contractcourt: use the sweeper for HTLC offered remote timeout resolution

In this commit, we bring the timeout resolver more in line with the
success resolver by using the sweeper to handle the HTLC offered remote
timeout outputs. These are outputs that we can sweep directly from the
remote party's commitment transaction when they broadcast their version
of the commitment transaction.

With this change, we slim down the scope slightly by only doing this for
anchor channels. Non-anchor channels will continue to use the
utxonursery for this output type for now.

contractcourt/htlc_timeout_resolver_test.go

@@ -294,12 +294,13 @@ func testHtlcTimeoutResolver(t *testing.T, testCase htlcTimeoutTestCase) {
 	chainCfg := ChannelArbitratorConfig{
 		ChainArbitratorConfig: ChainArbitratorConfig{
 			Notifier:   notifier,
+			Sweeper:    newMockSweeper(),
 			PreimageDB: witnessBeacon,
 			IncubateOutputs: func(wire.OutPoint,
 				fn.Option[lnwallet.OutgoingHtlcResolution],
 				fn.Option[lnwallet.IncomingHtlcResolution],
-				uint32, fn.Option[int32],
-			) error {
+				uint32, fn.Option[int32]) error {
+
 				incubateChan <- struct{}{}
 				return nil
 			},
@@ -311,17 +312,19 @@ func testHtlcTimeoutResolver(t *testing.T, testCase htlcTimeoutTestCase) {
 				}
 
 				resolutionChan <- msgs[0]
+
 				return nil
 			},
 			Budget: *DefaultBudgetConfig(),
 			QueryIncomingCircuit: func(circuit models.CircuitKey,
 			) *models.CircuitKey {
+
 				return nil
 			},
 		},
 		PutResolverReport: func(_ kvdb.RwTx,
-			_ *channeldb.ResolverReport,
-		) error {
+			_ *channeldb.ResolverReport) error {
+
 			return nil
 		},
 	}
@@ -329,8 +332,8 @@ func testHtlcTimeoutResolver(t *testing.T, testCase htlcTimeoutTestCase) {
 	cfg := ResolverConfig{
 		ChannelArbitratorConfig: chainCfg,
 		Checkpoint: func(_ ContractResolver,
-			reports ...*channeldb.ResolverReport,
-		) error {
+			reports ...*channeldb.ResolverReport) error {
+
 			checkPointChan <- struct{}{}
 
 			// Send all of our reports into the channel.
@@ -367,13 +370,15 @@ func testHtlcTimeoutResolver(t *testing.T, testCase htlcTimeoutTestCase) {
 
 		if testCase.timeout {
 			timeoutTxID := timeoutTx.TxHash()
-			reports = append(reports, &channeldb.ResolverReport{
-				OutPoint:        timeoutTx.TxIn[0].PreviousOutPoint,
+			report := &channeldb.ResolverReport{
+				OutPoint:        timeoutTx.TxIn[0].PreviousOutPoint, //nolint:lll
 				Amount:          testHtlcAmt.ToSatoshis(),
-				ResolverType:    channeldb.ResolverTypeOutgoingHtlc,
-				ResolverOutcome: channeldb.ResolverOutcomeFirstStage,
+				ResolverType:    channeldb.ResolverTypeOutgoingHtlc,  //nolint:lll
+				ResolverOutcome: channeldb.ResolverOutcomeFirstStage, //nolint:lll
 				SpendTxID:       &timeoutTxID,
-			})
+			}
+
+			reports = append(reports, report)
 		}
 	}
 
@@ -391,10 +396,21 @@ func testHtlcTimeoutResolver(t *testing.T, testCase htlcTimeoutTestCase) {
 		}
 	}()
 
-	// As the output isn't yet in the nursery, we expect that we
-	// should receive an incubation request.
+	// If this is a remote commit, then we expct the outputs should receive
+	// an incubation request to go through the sweeper, otherwise the
+	// nursery.
+	var sweepChan chan input.Input
+	if testCase.remoteCommit {
+		mockSweeper, ok := resolver.Sweeper.(*mockSweeper)
+		require.True(t, ok)
+		sweepChan = mockSweeper.sweptInputs
+	}
+
+	// The output should be offered to either the sweeper or
+	// the nursery.
 	select {
 	case <-incubateChan:
+	case <-sweepChan:
 	case err := <-resolveErr:
 		t.Fatalf("unable to resolve HTLC: %v", err)
 	case <-time.After(time.Second * 5):
@@ -450,7 +466,6 @@ func testHtlcTimeoutResolver(t *testing.T, testCase htlcTimeoutTestCase) {
 			t.Fatalf("resolution not sent")
 		}
 	} else {
-
 		// Otherwise, the HTLC should now timeout.  First, we
 		// should get a resolution message with a populated
 		// failure message.
@@ -559,10 +574,6 @@ func TestHtlcTimeoutSingleStage(t *testing.T) {
 	}
 
 	checkpoints := []checkpoint{
-		{
-			// Output should be handed off to the nursery.
-			incubating: true,
-		},
 		{
 			// We send a confirmation the sweep tx from published
 			// by the nursery.
@@ -594,7 +605,7 @@ func TestHtlcTimeoutSingleStage(t *testing.T) {
 			// After the sweep has confirmed, we expect the
 			// checkpoint to be resolved, and with the above
 			// report.
-			incubating: true,
+			incubating: false,
 			resolved:   true,
 			reports: []*channeldb.ResolverReport{
 				claim,
@@ -849,9 +860,9 @@ func TestHtlcTimeoutSingleStageRemoteSpend(t *testing.T) {
 	)
 }
 
-// TestHtlcTimeoutSecondStageRemoteSpend tests that when a remite commitment
-// confirms, and the remote spends the output using the success tx, we
-// properly detect this and extract the preimage.
+// TestHtlcTimeoutSecondStageRemoteSpend tests that when a remote commitment
+// confirms, and the remote spends the output using the success tx, we properly
+// detect this and extract the preimage.
 func TestHtlcTimeoutSecondStageRemoteSpend(t *testing.T) {
 	commitOutpoint := wire.OutPoint{Index: 2}
 
@@ -895,10 +906,6 @@ func TestHtlcTimeoutSecondStageRemoteSpend(t *testing.T) {
 	}
 
 	checkpoints := []checkpoint{
-		{
-			// Output should be handed off to the nursery.
-			incubating: true,
-		},
 		{
 			// We send a confirmation for the remote's second layer
 			// success transcation.
@@ -944,7 +951,7 @@ func TestHtlcTimeoutSecondStageRemoteSpend(t *testing.T) {
 			// After the sweep has confirmed, we expect the
 			// checkpoint to be resolved, and with the above
 			// report.
-			incubating: true,
+			incubating: false,
 			resolved:   true,
 			reports: []*channeldb.ResolverReport{
 				claim,
@@ -1321,8 +1328,8 @@ func TestHtlcTimeoutSecondStageSweeperRemoteSpend(t *testing.T) {
 }
 
 func testHtlcTimeout(t *testing.T, resolution lnwallet.OutgoingHtlcResolution,
-	checkpoints []checkpoint,
-) {
+	checkpoints []checkpoint) {
+
 	t.Helper()
 
 	defer timeout()()