Fix NPE when calling a ClientResponseFilter

[rober710]

When using the resteasy-reactive-client to make http calls, an NPE is thrown when using a custom filter and exception mapper. Here's the code to reproduce this:

private Configuration buildHttpConfig() {
    ConfigurationImpl configuration = new ConfigurationImpl(RuntimeType.CLIENT);
    configuration.property(QuarkusRestClientProperties.CONNECTION_TTL, 7);
    configuration.property(QuarkusRestClientProperties.CONNECTION_POOL_SIZE, 21);
    configuration.property(QuarkusRestClientProperties.KEEP_ALIVE_ENABLED, true);
    configuration.property(QuarkusRestClientProperties.MAX_REDIRECTS, 10);
    return configuration;
}

// Code in test service
ClientBuilder clientBuilder = ClientBuilder.newBuilder();
List<ResponseExceptionMapper<?>> exceptionMappers = Collections.singletonList(new DefaultMicroprofileRestClientExceptionMapper());
Client httpClient = clientBuilder.withConfig(buildHttpConfig())
                .register(new MicroProfileRestClientResponseFilter(exceptionMappers)).build();
try {
    String res = httpClient.target("http://httpbin.org/status/418").request().get(String.class);
    System.out.println(res);
} catch (Exception e) {
    if (e instanceof WebApplicationException webApplicationException) {
        String entity = webApplicationException.getResponse().readEntity(String.class);
        System.out.println(e.getMessage() + " entity " + entity);
    }
    e.printStackTrace();
}

Here's the stacktrace of the exception:

jakarta.ws.rs.ProcessingException: java.lang.NullPointerException: Cannot invoke "org.jboss.resteasy.reactive.client.impl.ClientRequestContextImpl.getRestClientRequestContext()" because "requestContext" is null
        at org.jboss.resteasy.reactive.client.handlers.ClientResponseFilterRestHandler.handle(ClientResponseFilterRestHandler.java:25)
        at org.jboss.resteasy.reactive.client.handlers.ClientResponseFilterRestHandler.handle(ClientResponseFilterRestHandler.java:10)
        at org.jboss.resteasy.reactive.common.core.AbstractResteasyReactiveContext.invokeHandler(AbstractResteasyReactiveContext.java:231)
        at org.jboss.resteasy.reactive.common.core.AbstractResteasyReactiveContext.run(AbstractResteasyReactiveContext.java:147)
        at org.jboss.resteasy.reactive.client.impl.RestClientRequestContext$1.lambda$execute$0(RestClientRequestContext.java:314)
        at io.vertx.core.impl.ContextInternal.dispatch(ContextInternal.java:279)
        at io.vertx.core.impl.ContextInternal.dispatch(ContextInternal.java:261)
        at io.vertx.core.impl.ContextInternal.lambda$runOnContext$0(ContextInternal.java:59)
        at io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:173)
        at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:166)
        at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:470)
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:566)
        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.base/java.lang.Thread.run(Thread.java:1583)
Caused by: java.lang.NullPointerException: Cannot invoke "org.jboss.resteasy.reactive.client.impl.ClientRequestContextImpl.getRestClientRequestContext()" because "requestContext" is null
        at io.quarkus.rest.client.reactive.runtime.MicroProfileRestClientResponseFilter.filter(MicroProfileRestClientResponseFilter.java:38)
        at org.jboss.resteasy.reactive.client.handlers.ClientResponseFilterRestHandler.handle(ClientResponseFilterRestHandler.java:21)
        ... 15 more

This happens in Quarkus 3.11.0 and also tested in latest 3.12.1. When making the change in this PR, compiling and using the generated snapshot, I'm able to read the response as expected.

[geoand]

Thanks for this!

I am actually very interested in seeing a sample that exhibits the NPE you mention so we can understand the exact conditions under which it occurs.

[rober710]

@geoand Sure! This is the test project I was working on to debug this: https://github.com/rober710/resteasy-reactive-reproducer

Note that this is a workaround for another issue: currently using the resteasy-reactive-client it's not possible to read the response on error, due to this:

quarkus/independent-projects/resteasy-reactive/client/runtime/src/main/java/org/jboss/resteasy/reactive/client/handlers/ClientSetResponseEntityRestHandler.java

Line 31 in 6d25d0a

throw new WebClientApplicationException(effectiveResponseStatus.getStatusCode(),

quarkus/independent-projects/resteasy-reactive/client/runtime/src/main/java/org/jboss/resteasy/reactive/client/api/WebClientApplicationException.java

Line 36 in 6d25d0a

super("Server response is: " + responseStatus, null, new DummyResponse(responseStatus, responseReasonPhrase));

Is it ok to make changes to those classes so that the response can be passed to the exception and made available to consumers? I'm working on a PR on that as well. Just wanted to understand if there's a reason a DummyResponse is created instead of a full response object with the entity returned by the server.

[geoand]

Thanks for the explanation!

I think that we should actually do context.getOrCreateClientRequestContext() in ClientSetResponseEntityRestHandler#handle, instead of the change made here.
Do you want to try that?

[rober710]

@geoand Done! It works calling the method there as well.

[geoand]

Great!

Can you please squash the commits?

[quarkus-bot]

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It should be safe to merge provided you have a look at the other checks in the summary.

You can consult the Develocity build scans.

[geoand]

Thanks!