A base mutation that checks for selections on `errors`

base_mutation.rb

# A base mutation that adds an errors field to all subclasses, and before resolving, it checks to make sure that the caller selected `errors`.
#
# (You could use `GraphQL::Schema::Mutation` as a base class, too.)
class Mutations::BaseMutation < GraphQL::Schema::RelayClassicMutation 
  # Add the errors field to all mutations 
  field :errors, [Types::MutationError], null: false 
  # Inject `lookahead` to the resolve method 
  extras [:lookahead] 

  def resolve_with_support(lookahead:, **kwargs)
    if !lookahead.selects?(:errors)
      raise GraphQL::ExecutionError, "Add a selection on `errors { ... }` to ensure that mutation errors are handled correctly"
    end 
    super(**kwargs)
  end
end