Accessing an unset deprecated field in input causes a crash

[pixelmatrix]

Summary

We recently deprecated a field in an input object.

As a result, codegen created a new default initializer that that excludes that field.

public init(newField: GraphQLNullable<MyType>) {
  __data = InputDict(["newField": newField])
}

@available(*, deprecated, message: "Argument 'oldField' is deprecated")
public init(oldField: GraphQLNullable<MyType>) {
  __data = InputDict(["oldField": oldField])
}

Now, when accessing the deprecated field through the input object, it crashes because that field is not actually present in the underlying InputDict.

Generated code for the property looks like:

@available(*, deprecated, message: "Use newField instead")
public var oldField: GraphQLNullable<MyType> {
  get { __data["oldField"] }
  set { __data["oldField"] = newValue }
}

…which calls:

public subscript<T: GraphQLOperationVariableValue>(key: String) -> T {
  get { data[key] as! T }
  set { data[key] = newValue }
}

Version

1.15.3

Steps to reproduce the behavior

1. Deprecate a field of an input object in your schema
2. Run codegen to pick up the field
3. Create an instance of the input object using the new default initializer

let input = MyInput()

4. Try accessing the deprecated field on the object

if input.oldField == .none { // crash!
  print("worked")
}

Logs

Could not cast value of type 'Swift.Optional<ApolloAPI.GraphQLOperationVariableValue>' (0x1f05300a0) to 'ApolloAPI.GraphQLNullable<Swift.String>' (0x1f052f388).

Anything else?

No response

[calvincestari]

Thanks for raising the issue @pixelmatrix. We'll take a look at the design intent here and get back to you.