Jetty Reactive client hangs for HTTP 401 responses

[bclozel]

Jetty version(s)
org.eclipse.jetty:jetty-reactive-httpclient:4.0.8

Jetty Environment
core

Java version/vendor (use: java -version)
openjdk version "17.0.13" 2024-10-15 LTS

OS type/version
macOS Sequoia 15.2 (24C101)

Description
When receiving an HTTP 401 response, the Jetty HTTP reactive client hangs and never publishes the response.

How to reproduce?

HttpClient httpClient = new HttpClient();
httpClient.getProtocolHandlers().remove(WWWAuthenticationProtocolHandler.NAME);
httpClient.start();
Request request = httpClient.newRequest("https://httpbin.org/status/401");
ReactiveRequest reactiveRequest = ReactiveRequest.newBuilder(request).abortOnCancel(true).build();
Mono<ReactiveResponse> responseMono = Mono.fromDirect(reactiveRequest.response());
ReactiveResponse reactiveResponse = responseMono.block(Duration.ofSeconds(3));
System.out.println(reactiveResponse.getHeaders().toString());
System.out.println(reactiveResponse.getStatus());

The subscriber times out waiting:

java.lang.IllegalStateException: Timeout on blocking read for 3000000000 NANOSECONDS
	at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:129) ~[reactor-core-3.6.12.jar:3.6.12]
	at reactor.core.publisher.Mono.block(Mono.java:1807) ~[reactor-core-3.6.12.jar:3.6.12]

Am I misusing the reactive API in this case? Note that changing the URL to "https://httpbin.org/status/404" works as expected.

[sbordet]

@bclozel you need to swap these 2 lines:

httpClient.getProtocolHandlers().remove(WWWAuthenticationProtocolHandler.NAME);
httpClient.start();

to be:

httpClient.start();
httpClient.getProtocolHandlers().remove(WWWAuthenticationProtocolHandler.NAME);

I agree that your code is more intuitive, but for historical reasons we add the ProtocolHandlers in doStart().

Having said that, we do have a bug, as your test should have worked (with WWWAuthenticationProtocolHandler present).

The issue is that ResponseListeners.emitEvents() does not notify onContentSource() for zero-length content.
In case of the reactive HttpClient the missing notification does not invoke ResponseListenerProcessor.onContentSource() which is vital to set up the publisher/subscriber chain.