From 279fe13b224353fcfe3f1855d2d411eff38ec448 Mon Sep 17 00:00:00 2001
From: Fabien Potencier <fabien@potencier.org>
Date: Wed, 3 Jun 2026 22:09:09 +0200
Subject: [PATCH] Fix nested block() resolution when a directly rendered block
 calls parent()

---
 CHANGELOG                                     |  1 +
 src/Template.php                              |  2 ++
 .../functions/block_with_template_parent.test | 28 +++++++++++++++++++
 3 files changed, 31 insertions(+)
 create mode 100644 tests/Fixtures/functions/block_with_template_parent.test

diff --git a/CHANGELOG b/CHANGELOG
index 1d347b542..a266a8a49 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,5 +1,6 @@
 # 3.27.2 (2026-XX-XX)
 
+ * Fix nested `block()` calls to resolve against the overriding template when a block rendered through `block(name, template)` calls `parent()`
  * Stop reporting a skipped test in `IntegrationTestCase` when there is no legacy test to run
  * Make the `IntegrationTestCase` and `NodeTestCase` test helpers compatible with PHPUnit 11
  * Cast printed expressions to string so values that cannot be converted to a string (arrays, non-`Stringable` objects, ...) report a usable stack trace at the print location
diff --git a/src/Template.php b/src/Template.php
index e32c85d0f..3d74460b0 100644
--- a/src/Template.php
+++ b/src/Template.php
@@ -440,6 +440,8 @@ abstract class Template
         } elseif (isset($this->blocks[$name])) {
             $template = $this->blocks[$name][0];
             $block = $this->blocks[$name][1];
+            // expose this template's own blocks so nested block() calls resolve against them when the block is rendered directly (e.g. block(name, template))
+            $blocks = array_merge($this->blocks, $blocks);
         } else {
             $template = null;
             $block = null;
diff --git a/tests/Fixtures/functions/block_with_template_parent.test b/tests/Fixtures/functions/block_with_template_parent.test
new file mode 100644
index 000000000..17a2698ea
--- /dev/null
+++ b/tests/Fixtures/functions/block_with_template_parent.test
@@ -0,0 +1,28 @@
+--TEST--
+"block" function with a template argument resolves nested "block" calls against the overriding template through parent()
+--TEMPLATE--
+{{ block('block1', 'theme.html.twig') }}
+--TEMPLATE(theme.html.twig)--
+{% extends 'base.html.twig' %}
+
+{%- block block1 -%}
+    {{- parent() -}}
+    BLOCK1THEME/
+{%- endblock -%}
+
+{%- block block2 -%}
+    BLOCK2THEME/
+{%- endblock -%}
+--TEMPLATE(base.html.twig)--
+{%- block block1 -%}
+    BLOCK1BASE/
+    {{- block('block2') -}}
+{%- endblock -%}
+
+{%- block block2 -%}
+    BLOCK2BASE/
+{%- endblock -%}
+--DATA--
+return []
+--EXPECT--
+BLOCK1BASE/BLOCK2THEME/BLOCK1THEME/