anchor.diff:                repairing=Repairing_list2,
                 dbg=Dbg2} = P2,
     RelativeToServer, __TODO_RetrospectiveP) ->
  + ?RETURN2(undefined),
    try
  -    put(why2, []),
       %% General notes:
       %%
       %% I'm making no attempt to be "efficient" here.  All of these data
  
positive.code: %% {[keep,del],[error]}   %% bad transition: 'bogus' not in Repair1'''
  
  simple_chain_state_transition_is_sane(UPI1, Repair1, UPI2) ->
      simple_chain_state_transition_is_sane(undefined, UPI1, Repair1,
                                            undefined, UPI2).
  
  simple_chain_state_transition_is_sane(_Author1, UPI1, Repair1, Author2, UPI2) ->
      put(why2, []),
      {KeepsDels, Orders} = mk(UPI1, Repair1, UPI2),
      NumKeeps = length([x || keep <- KeepsDels]),
      NumOrders = length(Orders),
  
negative.code:             %% always optimal for highest availability).
              ?RETURN2(true);
         true ->
              ?RETURN2(
                 simple_chain_state_transition_is_sane(Author1, UPI1, Repair1,
                                                       Author2, UPI2))
      end.
  
  %% @doc Create a 2-tuple that describes how `UPI1' + `Repair1' are
  