refactor: move proxy to real class converter to ClassUtil (#14)

src/Transformer/ObjectToObjectMetadata/Implementation/ProxyResolvingObjectToObjectMetadataFactory.php

@@ -15,6 +15,7 @@
 
 use Rekalogika\Mapper\Transformer\ObjectToObjectMetadata\ObjectToObjectMetadata;
 use Rekalogika\Mapper\Transformer\ObjectToObjectMetadata\ObjectToObjectMetadataFactoryInterface;
+use Rekalogika\Mapper\Util\ClassUtil;
 
 /**
  * @internal
@@ -31,31 +32,10 @@ public function createObjectToObjectMetadata(
         string $targetClass,
     ): ObjectToObjectMetadata {
         $metadata = $this->decorated->createObjectToObjectMetadata(
-            $this->resolveRealClass($sourceClass),
+            ClassUtil::determineRealClassFromPossibleProxy($sourceClass),
             $targetClass,
         );
 
         return $metadata;
     }
-
-    /**
-     * @param class-string $class
-     * @return class-string
-     */
-    private function resolveRealClass(string $class): string
-    {
-        $pos = strrpos($class, '\\__CG__\\');
-
-        if ($pos === false) {
-            $pos = strrpos($class, '\\__PM__\\');
-        }
-
-        if ($pos !== false) {
-            $class = substr($class, $pos + 8);
-        }
-
-        assert(class_exists($class), sprintf('Class "%s" does not exist', $class));
-
-        return $class;
-    }
 }

src/Util/ClassUtil.php

@@ -13,6 +13,7 @@
 
 namespace Rekalogika\Mapper\Util;
 
+use Rekalogika\Mapper\Exception\UnexpectedValueException;
 use Symfony\Component\VarExporter\Internal\Hydrator;
 
 /**
@@ -24,6 +25,50 @@ private function __construct()
     {
     }
 
+    /**
+     * @template T of object
+     * @param class-string<T> $class
+     * @return class-string<T>
+     */
+    public static function determineRealClassFromPossibleProxy(string $class): string
+    {
+        $inputClass = $class;
+
+        $pos = strrpos($class, '\\__CG__\\');
+
+        if ($pos === false) {
+            $pos = strrpos($class, '\\__PM__\\');
+        }
+
+        if ($pos !== false) {
+            $class = substr($class, $pos + 8);
+        }
+
+        if (!class_exists($class)) {
+            throw new UnexpectedValueException(sprintf(
+                'Trying to resolve the real class from possible proxy class "%s", got "%s", but the class does not exist',
+                $inputClass,
+                $class
+            ));
+        }
+
+        /** @psalm-suppress DocblockTypeContradiction */
+        if (!is_a($inputClass, $class, true)) {
+            /** @psalm-suppress NoValue */
+            throw new UnexpectedValueException(sprintf(
+                'Trying to resolve the real class from possible proxy class "%s", got "%s", but the proxy "%s" is not a subclass of "%s"',
+                $inputClass,
+                $class,
+                $inputClass,
+                $class,
+            ));
+        }
+
+        /** @var class-string<T> $class */
+
+        return $class;
+    }
+
     /**
      * @param class-string|\ReflectionClass<object> $class
      * @return int