issue #656 - hack around reflection in order to hydrate readonly properties

src/GeneratedHydrator/CodeGenerator/Visitor/HydratorMethodsVisitor.php

@@ -43,7 +43,7 @@ class HydratorMethodsVisitor extends NodeVisitorAbstract
      */
     private array $hiddenPropertyMap = [];
 
-    public function __construct(ReflectionClass $reflectedClass)
+    public function __construct(private ReflectionClass $reflectedClass)
     {
         foreach ($this->findAllInstanceProperties($reflectedClass) as $property) {
             $className = $property->getDeclaringClass()->getName();
@@ -101,20 +101,30 @@ static function (ReflectionProperty $property): bool {
      * @return string[]
      * @psalm-return list<string>
      */
-    private function generatePropertyHydrateCall(ObjectProperty $property, string $inputArrayName): array
+    private function generatePropertyHydrateCall(ObjectProperty $property, string $inputArrayName, string|null $className = null): array
     {
-        $propertyName = $property->name;
-        $escapedName  = var_export($propertyName, true);
+        $propertyName     = $property->name;
+        $escapedName      = var_export($propertyName, true);
+        $valueAccessor    = $inputArrayName . '[' . $escapedName . ']';
+        $escapedClassName = var_export($className ?? $this->reflectedClass->getName(), true);
+
+        if ($property->isReadOnly) {
+            return [
+                'if (\\array_key_exists(' . $escapedName . ', ' . $inputArrayName . ')) {',
+                '    ($ref ?? $ref = new \ReflectionClass(' . $escapedClassName . '))->getProperty(' . $escapedName . ')->setValue($object, ' . $valueAccessor . ');',
+                '}',
+            ];
+        }
 
         if ($property->allowsNull && ! $property->hasDefault) {
-            return ['$object->' . $propertyName . ' = ' . $inputArrayName . '[' . $escapedName . '] ?? null;'];
+            return ['$object->' . $propertyName . ' = ' . $valueAccessor . ' ?? null;'];
         }
 
         return [
-            'if (isset(' . $inputArrayName . '[' . $escapedName . '])',
+            'if (isset(' . $valueAccessor . ')',
             '    || $object->' . $propertyName . ' !== null && \\array_key_exists(' . $escapedName . ', ' . $inputArrayName . ')',
             ') {',
-            '    $object->' . $propertyName . ' = ' . $inputArrayName . '[' . $escapedName . '];',
+            '    $object->' . $propertyName . ' = ' . $valueAccessor . ';',
             '}',
         ];
     }
@@ -132,7 +142,7 @@ private function replaceConstructor(ClassMethod $method): void
             // Hydrate closures
             $bodyParts[] = '$this->hydrateCallbacks[] = \\Closure::bind(static function ($object, $values) {';
             foreach ($properties as $property) {
-                $bodyParts = array_merge($bodyParts, $this->generatePropertyHydrateCall($property, '$values'));
+                $bodyParts = array_merge($bodyParts, $this->generatePropertyHydrateCall($property, '$values', $className));
             }
 
             $bodyParts[] = '}, null, ' . var_export($className, true) . ');' . "\n";

src/GeneratedHydrator/CodeGenerator/Visitor/ObjectProperty.php

@@ -19,7 +19,7 @@ final class ObjectProperty
     public string $name;
 
     /** @psalm-param non-empty-string $name */
-    private function __construct(string $name, public bool $hasType, public bool $allowsNull, public bool $hasDefault)
+    private function __construct(string $name, public bool $hasType, public bool $allowsNull, public bool $hasDefault, public bool $isReadOnly)
     {
         $this->name = $name;
     }
@@ -32,14 +32,15 @@ public static function fromReflection(ReflectionProperty $property): self
         $defaultValues = $property->getDeclaringClass()->getDefaultProperties();
 
         if ($type === null) {
-            return new self($propertyName, false, true, array_key_exists($propertyName, $defaultValues));
+            return new self($propertyName, false, true, array_key_exists($propertyName, $defaultValues), $property->isReadOnly());
         }
 
         return new self(
             $propertyName,
             true,
             $type->allowsNull(),
             array_key_exists($propertyName, $defaultValues),
+            $property->isReadOnly(),
         );
     }
 }

tests/GeneratedHydratorTest/Functional/HydratorFunctionalTest.php

@@ -15,6 +15,7 @@
 use GeneratedHydratorTestAsset\ClassWithPrivatePropertiesAndParents;
 use GeneratedHydratorTestAsset\ClassWithProtectedProperties;
 use GeneratedHydratorTestAsset\ClassWithPublicProperties;
+use GeneratedHydratorTestAsset\ClassWithReadonlyProperties;
 use GeneratedHydratorTestAsset\ClassWithStaticProperties;
 use GeneratedHydratorTestAsset\ClassWithTypedProperties;
 use GeneratedHydratorTestAsset\EmptyClass;
@@ -100,6 +101,21 @@ public function testHydratorWillNotRaisedUnitiliazedTypedPropertyAccessError():
         ], $hydrator->extract($instance));
     }
 
+    /**
+     * Ensures that readonly properties are hydrated as well without raising.
+     *
+     * @requires PHP >= 8.1
+     */
+    public function testHydratorWillNotRaisedErrorWhenHydratingReadonlyProperties(): void
+    {
+        $instance = new ClassWithReadonlyProperties();
+        $hydrator = $this->generateHydrator($instance);
+
+        $hydrator->hydrate(['readonly0' => 7], $instance);
+
+        self::assertSame(['readonly0' => 7], $hydrator->extract($instance));
+    }
+
     /** @requires PHP >= 7.4 */
     public function testHydratorWillSetAllTypedProperties(): void
     {

tests/GeneratedHydratorTestAsset/ClassWithReadonlyProperties.php

@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace GeneratedHydratorTestAsset;
+
+/**
+ * Test PHP 8.1 readonly property hydration and dehydration.
+ */
+final class ClassWithReadonlyProperties
+{
+    private readonly int $readonly0;
+}