Keep PHP 8.1 enums as is

Author: Slamdunk

fixtures/f012/Suit.php

@@ -0,0 +1,11 @@
+<?php declare(strict_types=1);
+
+namespace DeepCopy\f012;
+
+enum Suit: string
+{
+    case Hearts = 'Hearts';
+    case Diamonds = 'Diamonds';
+    case Clubs = 'Clubs';
+    case Spades = 'Spades';
+}

src/DeepCopy/DeepCopy.php

@@ -140,6 +140,11 @@ private function recursiveCopy($var)
             return $var;
         }
 
+        // PHP 8.1 Enum
+        if (function_exists('enum_exists') && enum_exists($var::class)) {
+            return $var;
+        }
+
         // Object
         return $this->copyObject($var);
     }

tests/DeepCopyTest/DeepCopyTest.php

@@ -19,6 +19,7 @@
 use DeepCopy\f008;
 use DeepCopy\f009;
 use DeepCopy\f011;
+use DeepCopy\f012\Suit;
 use DeepCopy\Filter\KeepFilter;
 use DeepCopy\Filter\SetNullFilter;
 use DeepCopy\Matcher\PropertyNameMatcher;
@@ -495,6 +496,18 @@ public function test_it_ignores_uninitialized_typed_properties()
         $this->assertFalse(isset($copy->foo));
     }
 
+    /**
+     * @requires PHP 8.1
+     */
+    public function test_it_keeps_enums()
+    {
+        $enum = Suit::Clubs;
+
+        $copy = (new DeepCopy())->copy($enum);
+
+        $this->assertSame($enum, $copy);
+    }
+
     private function assertEqualButNotSame($expected, $val)
     {
         $this->assertEquals($expected, $val);