multi: use txid instead of tx in BreachRetribution

This commit replaces the field `BreachTransaction` with `BreachTxHash`
as there's no need to pass that large raw transaction.

contractcourt/breacharbiter.go

@@ -1243,7 +1243,7 @@ func newRetributionInfo(chanPoint *wire.OutPoint,
 	}
 
 	return &retributionInfo{
-		commitHash:      breachInfo.BreachTransaction.TxHash(),
+		commitHash:      breachInfo.BreachTxHash,
 		chainHash:       breachInfo.ChainHash,
 		chanPoint:       *chanPoint,
 		breachedOutputs: breachedOutputs,

contractcourt/breacharbiter_test.go

@@ -1051,7 +1051,7 @@ func TestBreachHandoffSuccess(t *testing.T) {
 			processACK <- brarErr
 		},
 		BreachRetribution: &lnwallet.BreachRetribution{
-			BreachTransaction: bobClose.CloseTx,
+			BreachTxHash: bobClose.CloseTx.TxHash(),
 			LocalOutputSignDesc: &input.SignDescriptor{
 				Output: &wire.TxOut{
 					PkScript: breachKeys[0],
@@ -1085,7 +1085,7 @@ func TestBreachHandoffSuccess(t *testing.T) {
 			processACK <- brarErr
 		},
 		BreachRetribution: &lnwallet.BreachRetribution{
-			BreachTransaction: bobClose.CloseTx,
+			BreachTxHash: bobClose.CloseTx.TxHash(),
 			LocalOutputSignDesc: &input.SignDescriptor{
 				Output: &wire.TxOut{
 					PkScript: breachKeys[0],
@@ -1137,7 +1137,7 @@ func TestBreachHandoffFail(t *testing.T) {
 			processACK <- brarErr
 		},
 		BreachRetribution: &lnwallet.BreachRetribution{
-			BreachTransaction: bobClose.CloseTx,
+			BreachTxHash: bobClose.CloseTx.TxHash(),
 			LocalOutputSignDesc: &input.SignDescriptor{
 				Output: &wire.TxOut{
 					PkScript: breachKeys[0],
@@ -1179,7 +1179,7 @@ func TestBreachHandoffFail(t *testing.T) {
 			processACK <- brarErr
 		},
 		BreachRetribution: &lnwallet.BreachRetribution{
-			BreachTransaction: bobClose.CloseTx,
+			BreachTxHash: bobClose.CloseTx.TxHash(),
 			LocalOutputSignDesc: &input.SignDescriptor{
 				Output: &wire.TxOut{
 					PkScript: breachKeys[0],

contractcourt/chain_watcher.go

@@ -812,7 +812,7 @@ func (c *chainWatcher) handlePossibleBreach(commitSpend *chainntnfs.SpendDetail,
 	// own broadcasted state we are looking at. Therefore check that the
 	// commit matches before assuming it was a breach.
 	commitHash := commitSpend.SpendingTx.TxHash()
-	if retribution.BreachTransaction.TxHash() != commitHash {
+	if retribution.BreachTxHash != commitHash {
 		return false, nil
 	}
 

lnwallet/channel.go

@@ -2213,10 +2213,10 @@ type HtlcRetribution struct {
 // transaction. The BreachRetribution is then sent over the ContractBreach
 // channel in order to allow the subscriber of the channel to dispatch justice.
 type BreachRetribution struct {
-	// BreachTransaction is the transaction which breached the channel
+	// BreachTxHash is the transaction hash which breached the channel
 	// contract by spending from the funding multi-sig with a revoked
 	// commitment transaction.
-	BreachTransaction *wire.MsgTx
+	BreachTxHash chainhash.Hash
 
 	// BreachHeight records the block height confirming the breach
 	// transaction, used as a height hint when registering for
@@ -2233,7 +2233,7 @@ type BreachRetribution struct {
 
 	// LocalOutputSignDesc is a SignDescriptor which is capable of
 	// generating the signature necessary to sweep the output within the
-	// BreachTransaction that pays directly us.
+	// breach transaction that pays directly us.
 	//
 	// NOTE: A nil value indicates that the local output is considered dust
 	// according to the remote party's dust limit.
@@ -2458,8 +2458,8 @@ func NewBreachRetribution(chanState *channeldb.OpenChannel, stateNum uint64,
 	// BreachRetribution struct which houses all the data necessary to
 	// swiftly bring justice to the cheating remote party.
 	return &BreachRetribution{
+		BreachTxHash:         commitHash,
 		ChainHash:            chanState.ChainHash,
-		BreachTransaction:    revokedSnapshot.CommitTx,
 		BreachHeight:         breachHeight,
 		RevokedStateNum:      stateNum,
 		LocalOutpoint:        ourOutpoint,

watchtower/wtclient/backup_task.go

@@ -346,7 +346,7 @@ func (t *backupTask) craftSessionPayload(
 		}
 	}
 
-	breachTxID := t.breachInfo.BreachTransaction.TxHash()
+	breachTxID := t.breachInfo.BreachTxHash
 
