bug #32497 [Messenger] DispatchAfterCurrentBusMiddleware does not cancel messages from delayed handlers (Nyholm, BastienClement)

This PR was merged into the 4.3 branch.

Discussion
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[Messenger] DispatchAfterCurrentBusMiddleware does not cancel messages from delayed handlers

| Q             | A
| ------------- | ---
| Branch?       | 4.3 for bug fixes
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? |no
| Tests pass?   | yes  (thanks @Nyholm)
| Fixed tickets | #32370
| License       | MIT
| Doc PR        | -

This is a fix for #32370. There is no need for anything sophisticated. There is no recursion or fancy stuff going on, just a queue of message handled sequentially. A simple variable is enough to keep track of the queue state.

Thanks @Nyholm for the test, it would clearly have been the hardest part of the job.

Commits
-------

1f5c8a6790 Cancel delayed message if handler fails
35c76a385d Added tests for #32370

src/Symfony/Component/Messenger/Middleware/DispatchAfterCurrentBusMiddleware.php

@@ -81,12 +81,16 @@ class DispatchAfterCurrentBusMiddleware implements MiddlewareInterface
         // "Root dispatch" call is finished, dispatch stored messages.
         $exceptions = [];
         while (null !== $queueItem = array_shift($this->queue)) {
+            // Save how many messages are left in queue before handling the message
+            $queueLengthBefore = \count($this->queue);
             try {
                 // Execute the stored messages
                 $queueItem->getStack()->next()->handle($queueItem->getEnvelope(), $queueItem->getStack());
             } catch (\Exception $exception) {
                 // Gather all exceptions
                 $exceptions[] = $exception;
+                // Restore queue to previous state
+                $this->queue = \array_slice($this->queue, 0, $queueLengthBefore);
             }
         }
 

src/Symfony/Component/Messenger/Tests/Middleware/DispatchAfterCurrentBusMiddlewareTest.php

@@ -99,6 +99,86 @@ class DispatchAfterCurrentBusMiddlewareTest extends TestCase
         $messageBus->dispatch($message);
     }
 
+    public function testLongChainWithExceptions()
+    {
+        $command = new DummyMessage('Level 0');
+
+        $eventL1a = new DummyEvent('Event level 1A');
+        $eventL1b = new DummyEvent('Event level 1B'); // will dispatch 2 more events
+        $eventL1c = new DummyEvent('Event level 1C');
+
+        $eventL2a = new DummyEvent('Event level 2A'); // Will dispatch 1 event and throw exception
+        $eventL2b = new DummyEvent('Event level 2B'); // Will dispatch 1 event
+
+        $eventL3a = new DummyEvent('Event level 3A'); // This should never get handled.
+        $eventL3b = new DummyEvent('Event level 3B');
+
+        $middleware = new DispatchAfterCurrentBusMiddleware();
+        $handlingMiddleware = $this->createMock(MiddlewareInterface::class);
+
+        $eventBus = new MessageBus([
+            $middleware,
+            $handlingMiddleware,
+        ]);
+
+        // The command bus will dispatch 3 events.
+        $commandBus = new MessageBus([
+            $middleware,
+            new DispatchingMiddleware($eventBus, [
+                new Envelope($eventL1a, [new DispatchAfterCurrentBusStamp()]),
+                new Envelope($eventL1b, [new DispatchAfterCurrentBusStamp()]),
+                new Envelope($eventL1c, [new DispatchAfterCurrentBusStamp()]),
+            ]),
+            $handlingMiddleware,
+        ]);
+
+        // Expect main dispatched message to be handled first:
+        $this->expectHandledMessage($handlingMiddleware, 0, $command);
+
+        $this->expectHandledMessage($handlingMiddleware, 1, $eventL1a);
+
+        // Handling $eventL1b will dispatch 2 more events
+        $handlingMiddleware->expects($this->at(2))->method('handle')->with($this->callback(function (Envelope $envelope) use ($eventL1b) {
+            return $envelope->getMessage() === $eventL1b;
+        }))->willReturnCallback(function ($envelope, StackInterface $stack) use ($eventBus, $eventL2a, $eventL2b) {
+            $envelope1 = new Envelope($eventL2a, [new DispatchAfterCurrentBusStamp()]);
+            $eventBus->dispatch($envelope1);
+            $eventBus->dispatch(new Envelope($eventL2b, [new DispatchAfterCurrentBusStamp()]));
+
+            return $stack->next()->handle($envelope, $stack);
+        });
+
+        $this->expectHandledMessage($handlingMiddleware, 3, $eventL1c);
+
+        // Handle $eventL2a will dispatch event and throw exception
+        $handlingMiddleware->expects($this->at(4))->method('handle')->with($this->callback(function (Envelope $envelope) use ($eventL2a) {
+            return $envelope->getMessage() === $eventL2a;
+        }))->willReturnCallback(function ($envelope, StackInterface $stack) use ($eventBus, $eventL3a) {
+            $eventBus->dispatch(new Envelope($eventL3a, [new DispatchAfterCurrentBusStamp()]));
+
+            throw new \RuntimeException('Some exception while handling Event level 2a');
+        });
+
+        // Make sure $eventL2b is handled, since it was dispatched from $eventL1b
+        $handlingMiddleware->expects($this->at(5))->method('handle')->with($this->callback(function (Envelope $envelope) use ($eventL2b) {
+            return $envelope->getMessage() === $eventL2b;
+        }))->willReturnCallback(function ($envelope, StackInterface $stack) use ($eventBus, $eventL3b) {
+            $eventBus->dispatch(new Envelope($eventL3b, [new DispatchAfterCurrentBusStamp()]));
+
+            return $stack->next()->handle($envelope, $stack);
+        });
+
+        // We dont handle exception L3a since L2a threw an exception.
+        $this->expectHandledMessage($handlingMiddleware, 6, $eventL3b);
+
+        // Note: $eventL3a should not be handled.
+
+        $this->expectException(DelayedMessageHandlingException::class);
+        $this->expectExceptionMessage('RuntimeException: Some exception while handling Event level 2a');
+
+        $commandBus->dispatch($command);
+    }
+
     public function testHandleDelayedEventFromQueue()
     {
         $message = new DummyMessage('Hello');