feature #39660 [Messenger] Deprecate option prefetch_count (jderusse)

This PR was merged into the 5.3-dev branch.

Discussion
----------

[Messenger] Deprecate option prefetch_count

| Q             | A
| ------------- | ---
| Branch?       | 5.x
| Bug fix?      | no
| New feature?  | no
| Deprecations? | yesno
| Tickets       | -
| License       | MIT
| Doc PR        | -

Revert #30671

Commits
-------

5b55097500 Deprecate option prefetch_count

UPGRADE-5.3.md

@@ -23,6 +23,11 @@ HttpKernel
 
  * Marked the class `Symfony\Component\HttpKernel\EventListener\DebugHandlersListener` as internal
 
+Messenger
+---------
+
+* Deprecated the `prefetch_count` parameter in the AMQP bridge, it has no effect and will be removed in Symfony 6.0.
+
 Notifier
 -------
 

UPGRADE-6.0.md

@@ -112,6 +112,7 @@ Messenger
  * Use of invalid options in Redis and AMQP connections now throws an error.
  * The signature of method `RetryStrategyInterface::isRetryable()` has been updated to `RetryStrategyInterface::isRetryable(Envelope $message, \Throwable $throwable = null)`.
  * The signature of method `RetryStrategyInterface::getWaitingTime()` has been updated to `RetryStrategyInterface::getWaitingTime(Envelope $message, \Throwable $throwable = null)`.
+ * Removed the `prefetch_count` parameter in the AMQP bridge.
 
 Mime
 ----

src/Symfony/Component/Messenger/Bridge/Amqp/CHANGELOG.md

@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+5.3.0
+-----
+
+* Deprecated the `prefetch_count` parameter, it has no effect and will be removed in Symfony 6.0.
+
 5.2.0
 -----
 

src/Symfony/Component/Messenger/Bridge/Amqp/Tests/Transport/ConnectionTest.php

@@ -439,6 +439,9 @@ class ConnectionTest extends TestCase
         $connection->publish('body');
     }
 
+    /**
+     * @group legacy
+     */
     public function testSetChannelPrefetchWhenSetup()
     {
         $factory = new TestAmqpFactory(
@@ -451,11 +454,11 @@ class ConnectionTest extends TestCase
         // makes sure the channel looks connected, so it's not re-created
         $amqpChannel->expects($this->any())->method('isConnected')->willReturn(true);
 
-        $amqpChannel->expects($this->exactly(2))->method('setPrefetchCount')->with(2);
+        $amqpChannel->expects($this->never())->method('setPrefetchCount');
+
+        $this->expectDeprecation('Since symfony/messenger 5.3: The "prefetch_count" option passed to the AMQP Messenger transport has no effect and should not be used.');
         $connection = Connection::fromDsn('amqp://localhost?prefetch_count=2', [], $factory);
         $connection->setup();
-        $connection = Connection::fromDsn('amqp://localhost', ['prefetch_count' => 2], $factory);
-        $connection->setup();
     }
 
     public function testAutoSetupWithDelayDeclaresExchangeQueuesAndDelay()

src/Symfony/Component/Messenger/Bridge/Amqp/Transport/Connection.php

@@ -149,7 +149,6 @@ class Connection
      *     * queue_name_pattern: Pattern to use to create the queues (Default: "delay_%exchange_name%_%routing_key%_%delay%")
      *     * exchange_name: Name of the exchange to be used for the delayed/retried messages (Default: "delays")
      *   * auto_setup: Enable or not the auto-setup of queues and exchanges (Default: true)
-     *   * prefetch_count: set channel prefetch count
      *
      *   * Connection tuning options (see http://www.rabbitmq.com/amqp-0-9-1-reference.html#connection.tune for details):
      *     * channel_max: Specifies highest channel number that the server permits. 0 means standard extension limit
@@ -238,6 +237,10 @@ class Connection
             trigger_deprecation('symfony/messenger', '5.1', 'Invalid option(s) "%s" passed to the AMQP Messenger transport. Passing invalid options is deprecated.', implode('", "', $invalidOptions));
         }
 
+        if (isset($options['prefetch_count'])) {
+            trigger_deprecation('symfony/messenger', '5.3', 'The "prefetch_count" option passed to the AMQP Messenger transport has no effect and should not be used.');
+        }
+
         if (\is_array($options['queues'] ?? false)) {
             foreach ($options['queues'] as $queue) {
                 if (!\is_array($queue)) {
@@ -492,10 +495,6 @@ class Connection
             }
             $this->amqpChannel = $this->amqpFactory->createChannel($connection);
 
-            if (isset($this->connectionOptions['prefetch_count'])) {
-                $this->amqpChannel->setPrefetchCount($this->connectionOptions['prefetch_count']);
-            }
-
             if ('' !== ($this->connectionOptions['confirm_timeout'] ?? '')) {
                 $this->amqpChannel->confirmSelect();
                 $this->amqpChannel->setConfirmCallback(