[CodingStyle] Skip readonly type property on AddArrayDefaultToArrayPropertyRector (#2196)

* Add failing test fixture for AddArrayDefaultToArrayPropertyRector

# Failing Test for AddArrayDefaultToArrayPropertyRector

Based on https://getrector.org/demo/0cb77e6c-9502-44fa-9ecd-e4d46838e7a2

* Closes #2195

* clean up

Co-authored-by: Martin Kluska <martin@kluska.cz>

rules-tests/CodingStyle/Rector/Class_/AddArrayDefaultToArrayPropertyRector/Fixture/skip_readonly_property.php.inc

@@ -0,0 +1,19 @@
+<?php
+
+namespace Rector\Tests\CodingStyle\Rector\Class_\AddArrayDefaultToArrayPropertyRector\Fixture;
+
+abstract class SkipReadonlyProperty
+{
+    /**
+     * @var array
+     */
+    public readonly array $changes;
+
+    public function __construct(Model $model)
+    {
+        $this->changes = $model->getChanges();
+    }
+}
+
+?>
+

rules/CodingStyle/Rector/Class_/AddArrayDefaultToArrayPropertyRector.php

@@ -22,6 +22,7 @@ use Rector\Core\NodeAnalyzer\ArgsAnalyzer;
 use Rector\Core\NodeAnalyzer\PropertyFetchAnalyzer;
 use Rector\Core\Rector\AbstractRector;
 use Rector\NodeTypeResolver\Node\AttributeKey;
+use Rector\Privatization\NodeManipulator\VisibilityManipulator;
 use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
 use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;
 
@@ -34,7 +35,8 @@ final class AddArrayDefaultToArrayPropertyRector extends AbstractRector
     public function __construct(
         private readonly PropertyFetchAnalyzer $propertyFetchAnalyzer,
         private readonly IterableTypeAnalyzer $iterableTypeAnalyzer,
-        private readonly ArgsAnalyzer $argsAnalyzer
+        private readonly ArgsAnalyzer $argsAnalyzer,
+        private readonly VisibilityManipulator $visibilityManipulator
     ) {
     }
 
@@ -127,6 +129,15 @@ CODE_SAMPLE
                 return null;
             }
 
+            $property = $node->getAttribute(AttributeKey::PARENT_NODE);
+            if (! $property instanceof Property) {
+                return null;
+            }
+
+            if ($this->visibilityManipulator->isReadonly($property)) {
+                return null;
+            }
+
             $propertyNames[] = $this->getName($node);
 
             return null;