Lists Of Primitives for Kotlin-types (String, Int etc.)

[hardysim]

Goal

I want to use the new Lists Of Primitives-Feature with Kotlin.
So it needs to support Kotlin-types as well (e.g. kotlin.String instead of only java.lang.String).

See https://realm.io/docs/java/latest/#lists-of-primitives
Refs #5031 (comment)

Expected Results

A RealmList with a Kotlin-type should be possible.

open class Foo(
        var bar: RealmList<kotlin.String>? = null
) : RealmObject()

Actual Results

The compiler gives the following error:

Error:Element type of RealmList must be a class implementing 'RealmModel' or one of the 'java.lang.String', 'byte[]', 'java.lang.Boolean', 'java.lang.Long', 'java.lang.Integer', 'java.lang.Short', 'java.lang.Byte', 'java.lang.Double', 'java.lang.Float', 'java.util.Date'.

Using RealmList<java.lang.String> produces the same error.

Steps & Code to Reproduce

Just create a new Kotlin-class with the code above and try to compile.

Code Sample

See code above

Version of Realm and tooling

Realm version(s): 4.2.0 / 4.3.0

Realm sync feature enabled: no

Android Studio version: 3.0.1

Which Android version and device: 8.1 beta (but doesn't matter)

[Zhuinden]

Can you try adding @Required annotation on it?

[hardysim]

Can you try adding @Required annotation on it?

Do you mean like this?

open class Foo(
        @Required
        var bar: RealmList<String>? = null
) : RealmObject()

Nope, does not work. Same error.

[Zhuinden]

Maybe @field:Required var bar: RealmList<String>? = null

[hardysim]

Maybe @field:Required var bar: RealmList<String>? = null

Nope. Does not compile neither.

---

And I don't see the idea behind this, because the compiler is clearly stating that the generic used for RealmList must be one of the mentioned classes:

java.lang.String, byte[], java.lang.Boolean, java.lang.Long, java.lang.Integer, java.lang.Short, java.lang.Byte, java.lang.Double, java.lang.Float, java.util.Date

So it looks like one need to modify the allowed types for the generic in RealmList (and not adding some annotations to the model-class).

---

Funny though, the signature of RealmList in realm-android-library-4.3.0-sources.jar looks like this:

public class RealmList<E> extends AbstractList<E> implements OrderedRealmCollection<E>

So it does not define any of those types and should actually allow any type?!

[Zhuinden]

The RealmList does, but the annotation processor will throw an error at compile time.

What's weird is that I'm pretty sure this worked for me last time I tried it. What's your Gradle plugin apply order?

[hardysim]

Ah ok, good to know. Thanks.

My order is:

apply plugin: 'com.android.library'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
apply plugin: 'com.jakewharton.hugo'
apply plugin: 'realm-android'

[Zhuinden]

Ah. apply plugin: 'kotlin-kapt' is missing from before realm-android

[hardysim]

apply plugin: 'kotlin-kapt' is missing

This does the trick!

I didn't saw it in the documentation but it's (now?) there.
So anyone stumbling over this issue have a look at https://realm.io/docs/java/latest/#kotlin