Execution fails with NRE when using generic field definition

Description

I’m defining model with a similar field in several types. E.g.

let WidgetsField name (getUser: ResolveFieldContext -> 'a -> User) =
    let resolve ctx xx =
        let user = getUser ctx xx 
        let widgets = user.Widgets |> List.toArray
        Connection.ofArray widgets

    Define.Field(name, ConnectionOf Widget, "A person's collection of widgets", Connection.allArgs, resolve)

which is instantiated as

fields = [
        Define.GlobalIdField(fun _ w -> w.Id)
        Define.Field("name", String, fun _ w -> w.Name)
        WidgetsField "widgets" (fun _ user -> user)
    ]

The issue is that only the first “widgets” field is functioning. All other instances causes exception in runtime.

Repro steps

Attaching modifed server.fsx for relay-starter-kit sample project.

• Put this server.fsx to the sample’s folder.
  • Start the server by fsi server.fsx.
  • Run the query (in Postman)

{"query": "{
    viewer {name}, widgets { edges }
}"}

Notice the first declared “widgets” field is fully functional.

Actual behavior

NRE exception is raised.

[johnberzy-bazinga]

@OlegZee @Horusiath

Until we investigate further, below is a workaround for that issue.

and WidgetConnection = ConnectionOf Widget
and WidgetsField name (getUser: ResolveFieldContext -> 'a -> User) =
    let resolve ctx xx =
        let user = getUser ctx xx 
        let widgets = user.Widgets |> List.toArray
        Connection.ofArray widgets

    Define.Field(name, WidgetConnection, "A person's collection of widgets", Connection.allArgs, resolve)

[johnberzy-bazinga]

This is fixed with the change made in #101