From 6b9a5c6d4ecc00e1f1d70c1f35bc0d4ebf5c0ee9 Mon Sep 17 00:00:00 2001
From: Fabien Potencier <fabien@potencier.org>
Date: Wed, 1 Jan 2025 14:38:42 +0100
Subject: [PATCH] Add VariableOptimizerNodeVisitor

---
 .../VariableOptimizerNodeVisitor.php          | 56 +++++++++++++++++++
 .../VariableOptimizerNodeVisitorTest.php      | 51 +++++++++++++++++
 2 files changed, 107 insertions(+)
 create mode 100644 src/NodeVisitor/VariableOptimizerNodeVisitor.php
 create mode 100644 tests/NodeVisitor/VariableOptimizerNodeVisitorTest.php

diff --git a/src/NodeVisitor/VariableOptimizerNodeVisitor.php b/src/NodeVisitor/VariableOptimizerNodeVisitor.php
new file mode 100644
index 00000000000..af243137d7b
--- /dev/null
+++ b/src/NodeVisitor/VariableOptimizerNodeVisitor.php
@@ -0,0 +1,56 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Twig\NodeVisitor;
+
+use Twig\Environment;
+use Twig\Node\Expression\NameExpression;
+use Twig\Node\ModuleNode;
+use Twig\Node\Node;
+use Twig\Node\TypesNode;
+
+/**
+ * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @internal
+ */
+final class VariableOptimizerNodeVisitor implements NodeVisitorInterface
+{
+    private array $types = [];
+
+    public function enterNode(Node $node, Environment $env): Node
+    {
+        if ($node instanceof TypesNode) {
+            $this->types = array_merge($this->types, $node->getAttribute('mapping'));
+        }
+
+        // A NameExpression is always defined if the variable is typed and not optional
+        if ($node instanceof NameExpression && isset($this->types[$node->getAttribute('name')]) && !$this->types[$node->getAttribute('name')]['optional']) {
+            $node->setAttribute('always_defined', true);
+        }
+
+        return $node;
+    }
+
+    public function leaveNode(Node $node, Environment $env): ?Node
+    {
+        if ($node instanceof ModuleNode) {
+            $this->types = [];
+        }
+
+        return $node;
+    }
+
+    public function getPriority(): int
+    {
+        return 255;
+    }
+}
diff --git a/tests/NodeVisitor/VariableOptimizerNodeVisitorTest.php b/tests/NodeVisitor/VariableOptimizerNodeVisitorTest.php
new file mode 100644
index 00000000000..e640a6e6b26
--- /dev/null
+++ b/tests/NodeVisitor/VariableOptimizerNodeVisitorTest.php
@@ -0,0 +1,51 @@
+<?php
+
+namespace Twig\Tests\NodeVisitor;
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+use PHPUnit\Framework\TestCase;
+use Twig\Environment;
+use Twig\Loader\ArrayLoader;
+use Twig\NodeTraverser;
+use Twig\NodeVisitor\VariableOptimizerNodeVisitor;
+use Twig\Source;
+
+class VariableOptimizerNodeVisitorTest extends TestCase
+{
+    /**
+     * @dataProvider getTypedVariablesData
+     */
+    public function testTypedVariables(string $template, string $expected)
+    {
+        $env = new Environment(new ArrayLoader(), ['autoescape' => false]);
+        $node = $env->parse($env->tokenize(new Source($template, 'index')));
+        $traverser = new NodeTraverser($env, [new VariableOptimizerNodeVisitor()]);
+        $node = $traverser->traverse($node);
+
+        $this->assertSame($expected, $this->stripCode($env->compile($node->getNode('body'))));
+    }
+
+    public function getTypedVariablesData()
+    {
+        yield 'regular' => ['{{ foo }}', 'yield ($context["foo"] ?? null);'];
+        yield 'typed_optional' => ['{% types { foo?: "string" } %}{{ foo }}', 'yield ($context["foo"] ?? null);'];
+        yield 'typed' => ['{% types { foo: "string" } %}{{ foo }}', 'yield $context["foo"];'];
+
+        yield 'is_defined_test' => ['{{ foo is defined }}', 'yield array_key_exists("foo", $context);'];
+        yield 'is_defined_test_typed_optional' => ['{% types { foo?: "string" } %}{{ foo is defined }}', 'yield array_key_exists("foo", $context);'];
+        yield 'is_defined_test_typed' => ['{% types { foo: "string" } %}{{ foo is defined }}', 'yield true;'];
+    }
+
+    private function stripCode(string $code): string
+    {
+        return trim(preg_replace("{^//.*\n}", '', $code));
+    }
+}