Don't use honest_makers in case: mempool conflict

Prior to this commit, if a tumbler coinjoin negotiation
failed in Phase 2, then the retry as per the logic in
taker_utils.tumbler_taker_finished_update would always
attempt to retry the transaction with those counterparties
that returned valid !sig responses. However this ignored
the case that all the counterparties responded validly,
but there was a mempool conflict in the created transaction.
After this commit, if it is detected that all counterparties
responded, it is assumed that a mempool conflict or similar
occurred with the transaction, and therefore it is better
to fallback to a schedule tweak and choose randomly again,
not to fix the counterparty set (which is likely to result
in failing again).

jmclient/jmclient/taker_utils.py

@@ -252,14 +252,22 @@ def tumbler_taker_finished_update(taker, schedulefile, tumble_log, options,
         else:
             # a transaction failed, either because insufficient makers
             # (acording to minimum_makers) responded in Phase 1, or not all
-            #makers responded in Phase 2. We'll first try to repeat without the
-            #troublemakers.
+            # makers responded in Phase 2, or the tx was a mempool conflict.
+            # If the tx was a mempool conflict, we should restart with random
+            # maker choice as usual. If someone didn't respond, we'll try to
+            # repeat without the troublemakers.
             log.info("Schedule entry: " + str(
                 taker.schedule[taker.schedule_index]) + \
                      " failed after timeout, trying again")
             taker.add_ignored_makers(taker.nonrespondants)
             #Is the failure in Phase 2?
             if not taker.latest_tx is None:
+                if len(taker.nonrespondants) == 0:
+                    # transaction was created validly but conflicted in the
+                    # mempool; just try again without honest settings;
+                    # i.e. fallback to same as Phase 1 failure.
+                    log.info("Invalid transaction; possible mempool conflict.")
+                else:
                     #Now we have to set the specific group we want to use, and hopefully
                     #they will respond again as they showed honesty last time.
                     #Note that we must wipe the list first; other honest makers needn't
@@ -270,8 +278,9 @@ def tumbler_taker_finished_update(taker, schedulefile, tumble_log, options,
                         taker.maker_utxo_data.keys()).symmetric_difference(
                             set(taker.nonrespondants))))
                     #If insufficient makers were honest, we can only tweak the schedule.
-                #If enough were, we prefer the restart with them only:
-                log.info("Inside a Phase 2 failure; number of honest respondants was: " + str(len(taker.honest_makers)))
+                    #If enough were, we prefer to restart with them only:
+                    log.info("Inside a Phase 2 failure; number of honest "
+                             "respondants was: " + str(len(taker.honest_makers)))
                     log.info("They were: " + str(taker.honest_makers))
                     if len(taker.honest_makers) >= jm_single().config.getint(
                         "POLICY", "minimum_makers"):