`.mapConnect()` and `.doOnRequestError()` are not called when `.headersWhen()` is used

[Mateusz Rzeszutek]

Expected Behavior

I would expect that the HTTP client executes its callbacks regardless of whether the headers were set using .headersWhen() or headers(). Currently this is not the case, .mapConnect() and .doOnRequestError() callbacks are not executed when deferred config is used.

Actual Behavior

.mapConnect() and .doOnRequestError() callbacks are not executed when deferred config is used.

Steps to Reproduce

This test prints out the two messages to stdout:

  @Test
  void headers() {
    HttpClient.create()
        .headers(h -> h.set("test", "test"))
        .mapConnect(connection -> {
          System.out.println("mapConnect()");
          return connection;
        })
        .doOnRequestError((request, throwable) -> System.out.println("doOnRequestError()"))
        .get()
        .uri("http://192.0.2.1")
        .response()
        .block();
  }

This one does not:

  @Test
  void headersWhen() {
    HttpClient.create()
        .headersWhen(h -> Mono.just(h.set("test", "test")))
        .mapConnect(connection -> {
          System.out.println("mapConnect()");
          return connection;
        })
        .doOnRequestError((request, throwable) -> System.out.println("doOnRequestError()"))
        .get()
        .uri("http://192.0.2.1")
        .response()
        .block();
  }

Possible Solution

reactor-netty/reactor-netty-http/src/main/java/reactor/netty/http/client/HttpClientConnect.java

Lines 111 to 118 in c7ba195

 Mono<? extends Connection> mono; 
 if (config.deferredConf != null) { 
 	return config.deferredConf.apply(Mono.just(config)) 
 	           .flatMap(MonoHttpConnect::new); 
 } 
 else { 
 	mono = new MonoHttpConnect(config); 
 } 

Removing the return in line 113 would allow the code in lines 120-133

reactor-netty/reactor-netty-http/src/main/java/reactor/netty/http/client/HttpClientConnect.java

Lines 120 to 133 in c7ba195

 if (config.doOnConnect() != null) { 
 	mono = mono.doOnSubscribe(s -> config.doOnConnect().accept(config)); 
 } 
  
 if (config.doOnRequestError != null) { 
 	mono = mono.onErrorResume(error -> 
 			Mono.deferContextual(Mono::just) 
 			    .doOnNext(ctx -> config.doOnRequestError.accept(new FailedHttpClientRequest(ctx, config), error)) 
 			    .then(Mono.error(error))); 
 } 
  
 if (config.connector != null) { 
 	mono = config.connector.apply(mono); 
 } 

to happen before the Mono is returned.

Your Environment

• Reactor version(s) used: this happens on any version starting from 1.0
• Other relevant libraries versions (eg. netty, ...):
• JVM version (java -version): OpenJDK Runtime Environment Temurin-17.0.2+8 (build 17.0.2+8)
• OS and version (eg. uname -a): Darwin Kernel Version 22.6.0

[Violeta Georgieva]

@mateuszrzeszutek Would you like to create a PR?

[Mateusz Rzeszutek]

Sure 👍
I'll submit a fix tomorrow

[Violeta Georgieva]

Please use as a base 1.0.x branch, later we will forward merge to main branch.

[Mateusz Rzeszutek]

Hey @violetagg ,
I'll need to make sure with my employer that I can sign the CLA -- it might take me a while, so unfortunately don't count on a quick fix from me.