Accept any callable as callback in CallbackIterator

src/Model/CallbackIterator.php

@@ -17,12 +17,13 @@
 
 namespace MongoDB\Model;
 
-use Closure;
 use Iterator;
 use IteratorIterator;
 use ReturnTypeWillChange;
 use Traversable;
 
+use function call_user_func;
+
 /**
  * Iterator to apply a callback before returning an element
  *
@@ -35,20 +36,20 @@
  */
 class CallbackIterator implements Iterator
 {
-    /** @var Closure(TValue, TKey): TCallbackValue */
-    private $callback;
+    /** @var callable(TValue, TKey): TCallbackValue */
+    private $callable;
 
     /** @var Iterator<TKey, TValue> */
     private $iterator;
 
     /**
-     * @param Traversable<TKey, TValue>             $traversable
-     * @param Closure(TValue, TKey): TCallbackValue $callback
+     * @param Traversable<TKey, TValue>              $traversable
+     * @param callable(TValue, TKey): TCallbackValue $callable
      */
-    public function __construct(Traversable $traversable, Closure $callback)
+    public function __construct(Traversable $traversable, callable $callable)
     {
         $this->iterator = $traversable instanceof Iterator ? $traversable : new IteratorIterator($traversable);
-        $this->callback = $callback;
+        $this->callable = $callable;
     }
 
     /**
@@ -58,7 +59,7 @@ public function __construct(Traversable $traversable, Closure $callback)
     #[ReturnTypeWillChange]
     public function current()
     {
-        return ($this->callback)($this->iterator->current(), $this->iterator->key());
+        return call_user_func($this->callable, $this->iterator->current(), $this->iterator->key());
     }
 
     /**

tests/Model/CallbackIteratorTest.php

@@ -8,6 +8,7 @@
 
 use function array_keys;
 use function iterator_to_array;
+use function strrev;
 
 class CallbackIteratorTest extends TestCase
 {
@@ -49,4 +50,21 @@ function ($value, $key) use (&$expectedKey, $expectedKeys) {
 
         $this->assertSame(['a' => 2, 'b' => 4, 'c' => 6], iterator_to_array($callbackIterator));
     }
+
+    public function testWithCallable(): void
+    {
+        $original = ['foo', 'bar', 'baz'];
+
+        $callbackIterator = new CallbackIterator(
+            new ArrayIterator($original),
+            [self::class, 'reverseValue']
+        );
+
+        $this->assertSame(['oof', 'rab', 'zab'], iterator_to_array($callbackIterator));
+    }
+
+    public static function reverseValue($value, $key)
+    {
+        return strrev($value);
+    }
 }