Move DiscardFunding generation into finish_close_channel

Currently the channel shutdown sequence has a number of steps which
all the shutdown callsites have to call. Because many shutdown
cases are rare error cases, its relatively easy to miss a call and
leave users without `Event`s or miss some important cleanup.

One of those steps, calling `issue_channel_close_events`, is rather
easy to remove, as it only generates two events, which can simply
be moved to another shutdown step.

Here we move the first of the two events, `DiscardFunding`, into
`finish_force_close_channel`.

diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs
index 1f50c76147de79cd5b136eec2c200cb0cd0304a3..dee972f39ec1ee7ccaeb7683d8ca745966c7b185 100644 (file)
--- a/lightning/src/ln/channel.rs
+++ b/lightning/src/ln/channel.rs
@@ -823,6 +823,7 @@ pub(crate) struct ShutdownResult {
        pub(crate) unbroadcasted_batch_funding_txid: Option<Txid>,
        pub(crate) channel_id: ChannelId,
        pub(crate) counterparty_node_id: PublicKey,
+       pub(crate) unbroadcasted_funding_tx: Option<Transaction>,
 }
 
 /// If the majority of the channels funds are to the fundee and the initiator holds only just
@@ -2402,6 +2403,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                        } else { None }
                } else { None };
                let unbroadcasted_batch_funding_txid = self.unbroadcasted_batch_funding_txid();
+               let unbroadcasted_funding_tx = self.unbroadcasted_funding();
 
                self.channel_state = ChannelState::ShutdownComplete;
                self.update_time_counter += 1;
@@ -2411,6 +2413,7 @@ impl<SP: Deref> ChannelContext<SP> where SP::Target: SignerProvider  {
                        unbroadcasted_batch_funding_txid,
                        channel_id: self.channel_id,
                        counterparty_node_id: self.counterparty_node_id,
+                       unbroadcasted_funding_tx,
                }
        }
 
@@ -4943,6 +4946,7 @@ impl<SP: Deref> Channel<SP> where
                                        unbroadcasted_batch_funding_txid: self.context.unbroadcasted_batch_funding_txid(),
                                        channel_id: self.context.channel_id,
                                        counterparty_node_id: self.context.counterparty_node_id,
+                                       unbroadcasted_funding_tx: self.context.unbroadcasted_funding(),
                                };
                                let tx = self.build_signed_closing_transaction(&mut closing_tx, &msg.signature, &sig);
                                self.context.channel_state = ChannelState::ShutdownComplete;
@@ -4973,6 +4977,7 @@ impl<SP: Deref> Channel<SP> where
                                                                unbroadcasted_batch_funding_txid: self.context.unbroadcasted_batch_funding_txid(),
                                                                channel_id: self.context.channel_id,
                                                                counterparty_node_id: self.context.counterparty_node_id,
+                                                               unbroadcasted_funding_tx: self.context.unbroadcasted_funding(),
                                                        };
                                                        self.context.channel_state = ChannelState::ShutdownComplete;
                                                        self.context.update_time_counter += 1;

diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index b2b28cdf365cce7ed07eda808089525c039ad015..51ea72ff4188641c5ccf41cee8b235b1da32dc7c 100644 (file)
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -2704,14 +2704,6 @@ where
        /// Helper function that issues the channel close events
        fn issue_channel_close_events(&self, context: &ChannelContext<SP>, closure_reason: ClosureReason) {
                let mut pending_events_lock = self.pending_events.lock().unwrap();
-               match context.unbroadcasted_funding() {
-                       Some(transaction) => {
-                               pending_events_lock.push_back((events::Event::DiscardFunding {
-                                       channel_id: context.channel_id(), transaction
-                               }, None));
-                       },
-                       None => {},
-               }
                pending_events_lock.push_back((events::Event::ChannelClosed {
                        channel_id: context.channel_id(),
                        user_channel_id: context.get_user_id(),
@@ -2897,6 +2889,15 @@ where
                                "Closing a batch where all channels have completed initial monitor update",
                        );
                }
+
+               {
+                       let mut pending_events = self.pending_events.lock().unwrap();
+                       if let Some(transaction) = shutdown_res.unbroadcasted_funding_tx {
+                               pending_events.push_back((events::Event::DiscardFunding {
+                                       channel_id: shutdown_res.channel_id, transaction
+                               }, None));
+                       }
+               }
                for shutdown_result in shutdown_results.drain(..) {
                        self.finish_close_channel(shutdown_result);
                }