[Messenger] Allow passing a string instead of an array in TransportNamesStamp

src/Symfony/Component/Messenger/CHANGELOG.md

@@ -9,6 +9,7 @@ CHANGELOG
    `Symfony\Component\Messenger\Transport\InMemoryTransportFactory` in favor of
    `Symfony\Component\Messenger\Transport\InMemory\InMemoryTransport` and
    `Symfony\Component\Messenger\Transport\InMemory\InMemoryTransportFactory`
+ * Allow passing a string instead of an array in `TransportNamesStamp`
 
 6.2
 ---

src/Symfony/Component/Messenger/Stamp/TransportNamesStamp.php

@@ -16,11 +16,14 @@
  */
 final class TransportNamesStamp implements StampInterface
 {
+    private array $transports;
+
     /**
-     * @param string[] $transports Transport names to be used for the message
+     * @param string[]|string $transports Transport names to be used for the message
      */
-    public function __construct(private array $transports)
+    public function __construct(array|string $transports)
     {
+        $this->transports = (array) $transports;
     }
 
     public function getTransportNames(): array

src/Symfony/Component/Messenger/Tests/Stamp/TransportNamesStampTest.php

@@ -27,4 +27,13 @@ public function testGetSenders()
             $this->assertSame($sender, $stampSenders[$key]);
         }
     }
+
+    public function testGetIndividualSender()
+    {
+        $stamp = new TransportNamesStamp('first_transport');
+        $stampSenders = $stamp->getTransportNames();
+
+        $this->assertCount(1, $stampSenders);
+        $this->assertSame('first_transport', $stampSenders[0]);
+    }
 }