Merge pull request #9491 from ziggie1984/closechannel-rpc

Allow coop closing a channel with HTLCs on it via lncli

lnrpc/lightning.proto

@@ -2146,9 +2146,13 @@ message CloseChannelRequest {
     // NOTE: This field is only respected if we're the initiator of the channel.
     uint64 max_fee_per_vbyte = 7;
 
-    // If true, then the rpc call will not block while it awaits a closing txid.
-    // Consequently this RPC call will not return a closing txid if this value
-    // is set.
+    // If true, then the rpc call will not block while it awaits a closing txid
+    // to be broadcasted to the mempool. To obtain the closing tx one has to
+    // listen to the stream for the particular updates. Moreover if a coop close
+    // is specified and this flag is set to true the coop closing flow will be
+    // initiated even if HTLCs are active on the channel. The channel will wait
+    // until all HTLCs are resolved and then start the coop closing process. The
+    // channel will be disabled in the meantime and will disallow any new HTLCs.
     bool no_wait = 8;
 }
 
@@ -2166,6 +2170,10 @@ message PendingUpdate {
 }
 
 message InstantUpdate {
+    // The number of pending HTLCs that are currently active on the channel.
+    // These HTLCs need to be resolved before the channel can be closed
+    // cooperatively.
+    int32 num_pending_htlcs = 1;
 }
 
 message ReadyForPsbtFunding {

lnrpc/lightning.swagger.json

@@ -878,7 +878,7 @@
           },
           {
             "name": "no_wait",
-            "description": "If true, then the rpc call will not block while it awaits a closing txid.\nConsequently this RPC call will not return a closing txid if this value\nis set.",
+            "description": "If true, then the rpc call will not block while it awaits a closing txid\nto be broadcasted to the mempool. To obtain the closing tx one has to\nlisten to the stream for the particular updates. Moreover if a coop close\nis specified and this flag is set to true the coop closing flow will be\ninitiated even if HTLCs are active on the channel. The channel will wait\nuntil all HTLCs are resolved and then start the coop closing process. The\nchannel will be disabled in the meantime and will disallow any new HTLCs.",
             "in": "query",
             "required": false,
             "type": "boolean"
@@ -5475,7 +5475,14 @@
       "default": "INITIATOR_UNKNOWN"
     },
     "lnrpcInstantUpdate": {
-      "type": "object"
+      "type": "object",
+      "properties": {
+        "num_pending_htlcs": {
+          "type": "integer",
+          "format": "int32",
+          "description": "The number of pending HTLCs that are currently active on the channel.\nThese HTLCs need to be resolved before the channel can be closed\ncooperatively."
+        }
+      }
     },
     "lnrpcInterceptFeedback": {
       "type": "object",