[BUG][KOTLIN] No JsonAdapter for LocalDateTime in Moshi serializer

[toXel]

Description

date-time fields can't be parsed from a generated Kotlin client with default configuration. It fails with this exception:
java.lang.IllegalArgumentException: Platform class java.time.LocalDateTime annotated [] requires explicit JsonAdapter to be registered

The reason for it is that in Serializer.kt.mustache Moshi only gets a JsonAdapter for the java.util.Date type but not for java.time.LocalDateTime (or org.threeten.bp.LocalDateTime when ThreeTen is used).

openapi-generator version

v3.3.1

Command line used for generation

generate -g kotlin -i https://petstore.swagger.io/v2/swagger.yaml -o swaggerClientTest

Steps to reproduce

It can be reproduced with the petstore swagger spec.

1. Generate Kotlin client with the command above.
2. Write a simple test like this:

@Test
fun getOrderById() {
    val order = StoreApi().getOrderById(1)
    assertNotNull(order)
}

3. It will fail with the respective exception.

Suggest a fix/enhancement

A workaround is to implement a JsonAdapter for the respective type and add it to Moshi in the generated Serializer class. Maybe this can be integrated in the generator.

[krevelen]

same for java.util.UUID

[jpmeijers]

I'm hitting this same issue with the OffsetDateTime type.

Applicable line in generated code looks like this:

    /* Absolute time when... */
    @Json(name = "absolute_time")
    val absoluteTime: java.time.OffsetDateTime? = null

Applicable lines in api.swagger.json:

        "absolute_time": {
          "type": "string",
          "format": "date-time",
          "description": "Absolute time when ..."
        }

And the exception that moshi is throwing:

    java.lang.IllegalArgumentException: Platform class java.time.OffsetDateTime requires explicit JsonAdapter to be registered
    for class java.time.OffsetDateTime absoluteTime

[ghost]

@jpmeijers did you find out how to use OffsetDateTime with Moshi? I have been trying to write a custom adapter but still getting errors. Thanks

[jpmeijers]

I'm not 100% sure as it's a while back, but looks like I created a custom adapter:
https://github.com/ttnmapper/ttnmapper-android-v3/blob/master/app/src/main/java/org/ttnmapper/phonesurveyor/model/ttnV3/OffsetDateTimeAdapter.kt

And then added that to the Moshi instance:

        val moshi = Moshi.Builder()
//                .add(KotlinJsonAdapterFactory())
                .add(OffsetDateTimeAdapter())
                .build()

[ghost]

Thanks for the response! I was able to get it working :)