[PHP 8.1] Refactor isEnum() downgrade to method_exists check (#186)

Author: TomasVotruba

composer.json

@@ -24,7 +24,8 @@
         "tomasvotruba/class-leak": "^0.1",
         "tomasvotruba/cognitive-complexity": "^0.1",
         "tomasvotruba/type-coverage": "^0.2",
-        "tomasvotruba/unused-public": "^0.2"
+        "tomasvotruba/unused-public": "^0.2",
+        "tracy/tracy": "^2.10"
     },
     "autoload": {
         "psr-4": {

rules-tests/DowngradePhp81/Rector/MethodCall/DowngradeIsEnumRector/Fixture/some_class.php.inc

@@ -20,7 +20,7 @@ class SomeClass
 {
     public function run(\ReflectionClass $reflectionClass)
     {
-        return false;
+        return method_exists($reflectionClass, 'isEnum') ? $reflectionClass->isEnum() : false;
     }
 }
 

rules/DowngradePhp81/Rector/MethodCall/DowngradeIsEnumRector.php

@@ -5,7 +5,10 @@
 namespace Rector\DowngradePhp81\Rector\MethodCall;
 
 use PhpParser\Node;
+use PhpParser\Node\Arg;
 use PhpParser\Node\Expr\MethodCall;
+use PhpParser\Node\Expr\Ternary;
+use PhpParser\Node\Scalar\String_;
 use PHPStan\Type\ObjectType;
 use Rector\Core\Rector\AbstractRector;
 use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
@@ -36,7 +39,7 @@ class SomeClass
 {
     public function run(ReflectionClass $reflectionClass)
     {
-        return false;
+        return method_exists($reflectionClass, 'isEnum') ? $reflectionClass->isEnum() : false;
     }
 }
 CODE_SAMPLE
@@ -65,6 +68,12 @@ public function refactor(Node $node): ?Node
             return null;
         }
 
-        return $this->nodeFactory->createFalse();
+        $args = [new Arg($node->var), new Arg(new String_('isEnum'))];
+
+        return new Ternary(
+            $this->nodeFactory->createFuncCall('method_exists', $args),
+            $node,
+            $this->nodeFactory->createFalse()
+        );
     }
 }