[PHP 8.0] Add ConstantListClassToEnumRector (#2404)

* [PHP 8.0] Add ConstantListClassToEnumRector

* [ci-review] Rector Rectify

Co-authored-by: GitHub Action <action@github.com>

phpstan.neon

@@ -704,3 +704,7 @@ parameters:
         -
             message: '#Class has a static method must so must contains "Static" in its name#'
             path: rules/CodingStyle/Enum/PreferenceSelfThis.php
+
+        # optional rule for PHP 8.0
+        - '#Register "Rector\\Php80\\Rector\\Class_\\ConstantListClassToEnumRector" service to "php80\.php" config set#'
+        - '#Rule Rector\\Php80\\Rector\\Class_\\ConstantListClassToEnumRector must implements Rector\\VersionBonding\\Contract\\MinPhpVersionInterface#'

rules-tests/Php80/Rector/Class_/ConstantListClassToEnumRector/ConstantListClassToEnumRectorTest.php

@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Tests\Php80\Rector\Class_\ConstantListClassToEnumRector;
+
+use Iterator;
+use Rector\Testing\PHPUnit\AbstractRectorTestCase;
+use Symplify\SmartFileSystem\SmartFileInfo;
+
+final class ConstantListClassToEnumRectorTest extends AbstractRectorTestCase
+{
+    /**
+     * @dataProvider provideData()
+     */
+    public function test(SmartFileInfo $fileInfo): void
+    {
+        $this->doTestFileInfo($fileInfo);
+    }
+
+    /**
+     * @return Iterator<SmartFileInfo>
+     */
+    public function provideData(): Iterator
+    {
+        return $this->yieldFilesFromDirectory(__DIR__ . '/Fixture');
+    }
+
+    public function provideConfigFilePath(): string
+    {
+        return __DIR__ . '/config/configured_rule.php';
+    }
+}

rules-tests/Php80/Rector/Class_/ConstantListClassToEnumRector/Fixture/some_class.php.inc

@@ -0,0 +1,24 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\Class_\ConstantListClassToEnumRector\Fixture;
+
+class Direction
+{
+    public const LEFT = 'left';
+
+    public const RIGHT = 'right';
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php80\Rector\Class_\ConstantListClassToEnumRector\Fixture;
+
+enum Direction : string
+{
+    case LEFT = 'left';
+    case RIGHT = 'right';
+}
+
+?>

rules-tests/Php80/Rector/Class_/ConstantListClassToEnumRector/config/configured_rule.php

@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\Config\RectorConfig;
+use Rector\Php80\Rector\Class_\ConstantListClassToEnumRector;
+
+return static function (RectorConfig $rectorConfig): void {
+    $rectorConfig->rule(ConstantListClassToEnumRector::class);
+};

rules/Php80/NodeAnalyzer/EnumConstListClassDetector.php

@@ -0,0 +1,68 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Php80\NodeAnalyzer;
+
+use PhpParser\Node\Stmt\Class_;
+use PhpParser\Node\Stmt\ClassConst;
+use Rector\NodeTypeResolver\NodeTypeResolver;
+
+final class EnumConstListClassDetector
+{
+    public function __construct(
+        private readonly NodeTypeResolver $nodeTypeResolver
+    ) {
+    }
+
+    public function detect(Class_ $class): bool
+    {
+        $classConstants = $class->getConstants();
+
+        // must have at least 2 constants, otherwise probably not enum
+        if (count($classConstants) < 2) {
+            return false;
+        }
+
+        // only constants are allowed, nothing else
+        if (count($class->stmts) !== count($classConstants)) {
+            return false;
+        }
+
+        // all constant must be public
+        foreach ($classConstants as $classConstant) {
+            if (! $classConstant->isPublic()) {
+                return false;
+            }
+        }
+
+        // all constants must have exactly 1 value
+        foreach ($classConstants as $classConstant) {
+            if (count($classConstant->consts) !== 1) {
+                return false;
+            }
+        }
+
+        $constantUniqueTypeCount = $this->resolveConstantUniqueTypeCount($classConstants);
+        // must be exactly 1 type
+        return $constantUniqueTypeCount === 1;
+    }
+
+    /**
+     * @param ClassConst[] $classConsts
+     */
+    private function resolveConstantUniqueTypeCount(array $classConsts): int
+    {
+        $typeClasses = [];
+
+        // all constants must have same type
+        foreach ($classConsts as $classConst) {
+            $const = $classConst->consts[0];
+            $constantType = $this->nodeTypeResolver->getType($const->value);
+            $typeClasses[] = $constantType::class;
+        }
+
+        $uniqueTypeClasses = array_unique($typeClasses);
+        return count($uniqueTypeClasses);
+    }
+}

rules/Php80/Rector/Class_/ConstantListClassToEnumRector.php

@@ -0,0 +1,71 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Php80\Rector\Class_;
+
+use PhpParser\Node;
+use PhpParser\Node\Stmt\Class_;
+use Rector\Core\Rector\AbstractRector;
+use Rector\Php80\NodeAnalyzer\EnumConstListClassDetector;
+use Rector\Php81\NodeFactory\EnumFactory;
+use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
+use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;
+
+/**
+ * @see \Rector\Tests\Php80\Rector\Class_\ConstantListClassToEnumRector\ConstantListClassToEnumRectorTest
+ */
+final class ConstantListClassToEnumRector extends AbstractRector
+{
+    public function __construct(
+        private readonly EnumConstListClassDetector $enumConstListClassDetector,
+        private readonly EnumFactory $enumFactory
+    ) {
+    }
+
+    public function getRuleDefinition(): RuleDefinition
+    {
+        return new RuleDefinition('Upgrade constant list classes to full blown enum', [
+            new CodeSample(
+                <<<'CODE_SAMPLE'
+class Direction
+{
+    public const LEFT = 'left';
+
+    public const RIGHT = 'right';
+}
+CODE_SAMPLE
+
+                ,
+                <<<'CODE_SAMPLE'
+enum Direction
+{
+    case LEFT;
+
+    case RIGHT;
+}
+CODE_SAMPLE
+            ),
+        ]);
+    }
+
+    /**
+     * @return array<class-string<Node>>
+     */
+    public function getNodeTypes(): array
+    {
+        return [Class_::class];
+    }
+
+    /**
+     * @param Class_ $node
+     */
+    public function refactor(Node $node): ?Node
+    {
+        if (! $this->enumConstListClassDetector->detect($node)) {
+            return null;
+        }
+
+        return $this->enumFactory->createFromClass($node);
+    }
+}