rpcserver+lnrpc+lncli: add AbandonChannel rpc call

Using AbandonChannel, a channel can be abandoned. This means
removing all state without any on-chain or off-chain action.
A close summary is the only thing that is stored in the db after
abandoning.

A specific close type Abandoned is added. Abandoned channels
can be retrieved via the ClosedChannels RPC.

lnrpc/rpc.pb.gw.go

@@ -301,6 +301,52 @@ func request_Lightning_CloseChannel_0(ctx context.Context, marshaler runtime.Mar
 
 }
 
+var (
+	filter_Lightning_AbandonChannel_0 = &utilities.DoubleArray{Encoding: map[string]int{"channel_point": 0, "funding_txid_str": 1, "output_index": 2}, Base: []int{1, 1, 1, 2, 0, 0}, Check: []int{0, 1, 2, 2, 3, 4}}
+)
+
+func request_Lightning_AbandonChannel_0(ctx context.Context, marshaler runtime.Marshaler, client LightningClient, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
+	var protoReq AbandonChannelRequest
+	var metadata runtime.ServerMetadata
+
+	var (
+		val string
+		ok  bool
+		err error
+		_   = err
+	)
+
+	val, ok = pathParams["channel_point.funding_txid_str"]
+	if !ok {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "missing parameter %s", "channel_point.funding_txid_str")
+	}
+
+	err = runtime.PopulateFieldFromPath(&protoReq, "channel_point.funding_txid_str", val)
+
+	if err != nil {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "type mismatch, parameter: %s, error: %v", "channel_point.funding_txid_str", err)
+	}
+
+	val, ok = pathParams["channel_point.output_index"]
+	if !ok {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "missing parameter %s", "channel_point.output_index")
+	}
+
+	err = runtime.PopulateFieldFromPath(&protoReq, "channel_point.output_index", val)
+
+	if err != nil {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "type mismatch, parameter: %s, error: %v", "channel_point.output_index", err)
+	}
+
+	if err := runtime.PopulateQueryParameters(&protoReq, req.URL.Query(), filter_Lightning_AbandonChannel_0); err != nil {
+		return nil, metadata, status.Errorf(codes.InvalidArgument, "%v", err)
+	}
+
+	msg, err := client.AbandonChannel(ctx, &protoReq, grpc.Header(&metadata.HeaderMD), grpc.Trailer(&metadata.TrailerMD))
+	return msg, metadata, err
+
+}
+
 func request_Lightning_SendPaymentSync_0(ctx context.Context, marshaler runtime.Marshaler, client LightningClient, req *http.Request, pathParams map[string]string) (proto.Message, runtime.ServerMetadata, error) {
 	var protoReq SendRequest
 	var metadata runtime.ServerMetadata
@@ -1220,6 +1266,35 @@ func RegisterLightningHandler(ctx context.Context, mux *runtime.ServeMux, conn *
 
 	})
 
+	mux.Handle("DELETE", pattern_Lightning_AbandonChannel_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
+		ctx, cancel := context.WithCancel(ctx)
+		defer cancel()
+		if cn, ok := w.(http.CloseNotifier); ok {
+			go func(done <-chan struct{}, closed <-chan bool) {
+				select {
+				case <-done:
+				case <-closed:
+					cancel()
+				}
+			}(ctx.Done(), cn.CloseNotify())
+		}
+		inboundMarshaler, outboundMarshaler := runtime.MarshalerForRequest(mux, req)
+		rctx, err := runtime.AnnotateContext(ctx, mux, req)
+		if err != nil {
+			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
+			return
+		}
+		resp, md, err := request_Lightning_AbandonChannel_0(rctx, inboundMarshaler, client, req, pathParams)
+		ctx = runtime.NewServerMetadataContext(ctx, md)
+		if err != nil {
+			runtime.HTTPError(ctx, mux, outboundMarshaler, w, req, err)
+			return
+		}
+
+		forward_Lightning_AbandonChannel_0(ctx, mux, outboundMarshaler, w, req, resp, mux.GetForwardResponseOptions()...)
+
+	})
+
 	mux.Handle("POST", pattern_Lightning_SendPaymentSync_0, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
 		ctx, cancel := context.WithCancel(ctx)
 		defer cancel()
@@ -1745,6 +1820,8 @@ var (
 
 	pattern_Lightning_CloseChannel_0 = runtime.MustPattern(runtime.NewPattern(1, []int{2, 0, 2, 1, 1, 0, 4, 1, 5, 2, 1, 0, 4, 1, 5, 3}, []string{"v1", "channels", "channel_point.funding_txid_str", "channel_point.output_index"}, ""))
 
