Basic support for virtual fields using hydration

[gnawf]

So the phrase virtual fields here refers to a @hydrated field at the top level that doesn't use any $source arguments.

Though in a new branch I've repurposed it and renamed hydratedField etc. to virtual field and actor field to backing field.

[gnawf]

This is redundant, it looks up the field definition using the __typename in the result, but that's already been done because we've resolved an instruction at the call site.

This change just passes in the instruction and looks an the field definition in the instruction.

Likely this was a mistake due to copy paste during refactoring.

[bbakerman]

Question -

So when we make a virtual type - we say that all fields in other types get made "virtual" as well - eg the shape of virtual type is actually the backing type shapes

What happens if the types reference themselves

 type VirtualEcho {
                    echo: String
                    info: VirtualEchoInfo
                    selfReference : VirtualEcho.  # what happens here
                }

[bbakerman]

will it go into a infinite loop and if not can we have a test for that?

[gnawf]

There's code to protect against that, I've created a test for that though.

[bbakerman]

Does this code have a "get all other parameters" and stuff them into a map code yet?

[gnawf]

Not yet, coming in another PR.

Branch is https://github.com/atlassian-labs/nadel/tree/remaining-arguments