lnrpc+rpcserver: add custom channel data for closed channels

docs/release-notes/release-notes-0.19.0.md

@@ -118,6 +118,9 @@
   RPC method now applies a default timeout of 60 seconds when the
   `timeout_seconds` field is not set or is explicitly set to 0.
 
+* [`lnrpc.ClosedChannels` now also includes the `custom_channel_data` used by
+  custom channels](https://github.com/lightningnetwork/lnd/pull/9504).
+
 ## lncli Additions
 
 * [A pre-generated macaroon root key can now be specified in `lncli create` and

lnrpc/lightning.proto

@@ -1751,6 +1751,10 @@ message ChannelCloseSummary {
 
     //  The confirmed SCID for a zero-conf channel.
     uint64 zero_conf_confirmed_scid = 15 [jstype = JS_STRING];
+
+    // The TLV encoded custom channel data records for this output, which might
+    // be set for custom channels.
+    bytes custom_channel_data = 16;
 }
 
 enum ResolutionType {

lnrpc/lightning.swagger.json

@@ -4182,6 +4182,11 @@
           "type": "string",
           "format": "uint64",
           "description": "The confirmed SCID for a zero-conf channel."
+        },
+        "custom_channel_data": {
+          "type": "string",
+          "format": "byte",
+          "description": "The TLV encoded custom channel data records for this output, which might\nbe set for custom channels."
         }
       }
     },

rpcserver.go

@@ -4447,6 +4447,16 @@ func (r *rpcServer) ClosedChannels(ctx context.Context,
 		resp.Channels = append(resp.Channels, channel)
 	}
 
+	err = fn.MapOptionZ(
+		r.server.implCfg.AuxDataParser,
+		func(parser AuxDataParser) error {
+			return parser.InlineParseCustomData(resp)
+		},
+	)
+	if err != nil {
+		return nil, fmt.Errorf("error parsing custom data: %w", err)
+	}
+
 	return resp, nil
 }
 
@@ -4899,7 +4909,8 @@ func createRPCOpenChannel(r *rpcServer, dbChannel *channeldb.OpenChannel,
 // createRPCClosedChannel creates an *lnrpc.ClosedChannelSummary from a
 // *channeldb.ChannelCloseSummary.
 func (r *rpcServer) createRPCClosedChannel(
-	dbChannel *channeldb.ChannelCloseSummary) (*lnrpc.ChannelCloseSummary, error) {
+	dbChannel *channeldb.ChannelCloseSummary) (*lnrpc.ChannelCloseSummary,
+	error) {
 
 	nodePub := dbChannel.RemotePub
 	nodeID := hex.EncodeToString(nodePub.SerializeCompressed())
@@ -4913,9 +4924,7 @@ func (r *rpcServer) createRPCClosedChannel(
 
 	// Lookup local and remote cooperative initiators. If these values
 	// are not known they will just return unknown.
-	openInit, closeInitiator, err = r.getInitiators(
-		&dbChannel.ChanPoint,
-	)
+	openInit, closeInitiator, err = r.getInitiators(&dbChannel.ChanPoint)
 	if err != nil {
 		return nil, err
 	}
@@ -4982,6 +4991,14 @@ func (r *rpcServer) createRPCClosedChannel(
 			channel.ZeroConfConfirmedScid = confirmedScid
 		}
 
+		// Finally we'll attempt to encode the custom channel data if
+		// any exists.
+		channel.CustomChannelData, err = encodeCustomChanData(histChan)
+		if err != nil {
+			return nil, fmt.Errorf("unable to encode open chan "+
+				"data: %w", err)
+		}
+
 	// Non-nil error not due to older versions of lnd.
 	default:
 		return nil, err