GsonBuilder.disableUnsafe

While it is nice to know that Unsafe is only used when no-arg ctors or instance 
creators are not present, it would be better to have a means to enforce it 
cannot be used.  Particularly in google app engine, I'd like to know that the 
code I use offline is safe inside GAE, rather than a delayed 
UnsupportedOperationException

Can you add GsonBuilder.disableUnsafe or similar?

Original issue reported on code.google.com by [e-mail] on 16 May 2012 at 5:58

[fab1an]

That worked, thanks a lot. For the record: my kotlin-code:

/* throw when no default-constructor was found */
object WarnConstructorFactory : TypeAdapterFactory {

    private val wrappers = listOf(
        java.lang.Boolean::class.java,
        java.lang.Character::class.java,
        java.lang.String::class.java,
        java.lang.Byte::class.java,
        java.lang.Short::class.java,
        java.lang.Integer::class.java,
        java.lang.Long::class.java,
        java.lang.Float::class.java,
        java.lang.Double::class.java
    )

    override fun <T> create(gson: Gson, type: TypeToken<T>): TypeAdapter<T>? {

        val rawType = type.rawType
        if (!(rawType in wrappers || rawType.isInterface || 
              rawType.isPrimitive || rawType.isEnum)) {

            check(
                rawType.constructors.any { it.parameterTypes.count() == 0 },
                { "$type has no public no-args constructor" }
            )
        }
        return null;
    }
}

[fab1an]

Yes. I use kotlin’s data-classes. If I supply default-values for all constructor parameters, a no-args constructor is generated and everything works fine. If I forget a default-value somewhere though, gson initializes the class with all fields set to null, which then crash with a NPE when I access them, even though kotlin “guarantees” them to be not-null.

So I need gson to crash to see that I forgot to set the parameter.