From 4d5d233776d840b6272d7b94e85e459d804f35d3 Mon Sep 17 00:00:00 2001
From: Fabien Potencier <fabien@potencier.org>
Date: Tue, 22 Sep 2026 21:30:14 +0100
Subject: [PATCH] Compile the generator guard as an unreachable yield instead
 of a yield from

---
 CHANGELOG                 | 1 +
 src/Node/BlockNode.php    | 2 +-
 src/Node/CaptureNode.php  | 2 +-
 src/Node/ModuleNode.php   | 2 +-
 tests/Node/BlockTest.php  | 2 +-
 tests/Node/MacroTest.php  | 4 ++--
 tests/Node/MacrosTest.php | 2 +-
 tests/Node/ModuleTest.php | 2 +-
 tests/Node/SetTest.php    | 4 ++--
 9 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG
index de9dd304e..fdf14d885 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -2,6 +2,7 @@
 
  * Fix the escaping safe analysis retaining every compiled template node for the lifetime of the environment
  * Speed up loading a template that the environment has already loaded
+ * Speed up rendering by compiling a cheaper generator guard into templates
  * Fix `IntlExtension` letting the pattern derived from a date formatter prototype override an explicit locale
  * Fix `IntlExtension` not honoring the locale of a date formatter prototype configured with no date and time styles
  * Speed up macro calls
diff --git a/src/Node/BlockNode.php b/src/Node/BlockNode.php
index b4f939cf6..b736b2d4c 100644
--- a/src/Node/BlockNode.php
+++ b/src/Node/BlockNode.php
@@ -42,7 +42,7 @@ class BlockNode extends Node
 
         $compiler
             ->subcompile($this->getNode('body'))
-            ->write("yield from [];\n")
+            ->write("return; yield;\n")
             ->outdent()
             ->write("}\n\n")
         ;
diff --git a/src/Node/CaptureNode.php b/src/Node/CaptureNode.php
index 3b7f0b6d8..2f4ef5a79 100644
--- a/src/Node/CaptureNode.php
+++ b/src/Node/CaptureNode.php
@@ -39,7 +39,7 @@ class CaptureNode extends Node
             ->raw("(function () use (&\$context, \$macros, \$blocks) {\n")
             ->indent()
             ->subcompile($this->getNode('body'))
-            ->write("yield from [];\n")
+            ->write("return; yield;\n")
             ->outdent()
             ->write('})()')
         ;
diff --git a/src/Node/ModuleNode.php b/src/Node/ModuleNode.php
index 5c27a10ea..8f2283475 100644
--- a/src/Node/ModuleNode.php
+++ b/src/Node/ModuleNode.php
@@ -379,7 +379,7 @@ final class ModuleNode extends Node implements CoercesChildrenToStringInterface
         $compiler->subcompile($this->getNode('display_end'));
 
         if (!$this->hasNode('parent')) {
-            $compiler->write("yield from [];\n");
+            $compiler->write("return; yield;\n");
         }
 
         $compiler
diff --git a/tests/Node/BlockTest.php b/tests/Node/BlockTest.php
index 8606484ba..0006fb16e 100644
--- a/tests/Node/BlockTest.php
+++ b/tests/Node/BlockTest.php
@@ -49,7 +49,7 @@ public function block_foo(array \$context, array \$blocks = []): iterable
 {
     \$macros = \$this->macros;
     yield "foo";
-    yield from [];
+    return; yield;
 }
 EOF, new Environment(new ArrayLoader()),
         ];
diff --git a/tests/Node/MacroTest.php b/tests/Node/MacroTest.php
index 29a0b5cd8..08940c845 100644
--- a/tests/Node/MacroTest.php
+++ b/tests/Node/MacroTest.php
@@ -77,7 +77,7 @@ new \\Twig\\TwigMacro("foo", function (\$foo = null, \$bar = "Foo", \$_underscor
 
     return ('' === \$tmp = implode('', iterator_to_array((function () use (&\$context, \$macros, \$blocks) {
         yield "foo";
-        yield from [];
+        return; yield;
     })(), false))) ? '' : new Markup(\$tmp, \$this->env->getCharset());
 }, ["foo" => true, "bar" => true, "_underscore" => true], false)
 EOF, new Environment(new ArrayLoader(), ['use_yield' => true]),
@@ -98,7 +98,7 @@ new \\Twig\\TwigMacro("foo", function (\$foo = null, \$bar = "Foo", \$_underscor
 
     return ('' === \$tmp = \\Twig\\Extension\\CoreExtension::captureOutput((function () use (&\$context, \$macros, \$blocks) {
         yield "foo";
-        yield from [];
+        return; yield;
     })())) ? '' : new Markup(\$tmp, \$this->env->getCharset());
 }, ["foo" => true, "bar" => true, "_underscore" => true], false)
 EOF, new Environment(new ArrayLoader(), ['use_yield' => false]),
diff --git a/tests/Node/MacrosTest.php b/tests/Node/MacrosTest.php
index 7a5687e69..1d2687027 100644
--- a/tests/Node/MacrosTest.php
+++ b/tests/Node/MacrosTest.php
@@ -74,7 +74,7 @@ protected function loadDeclaredMacros(): array
 
             return ('' === \$tmp = implode('', iterator_to_array((function () use (&\$context, \$macros, \$blocks) {
                 yield "foo";
-                yield from [];
+                return; yield;
             })(), false))) ? '' : new Markup(\$tmp, \$this->env->getCharset());
         }, ["foo" => true], false),
     ];
diff --git a/tests/Node/ModuleTest.php b/tests/Node/ModuleTest.php
index 670309367..8988eef83 100644
--- a/tests/Node/ModuleTest.php
+++ b/tests/Node/ModuleTest.php
@@ -159,7 +159,7 @@ class __TwigTemplate_%x extends Template
         \$macros = \$this->macros;
         // line 1
         yield "foo";
-        yield from [];
+        return; yield;
     }
 
     /**
diff --git a/tests/Node/SetTest.php b/tests/Node/SetTest.php
index 4cfd85aca..4230578ee 100644
--- a/tests/Node/SetTest.php
+++ b/tests/Node/SetTest.php
@@ -65,7 +65,7 @@ EOF
 // line 1
 \$context["foo"] = ('' === \$tmp = implode('', iterator_to_array((function () use (&\$context, \$macros, \$blocks) {
     yield "foo";
-    yield from [];
+    return; yield;
 })(), false))) ? '' : new Markup(\$tmp, \$this->env->getCharset());
 EOF, new Environment(new ArrayLoader(), ['use_yield' => true]),
         ];
@@ -74,7 +74,7 @@ EOF, new Environment(new ArrayLoader(), ['use_yield' => true]),
 // line 1
 $context["foo"] = ('' === $tmp = \Twig\Extension\CoreExtension::captureOutput((function () use (&$context, $macros, $blocks) {
     yield "foo";
-    yield from [];
+    return; yield;
 })())) ? '' : new Markup($tmp, $this->env->getCharset());
 EOF, new Environment(new ArrayLoader(), ['use_yield' => false]),
         ];