fix renaming class to existing one [closes #1438]

packages/Renaming/src/Exception/InvalidPhpCodeException.php

@@ -0,0 +1,9 @@
+<?php declare(strict_types=1);
+
+namespace Rector\Renaming\Exception;
+
+use Exception;
+
+final class InvalidPhpCodeException extends Exception
+{
+}

packages/Renaming/src/Rector/Class_/RenameClassRector.php

@@ -17,12 +17,15 @@ use PhpParser\Node\Stmt\Use_;
 use PhpParser\Node\Stmt\UseUse;
 use PHPStan\Type\ObjectType;
 use Rector\CodingStyle\Naming\ClassNaming;
+use Rector\NodeTypeResolver\ClassExistenceStaticHelper;
 use Rector\NodeTypeResolver\Node\AttributeKey;
 use Rector\PhpDoc\PhpDocClassRenamer;
 use Rector\PHPStan\Type\FullyQualifiedObjectType;
 use Rector\Rector\AbstractRector;
 use Rector\RectorDefinition\ConfiguredCodeSample;
 use Rector\RectorDefinition\RectorDefinition;
+use Rector\Renaming\Exception\InvalidPhpCodeException;
+use ReflectionClass;
 
 /**
  * @see \Rector\Renaming\Tests\Rector\Class_\RenameClassRector\RenameClassRectorTest
@@ -262,6 +265,8 @@ PHP
         $newClassNamePart = $this->classNaming->getShortName($newName);
         $newNamespacePart = $this->classNaming->getNamespace($newName);
 
+        $this->ensureClassWillNotBeDuplicate($newName, $name);
+
         $classLike->name = new Identifier($newClassNamePart);
 
         // Old class did not have any namespace, we need to wrap class with Namespace_ node
@@ -323,4 +328,20 @@ PHP
 
         $this->phpDocClassRenamer->changeTypeInAnnotationTypes($node, $this->oldToNewClasses);
     }
+
+    private function ensureClassWillNotBeDuplicate(string $newName, string $oldName): void
+    {
+        if (! ClassExistenceStaticHelper::doesClassLikeExist($newName)) {
+            return;
+        }
+
+        $classReflection = new ReflectionClass($newName);
+
+        throw new InvalidPhpCodeException(sprintf(
+            'Renaming class "%s" to "%s" would create a duplicated class/interface/trait (already existing in "%s") and cause PHP code to be invalid.',
+            $oldName,
+            $newName,
+            $classReflection->getFileName()
+        ));
+    }
 }

packages/Renaming/tests/Rector/Class_/RenameClassRector/Fixture/DuplicatedClass.php

@@ -0,0 +1,7 @@
+<?php
+
+namespace Rector\Renaming\Tests\Rector\Class_\RenameClassRector\Fixture;
+
+class DuplicatedClass
+{
+}

packages/Renaming/tests/Rector/Class_/RenameClassRector/Fixture/skip_duplicated_class.php.inc

@@ -0,0 +1,7 @@
+<?php
+
+namespace Rector\Renaming\Tests\Rector\Class_\RenameClassRector\Fixture;
+
+class SingularClass
+{
+}

packages/Renaming/tests/Rector/Class_/RenameClassRector/RenameClassRectorTest.php

@@ -5,7 +5,9 @@ namespace Rector\Renaming\Tests\Rector\Class_\RenameClassRector;
 use Iterator;
 use Manual\Twig\TwigFilter;
 use Manual_Twig_Filter;
+use Rector\Renaming\Exception\InvalidPhpCodeException;
 use Rector\Renaming\Rector\Class_\RenameClassRector;
+use Rector\Renaming\Tests\Rector\Class_\RenameClassRector\Fixture\DuplicatedClass;
 use Rector\Renaming\Tests\Rector\Class_\RenameClassRector\Source\AbstractManualExtension;
 use Rector\Renaming\Tests\Rector\Class_\RenameClassRector\Source\NewClass;
 use Rector\Renaming\Tests\Rector\Class_\RenameClassRector\Source\NewClassWithoutTypo;
@@ -51,6 +53,15 @@ final class RenameClassRectorTest extends AbstractRectorTestCase
         yield [__DIR__ . '/Fixture/rename_class_to_class_without_namespace.php.inc'];
     }
 
+    /**
+     * @see https://github.com/rectorphp/rector/issues/1438
+     */
+    public function testClassNameDuplication(): void
+    {
+        $this->expectException(InvalidPhpCodeException::class);
+        $this->doTestFile(__DIR__ . '/Fixture/skip_duplicated_class.php.inc');
+    }
+
     /**
      * @return mixed[]
      */
@@ -73,6 +84,8 @@ final class RenameClassRectorTest extends AbstractRectorTestCase
                     'MyOldClass' => 'MyNamespace\MyNewClass',
                     'AnotherMyOldClass' => 'AnotherMyNewClass',
                     'MyNamespace\AnotherMyClass' => 'MyNewClassWithoutNamespace',
+                    // test duplicated class - @see https://github.com/rectorphp/rector/issues/1438
+                    'Rector\Renaming\Tests\Rector\Class_\RenameClassRector\Fixture\SingularClass' => DuplicatedClass::class,
                 ],
             ],
         ];