rpc: non-existence of a nursery report is no longer an error

This commit fixes a slight logic error that could render the
`pendingchannels` RPC unusable if a node was on the reciting end of a
channel force close with no time-locked balance. In such a case the
channel wouldn’t be sent to the utxoNursery, resulting in an “contract
not found error”.

To fix this behavior, we’ve created a typed error that can be checked
within the RPC, thus we no longer treat this routine case as an error
case.

rpcserver.go

@@ -721,13 +721,14 @@ func (r *rpcServer) forceCloseChan(channel *lnwallet.LightningChannel) (*chainha
 	chanPoint := channel.ChannelPoint()
 	chanInfo := channel.StateSnapshot()
 	closeInfo := &channeldb.ChannelCloseSummary{
-		ChanPoint:   *chanPoint,
+		ChanPoint:         *chanPoint,
-		ClosingTXID: closeTx.TxHash(),
+		ClosingTXID:       closeTx.TxHash(),
-		RemotePub:   &chanInfo.RemoteIdentity,
+		RemotePub:         &chanInfo.RemoteIdentity,
-		Capacity:    chanInfo.Capacity,
+		Capacity:          chanInfo.Capacity,
-		OurBalance:  chanInfo.LocalBalance,
+		SettledBalance:    chanInfo.LocalBalance,
-		CloseType:   channeldb.ForceClose,
+		TimeLockedBalance: chanInfo.LocalBalance,
-		IsPending:   true,
+		CloseType:         channeldb.ForceClose,
+		IsPending:         true,
 	}
 	if err := channel.DeleteState(closeInfo); err != nil {
 		return nil, err
@@ -767,7 +768,8 @@ func (r *rpcServer) GetInfo(ctx context.Context,
 
 	isSynced, err := r.server.lnwallet.IsSynced()
 	if err != nil {
-		return nil, fmt.Errorf("unable to sync PoV of the wallet with current best block in the main chain: %v", err)
+		return nil, fmt.Errorf("unable to sync PoV of the wallet "+
+			"with current best block in the main chain: %v", err)
 	}
 
 	activeChains := make([]string, registeredChains.NumActiveChains())
@@ -933,7 +935,7 @@ func (r *rpcServer) PendingChannels(ctx context.Context,
 			RemoteNodePub: hex.EncodeToString(pub),
 			ChannelPoint:  chanPoint.String(),
 			Capacity:      int64(pendingClose.Capacity),
-			LocalBalance:  int64(pendingClose.OurBalance),
+			LocalBalance:  int64(pendingClose.SettledBalance),
 		}
 
 		closeTXID := pendingClose.ClosingTXID.String()
@@ -961,9 +963,14 @@ func (r *rpcServer) PendingChannels(ctx context.Context,
 				ClosingTxid: closeTXID,
 			}
 
+			// Query for the maturity state for this force closed
+			// channel. If we didn't have any time-locked outputs,
+			// then the nursery may not know of the contract.
 			nurseryInfo, err := r.server.utxoNursery.NurseryReport(&chanPoint)
-			if err != nil {
+			if err != nil && err != ErrContractNotFound {
-				return nil, err
+				return nil, fmt.Errorf("unable to obtain "+
+					"nursery report for ChannelPoint(%v): %v",
+					chanPoint, err)
 			}
 
 			// If the nursery knows of this channel, then we can
@@ -996,7 +1003,6 @@ func (r *rpcServer) PendingChannels(ctx context.Context,
 
 // ListChannels returns a description of all direct active, open channels the
 // node knows of.
-// TODO(roasbeef): add 'online' bit to response
 func (r *rpcServer) ListChannels(ctx context.Context,
 	in *lnrpc.ListChannelsRequest) (*lnrpc.ListChannelsResponse, error) {
 

utxonursery.go

@@ -70,6 +70,12 @@ var (
 	byteOrder = binary.BigEndian
 )
 
+var (
+	// ErrContractNotFound is returned when the nursery is unable to
+	// retreive information about a queried contract.
+	ErrContractNotFound = fmt.Errorf("unable to locate contract")
+)
+
 // witnessType determines how an output's witness will be generated. The
 // default commitmentTimeLock type will generate a witness that will allow
 // spending of a time-locked transaction enforced by CheckSequenceVerify.
@@ -317,9 +323,9 @@ type incubationRequest struct {
 func (u *utxoNursery) IncubateOutputs(closeSummary *lnwallet.ForceCloseSummary) {
 	var incReq incubationRequest
 
-	// It could be that our to-self output was below the dust limit. In that
+	// It could be that our to-self output was below the dust limit. In
-	// case the SignDescriptor would be nil and we would not have that output
+	// that case the SignDescriptor would be nil and we would not have that
-	// to incubate.
+	// output to incubate.
 	if closeSummary.SelfOutputSignDesc != nil {
 		outputAmt := btcutil.Amount(closeSummary.SelfOutputSignDesc.Output.Value)
 		selfOutput := &kidOutput{
@@ -510,7 +516,7 @@ func (u *utxoNursery) NurseryReport(chanPoint *wire.OutPoint) (*contractMaturity
 			// entry for this particular contract.
 			indexInfo := indexBucket.Get(chanPointBytes)
 			if indexInfo == nil {
-				return fmt.Errorf("contract not found in index")
+				return ErrContractNotFound
 			}
 
 			// If an entry is found, then using the height store in
@@ -519,7 +525,7 @@ func (u *utxoNursery) NurseryReport(chanPoint *wire.OutPoint) (*contractMaturity
 			height := indexInfo[:4]
 			heightRow := kgtnBucket.Get(height)
 			if heightRow == nil {
-				return fmt.Errorf("contract not found")
+				return ErrContractNotFound
 			}
 
 			// Once we have the entry itself, we'll slice of the