Expected undefined to be a GraphQL leaf type

I am getting the following error when running relay-compiler in my project

$ get-graphql-schema http://localhost/api/office > schema.graphql   
$ relay-compiler --src ./src/client --schema schema.graphql  
Watchman:  Watchman was not found in PATH.  See https://facebook.github.io/watchman/docs/install.html for installation instructions  
HINT: pass --watch to keep watching for changes.  

Writing js  
ERROR:  
Expected undefined to be a GraphQL leaf type.  
error Command failed with exit code 100.

Any suggestions on how to go about debugging this, the only recent change in my project (famous last words) was upgrading to relay 1.5. I suspect it is something in the graphql schema that needs to change to fit within the new relay-compiler, but I am not seeing it.

The schema.graphql is below:

schema {
  query: RootQuery
  mutation: RootMutation
}

type Delete {
  n: String
  nModified: String
  ok: String
}

type Room {
  _uuid: String
  roomName: String
  serviceName: String
  roomURL: String
  roomID: String
  phoneNumber1: String
  phoneNumber2: String
  participantCode: String
  moderatorCode: String
  video: String
  otherLink1: String
  otherLink2: String
  color: String
}

# Mutation interface
type RootMutation {
  createRoom(
    # Name of the room owner
    ownerName: String

    # Email of the room owner
    ownerEmail: String!

    # Name of the room
    roomName: String!

    # Service name
    serviceName: String!

    # URL
    roomURL: String!

    # ID to meeting room
    roomID: String

    # Phone number 1
    phoneNumber1: String!

    # Phone number 2
    phoneNumber2: String

    # Participant code
    participantCode: String!

    # Moderator code
    moderatorCode: String!

    # Video
    video: String

    # Color
    color: String
  ): Room
  deleteRoom(
    # Email of the room owner
    ownerEmail: String!

    # Name of the room
    roomName: String!
  ): Delete
}

type RootQuery {
  meetingsUser(ownerEmail: String!, _uuid: String, refetch: Boolean): [User]
}

type User {
  _id: String
  ownerEmail: String
  ownerName: String

  # Provides a list of all rooms owned by the user
  rooms: Room
}

Solution

This is because you are missing global id field on your type.

I had the same issue, but adding

type MyType = {
  id: ID
   ...
}

solved the problem.