Relay-compliant mutation helpers with clientMutationId support.

This module provides macros for defining Relay-style mutations that automatically handle the clientMutationId field.

Usage

Use relay_mutation instead of field for Relay-compliant mutations:

defmodule MyApp.GraphQL.Mutations.UserMutations do
  use GreenFairy.Mutation
  import GreenFairy.Relay.Mutation

  mutations do
    relay_mutation :create_user do
      @desc "Creates a new user"

      input do
        field :email, non_null(:string)
        field :name, :string
      end

      output do
        field :user, :user
        field :errors, list_of(:string)
      end

      resolve fn input, ctx ->
        case MyApp.Accounts.create_user(input) do
          {:ok, user} -> {:ok, %{user: user}}
          {:error, changeset} -> {:ok, %{errors: format_errors(changeset)}}
        end
      end
    end
  end
end

This generates:

• CreateUserInput input type with clientMutationId field
• CreateUserPayload output type with clientMutationId field
• Automatic passthrough of clientMutationId from input to output