+	pattern_Lightning_AbandonChannel_0 = runtime.MustPattern(runtime.NewPattern(1, []int{2, 0, 2, 1, 1, 0, 4, 1, 5, 2, 1, 0, 4, 1, 5, 3}, []string{"v1", "channels", "channel_point.funding_txid_str", "channel_point.output_index"}, ""))
+
 	pattern_Lightning_SendPaymentSync_0 = runtime.MustPattern(runtime.NewPattern(1, []int{2, 0, 2, 1, 2, 2}, []string{"v1", "channels", "transactions"}, ""))
 
 	pattern_Lightning_SendToRouteSync_0 = runtime.MustPattern(runtime.NewPattern(1, []int{2, 0, 2, 1, 2, 2, 2, 3}, []string{"v1", "channels", "transactions", "route"}, ""))
@@ -1809,6 +1886,8 @@ var (
 
 	forward_Lightning_CloseChannel_0 = runtime.ForwardResponseStream
 
+	forward_Lightning_AbandonChannel_0 = runtime.ForwardResponseMessage
+
 	forward_Lightning_SendPaymentSync_0 = runtime.ForwardResponseMessage
 
 	forward_Lightning_SendToRouteSync_0 = runtime.ForwardResponseMessage

lnrpc/rpc.proto

@@ -389,6 +389,19 @@ service Lightning {
         };
     }
 
+    /** lncli: `abandonchannel`
+    AbandonChannel removes all channel state from the database except for a
+    close summary. This method can be used to get rid of permanently unusable
+    channels due to bugs fixed in newer versions of lnd. Only available
+    when in debug builds of lnd.
+    */
+    rpc AbandonChannel (AbandonChannelRequest) returns (AbandonChannelResponse) {
+        option (google.api.http) = {
+            delete: "/v1/channels/{channel_point.funding_txid_str}/{channel_point.output_index}"
+        };
+    }
+
+
     /** lncli: `sendpayment`
     SendPayment dispatches a bi-directional streaming RPC for sending payments
     through the Lightning Network. A single RPC invocation creates a persistent
@@ -991,6 +1004,7 @@ message ChannelCloseSummary {
         REMOTE_FORCE_CLOSE = 2;
         BREACH_CLOSE = 3;
         FUNDING_CANCELED = 4;
+        ABANDONED = 5;
     }
 
     /// Details on how the channel was closed.
@@ -1003,6 +1017,7 @@ message ClosedChannelsRequest {
     bool remote_force = 3;
     bool breach = 4;
     bool funding_canceled = 5;
+    bool abandoned = 6;
 }
 
 message ClosedChannelsResponse { 
@@ -1820,6 +1835,14 @@ message DeleteAllPaymentsRequest {
 message DeleteAllPaymentsResponse {
 }
 
+message AbandonChannelRequest {
+    ChannelPoint channel_point = 1;
+}
+
+message AbandonChannelResponse {
+}
+
+
 message DebugLevelRequest {
     bool show = 1;
     string level_spec = 2;

lnrpc/rpc.swagger.json

@@ -195,6 +195,13 @@
             "required": false,
             "type": "boolean",
             "format": "boolean"
+          },
+          {
+            "name": "abandoned",
+            "in": "query",
+            "required": false,
+            "type": "boolean",
+            "format": "boolean"
           }
         ],
         "tags": [
@@ -275,13 +282,13 @@
     },
     "/v1/channels/{channel_point.funding_txid_str}/{channel_point.output_index}": {
       "delete": {
-        "summary": "* lncli: `closechannel`\nCloseChannel attempts to close an active channel identified by its channel\noutpoint (ChannelPoint). The actions of this method can additionally be\naugmented to attempt a force close after a timeout period in the case of an\ninactive peer. If a non-force close (cooperative closure) is requested,\nthen the user can specify either a target number of blocks until the\nclosure transaction is confirmed, or a manual fee rate. If neither are\nspecified, then a default lax, block confirmation target is used.",
-        "operationId": "CloseChannel",
+        "summary": "* lncli: `abandonchannel`\nAbandonChannel removes all channel state from the database except for a\nclose summary. This method can be used to get rid of permanently unusable\nchannels due to bugs fixed in newer versions of lnd. Only available\nwhen in debug builds of lnd.",
+        "operationId": "AbandonChannel",
         "responses": {
           "200": {
-            "description": "(streaming responses)",
+            "description": "",
             "schema": {
-              "$ref": "#/definitions/lnrpcCloseStatusUpdate"
+              "$ref": "#/definitions/lnrpcAbandonChannelResponse"
             }
           }
         },
@@ -970,7 +977,8 @@
         "LOCAL_FORCE_CLOSE",
         "REMOTE_FORCE_CLOSE",
         "BREACH_CLOSE",
-        "FUNDING_CANCELED"
+        "FUNDING_CANCELED",
+        "ABANDONED"
       ],
       "default": "COOPERATIVE_CLOSE"
     },
@@ -1092,6 +1100,9 @@
         }
       }
     },
+    "lnrpcAbandonChannelResponse": {
+      "type": "object"
+    },
     "lnrpcAddInvoiceResponse": {
       "type": "object",
       "properties": {