anchor.diff:  cc_commit_write({_WL, Vers}, _WF, _Val = {_TxId, TLogVers, _NewVal}) ->
       Checks =
           [ { Vers =:= TLogVers,  {version_mismatch, TLogVers, Vers} } ],
  -    cc_return_val(cc_commit_write, Checks, _UI_if_ok = none, _Log = true);
  +    cc_return_val(cc_commit_write, Checks, _UI_if_ok = none, ?LOG_CC_FAILS);
   %% in case of fast write we get the value of the last read as write
   %% value, which here was produced by the read filter of set_lock
   cc_commit_write({_RL, _WL, Vers}, _WF, _Val = {_TxId, TLogVers, _NewVal}) ->
       Checks =
           [ { Vers =:= TLogVers,  {version_mismatch, TLogVers, Vers} } ],
  -    cc_return_val(cc_commit_write, Checks, _UI_if_ok = none, _Log = true).
  +    cc_return_val(cc_commit_write, Checks, _UI_if_ok = none, ?LOG_CC_FAILS).
   
   
   -spec wf_val_unset_wl
  
positive.code: cc_set_rl({WL, Vers}, _WF, _Val = {_TxId, TLogVers}) ->
      Checks = [ { TLogVers =:= Vers, {version_mismatch, TLogVers, Vers} },
                 { false =:= WL,      writelock_is_set } ],
      cc_return_val(cc_set_rl, Checks, _UI_if_ok = none, _Log = true).
  
  -spec wf_set_rl(db_entry(), UI :: {writelock(), version()} | no_value_yet,
                  {txid_on_cseq:txid(), version()}) -> db_entry().
  
negative.code: wf_set_wl(prbr_bottom, _UI = none, {TxId, -1}) ->
      set_writelock(new_entry(), TxId);
  wf_set_wl(prbr_bottom, _UI = none, {TxId, _}) ->
  %%    ct:pal("should only happen in tester unittests~n"),
      set_writelock(new_entry(), TxId);
  wf_set_wl(DBEntry, _UI = none, {TxId, _Vers}) ->
      set_writelock(DBEntry, TxId).
  