lnwallet: add more godoc to InputScript rename ScriptSig field to SigScript

lnwallet/btcwallet/signer.go

@@ -180,9 +180,10 @@ func (b *BtcWallet) SignOutputRaw(tx *wire.MsgTx,
 	// TODO(roasbeef): generate sighash midstate if not present?
 
 	amt := signDesc.Output.Value
-	sig, err := txscript.RawTxInWitnessSignature(tx, signDesc.SigHashes,
-		signDesc.InputIndex, amt, witnessScript, signDesc.HashType,
-		privKey)
+	sig, err := txscript.RawTxInWitnessSignature(
+		tx, signDesc.SigHashes, signDesc.InputIndex, amt,
+		witnessScript, signDesc.HashType, privKey,
+	)
 	if err != nil {
 		return nil, err
 	}
@@ -227,8 +228,9 @@ func (b *BtcWallet) ComputeInputScript(tx *wire.MsgTx,
 		// spend the p2sh output. The sigScript will contain only a
 		// single push of the p2wkh witness program corresponding to
 		// the matching public key of this address.
-		p2wkhAddr, err := btcutil.NewAddressWitnessPubKeyHash(pubKeyHash,
-			b.netParams)
+		p2wkhAddr, err := btcutil.NewAddressWitnessPubKeyHash(
+			pubKeyHash, b.netParams,
+		)
 		if err != nil {
 			return nil, err
 		}
@@ -244,7 +246,7 @@ func (b *BtcWallet) ComputeInputScript(tx *wire.MsgTx,
 			return nil, err
 		}
 
-		inputScript.ScriptSig = sigScript
+		inputScript.SigScript = sigScript
 
 	// Otherwise, this is a regular p2wkh output, so we include the
 	// witness program itself as the subscript to generate the proper
@@ -267,7 +269,8 @@ func (b *BtcWallet) ComputeInputScript(tx *wire.MsgTx,
 	// TODO(roasbeef): adhere to passed HashType
 	witnessScript, err := txscript.WitnessSignature(tx, signDesc.SigHashes,
 		signDesc.InputIndex, signDesc.Output.Value, witnessProgram,
-		signDesc.HashType, privKey, true)
+		signDesc.HashType, privKey, true,
+	)
 	if err != nil {
 		return nil, err
 	}

lnwallet/reservation.go

@@ -50,11 +50,15 @@ func (c *ChannelContribution) toChanConfig() channeldb.ChannelConfig {
 }
 
 // InputScript represents any script inputs required to redeem a previous
-// output. This struct is used rather than just a witness, or scripSig in
-// order to accommodate nested p2sh which utilizes both types of input scripts.
+// output. This struct is used rather than just a witness, or scripSig in order
+// to accommodate nested p2sh which utilizes both types of input scripts.
 type InputScript struct {
-	Witness   [][]byte
-	ScriptSig []byte
+	// Witness is the full witness stack required to unlock this output.
+	Witness wire.TxWitness
+
+	// SigScript will only be populated if this is an input script sweeping
+	// a nested p2sh output.
+	SigScript []byte
 }
 
 // ChannelReservation represents an intent to open a lightning payment channel

lnwallet/test_utils.go

@@ -438,13 +438,15 @@ func (m *mockSigner) ComputeInputScript(tx *wire.MsgTx, signDesc *SignDescriptor
 				"address %v", addresses[0])
 		}
 
-		scriptSig, err := txscript.SignatureScript(tx, signDesc.InputIndex,
-			signDesc.Output.PkScript, txscript.SigHashAll, privKey, true)
+		sigScript, err := txscript.SignatureScript(
+			tx, signDesc.InputIndex, signDesc.Output.PkScript,
+			txscript.SigHashAll, privKey, true,
+		)
 		if err != nil {
 			return nil, err
 		}
 
-		return &InputScript{ScriptSig: scriptSig}, nil
+		return &InputScript{SigScript: sigScript}, nil
 
 	case txscript.WitnessV0PubKeyHashTy:
 		privKey := m.findKey(addresses[0].ScriptAddress(), signDesc.SingleTweak,

lnwallet/wallet.go

@@ -747,14 +747,15 @@ func (l *LightningWallet) handleContributionMsg(req *addContributionMsg) {
 		signDesc.Output = info
 		signDesc.InputIndex = i
 
-		inputScript, err := l.Cfg.Signer.ComputeInputScript(fundingTx,
-			&signDesc)
+		inputScript, err := l.Cfg.Signer.ComputeInputScript(
+			fundingTx, &signDesc,
+		)
 		if err != nil {
 			req.err <- err
 			return
 		}
 
-		txIn.SignatureScript = inputScript.ScriptSig
+		txIn.SignatureScript = inputScript.SigScript
 		txIn.Witness = inputScript.Witness
 		pendingReservation.ourFundingInputScripts = append(
 			pendingReservation.ourFundingInputScripts,
@@ -958,7 +959,7 @@ func (l *LightningWallet) handleFundingCounterPartySigs(msg *addCounterPartySigs
 		if len(inputScripts) != 0 && len(txin.Witness) == 0 {
 			// Attach the input scripts so we can verify it below.
 			txin.Witness = inputScripts[sigIndex].Witness
-			txin.SignatureScript = inputScripts[sigIndex].ScriptSig
+			txin.SignatureScript = inputScripts[sigIndex].SigScript
 
 			// Fetch the alleged previous output along with the
 			// pkscript referenced by this input.
@@ -1256,7 +1257,6 @@ func (l *LightningWallet) handleSingleFunderSigs(req *addSingleFunderSigsMsg) {
 // selection is successful/possible, then the selected coins are available
 // within the passed contribution's inputs. If necessary, a change address will
 // also be generated.
-// TODO(roasbeef): remove hardcoded fees.
 func (l *LightningWallet) selectCoinsAndChange(feeRate SatPerKWeight,
 	amt btcutil.Amount, minConfs int32,
 	contribution *ChannelContribution) error {