Jetty 12: X-Powered-By header is added 2 times (if enabled)

[uschindler]

Jetty version(s)
Jetty 12

Jetty Environment
core

Description
If you enable HttpConfiguration#setSendXPoweredBy(true), then Jetty returns the header 2 times (at least with HTTP/1.1):

> curl -I http://localhost:8081/
HTTP/1.1 200 OK
X-Powered-By: Jetty(12.0.0)
Date: Mon, 14 Aug 2023 18:38:26 GMT
Content-Type: text/plain;charset=utf-8
Content-Length: 46
X-Powered-By: Jetty(12.0.0)

[uschindler]

Simple reproducer:

public class JettyTest {

  public static void main(String[] args) throws Exception {
    final var server=new Server();
    
    // setup connector
    final var http_config = new HttpConfiguration();
    final var cust = new ForwardedRequestCustomizer();
    http_config.addCustomizer(cust);
    http_config.setSendServerVersion(false);
    http_config.setSendXPoweredBy(true);
    final var connector = new ServerConnector(server, new HttpConnectionFactory(http_config));
    connector.setHost(System.getProperty("server.host", "127.0.0.1"));
    connector.setPort(Integer.getInteger("server.port", 8081));
    server.addConnector(connector);

    // startup:
    server.start();
    server.join();
  }
}

[joakime]

Opened PR #10310 to address this

[joakime]

Basic fix merged in PR #10310