Rest Client Reactive: unwrap exceptions set by mappers in async

[michalszynkiewicz]

fixes #19415

[quarkus-bot]

This workflow status is outdated as a new workflow run has been triggered.

Failing Jobs - Building bed695a

Status	Name	Step	Test failures	Logs	Raw logs
✔️	JVM Tests - JDK 11
✖	JVM Tests - JDK 11 Windows	Build	Test failures	Logs	Raw logs
✔️	JVM Tests - JDK 16

Full information is available in the Build summary check run.

Test Failures

⚙️ JVM Tests - JDK 11 Windows #

📦 extensions/resteasy-reactive/quarkus-resteasy-reactive/deployment

✖ io.quarkus.resteasy.reactive.server.test.simple.SimpleQuarkusRestTestCase.testHeaderParamInCtor line 284 - More details - Source on GitHub

java.lang.AssertionError: 
1 expectation failed.
Response body doesn't match expectation.
Expected: "v11"
  Actual: An Internal Server Error with stack trace:
java.lang.NullPointerException
	at org.jboss.resteasy.reactive.server.injection.ContextProducers.getTarget(ContextProducers.java:108)
	at org.jboss.resteasy.reactive.server.injection.ContextProducers.resourceInfo(ContextProducers.java:90)
	at org.jboss.resteasy.reactive.server.injection.ContextProducers_ProducerMethod_resourceInfo_be7f5503a87442251cde9fbc1d406fb350a529f0_Bean.create(ContextProducers_ProducerMethod_resourceInfo_be7f5503a87442251cde9fbc1d406fb350a529f0_Bean.zig:163)
	at org.jboss.resteasy.reactive.server.injection.ContextProducers_ProducerMethod_resourceInfo_be7f5503a87442251cde9fbc1d406fb350a529f0_Bean.create(ContextProducers_ProducerMethod_resourceInfo_be7f5503a87442251cde9fbc1d406fb350a529f0_Bean.zig:194)
	at io.quarkus.arc.impl.RequestContext.getIfActive(RequestContext.java:68)
	at io.quarkus.arc.impl.Client...