Kotlin master (3.0) test failures -- due to MapperFeature.ALLOW_FINAL_FIELDS_AS_MUTATORS default change; SORT_PROPERTIES_ALPHABETICALLY

[cowtowncoder]

So, Kotlin module unit tests on master fail -- now that we have dependent builds, builds are triggered on jackson-databind changes.
Looking at fail message, I think it has same root cause as Scala fails:

FasterXML/jackson-module-scala#678

and similar solutions (either change tests not to rely on forcing setting of final fields; or change MapperFeature setting used by mapper).

[cowtowncoder]

cc @k163377 @JooHyukKim I hope above is enough to solve issues.

[JooHyukKim]

Changing MapperFeature.ALLOW_FINAL_FIELDS_AS_MUTATORS default fixes the issue (tested locally).

If I try connecting the dots, we have two options.

~~- Quick and easy solution : just flip ALLOW_FINAL_FIELDS_AS_MUTATORS on Kotlin-module side, suffer long term. ~~
- Possible concern, users who use ObjectMapper for both java and Kotlin classes should also know about it?
- More-work-needed solution : Make #805 work (if I understood correctly, would solve this issue)

[cowtowncoder]

I don't think #805 matters here: the problem is that some tests were only working if Jackson is allowed to force (Via reflection) setting of final field values (isn't it interesting this ever works?! It is likely required for JDK serialization functionality).

So I think tests in question are likely wrong: jackson-databind had one or two as well, but in those cases it was unintentional.

By more work I meant investigating tests themselves to see why they need this setting, and if the tests might be buggy, in a way. Not so much that more work is needed on non-test code.

I don't think users really should enable this MapperFeature, fwtw; it will probably not work in future with later JDKs.
So turning it off just exposes possibly bad unit tests.

[JooHyukKim]

(either change tests not to rely on forcing setting of final fields; or change MapperFeature setting used by mapper).

Ah okay, I understand now what it meant 👍🏼

[cowtowncoder]

Yea it's, an odd setting. Had to be added because code was already setting final fields without intending (I had not filtered out final fields :) -- someone pointed this out to me, thinking it was a Feature... not a bug ! )

[cowtowncoder]

Noting that MapperFeature.SORT_PROPERTIES_ALPHABETICALLY default change contributes to fails as well.

[JooHyukKim]

I think we could probably go ahead and fix the tests via changing configuration defaults? @cowtowncoder WDYT?

[cowtowncoder]

@JooHyukKim yes, I think that'd be the simplest immediate solution.

[JooHyukKim]

filed #808.

[cowtowncoder]

Note: we are almost good, but there's now #813 for Kotlin 2.0 issues of some kind wrt master branch.