KSerialClassDesc should include the KClass being serialized

[ansman]

Currently the KSerialClassDesc only includes the name of the class which makes it hard to load custom serializers for some libraries.

[pdvrieze]

@ansman This is because in javascript there is no class object. If you look at the implementation then you see that it uses a multiplatform function that uses Class.forName under water.

[ansman]

Ah, I thought KClass existed in kotlin-js but obviously not Class.

But this means that Class.forName(desc.name) should pretty much always be safe?

[sandwwraith]

While KClass exists on JS (but can't provide almost nothing except class name), Class.forName totally unavailable on JS, thats why #101 request exists.

On JVM, Class.forName(desc.name) should work for every @Serializable white-listed class except nested (#126 )

[ansman]

So what would be the downside of including KClass rather than the name? Seems like a more flexible solution?

[pdvrieze]

@ansman Except that there currently is no way on javascript to get a serializer for a named type.

[ansman]

I don't really understand. If you simply replace .name with .klass on the descriptor then you could simply name .name be .klass.qualifiedName?

[pdvrieze]

@ansman The code at some point needs to have an actual class object that it can retrieve a serializer for. Javascript has no way to store annotations yet (shouldn't be hard to emulate though)

[sandwwraith]

KClass won't be included in descriptor because reflection API is very limited in multiplatform setup and there will be almost no benefit in it.

Instead, suggested approach is to use extended features of SerialDescriptor (https://github.com/Kotlin/KEEP/blob/master/proposals/extensions/serialization.md#saving-schemas-with-a-descriptor) to introspect class and obtain information about its properties, their types, and annotations.