Log more during ChannelMonitor updating

Fixes #1323.

diff --git a/lightning/src/chain/channelmonitor.rs b/lightning/src/chain/channelmonitor.rs
index 96caaad27636acdfe5ebc18044e9a74ff69ce080..91544f11334e4eb5bcf4683da632262cfd7dce82 100644 (file)
--- a/lightning/src/chain/channelmonitor.rs
+++ b/lightning/src/chain/channelmonitor.rs
@@ -473,6 +473,19 @@ pub(crate) enum ChannelMonitorUpdateStep {
        },
 }
 
+impl ChannelMonitorUpdateStep {
+       fn variant_name(&self) -> &'static str {
+               match self {
+                       ChannelMonitorUpdateStep::LatestHolderCommitmentTXInfo { .. } => "LatestHolderCommitmentTXInfo",
+                       ChannelMonitorUpdateStep::LatestCounterpartyCommitmentTXInfo { .. } => "LatestCounterpartyCommitmentTXInfo",
+                       ChannelMonitorUpdateStep::PaymentPreimage { .. } => "PaymentPreimage",
+                       ChannelMonitorUpdateStep::CommitmentSecret { .. } => "CommitmentSecret",
+                       ChannelMonitorUpdateStep::ChannelForceClosed { .. } => "ChannelForceClosed",
+                       ChannelMonitorUpdateStep::ShutdownScript { .. } => "ShutdownScript",
+               }
+       }
+}
+
 impl_writeable_tlv_based_enum_upgradable!(ChannelMonitorUpdateStep,
        (0, LatestHolderCommitmentTXInfo) => {
                (0, commitment_tx, required),
@@ -1871,16 +1884,21 @@ impl<Signer: Sign> ChannelMonitorImpl<Signer> {
                    F::Target: FeeEstimator,
                    L::Target: Logger,
        {
+               log_info!(logger, "Applying update to monitor {}, bringing update_id from {} to {} with {} changes.",
+                       log_funding_info!(self), self.latest_update_id, updates.update_id, updates.updates.len());
                // ChannelMonitor updates may be applied after force close if we receive a
                // preimage for a broadcasted commitment transaction HTLC output that we'd
                // like to claim on-chain. If this is the case, we no longer have guaranteed
                // access to the monitor's update ID, so we use a sentinel value instead.
                if updates.update_id == CLOSED_CHANNEL_UPDATE_ID {
+                       assert_eq!(updates.updates.len(), 1);
                        match updates.updates[0] {
                                ChannelMonitorUpdateStep::PaymentPreimage { .. } => {},
-                               _ => panic!("Attempted to apply post-force-close ChannelMonitorUpdate that wasn't providing a payment preimage"),
+                               _ => {
+                                       log_error!(logger, "Attempted to apply post-force-close ChannelMonitorUpdate of type {}", updates.updates[0].variant_name());
+                                       panic!("Attempted to apply post-force-close ChannelMonitorUpdate that wasn't providing a payment preimage");
+                               },
                        }
-                       assert_eq!(updates.updates.len(), 1);
                } else if self.latest_update_id + 1 != updates.update_id {
                        panic!("Attempted to apply ChannelMonitorUpdates out of order, check the update_id before passing an update to update_monitor!");
                }