From afb2e45b6a8ca9b99a50e64b3c766c6c9ba09382 Mon Sep 17 00:00:00 2001
From: Tomas Votruba <tomas.vot@gmail.com>
Date: Wed, 23 Sep 2026 14:06:23 +0200
Subject: [PATCH] [Renaming] Throw on same old and new class in
 RenameClassRector configuration

---
 .../Rector/Name/RenameClassRector.php         | 10 ++++++++
 .../SameOldToNewClassTest.php                 | 23 +++++++++++++++++++
 2 files changed, 33 insertions(+)
 create mode 100644 tests/Renaming/Rector/Name/RenameClassRector/SameOldToNewClassTest.php

diff --git a/rules/Renaming/Rector/Name/RenameClassRector.php b/rules/Renaming/Rector/Name/RenameClassRector.php
index e98cbd736ca..a09de4ae8c0 100644
--- a/rules/Renaming/Rector/Name/RenameClassRector.php
+++ b/rules/Renaming/Rector/Name/RenameClassRector.php
@@ -15,6 +15,7 @@
 use PHPStan\Reflection\ReflectionProvider;
 use Rector\Configuration\RenamedClassesDataCollector;
 use Rector\Contract\Rector\ConfigurableRectorInterface;
+use Rector\Exception\Configuration\InvalidConfigurationException;
 use Rector\NodeTypeResolver\Node\AttributeKey;
 use Rector\Rector\AbstractRector;
 use Rector\Renaming\NodeManipulator\ClassRenamer;
@@ -119,6 +120,15 @@ public function configure(array $configuration): void
         Assert::allString($configuration);
         Assert::allString(array_keys($configuration));
 
+        foreach ($configuration as $oldClass => $newClass) {
+            if ($oldClass === $newClass) {
+                throw new InvalidConfigurationException(sprintf(
+                    'Rename "%s" class to a different one, as the old and new class name are the same',
+                    $oldClass
+                ));
+            }
+        }
+
         $this->renamedClassesDataCollector->addOldToNewClasses($configuration);
     }
 
diff --git a/tests/Renaming/Rector/Name/RenameClassRector/SameOldToNewClassTest.php b/tests/Renaming/Rector/Name/RenameClassRector/SameOldToNewClassTest.php
new file mode 100644
index 00000000000..0a595021233
--- /dev/null
+++ b/tests/Renaming/Rector/Name/RenameClassRector/SameOldToNewClassTest.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Tests\Renaming\Rector\Name\RenameClassRector;
+
+use Rector\Exception\Configuration\InvalidConfigurationException;
+use Rector\Renaming\Rector\Name\RenameClassRector;
+use Rector\Testing\PHPUnit\AbstractLazyTestCase;
+
+final class SameOldToNewClassTest extends AbstractLazyTestCase
+{
+    public function test(): void
+    {
+        $renameClassRector = $this->make(RenameClassRector::class);
+
+        $this->expectException(InvalidConfigurationException::class);
+
+        $renameClassRector->configure([
+            'App\SomeClass' => 'App\SomeClass',
+        ]);
+    }
+}