Fix the null coalescing operator when the test returns null

CHANGELOG

@@ -1,5 +1,6 @@
 # 3.17.1 (2024-XX-XX)
 
+ * Fix the null coalescing operator when the test returns null
  * Fix the Elvis operator when used as '? :' instead of '?:'
 
 # 3.17.0 (2024-12-10)

src/Node/Expression/Binary/NullCoalesceBinary.php

@@ -29,8 +29,7 @@ final class NullCoalesceBinary extends AbstractBinary implements OperatorEscapeI
         parent::__construct($left, $right, $lineno);
 
         if (!$left instanceof NameExpression) {
-            $left = clone $left;
-            $test = new DefinedTest($left, new TwigTest('defined'), new EmptyNode(), $left->getTemplateLine());
+            $test = new DefinedTest(clone $left, new TwigTest('defined'), new EmptyNode(), $left->getTemplateLine());
             // for "block()", we don't need the null test as the return value is always a string
             if (!$left instanceof BlockReferenceExpression) {
                 $test = new AndBinary(

tests/Fixtures/tests/null_coalesce.test

@@ -13,8 +13,10 @@ Twig supports the ?? operator
 {{ nope ?? (nada ?? 'OK') }}
 {{ 1 + (nope ?? (nada ?? 2)) }}
 {{ 1 + (nope ?? 3) + (nada ?? 2) }}
+{{ obj.null() ?? 'OK' }}
+{{ obj.empty() ?? 'KO' }}
 --DATA--
-return ['bar' => 'OK', 'foo' => ['bar' => 'OK']]
+return ['bar' => 'OK', 'foo' => ['bar' => 'OK'], 'obj' => new Twig\Tests\TwigTestFoo()]
 --EXPECT--
 OK
 OK
@@ -28,3 +30,4 @@ OK
 OK
 3
 6
+OK

tests/IntegrationTest.php

@@ -77,6 +77,16 @@ class TwigTestFoo implements \Iterator
         return 'foo';
     }
 
+    public function getEmpty()
+    {
+        return '';
+    }
+
+    public function getNull()
+    {
+        return null;
+    }
+
     public function getSelf()
     {
         return $this;