Fix client transport leak on reconnect

docs/client/connecting.md

@@ -214,6 +214,8 @@ speaks revision `2026-07-28`, the connection is ready. If it doesn't, the client
 `initialize` handshake and offers `2025-11-25`, or the revision set with
 `setFallbackProtocolVersion()`. A server process that exits fails the connection instead.
 
+Calling `connect()` again on the same client closes its current transport before opening the new one.
+
 With `setFallbackProtocolVersion(null)`, `connect()` fails instead. See
 [How the client settles on an era](../protocol-versions.md#how-the-client-settles-on-an-era).
 

src/Client.php

@@ -92,6 +92,8 @@ public static function builder(): Builder
      */
     public function connect(TransportInterface $transport): void
     {
+        $this->disconnect();
+
         $this->transport = $transport;
         $this->protocol->connect($transport, $this->config);
 

tests/Unit/Client/ClientTest.php

@@ -21,6 +21,29 @@
 
 final class ClientTest extends TestCase
 {
+    public function testReconnectClosesPreviousTransport(): void
+    {
+        $client = Client::builder()->build();
+        $firstTransport = $this->createMock(TransportInterface::class);
+        $firstTransport->expects($this->once())->method('close');
+        $firstTransport->method('setState')->willReturnCallback(static function (ClientStateInterface $state): void {
+            $state->setInitialized(true);
+        });
+
+        $secondTransport = $this->createMock(TransportInterface::class);
+        $secondTransport->expects($this->once())->method('close');
+        $secondTransport->method('setState')->willReturnCallback(static function (ClientStateInterface $state): void {
+            $state->setInitialized(true);
+        });
+
+        $client->connect($firstTransport);
+        $client->connect($secondTransport);
+
+        $this->assertTrue($client->isConnected());
+
+        $client->disconnect();
+    }
+
     public function testSendRootsListChangedSendsNotificationWhenCapabilityDeclared(): void
     {
         $sent = [];