Prevent getting items from invalid iterators

The library should not stringify an iterator when it is in an invalid
state because the iterator could throw an exception because of that.

Signed-off-by: Henrique Moody <henriquemoody@gmail.com>

Author: henriquemoody

src/Stringifiers/IteratorObjectStringifier.php

@@ -31,6 +31,10 @@ public function stringify(mixed $raw, int $depth): ?string
             return null;
         }
 
+        if (!$raw->valid()) {
+            return null;
+        }
+
         return $this->quoter->quote(
             $this->format($raw, 'current() =>', $this->stringifier->stringify($raw->current(), $depth + 1)),
             $depth

tests/unit/Stringifiers/IteratorObjectStringifierTest.php

@@ -10,6 +10,7 @@
 
 namespace Respect\Stringifier\Test\Unit\Stringifiers;
 
+use ArrayIterator;
 use ConcreteIterator;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\Test;
@@ -35,6 +36,14 @@ public function itShouldNotStringifyRawValueWhenItIsNotTraversable(): void
         self::assertNull($sut->stringify([1, 2, 3, 4], self::DEPTH));
     }
 
+    #[Test]
+    public function itShouldNotStringifyRawValueWhenItIsIterableThatIsNotValid(): void
+    {
+        $sut = new IteratorObjectStringifier(new FakeStringifier(), new FakeQuoter());
+
+        self::assertNull($sut->stringify(new ArrayIterator([]), self::DEPTH));
+    }
+
     #[Test]
     public function itShouldStringifyRawValueWhenItIsAnInstanceOfIterator(): void
     {