contractcourt/chain_watcher: add channel sync message to CloseChannelSummary

contractcourt/chain_watcher.go

@@ -522,6 +522,15 @@ func (c *chainWatcher) dispatchCooperativeClose(commitSpend *chainntnfs.SpendDet
 		LocalChanConfig:         c.cfg.chanState.LocalChanCfg,
 	}
 
+	// Attempt to add a channel sync message to the close summary.
+	chanSync, err := lnwallet.ChanSyncMsg(c.cfg.chanState)
+	if err != nil {
+		log.Errorf("ChannelPoint(%v): unable to create channel sync "+
+			"message: %v", c.cfg.chanState.FundingOutpoint, err)
+	} else {
+		closeSummary.LastChanSyncMsg = chanSync
+	}
+
 	// Create a summary of all the information needed to handle the
 	// cooperative closure.
 	closeInfo := &CooperativeCloseInfo{
@@ -590,6 +599,15 @@ func (c *chainWatcher) dispatchLocalForceClose(
 		closeSummary.TimeLockedBalance += htlcValue
 	}
 
+	// Attempt to add a channel sync message to the close summary.
+	chanSync, err := lnwallet.ChanSyncMsg(c.cfg.chanState)
+	if err != nil {
+		log.Errorf("ChannelPoint(%v): unable to create channel sync "+
+			"message: %v", c.cfg.chanState.FundingOutpoint, err)
+	} else {
+		closeSummary.LastChanSyncMsg = chanSync
+	}
+
 	// With the event processed, we'll now notify all subscribers of the
 	// event.
 	closeInfo := &LocalUnilateralCloseInfo{
@@ -749,6 +767,15 @@ func (c *chainWatcher) dispatchContractBreach(spendEvent *chainntnfs.SpendDetail
 		LocalChanConfig:         c.cfg.chanState.LocalChanCfg,
 	}
 
+	// Attempt to add a channel sync message to the close summary.
+	chanSync, err := lnwallet.ChanSyncMsg(c.cfg.chanState)
+	if err != nil {
+		log.Errorf("ChannelPoint(%v): unable to create channel sync "+
+			"message: %v", c.cfg.chanState.FundingOutpoint, err)
+	} else {
+		closeSummary.LastChanSyncMsg = chanSync
+	}
+
 	if err := c.cfg.chanState.CloseChannel(&closeSummary); err != nil {
 		return err
 	}

lnwallet/channel.go

@@ -5116,6 +5116,15 @@ func NewUnilateralCloseSummary(chanState *channeldb.OpenChannel, signer Signer,
 		LocalChanConfig:         chanState.LocalChanCfg,
 	}
 
+	// Attempt to add a channel sync message to the close summary.
+	chanSync, err := ChanSyncMsg(chanState)
+	if err != nil {
+		walletLog.Errorf("ChannelPoint(%v): unable to create channel sync "+
+			"message: %v", chanState.FundingOutpoint, err)
+	} else {
+		closeSummary.LastChanSyncMsg = chanSync
+	}
+
 	return &UnilateralCloseSummary{
 		SpendDetail:         commitSpend,
 		ChannelCloseSummary: closeSummary,