lightningd: notify plugins when finalizing channel

Changelog-Added: Plugins now receive `channel_state_changed` notification upon final change to `CLOSED` state.

cln-grpc/proto/node.proto

@@ -4227,5 +4227,5 @@ message ChannelStateChangedNotification {
 	optional ChannelState old_state = 5;
 	ChannelState new_state = 6;
 	ChannelStateChangedCause cause = 7;
-	string message = 8;
+	optional string message = 8;
 }

cln-grpc/src/convert.rs

@@ -4518,7 +4518,7 @@ impl From<notifications::ChannelStateChangedNotification> for pb::ChannelStateCh
         Self {
             cause: c.cause as i32,
             channel_id: <Sha256 as AsRef<[u8]>>::as_ref(&c.channel_id).to_vec(), // Rule #2 for type hash
-            message: c.message, // Rule #2 for type string
+            message: c.message, // Rule #2 for type string?
             new_state: c.new_state as i32,
             old_state: c.old_state.map(|v| v as i32),
             peer_id: c.peer_id.serialize().to_vec(), // Rule #2 for type pubkey

cln-rpc/src/notifications.rs

@@ -192,6 +192,8 @@ impl ToString for ChannelStateChangedCause {
 
 #[derive(Clone, Debug, Deserialize, Serialize)]
 pub struct ChannelStateChangedNotification {
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub message: Option<String>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub old_state: Option<ChannelState>,
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -201,7 +203,6 @@ pub struct ChannelStateChangedNotification {
     // Path `channel_state_changed.new_state`
     pub new_state: ChannelState,
     pub channel_id: Sha256,
-    pub message: String,
     pub peer_id: PublicKey,
     pub timestamp: String,
 }

contrib/msggen/msggen/schema.json

@@ -37659,8 +37659,7 @@
           "channel_id",
           "timestamp",
           "new_state",
-          "cause",
-          "message"
+          "cause"
         ],
         "properties": {
           "peer_id": {

lightningd/channel.c

@@ -85,7 +85,8 @@ static void destroy_channel(struct channel *channel)
 	list_del_from(&channel->peer->channels, &channel->list);
 }
 
-void delete_channel(struct channel *channel STEALS, bool completely_eliminate)
+void delete_channel(struct channel *channel STEALS,
+		    bool completely_eliminate)
 {
 	const u8 *msg;
 	struct peer *peer = channel->peer;
@@ -109,6 +110,16 @@ void delete_channel(struct channel *channel STEALS, bool completely_eliminate)
 			fatal("HSM gave bad hsm_forget_channel_reply %s", tal_hex(msg, msg));
 	}
 
+	notify_channel_state_changed(channel->peer->ld,
+				     &channel->peer->id,
+				     &channel->cid,
+				     channel->scid,
+				     clock_time(),
+				     channel->state,
+				     CLOSED,
+				     REASON_UNKNOWN,
+				     NULL);
+
 	tal_free(channel);
 
 	maybe_delete_peer(peer);

lightningd/channel.h

@@ -490,7 +490,8 @@ channel_current_inflight(const struct channel *channel);
 u32 channel_last_funding_feerate(const struct channel *channel);
 
 /* Only set completely_eliminate for never-existed channels */
-void delete_channel(struct channel *channel STEALS, bool completely_eliminate);
+void delete_channel(struct channel *channel STEALS,
+		    bool completely_eliminate);
 
 /* Add a historic (public) short_channel_id to this channel */
 void channel_add_old_scid(struct channel *channel,

wallet/test/run-wallet.c

@@ -503,17 +503,6 @@ void notify_channel_mvt(struct lightningd *ld UNNEEDED,
 void notify_channel_open_failed(struct lightningd *ld UNNEEDED,
                                 const struct channel_id *cid UNNEEDED)
 { fprintf(stderr, "notify_channel_open_failed called!\n"); abort(); }
-/* Generated stub for notify_channel_state_changed */
-void notify_channel_state_changed(struct lightningd *ld UNNEEDED,
-				  const struct node_id *peer_id UNNEEDED,
-				  const struct channel_id *cid UNNEEDED,
-				  const struct short_channel_id *scid UNNEEDED,
-				  struct timeabs timestamp UNNEEDED,
-				  enum channel_state old_state UNNEEDED,
-				  enum channel_state new_state UNNEEDED,
-				  enum state_change cause UNNEEDED,
-				  const char *message UNNEEDED)
-{ fprintf(stderr, "notify_channel_state_changed called!\n"); abort(); }
 /* Generated stub for notify_connect */
 void notify_connect(struct lightningd *ld UNNEEDED,
 		    const struct node_id *nodeid UNNEEDED,
@@ -810,6 +799,17 @@ u8 *wire_sync_read(const tal_t *ctx UNNEEDED, int fd UNNEEDED)
 void plugin_hook_db_sync(struct db *db UNNEEDED)
 {
 }
+void notify_channel_state_changed(struct lightningd *ld UNNEEDED,
+				  const struct node_id *peer_id UNNEEDED,
+				  const struct channel_id *cid UNNEEDED,
+				  const struct short_channel_id *scid UNNEEDED,
+				  struct timeabs timestamp UNNEEDED,
+				  enum channel_state old_state UNNEEDED,
+				  enum channel_state new_state UNNEEDED,
+				  enum state_change cause UNNEEDED,
+				  const char *message UNNEEDED)
+{
+}
 bool fromwire_hsmd_get_channel_basepoints_reply(const void *p UNNEEDED,
 					       struct basepoints *basepoints,
 					       struct pubkey *funding_pubkey)