Kotlin 1.4 support

[efenderbosch]

Maybe this can be just a meta-issue to collect issues w/ Kotlin 1.4.

First thing I noticed is that inline classes no longer serialize properly.

w/ Kotlin 1.3:

{
  "type" : "SHOPPING_CART",
  "url" : "http://example.com"
}

w/ Kotlin 1.4:

{
  "type" : "SHOPPING_CART",
  "url-6j4v_q1g" : "http://example.com"
}

[daviddenton]

Is there a plan around Kotlin 1.4.0 support? Will it be released as part of 2.12 or will it be held off to v3?

I've speculatively upgraded on the 2.12 branch and have created 357 . All the tests pass on that PR, so it looks like there is at maybe some missing coverage around the issue mentioned by @efenderbosch above?

[efenderbosch]

I did some digging and I think that KotlinNamesAnnotationIntrospector::findImplicitPropertyName needs another branch to handle these mangled getter names.

if (member is AnnotatedMethod) {
    // pseudo code
    if (member.name is like "getFooBar-junk") {
        find fooBar member on the Kotlin class
        if the member's Kotlin class has "box-impl" or "unbox-impl" methods, then it is an inline class
        if it is an inline class, then return "fooBar"
    }
}

[efenderbosch]

If there is missing coverage, this simple test might be enough.

class InlineClassTest {

    @Test
    fun test() {
        val mapper = ObjectMapper().registerModule(KotlinModule())
        val original = SomeOtherClass(MyInlineClass("bar"))
        val json = mapper.writeValueAsString(original)
        val deserialized = mapper.readValue(json, SomeOtherClass::class.java)
        assertThat(deserialized, equalTo(original))
    }
}

inline class MyInlineClass(val inner: String)

@JsonDeserialize(builder = SomeOtherClass.JacksonBuilder::class)
data class SomeOtherClass(val fooBar: MyInlineClass) {
    data class JacksonBuilder private constructor(val fooBar: String) {
        fun build() = SomeOtherClass(MyInlineClass(fooBar))
    }
}

Passes w/ Kotlin 1.3. Currently fails w/ Kotlin 1.4 with a MissingKotlinParameterException since it expects {"fooBar":"bar"} but finds {"fooBar-dSSZTOk":"bar"}

[cowtowncoder]

Since Jackson 3.x is still ways out (no good idea of when focus should move back), I think that support for 2.12 would make sense (or 2.13, there will be minor 2.x versions past 2.12).

[andmoos]

Having hit this issue today myself I found that as workaround @JvmField annotations effectively disable the mangling.

[eugenio1590]

any progress here?

[dinomite]

I created a kotlin-1.4 branch and this PR (I cherry picked @daviddenton's commits because I was stymied by Git) #374

[dinomite]

@efenderbosch I added a (failing) test for that issue to the branch.

[dinomite]

Well, it should be failing. Looks like I have more messing around to do with CircleCI

[dinomite]

Ok, failing now; I wasn't following Maven Surefire's redundancy rules

[dinomite]

I think we should move ahead with updating the module to Kotlin 1.4.10 in spite of this bug. There is a test for this issue on the kotlin-1.4 branch which is help to anyone who would like to give a shot at fixing this bug.

[elektro-wolle]

I've added simple demangling code via the above commit. Not sure, if this is enough (but all tests are green).

[cowtowncoder]

One quick note: I released 2.12.0-rc1 yesterday. Will probably take at least over end of October to find out regressions, so final 2.12.0 will not go out before November 2020. But if this change is to be done for 2.12, would be good to coordinate.
(not saying it has to, could go in 2.13, but definitely sounds like something to do in a minor release, not patch, and timing of 2.12 seems plausible).

[dinomite]

@elektro-wolle I used your commit in this PR #383

[dinomite]

The 2.12 branch is now on Kotlin 1.4.10. Any new problems can be filed as new issues.