Honor existing return types when generating decorators

Author: nicolas-grekas

src/ProxyManager/Generator/MagicMethodGenerator.php

@@ -6,6 +6,7 @@
 
 use Laminas\Code\Generator\ParameterGenerator;
 use ReflectionClass;
+use ReflectionNamedType;
 
 use function strtolower;
 
@@ -31,6 +32,13 @@ public function __construct(ReflectionClass $originalClass, string $name, array
             return;
         }
 
-        $this->setReturnsReference($originalClass->getMethod($name)->returnsReference());
+        $originalMethod = $originalClass->getMethod($name);
+        $returnType     = $originalMethod->getReturnType();
+
+        if ($returnType instanceof ReflectionNamedType) {
+            $this->setReturnType($returnType->getName());
+        }
+
+        $this->setReturnsReference($originalMethod->returnsReference());
     }
 }

src/ProxyManager/ProxyGenerator/NullObject/MethodGenerator/NullObjectMethodInterceptor.php

@@ -7,6 +7,9 @@
 use Laminas\Code\Reflection\MethodReflection;
 use ProxyManager\Generator\MethodGenerator;
 use ProxyManager\Generator\Util\IdentifierSuffixer;
+use ReflectionNamedType;
+
+use function in_array;
 
 /**
  * Method decorator for null objects
@@ -20,10 +23,13 @@ public static function generateMethod(MethodReflection $originalMethod): self
     {
         $method = static::fromReflectionWithoutBodyAndDocBlock($originalMethod);
 
-        if ($originalMethod->returnsReference()) {
+        $returnType = $originalMethod->getReturnType();
+        $nullCast   = $returnType instanceof ReflectionNamedType && in_array($returnType->getName(), ['array', 'float', 'int', 'string'], true)  ? '(' . $returnType->getName() . ') ' : '';
+
+        if ($originalMethod->returnsReference() || $nullCast !== '') {
             $reference = IdentifierSuffixer::getIdentifier('ref');
 
-            $method->setBody("\$reference = null;\nreturn \$" . $reference . ';');
+            $method->setBody('$' . $reference . ' = ' . $nullCast . "null;\nreturn \$" . $reference . ';');
         }
 
         return $method;

tests/ProxyManagerTest/ProxyGenerator/NullObjectGeneratorTest.php

@@ -94,7 +94,7 @@ public function testGeneratesValidCode(string $className): void
             $callback = [$proxy, $method->getName()];
 
             self::assertIsCallable($callback);
-            self::assertNull($callback());
+            self::assertEmpty($callback());
         }
     }
 

tests/ProxyManagerTestAsset/ClassWithMagicMethods.php

@@ -32,7 +32,7 @@ public function __unset($name)
         return (bool) $name;
     }
 
-    public function __sleep()
+    public function __sleep(): array
     {
         return [];
     }