When selecting a field whose type is nullable in the schema, the corresponding field in the generated Kotlin model will also be nullable. Null safety on fieldsĪpollo Kotlin generates models based on your project’s GraphQL operations and the type information found in the schema. Let’s look at a few ways the library deals with nullability. In fact, nullability is one of the key features of GraphQL, allowing API authors to clearly specify which fields of a type are nullable.Īs for Kotlin, the language supports nullability in its type system, significantly reducing the risk for errors – for example assigning a potentially null value to a non-nullable field won’t even compile!Īt the intersection of these two worlds lies Apollo Kotlin, the GraphQL typesafe client library for Kotlin. Mistake or not, null is here to stay and there are ways to coexist peacefully! What’s disturbing is the lack of consciousness that this happens, which can cost much.Īre you sure the library you are using is not doing that internally? There are a couple of them out there.Ĭode snippets can be found on GitHub.The concept of null is sometimes called a “ billion dollar mistake”.

In this case, we simply need to perform checks manually after instantiation, which is not super problematic. If we try to access the Unsafe instance, we encounter a private constructor, and a static getUnsafe() method that raises a SecurityException practically every time we call it: public final class Unsafe ', Foo::class.java) This class is like one of those scary computer game creatures that are there only to intimidate us, in theory, we can’t get close because they are part of the environment, but it’s often possible by exploiting glitches or holes. The class is an internal JVM tool for executing low-level operations like off-heap memory allocation, thread parking, CAS, and much more. In this short article, we’ll have a look at how we can bypass Kotlin’s native null-safety with, and see why it can be dangerous even if we aren’t messing up with it directly.

If null kotlin