Input Types in codegen: optional properties should be Optional<>

[tippfelher]

The graphqls description

input SomeInput {
  title: String
}

incorrectly generates SomeInput.java

public class SomeInput {
  String title
}

When @InputArgument SomeInput input is used in a resolver (data fetcher) there is no way to distinguish between

• the argument input.title was provided with value null
• the argument input.title is absent (wasn't provided by the user)

I therefore expected SomeInput.java to look like

public class SomeInput {
  Optional<String> title
}

to support the use case above (distinguish between null and absence for partial updates for example)

As a workaround we can use the DataFetchingEnvironment to check for certain fields but this pollutes the code base and doesn't feel good.

Is there an option we can set for code generation to replace T with Optional<T> or am I misunderstanding something here?

[tippfelher]

I found a related discussion and PR, but have no idea how to use it. 😟 (I assume this is because it has nothing to do with codegen)

[tippfelher]

I finally figured it out: when manually implementing the Input classes the Absence of a Property can easily be determined by utilizing Optional<T> and setters (that is the point of the PR).

I believe this functionality should be available as a code generation option, as implementing these classes feels overly repetitive and unnecessary. Perhaps once I gain more experience with DGS and Kotlin, I’ll consider contributing a feature for it. For now, though, my issue is resolved.

Also I don't know if this feature is properly documented or maybe I just missed it?