bug #29714 [Event Dispatcher] fixed 29703: TraceableEventDispatcher r…

…eset() callStack to null (mlievertz)

This PR was merged into the 3.4 branch.

Discussion
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[Event Dispatcher] fixed 29703: TraceableEventDispatcher reset() callStack to null

[Event Dispatcher] fixed 29703: TraceableEventDispatcher reset now sets callStack to null with test to dispatch after reset.

| Q             | A
| ------------- | ---
| Branch?       | 3.4 <!-- see below -->
| Bug fix?      | yes
| New feature?  | no <!-- don't forget to update src/**/CHANGELOG.md files -->
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no <!-- don't forget to update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | #29703    <!-- #-prefixed issue number(s), if any -->
| License       | MIT
| Doc PR        | N/A <!-- required for new features -->

[Event Dispatcher] fixed 29703: TraceableEventDispatcher reset now sets callStack to null with test to dispatch after reset. Basically #29411 introduced an issue where calling dispatch after a reset would throw an error because now reset set callStack to array but dispatch expected either SplObjectStorage or null. Now reset sets null. Also added a test to verify dispatch works following a call to reset.

Commits
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51bcdb8 [Event Dispatcher] fixed 29703: TraceableEventDispatcher reset now sets callStack to null with test to dispatch after reset.

src/Symfony/Component/EventDispatcher/Debug/TraceableEventDispatcher.php

@@ -221,7 +221,7 @@ public function getNotCalledListeners()
 
     public function reset()
     {
-        $this->callStack = array();
+        $this->callStack = null;
     }
 
     /**

src/Symfony/Component/EventDispatcher/Tests/Debug/TraceableEventDispatcherTest.php

@@ -139,6 +139,18 @@ public function testClearCalledListeners()
         $this->assertEquals(array(array('event' => 'foo', 'pretty' => 'closure', 'priority' => 5)), $listeners);
     }
 
+    public function testDispatchAfterReset()
+    {
+        $tdispatcher = new TraceableEventDispatcher(new EventDispatcher(), new Stopwatch());
+        $tdispatcher->addListener('foo', function () {}, 5);
+
+        $tdispatcher->reset();
+        $tdispatcher->dispatch('foo');
+
+        $listeners = $tdispatcher->getCalledListeners();
+        $this->assertArrayHasKey('stub', $listeners[0]);
+    }
+
     public function testGetCalledListenersNested()
     {
         $tdispatcher = null;