Use ReflectionProperty for stack reset in tearDown and add thread-safety note

Agent-Logs-Url: https://github.com/yiisoft/html/sessions/b46b1e7f-121d-4291-8e33-7a1403732003

Co-authored-by: samdark <47294+samdark@users.noreply.github.com>

Author: Copilot

src/Tag/Form.php

@@ -22,6 +22,11 @@ final class Form extends NormalTag
 
     /**
      * @var static[]
+     *
+     * @note This static stack is process-scoped. In long-running PHP runtimes
+     * (e.g. Swoole, RoadRunner) each coroutine or request shares the same
+     * static property. Ensure {@see begin()} and {@see end()} are always
+     * paired within the same request/coroutine context.
      */
     private static array $stack = [];
 

tests/Tag/FormTest.php

@@ -15,15 +15,10 @@ final class FormTest extends TestCase
 {
     protected function tearDown(): void
     {
-        // Drain any Form::begin() calls that were not matched with Form::end()
-        // to ensure a clean static stack between tests.
-        try {
-            while (true) {
-                Form::end();
-            }
-        } catch (\RuntimeException) {
-            // Stack is now empty.
-        }
+        // Reset the static stack to ensure test isolation.
+        $ref = new \ReflectionProperty(Form::class, 'stack');
+        $ref->setAccessible(true);
+        $ref->setValue(null, []);
     }
 
     public function testBase(): void