Hey, I wan to use a custom annotation class during...

# serialization

[hfhbd]

Hey, I wan to use a custom annotation class during encoding. So I marked my annotation class with @SerialInfo and I use descriptor.getElementAnnotations(index), but the annotation for this property is not found. Did I miss something?

[hfhbd]

@ExperimentalSerializationApi
internal fun SerialDescriptor.fixedLengthElement(index: Int) =
    getElementAnnotations(index).filterIsInstance<FixedLength>().singleOrNull()
        ?: error("$serialName not annotated with @FixedLength")

@ExperimentalSerializationApi
@SerialInfo
public annotation class FixedLength(val length: Int)

// usage
override fun <T> encodeSerializableElement(
        descriptor: SerialDescriptor,
        index: Int,
        serializer: SerializationStrategy<T>,
        value: T
    ) {
        serializer.serialize(
            FixedLengthPrimitiveEncoder(
                serializersModule,
                descriptor.fixedLengthElement(index).length,
                builder
            ), value
        )
    }

@Serializable
    data class Sample(
        @FixedLength(10) val date: Instant
    )

[hfhbd]

I filled a bug. https://github.com/Kotlin/kotlinx.serialization/issues/1923