Spring RestTemplate with jetty client leads to IllegalArgumentException with "Self-suppression not permitted"

Affects: - spring-web 6.1.11

There is a bug in the exception handling of the JettyClientHttpRequest.

If a RestTemplate is used with the Jetty client and we try to connect to a nonexistent HTTP endpoint, we get an IllegalArgumentException with the message Self-suppression not permitted.

You can find a reproducer in the attached zip, including a pom.xml.

 assertThatThrownBy(() -> this.restTemplateBuilder.build().exchange("http://localhost:12345", HttpMethod.POST, new HttpEntity<>("body", new HttpHeaders()), String.class))
    .isNotInstanceOf(IllegalArgumentException.class)
    .hasMessageNotContaining("Self-suppression not permitted");

Comment From: sdeleuze

@ReuDa Thanks for the repro, I tend to think this bug is on Jetty side and looks like similar with https://github.com/jetty/jetty.project/issues/12029. Do you agree?

Comment From: ReuDa

@sdeleuze Yes, that seems to be a perfect fit. The described workaround in the linked issue is working fine for me.

Thanks and sorry for the noise!

Comment From: sdeleuze

Np, thanks for the quick feedback.