feat(validation): support nullable enums (#1739)

Co-authored-by: Brent Roose <[email protected]>

Author: laylatichy

packages/validation/src/Rules/IsEnum.php

@@ -26,6 +26,7 @@ public function __construct(
         private string $enum,
         private array $only = [],
         private array $except = [],
+        private bool $orNull = false,
     ) {
         if (! enum_exists($this->enum)) {
             throw new UnexpectedValueException(sprintf(
@@ -37,6 +38,10 @@ public function __construct(
 
     public function isValid(mixed $value): bool
     {
+        if ($this->orNull && $value === null) {
+            return true;
+        }
+
         if ($value instanceof $this->enum) {
             return $this->isDesirable($value);
         }

packages/validation/src/Validator.php

@@ -139,7 +139,7 @@ public function validateValueForProperty(PropertyReflector $property, mixed $val
         }
 
         if ($property->getType()->isEnum()) {
-            $rules[] = new IsEnum($property->getType()->getName());
+            $rules[] = new IsEnum(enum: $property->getType()->getName(), orNull: $property->isNullable());
         }
 
         return $this->validateValue($value, $rules);

packages/validation/tests/Rules/IsEnumTest.php

@@ -70,4 +70,22 @@ public function test_validating_except_backed_enums(): void
         $this->assertTrue($rule->except(SomeBackedEnum::Test2)->isValid('one'));
         $this->assertFalse($rule->except(SomeBackedEnum::Test)->isValid('one'));
     }
+
+    public function test_validating_with_or_null(): void
+    {
+        $rule = new IsEnum(enum: SomeEnum::class, orNull: true);
+
+        $this->assertTrue(condition: $rule->isValid(value: null));
+        $this->assertFalse(condition: $rule->isValid(value: 'NOPE_NOT_HERE'));
+        $this->assertTrue(condition: $rule->isValid(value: 'VALUE_1'));
+    }
+
+    public function test_failing_to_validate_with_or_null(): void
+    {
+        $rule = new IsEnum(enum: SomeEnum::class, orNull: false);
+
+        $this->assertFalse(condition: $rule->isValid(value: null));
+        $this->assertFalse(condition: $rule->isValid(value: 'NOPE_NOT_HERE'));
+        $this->assertTrue(condition: $rule->isValid(value: 'VALUE_1'));
+    }
 }