lnwallet/btcwallet: check publication error types, handle replacement

error

Since btcwallet will return typed errors now, we can simplify the
matching logic in order to return ErrDoubleSpend.

In case a transaction cannot be published since it did not satisfy the
requirements for a valid replacement, return ErrDoubleSpend to indicate
it was not propagated.

lnwallet/btcwallet/btcwallet.go

@@ -5,7 +5,6 @@ import (
 	"encoding/hex"
 	"fmt"
 	"math"
-	"strings"
 	"sync"
 	"time"
 
@@ -429,47 +428,25 @@ func (b *BtcWallet) ListUnspentWitness(minConfs, maxConfs int32) (
 // network (either in the mempool or chain) no error will be returned.
 func (b *BtcWallet) PublishTransaction(tx *wire.MsgTx) error {
 	if err := b.wallet.PublishTransaction(tx); err != nil {
-		switch b.chain.(type) {
-		case *chain.RPCClient:
-			if strings.Contains(err.Error(), "already spent") {
-				// Output was already spent.
-				return lnwallet.ErrDoubleSpend
-			}
-			if strings.Contains(err.Error(), "already been spent") {
-				// Output was already spent.
-				return lnwallet.ErrDoubleSpend
-			}
-			if strings.Contains(err.Error(), "orphan transaction") {
-				// Transaction is spending either output that
-				// is missing or already spent.
-				return lnwallet.ErrDoubleSpend
-			}
 
-		case *chain.BitcoindClient:
+		// If we failed to publish the transaction, check whether we
-			if strings.Contains(err.Error(), "txn-mempool-conflict") {
+		// got an error of known type.
-				// Output was spent by other transaction
+		switch err.(type) {
-				// already in the mempool.
-				return lnwallet.ErrDoubleSpend
-			}
-			if strings.Contains(err.Error(), "insufficient fee") {
-				// RBF enabled transaction did not have enough fee.
-				return lnwallet.ErrDoubleSpend
-			}
-			if strings.Contains(err.Error(), "Missing inputs") {
-				// Transaction is spending either output that
-				// is missing or already spent.
-				return lnwallet.ErrDoubleSpend
-			}
 
-		case *chain.NeutrinoClient:
+		// If the wallet reports a double spend, convert it to our
-			if strings.Contains(err.Error(), "already spent") {
+		// internal ErrDoubleSpend and return.
-				// Output was already spent.
+		case *base.ErrDoubleSpend:
-				return lnwallet.ErrDoubleSpend
+			return lnwallet.ErrDoubleSpend
-			}
+
+		// If the wallet reports a replacement error, return
+		// ErrDoubleSpend, as we currently are never attempting to
+		// replace transactions.
+		case *base.ErrReplacement:
+			return lnwallet.ErrDoubleSpend
 
 		default:
+			return err
 		}
-		return err
 	}
 	return nil
 }