Drop default priority 0 in EventSubscriberToAttributeRector

rules-tests/CodeQuality/Rector/Class_/EventSubscriberToAttributeRector/Fixture/drop_default_priority.php.inc

@@ -0,0 +1,33 @@
+<?php
+
+namespace Rector\Symfony\Tests\CodeQuality\Rector\Class_\EventSubscriberToAttributeRector\Fixture;
+
+class DropDefaultPriorityEventSubscriber implements \Symfony\Component\EventDispatcher\EventSubscriberInterface
+{
+    public function callMe()
+    {
+    }
+    /**
+     * @return array<string, mixed>
+     */
+    public static function getSubscribedEvents(): array
+    {
+        return ['some_event' => ['callMe', 0]];
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Symfony\Tests\CodeQuality\Rector\Class_\EventSubscriberToAttributeRector\Fixture;
+
+class DropDefaultPriorityEventSubscriber
+{
+    #[\Symfony\Component\EventDispatcher\Attribute\AsEventListener(event: 'some_event')]
+    public function callMe()
+    {
+    }
+}
+
+?>

rules/CodeQuality/Rector/Class_/EventSubscriberToAttributeRector.php

@@ -14,6 +14,7 @@
 use PhpParser\Node\Expr\ClassConstFetch;
 use PhpParser\Node\Identifier;
 use PhpParser\Node\Name\FullyQualified;
+use PhpParser\Node\Scalar\Int_;
 use PhpParser\Node\Scalar\String_;
 use PhpParser\Node\Stmt;
 use PhpParser\Node\Stmt\Class_;
@@ -237,7 +238,13 @@ private function resolveMethodsWithPriorities(Expr $expr): ?array
                 return null;
             }
 
-            $methodsWithPriorities[] = [$methodName->value->value, $priority?->value];
+            // priority 0 is the default, drop it to keep the attribute clean
+            $priorityExpr = $priority?->value;
+            if ($priorityExpr instanceof Int_ && $priorityExpr->value === 0) {
+                $priorityExpr = null;
+            }
+
+            $methodsWithPriorities[] = [$methodName->value->value, $priorityExpr];
         }
 
         return $methodsWithPriorities;