Avoid refusing ChannelMonitorUpdates we expect to receive after closing

There is no need to fill the user's logs with errors that are expected
to be hit based on specific edge cases, like providing preimages after
a monitor has seen a confirmed commitment on-chain.

This doesn't really change our behavior – we still apply and persist the
state changes resulting from processing these updates regardless of
whether they succeed or not.

diff --git a/lightning/src/chain/channelmonitor.rs b/lightning/src/chain/channelmonitor.rs
index df5160df015fae8550c487660d0a959c59687fe6..97e1e8ee6125e2f583cf9a1aaa155a9121a0e60d 100644 (file)
--- a/lightning/src/chain/channelmonitor.rs
+++ b/lightning/src/chain/channelmonitor.rs
@@ -2373,6 +2373,13 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
                                },
                        }
                }
+
+               // If the updates succeeded and we were in an already closed channel state, then there's no
+               // need to refuse any updates we expect to receive afer seeing a confirmed commitment.
+               if ret.is_ok() && updates.update_id == CLOSED_CHANNEL_UPDATE_ID && self.latest_update_id == updates.update_id {
+                       return Ok(());
+               }
+
                self.latest_update_id = updates.update_id;
 
                if ret.is_ok() && self.funding_spend_seen {