[PHP][CodingStyle] string class to ::class

config/level/coding-style/coding-style.yaml

@@ -14,3 +14,6 @@ services:
     Rector\CodingStyle\Rector\ClassConst\SplitGroupedConstantsAndPropertiesRector: ~
     Rector\CodingStyle\Rector\String_\SplitStringClassConstantToClassConstFetchRector: ~
     Rector\CodingStyle\Rector\Namespace_\ImportFullyQualifiedNamesRector: ~
+
+    # 'ClassName' → ClassName::class
+    Rector\Php\Rector\String_\StringClassNameToClassConstantRector: ~

config/level/php/php55.yaml

@@ -0,0 +1,2 @@
+services:
+    Rector\Php\Rector\String_\StringClassNameToClassConstantRector: ~

packages/Php/src/Rector/String_/StringClassNameToClassConstantRector.php

@@ -0,0 +1,104 @@
+<?php declare(strict_types=1);
+
+namespace Rector\Php\Rector\String_;
+
+use PhpParser\Node;
+use PhpParser\Node\Scalar\String_;
+use Rector\Rector\AbstractRector;
+use Rector\RectorDefinition\CodeSample;
+use Rector\RectorDefinition\RectorDefinition;
+use Rector\Util\RectorStrings;
+
+/**
+ * @see https://wiki.php.net/rfc/class_name_scalars
+ */
+final class StringClassNameToClassConstantRector extends AbstractRector
+{
+    /**
+     * @var string[]
+     */
+    private $classesToSkip = [];
+
+    /**
+     * @param string[] $classesToSkip
+     */
+    public function __construct(array $classesToSkip = [
+        'Error', // can be string
+    ])
+    {
+        $this->classesToSkip = $classesToSkip;
+    }
+
+    public function getDefinition(): RectorDefinition
+    {
+        return new RectorDefinition('Replace string class names by <class>::class constant', [
+            new CodeSample(
+                <<<'CODE_SAMPLE'
+class AnotherClass
+{
+}
+
+class SomeClass
+{
+    public function run()
+    {
+        return 'AnotherClass';
+    }
+}
+CODE_SAMPLE
+                ,
+                <<<'CODE_SAMPLE'
+class AnotherClass
+{
+}
+
+class SomeClass
+{
+    public function run()
+    {
+        return \AnotherClass::class;
+    }
+}
+CODE_SAMPLE
+            ),
+        ]);
+    }
+
+    /**
+     * @return string[]
+     */
+    public function getNodeTypes(): array
+    {
+        return [String_::class];
+    }
+
+    /**
+     * @param String_ $node
+     */
+    public function refactor(Node $node): ?Node
+    {
+        $classLikeName = $node->value;
+        if (! $this->classLikeExists($classLikeName)) {
+            return null;
+        }
+
+        if (RectorStrings::isInArrayInsensitive($classLikeName, $this->classesToSkip)) {
+            return null;
+        }
+
+        return new Node\Expr\ClassConstFetch(new Node\Name\FullyQualified($classLikeName), 'class');
+    }
+
+    private function classLikeExists(string $classLikeName): bool
+    {
+        if (class_exists($classLikeName)) {
+            return true;
+        }
+
+        if (interface_exists($classLikeName)) {
+            return true;
+        }
+
+        return trait_exists($classLikeName);
+    }
+}

packages/Php/tests/Rector/String_/StringClassNameToClassConstantRector/Fixture/fixture.php.inc

@@ -0,0 +1,35 @@
+<?php
+
+namespace Rector\Php\Tests\Rector\String_\StringClassNameToClassConstantRector\Fixture;
+
+class AnotherClass
+{
+}
+
+class SomeClass
+{
+    public function run()
+    {
+        return 'Rector\Php\Tests\Rector\String_\StringClassNameToClassConstantRector\Fixture\AnotherClass';
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Php\Tests\Rector\String_\StringClassNameToClassConstantRector\Fixture;
+
+class AnotherClass
+{
+}
+
+class SomeClass
+{
+    public function run()
+    {
+        return \Rector\Php\Tests\Rector\String_\StringClassNameToClassConstantRector\Fixture\AnotherClass::class;
+    }
+}
+
+?>

packages/Php/tests/Rector/String_/StringClassNameToClassConstantRector/Fixture/skip_error.php.inc

@@ -0,0 +1,13 @@
+<?php
+
+namespace Rector\Php\Tests\Rector\String_\StringClassNameToClassConstantRector\Fixture;
+
+class SkipError
+{
+    public function run()
+    {
+        return 'Error';
+
+        return 'ERROR';
+    }
+}

packages/Php/tests/Rector/String_/StringClassNameToClassConstantRector/StringClassNameToClassConstantRectorTest.php

@@ -0,0 +1,19 @@
+<?php declare(strict_types=1);
+
+namespace Rector\Php\Tests\Rector\String_\StringClassNameToClassConstantRector;
+
+use Rector\Php\Rector\String_\StringClassNameToClassConstantRector;
+use Rector\Testing\PHPUnit\AbstractRectorTestCase;
+
+final class StringClassNameToClassConstantRectorTest extends AbstractRectorTestCase
+{
+    public function test(): void
+    {
+        $this->doTestFiles([__DIR__ . '/Fixture/fixture.php.inc', __DIR__ . '/Fixture/skip_error.php.inc']);
+    }
+
+    protected function getRectorClass(): string
+    {
+        return StringClassNameToClassConstantRector::class;
+    }
+}

src/Util/RectorStrings.php

@@ -18,6 +18,20 @@ public static function splitCommandToItems(string $command): array
         return $privatesCaller->callPrivateMethod(new StringInput(''), 'tokenize', $command);
     }
 
+    /**
+     * @param string[] $array
+     */
+    public static function isInArrayInsensitive(string $checkedItem, array $array): bool
+    {
+        foreach ($array as $item) {
+            if (Strings::lower($item) === Strings::lower($checkedItem)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
     public static function camelCaseToDashes(string $input): string
     {
         return self::camelCaseToGlue($input, '-');