDefault)($this, $e);
+				}
+
 				return [];
 			}
 

src/TypeAdapter/Primitive/ClassProperties/Property/DefaultBoundClassPropertyFactory.php

@@ -10,6 +10,7 @@
 use GoodPhp\Reflection\Type\Type;
 use GoodPhp\Serialization\MissingValue;
 use GoodPhp\Serialization\Serializer;
+use GoodPhp\Serialization\TypeAdapter\Exception\UnexpectedValueException;
 use GoodPhp\Serialization\TypeAdapter\Primitive\ClassProperties\Property\Flattening\Flatten;
 use GoodPhp\Serialization\TypeAdapter\Primitive\ClassProperties\Property\Flattening\FlatteningBoundClassProperty;
 use Webmozart\Assert\Assert;
@@ -18,8 +19,12 @@ class DefaultBoundClassPropertyFactory implements BoundClassPropertyFactory
 {
 	private readonly NamedType $missingValueType;
 
-	public function __construct()
-	{
+	/**
+	 * @param callable(BoundClassProperty<object>, UnexpectedValueException): void|null $reportUnexpectedDefault
+	 */
+	public function __construct(
+		private readonly mixed $reportUnexpectedDefault = null,
+	) {
 		$this->missingValueType = new NamedType(MissingValue::class);
 	}
 
@@ -49,6 +54,7 @@ public function create(
 			hasDefaultValue: $this->hasDefaultValue($property),
 			nullable: $type instanceof NullableType,
 			useDefaultForUnexpected: $property->attributes()->has(UseDefaultForUnexpected::class),
+			reportUnexpectedDefault: $this->reportUnexpectedDefault,
 		);
 	}
 

tests/Integration/JsonSerializationTest.php

@@ -23,6 +23,7 @@
 use Tests\Stubs\BackedEnumStub;
 use Tests\Stubs\ClassStub;
 use Tests\Stubs\NestedStub;
+use Tests\Stubs\UseDefaultStub;
 use Tests\Stubs\ValueEnumStub;
 use Throwable;
 
@@ -335,6 +336,18 @@ public static function deserializesProvider(): iterable
 			),
 			'{"primitive":1,"nested":{},"date":"2020-01-01T00:00:00.000000Z","carbonImmutable":"2020-01-01T00:00:00.000000Z"}',
 		];
+
+		yield '#[UseDefaultForUnexpected] with unexpected values' => [
+			new NamedType(UseDefaultStub::class),
+			new UseDefaultStub(),
+			'{"null":"unknown value","enum":"also unknown"}',
+		];
+
+		yield '#[UseDefaultForUnexpected] with expected values' => [
+			new NamedType(UseDefaultStub::class),
+			new UseDefaultStub(BackedEnumStub::ONE, BackedEnumStub::TWO),
+			'{"null":"one","enum":"two"}',
+		];
 	}
 
 	/**

tests/Stubs/UseDefaultStub.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace Tests\Stubs;
+
+use GoodPhp\Serialization\TypeAdapter\Primitive\ClassProperties\Property\UseDefaultForUnexpected;
+
+class UseDefaultStub
+{
+	public function __construct(
+		#[UseDefaultForUnexpected]
+		public ?BackedEnumStub $null = null,
+		#[UseDefaultForUnexpected]
+		public BackedEnumStub $enum = BackedEnumStub::ONE,
+	) {}
+}