sweep: only remove the other input from the exclusive group

We now make sure when removing inputs identified by the exclusive group
ID, we only remove the other one, not the one that invoked the removal.

Author: yyforyongyu

sweep/sweeper.go

@@ -740,15 +740,23 @@ func (s *UtxoSweeper) collector() {
 	}
 }
 
-// removeExclusiveGroup removes all inputs in the given exclusive group. This
-// function is called when one of the exclusive group inputs has been spent. The
-// other inputs won't ever be spendable and can be removed. This also prevents
-// them from being part of future sweep transactions that would fail. In
-// addition sweep transactions of those inputs will be removed from the wallet.
-func (s *UtxoSweeper) removeExclusiveGroup(group uint64) {
+// removeExclusiveGroup removes all inputs in the given exclusive group except
+// the input specified by the outpoint. This function is called when one of the
+// exclusive group inputs has been spent or updated. The other inputs won't ever
+// be spendable and can be removed. This also prevents them from being part of
+// future sweep transactions that would fail. In addition sweep transactions of
+// those inputs will be removed from the wallet.
+func (s *UtxoSweeper) removeExclusiveGroup(group uint64, op wire.OutPoint) {
 	for outpoint, input := range s.inputs {
 		outpoint := outpoint
 
+		// Skip the input that caused the exclusive group to be removed.
+		if outpoint == op {
+			log.Debugf("Skipped removing exclusive input %v", input)
+
+			continue
+		}
+
 		// Skip inputs that aren't exclusive.
 		if input.params.ExclusiveGroup == nil {
 			continue
@@ -767,6 +775,8 @@ func (s *UtxoSweeper) removeExclusiveGroup(group uint64) {
 			continue
 		}
 
+		log.Debugf("Removing exclusive group for input %v", input)
+
 		// Signal result channels.
 		s.signalResult(input, Result{
 			Err: ErrExclusiveGroupSpend,
@@ -1367,22 +1377,19 @@ func (s *UtxoSweeper) decideRBFInfo(
 func (s *UtxoSweeper) handleExistingInput(input *sweepInputMessage,
 	oldInput *SweeperInput) {
 
-	// Before updating the input details, check if an exclusive group was
-	// set. In case the same input is registered again without an exclusive
-	// group set, the previous input and its sweep parameters are outdated
-	// hence need to be replaced. This scenario currently only happens for
-	// anchor outputs. When a channel is force closed, in the worst case 3
-	// different sweeps with the same exclusive group are registered with
-	// the sweeper to bump the closing transaction (cpfp) when its time
-	// critical. Receiving an input which was already registered with the
-	// sweeper but now without an exclusive group means non of the previous
-	// inputs were used as CPFP, so we need to make sure we update the
-	// sweep parameters but also remove all inputs with the same exclusive
-	// group because the are outdated too.
+	// Before updating the input details, check if a previous exclusive
+	// group was set. In case the same input is registered again, the
+	// previous input and its sweep parameters are outdated hence need to be
+	// replaced. This scenario currently only happens for anchor outputs.
+	// When a channel is force closed, in the worst case 3 different sweeps
+	// with the same exclusive group are registered with the sweeper to bump
+	// the closing transaction (cpfp) when its time critical. Receiving an
+	// input which was already registered with the sweeper means none of the
+	// previous inputs were used as CPFP, so we need to make sure we update
+	// the sweep parameters but also remove all inputs with the same
+	// exclusive group because they are outdated too.
 	var prevExclGroup *uint64
-	if oldInput.params.ExclusiveGroup != nil &&
-		input.params.ExclusiveGroup == nil {
-
+	if oldInput.params.ExclusiveGroup != nil {
 		prevExclGroup = new(uint64)
 		*prevExclGroup = *oldInput.params.ExclusiveGroup
 	}
@@ -1401,7 +1408,7 @@ func (s *UtxoSweeper) handleExistingInput(input *sweepInputMessage,
 	oldInput.listeners = append(oldInput.listeners, input.resultChan)
 
 	if prevExclGroup != nil {
-		s.removeExclusiveGroup(*prevExclGroup)
+		s.removeExclusiveGroup(*prevExclGroup, input.input.OutPoint())
 	}
 }
 
@@ -1493,7 +1500,9 @@ func (s *UtxoSweeper) markInputsSwept(tx *wire.MsgTx, isOurTx bool) {
 
 		// Remove all other inputs in this exclusive group.
 		if input.params.ExclusiveGroup != nil {
-			s.removeExclusiveGroup(*input.params.ExclusiveGroup)
+			s.removeExclusiveGroup(
+				*input.params.ExclusiveGroup, outpoint,
+			)
 		}
 	}
 }
@@ -1908,7 +1917,9 @@ func (s *UtxoSweeper) markInputSwept(inp *SweeperInput, tx *wire.MsgTx) {
 
 	// Remove all other inputs in this exclusive group.
 	if inp.params.ExclusiveGroup != nil {
-		s.removeExclusiveGroup(*inp.params.ExclusiveGroup)
+		s.removeExclusiveGroup(
+			*inp.params.ExclusiveGroup, inp.OutPoint(),
+		)
 	}
 }