 	// Compute the breach key as SHA256(txid).
 	hint, key := blob.NewBreachHintAndKeyFromHash(&breachTxID)

watchtower/wtclient/backup_task_internal_test.go

@@ -124,8 +124,8 @@ func genTaskTest(
 	// the breach transaction, which we will continue to modify.
 	breachTxn := wire.NewMsgTx(2)
 	breachInfo := &lnwallet.BreachRetribution{
-		RevokedStateNum:   stateNum,
-		BreachTransaction: breachTxn,
+		RevokedStateNum: stateNum,
+		BreachTxHash:    breachTxn.TxHash(),
 		KeyRing: &lnwallet.CommitmentKeyRing{
 			RevocationKey: revPK,
 			ToLocalKey:    toLocalPK,
@@ -607,7 +607,7 @@ func testBackupTask(t *testing.T, test backupTaskTest) {
 	}
 
 	// Verify that the breach hint matches the breach txid's prefix.
-	breachTxID := test.breachInfo.BreachTransaction.TxHash()
+	breachTxID := test.breachInfo.BreachTxHash
 	expHint := blob.NewBreachHintFromHash(&breachTxID)
 	if hint != expHint {
 		t.Fatalf("breach hint mismatch, want: %x, got: %v",

watchtower/wtclient/client_test.go

@@ -10,6 +10,7 @@ import (
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/channeldb"
@@ -300,7 +301,7 @@ func (c *mockChannel) createRemoteCommitTx(t *testing.T) {
 	}
 
 	retribution := &lnwallet.BreachRetribution{
-		BreachTransaction:    commitTxn,
+		BreachTxHash:         commitTxn.TxHash(),
 		RevokedStateNum:      c.commitHeight,
 		KeyRing:              commitKeyRing,
 		RemoteDelay:          c.csvDelay,
@@ -360,13 +361,15 @@ func (c *mockChannel) receivePayment(t *testing.T, amt lnwire.MilliSatoshi) {
 }
 
 // getState retrieves the channel's commitment and retribution at state i.
-func (c *mockChannel) getState(i uint64) (*wire.MsgTx, *lnwallet.BreachRetribution) {
+func (c *mockChannel) getState(
+	i uint64) (chainhash.Hash, *lnwallet.BreachRetribution) {
+
 	c.mu.Lock()
 	defer c.mu.Unlock()
 
 	retribution := c.retributions[i]
 
-	return retribution.BreachTransaction, retribution
+	return retribution.BreachTxHash, retribution
 }
 
 type testHarness struct {
@@ -608,8 +611,7 @@ func (h *testHarness) advanceChannelN(id uint64, n int) []blob.BreachHint {
 	var hints []blob.BreachHint
 	for i := uint64(0); i < uint64(n); i++ {
 		channel.advanceState(h.t)
-		commitTx, _ := h.channel(id).getState(i)
-		breachTxID := commitTx.TxHash()
+		breachTxID, _ := h.channel(id).getState(i)
 		hints = append(hints, blob.NewBreachHintFromHash(&breachTxID))
 	}
 
@@ -654,8 +656,7 @@ func (h *testHarness) sendPayments(id, from, to uint64,
 	var hints []blob.BreachHint
 	for i := from; i < to; i++ {
 		h.channel(id).sendPayment(h.t, amt)
-		commitTx, _ := channel.getState(i)
-		breachTxID := commitTx.TxHash()
+		breachTxID, _ := channel.getState(i)
 		hints = append(hints, blob.NewBreachHintFromHash(&breachTxID))
 	}
 
@@ -675,8 +676,7 @@ func (h *testHarness) recvPayments(id, from, to uint64,
 	var hints []blob.BreachHint
 	for i := from; i < to; i++ {
 		channel.receivePayment(h.t, amt)
-		commitTx, _ := channel.getState(i)
-		breachTxID := commitTx.TxHash()
+		breachTxID, _ := channel.getState(i)
 		hints = append(hints, blob.NewBreachHintFromHash(&breachTxID))
 	}