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Generic custom serializer breaks kotlin-kapt compilation
See original GitHub issueDescribe the bug
When using a generic custom serializer (see example below), adding the kotlin-kapt plugin with something that uses kapt (like data binding or Dagger) causes a Kotlin compiler error.
To Reproduce
The following generic custom serializer works as expected in an Android project when kotlin-kapt is not in use:
data class Wrapped<T>(
val value: T
)
open class WrappedSerializer<T>(private val serializer: KSerializer<T>): KSerializer<Wrapped<T>> {
override val descriptor: SerialDescriptor = serializer.descriptor
override fun deserialize(decoder: Decoder): Wrapped<T> =
Wrapped(serializer.deserialize(decoder))
override fun serialize(encoder: Encoder, obj: Wrapped<T>) =
serializer.serialize(encoder, obj.value)
}
@Serializable
data class A(
@Serializable(with = WrappedSerializer::class)
val value: Wrapped<String>
)
However, adding
apply plugin: 'kotlin-kapt'
and
android {
dataBinding {
enabled = true
}
}
causes building the build to fail with the following compiler exception:
error: incompatible types: Class<WrappedSerializer> cannot be converted to Class<? extends KSerializer<?>> @kotlinx.serialization.Serializable(with = com.alexvanyo.kotlintest.WrappedSerializer.class)
Expected behavior
Applying the kotlin-kapt plugin shouldn’t cause a compiler error.
As a temporary workaround, specifying the type does allow compilation with kotlin-kapt, but this isn’t ideal as it requires a separate class for every serialized type:
class StringWrappedSerializer(serializer: KSerializer<String>): WrappedSerializer<String>(serializer)
@Serializable
data class A(
@Serializable(with = StringWrappedSerializer::class)
val value: Wrapped<String>
)
Environment
- Kotlin version: 1.3.61
- Library version: 0.14.0
- Kotlin platform: JVM
- Gradle version: 5.4.1
- IDE version: Android Studio 3.5.3
Issue Analytics
- State:
- Created 4 years ago
- Reactions:11
- Comments:8
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I have the same issue as @eugenio1590 describes.
I have the following enum with a
JsonNamesattribute with two values:This causes the build to fail:
If i remove the second value of
JsonNames, the build succeeds:I am getting an issue similar to this. I am using databinding and kotlinx.serialization. I have an attribute with different names, so I included the @JsonNames annotation with more that one name.
But when I tried to build the project, the console printed the following error:
This didn’t happen when I disabled the databinding. To solve this, I changed the implementation of my DocMessage class
or
But none of the solutions solves the original problem completely. @JsonNames cannot be used with more than one value and requires to be used with the @SerialName to work.