jackson-databind 2.11.0-SNAPSHOT no longer supports Scala Either[L,R]

[pjfanning]

I've isolated the change in jackson-databind to changes of 9 Nov 2019.

• https://travis-ci.org/FasterXML/jackson-module-scala/jobs/621987475
• Added default value support jackson-module-scala#439

[cowtowncoder]

From warnings, this seems relevant:

[warn]         ctxt.reportWrongTokenException(jp, JsonToken.END_ARRAY,
[warn]              ^
[warn] /home/travis/build/FasterXML/jackson-module-scala/src/main/scala/com/fasterxml/jackson/module/scala/ser/EitherSerializer.scala:60: method findConvertingContentSerializer in class StdSerializer is deprecated: see corresponding Javadoc for more information.
[warn]     ser = Option(findConvertingContentSerializer(prov, prop, ser.orNull))
[warn]                  ^
[warn] 5 warnings found

and as per Javadocs

    /**
     * @deprecated Since 2.9 use {link {@link #findContextualConvertingSerializer} instead
     */
    @Deprecated
    protected JsonSerializer<?> findConvertingContentSerializer(SerializerProvider provider,
            BeanProperty prop, JsonSerializer<?> existingSerializer)

Not sure if what might have changed since deprecation was bit earlier but typically behavior of deprecated methods is less well tested after deprecated (that is, test code is updated to use non-deprecated functionality, most of the time).

But it probably makes sense to start by changing the call as suggested and see if that helps.

[pjfanning]

I removed the use of the findConvertingContentSerializer method but the same issue occurs.

[pjfanning]

In my testing, I isolated the change that caused the issue to the commits of Nov 9. https://github.com/FasterXML/jackson-databind/commits/2.11?after=2f89b9ca71f8e009f50b86506dc5f11804b5ad94+34

[cowtowncoder]

Did not realize that Either was a ReferenceType. This could be related since registration of serializers is based on subtype of JavaType.

Unfortunately I can't quite decipher Scala code with traits and all so I don't know where and how EitherSerializer is registered -- but I suspect it may be relying on older mechanism wherein default ("bean" / POJO) lookup was (also) called, not just one added for ReferenceType (which itself was added in 2.6).

[pjfanning]

@cowtowncoder I fixed jackson-module-scala with FasterXML/jackson-module-scala@2718645 - in the past, findBeanDeserializer worked but now findReferenceDeserializer is needed

[cowtowncoder]

@pjfanning excellent, thank you.

I am not sure how this could be done, but it would be great to figure out a way to do Travis builds to help figure out breaking changes in jackson-databind (or theoretically jackson-core) wrt downstream dependencies, during development of new minor versions.
This would make it much easier to resolve issues if they were discovered earlier.

[pjfanning]

@cowtowncoder I set up a daily build on jackson-module-scala 2.11 branch - based on https://docs.travis-ci.com/user/cron-jobs/ - I'll see if it runs as expected

[cowtowncoder]

the only (?) trick really would be to trigger that build when jackson-databind or jackson-core runs. Perhaps it could be triggered by availability of a new snapshot version at Sonatype snapshot repo?

I am specifically worried about changes in databind, over time. Changes in modules themselves are caught quite well by travis builds already.

[pjfanning]

the cron-based build I set up for jackson-module-scala pulls in latest jackson 2.11.0-SNAPSHOT jars

[cowtowncoder]

@pjfanning ah so it runs on regular schedule, in addition to being triggered by new commits? That would work.

Unrelated, but now that we are talking: just filed this

#2571

which is more triggered by needs of Kotlin (originally filed #2527) but might help resolve some long term Scala module challenges too.

[pjfanning]

yes it builds off both commits and a daily schedule

[cowtowncoder]

Not related to this issue which is now fixed it sounds like (yay!), but completing #2527 which supports Kotlin's approach via new AnnotationIntrospector method. Not sure it would be useful for Scala, but will mention for sake of completeness.