bug symfony#52307 [Scheduler] Save checkpoint in a finally block (FrancoisPog)

This PR was squashed before being merged into the 6.3 branch.

Discussion
----------

[Scheduler] Save checkpoint in a finally block

| Q             | A
| ------------- | ---
| Branch?       | 6.3  <!-- see below -->
| Bug fix?      | yes
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Issues        | Fix symfony#52288 <!-- prefix each issue number with "Fix #", no need to create an issue if none exists, explain below instead -->
| License       | MIT

As described in the linked issue :
> The message generator appears to store stateful data by loading and saving the checkpoint with the cache.
>
> But if the worker is configured to stop after X message(s), once the last message is handled, the (messenger) worker will break its loop and stop. In this case, the execution stop and the stateful data of the message (time of last execution for example) will not be saved.
>
> So when the consumer restarts it will re-handle the message because the last execution was not stored.
>

So the solution here is to put the code that save the checkpoint in a `finally` block.
Thanks [maelanleborgne](https://github.com/maelanleborgne).

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Commits
-------

598d5bd [Scheduler] Save checkpoint in a finally block

Author: fabpot

src/Symfony/Component/Scheduler/Generator/MessageGenerator.php

@@ -72,8 +72,11 @@ public function getMessages(): \Generator
             }
 
             if ($yield) {
-                yield (new MessageContext($this->name, $id, $trigger, $time, $nextTime)) => $message;
-                $checkpoint->save($time, $index);
+                try {
+                    yield (new MessageContext($this->name, $id, $trigger, $time, $nextTime)) => $message;
+                } finally {
+                    $checkpoint->save($time, $index);
+                }
             }
         }
 

src/Symfony/Component/Scheduler/Tests/Generator/MessageGeneratorTest.php

@@ -14,6 +14,8 @@
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\Cache\Adapter\ArrayAdapter;
 use Symfony\Component\Clock\ClockInterface;
+use Symfony\Component\Clock\MockClock;
+use Symfony\Component\Scheduler\Generator\Checkpoint;
 use Symfony\Component\Scheduler\Generator\MessageContext;
 use Symfony\Component\Scheduler\Generator\MessageGenerator;
 use Symfony\Component\Scheduler\RecurringMessage;
@@ -128,6 +130,32 @@ public function testYieldedContext()
         $this->assertEquals(self::makeDateTime('22:16:00'), $context->nextTriggerAt);
     }
 
+    public function testCheckpointSavedInBrokenLoop()
+    {
+        $clock = new MockClock(self::makeDateTime('22:12:00'));
+
+        $message = $this->createMessage((object) ['id' => 'message'], '22:13:00', '22:14:00', '22:16:00');
+        $schedule = (new Schedule())->add($message);
+
+        $cache = new ArrayAdapter();
+        $schedule->stateful($cache);
+        $checkpoint = new Checkpoint('dummy', cache: $cache);
+
+        $scheduler = new MessageGenerator($schedule, 'dummy', clock: $clock, checkpoint: $checkpoint);
+
+        // Warmup. The first run is always returns nothing.
+        $this->assertSame([], iterator_to_array($scheduler->getMessages(), false));
+
+        $clock->sleep(60 + 10); // 22:13:10
+
+        foreach ($scheduler->getMessages() as $message) {
+            // Message is handled but loop is broken just after
+            break;
+        }
+
+        $this->assertEquals(self::makeDateTime('22:13:00'), $checkpoint->time());
+    }
+
     public static function messagesProvider(): \Generator
     {
         $first = (object) ['id' => 'first'];