JSON Jackson does not handle resource returning CompletionStage<X> #3672

[mageshwaranr]

A resource method like below fails with java.lang.IllegalArgumentException: Class * not subtype of *.

@GET
@Produces({"application/json" })
@Path("async")
public CompletionStage<Hello> asyncHello(@NotNull @PathParam(value = "lang") String lang,
                                         @NotNull @Size(min = 2) @QueryParam("yo") String greet){
        return CompletableFuture.supplyAsync(() -> new Hello(lang, greet);
}

This pull request attempts to fix this. Let me know whether the fix is appropriate.

[jansupol]

#3672

[jansupol]

There is a valid ECA on file for mageshwaran.r@gmail.com.

[jansupol]

Thank you for the PR, it looks good. However, any PR that modifies the code should have a test. Jackson seems to have tests under examples/json-jackson.

[mageshwaranr]

Sorry for the delay. Added test cases. Is there a way to re-trigger build ?
Not sure whether test is failing due to code issue.

[mageshwaranr]

Attempting to re-trigger the build

[mageshwaranr]

@jansupol Anything expected from me to take this forward ?

[mageshwaranr]

Added required test cases

[dandew]

@jansupol Can we please have this in 2.29? This has been hurting for a while now 😅

[jansupol]

Hm,...I was about to approve this...but then I realized (late, sorry)...

org/glassfish/jersey/jackson/internal/jackson/jaxrs/base/ProviderBase.java is actually repackaged from Jackson 2.8.10.

Should the PR be made against Jackson rather than against Jersey? If a new version gets repackaged, the code could be lost...The best way is to create a PR against Jackson (2.9.x) and then a PR/issue to Jersey to repackage the latest version

Sorry for that coming late, but it still is doable before 2.29.

[jansupol]

Hm... If it gets merged to Jackson, we can merge this to Jersey, too. But since this is 3rd party code, we need to ask for a CQ, first.

[jansupol]

The last commit is missing sign-off-by (-s)...

[jansupol]

Copyright header is missing

[jansupol]

@mageshwaranr The code in Jackson seems to be stable at least from 2.8.4. I think we could add this to Jersey. Can you please fix the reported issues?

• copyright header in the example resource class
• add sign off
• please force push so that git hub check does not see the commit with the missing sign-off

[jansupol]

We have adopted Jackson 2.9.9

[edinardo]

@mageshwaranr could you please add the last request from @jansupol so we can have it.
So far, this is the only impediment to use JAX-RS 2.1 async standard with the official build.

[jpadre]

@mageshwaranr could you please add the last request from @jansupol so we can have it.
So far, this is the only impediment to use JAX-RS 2.1 async standard with the official build.

There's one more thing missing to complete this for me, which is to unwrap CompletionException properly so appropriate javax.ws.rs.ext.ExceptionMapper are called down the line.

If it helps anyone else, I am modifying the mapException method of org.glassfish.jersey.server.ServerRuntime using this code to workaround it, but unsure if there's a better way it can be integrated:

private Response mapException(final Throwable originalThrowable) throws Throwable {
	LOGGER.log(Level.FINER, LocalizationMessages.EXCEPTION_MAPPING_START(), originalThrowable);
	Throwable throwable = originalThrowable;
	boolean inMappable = false;
	boolean mappingNotFound = false;

	do {
		//---------------------------------- Begin Change -----------------------------------
		if (throwable instanceof CompletionException && throwable.getCause() != null) {
			throwable = throwable.getCause();
		}
		//----------------------------------- End Change ------------------------------------   
		if (throwable instanceof MappableException)