From 9de1b3db98c03f8d0fc7a77656aa420ab649e611 Mon Sep 17 00:00:00 2001
From: Ilia Alshanetsky <ilia@ilia.ws>
Date: Sat, 22 Aug 2026 12:36:24 -0400
Subject: [PATCH] Fix array destructuring from a Traversable

Sequence destructuring compiled its right-hand side straight into
array_pad(), which throws "Argument #1 must be of type array" when a
Traversable is provided:

    {% do [a, b] = items %}

with an IteratorAggregate/Generator for items crashed with a TypeError.
Coerce Traversables via iterator_to_array() before padding, matching
the behavior of the spread, merge, and slice operations which already
accept Traversables.
---
 .../Binary/SequenceDestructuringSetBinary.php          | 10 +++++++++-
 tests/Fixtures/expressions/set.test                    |  9 ++++++++-
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/Node/Expression/Binary/SequenceDestructuringSetBinary.php b/src/Node/Expression/Binary/SequenceDestructuringSetBinary.php
index 394e7c053..0667b4645 100644
--- a/src/Node/Expression/Binary/SequenceDestructuringSetBinary.php
+++ b/src/Node/Expression/Binary/SequenceDestructuringSetBinary.php
@@ -57,7 +57,15 @@ class SequenceDestructuringSetBinary extends AbstractBinary
                 $compiler->raw('$context[')->repr($name)->raw(']');
             }
         }
-        $compiler->raw('] = array_pad(')->subcompile($this->getNode('right'))->raw(', ')->repr(\count($this->variables))->raw(', null)');
+        $compiler->raw('] = array_pad((');
+        $var = '$'.$compiler->getVarName();
+        $compiler
+            ->raw($var.' = ')
+            ->subcompile($this->getNode('right'))
+            ->raw(') instanceof \Traversable ? iterator_to_array('.$var.') : '.$var)
+            ->raw(', ')
+            ->repr(\count($this->variables))
+            ->raw(', null)');
     }
 
     public function operator(Compiler $compiler): Compiler
diff --git a/tests/Fixtures/expressions/set.test b/tests/Fixtures/expressions/set.test
index 439e1648f..cb54d24d4 100644
--- a/tests/Fixtures/expressions/set.test
+++ b/tests/Fixtures/expressions/set.test
@@ -22,6 +22,9 @@ Twig supports the "=" operator (assignment)
 {% do {first_name, last_name} = user_map %}{{ first_name }} {{ last_name }}
 {% do {name} = user_obj %}{{ name }}
 
+# Array destructuring from a Traversable
+{% do [p, q] = pair_traversable %}{{ p }} {{ q }}
+
 # Object destructuring with renaming
 {% do {name: userName, email: userEmail} = user %}{{ userName }} {{ userEmail }}
 {% do {first_name: first, last_name: last} = user_map %}{{ first }} {{ last }}
@@ -34,7 +37,8 @@ return [
     'user_obj' => new class {
         public function getName() { return 'Fabien'; }
     },
-    'null_obj' => null
+    'null_obj' => null,
+    'pair_traversable' => new ArrayIterator(['Fabien', 'Potencier']),
 ]
 --EXPECT--
 4
@@ -54,6 +58,9 @@ Fabien fabien@example.com
 Fabien Potencier
 Fabien
 
+# Array destructuring from a Traversable
+Fabien Potencier
+
 # Object destructuring with renaming
 Fabien fabien@example.com
 Fabien Potencier