CompletionStage not unwrapped in 3.0.6

[mihalyr]

Hi,

our resources returning a CompletionStage are broken on 3.0.6 but work fine on 3.0.5.

This is a regression for the issue in #4640 which was fixed with https://github.com/eclipse-ee4j/jersey/pull/4885/files

The error I get is:

java.lang.IllegalArgumentException: Class `xyz.SearchResult` not subtype of `java.util.concurrent.CompletableFuture<xyz.SearchResult>`
	at com.fasterxml.jackson.databind.type.TypeFactory.constructSpecializedType(TypeFactory.java:446) ~[jackson-databind-2.13.3.jar:2.13.3]
	at com.fasterxml.jackson.databind.type.TypeFactory.constructSpecializedType(TypeFactory.java:408) ~[jackson-databind-2.13.3.jar:2.13.3]
	at org.glassfish.jersey.jackson.internal.jackson.jaxrs.base.ProviderBase.writeTo(ProviderBase.java:621) ~[jersey-media-json-jackson-3.0.6.jar:?]
	at org.glassfish.jersey.message.internal.WriterInterceptorExecutor$TerminalWriterInterceptor.invokeWriteTo(WriterInterceptorExecutor.java:242) ~[jersey-common-3.0.6.jar:?]
	at org.glassfish.jersey.message.internal.WriterInterceptorExecutor$TerminalWriterInterceptor.aroundWriteTo(WriterInterceptorExecutor.java:227) ~[jersey-common-3.0.6.jar:?]
	at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:139) ~[jersey-common-3.0.6.jar:?]
	at org.glassfish.jersey.server.internal.JsonWithPaddingInterceptor.aroundWriteTo(JsonWithPaddingInterceptor.java:85) ~[jersey-server-3.0.6.jar:?]
	at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:139) ~[jersey-common-3.0.6.jar:?]
	at org.glassfish.jersey.server.internal.MappableExceptionWrapperInterceptor.aroundWriteTo(MappableExceptionWrapperInterceptor.java:61) ~[jersey-server-3.0.6.jar:?]
	at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:139) ~[jersey-common-3.0.6.jar:?]
	at org.glassfish.jersey.message.internal.MessageBodyFactory.writeTo(MessageBodyFactory.java:1116) ~[jersey-common-3.0.6.jar:?]
	at org.glassfish.jersey.server.ServerRuntime$Responder.writeResponse(ServerRuntime.java:642) ~[jersey-server-3.0.6.jar:?]

One of the changes in #4885 fix was changing UNWRAP_COMPLETION_STAGE_IN_WRITER_ENABLE to true in unwrapInvocableResponseType in ResourceMethodInvoker.java

I've noticed that a merge commit included in 3.0.6 reverted those lines in 3619462#diff-9a15f3d079f85bb08c309d8c3ec510242d1a284b7145b5f35978c519ba20355bL490

For now I stick to 3.0.5 which seems to be working fine.

[jansupol]

@mihalyr Thanks for spotting this, in 2.x the default should be false, in 3.x true. Seems like false got propagated from master. I would expect a test would be failing :(