Merge pull request #2946 from tnull/2024-03-txsync-readd-reorged-output-spends

[rust-lightning] / lightning-transaction-sync / src / common.rs

diff --git a/lightning-transaction-sync/src/common.rs b/lightning-transaction-sync/src/common.rs
index be49fbe96ff017aa73d0c8e87265bb442b50fffc..c635f7385c6ecbd47bb6b4e90f5abb335feca8f5 100644 (file)
--- a/lightning-transaction-sync/src/common.rs
+++ b/lightning-transaction-sync/src/common.rs
@@ -1,4 +1,5 @@
 use lightning::chain::{Confirm, WatchedOutput};
+use lightning::chain::channelmonitor::ANTI_REORG_DELAY;
 use bitcoin::{Txid, BlockHash, Transaction, OutPoint};
 use bitcoin::block::Header;
 
@@ -13,6 +14,9 @@ pub(crate) struct SyncState {
        // Outputs that were previously processed, but must not be forgotten yet as
        // as we still need to monitor any spends on-chain.
        pub watched_outputs: HashMap<OutPoint, WatchedOutput>,
+       // Outputs for which we previously saw a spend on-chain but kept around until the spends reach
+       // sufficient depth.
+       pub outputs_spends_pending_threshold_conf: Vec<(Txid, u32, OutPoint, WatchedOutput)>,
        // The tip hash observed during our last sync.
        pub last_sync_hash: Option<BlockHash>,
        // Indicates whether we need to resync, e.g., after encountering an error.
@@ -24,6 +28,7 @@ impl SyncState {
                Self {
                        watched_transactions: HashSet::new(),
                        watched_outputs: HashMap::new(),
+                       outputs_spends_pending_threshold_conf: Vec::new(),
                        last_sync_hash: None,
                        pending_sync: false,
                }
@@ -38,6 +43,17 @@ impl SyncState {
                        }
 
                        self.watched_transactions.insert(txid);
+
+                       // If a previously-confirmed output spend is unconfirmed, re-add the watched output to
+                       // the tracking map.
+                       self.outputs_spends_pending_threshold_conf.retain(|(conf_txid, _, prev_outpoint, output)| {
+                               if txid == *conf_txid {
+                                       self.watched_outputs.insert(*prev_outpoint, output.clone());
+                                       false
+                               } else {
+                                       true
+                               }
+                       })
                }
        }
 
@@ -57,10 +73,18 @@ impl SyncState {
                        self.watched_transactions.remove(&ctx.tx.txid());
 
                        for input in &ctx.tx.input {
-                               self.watched_outputs.remove(&input.previous_output);
+                               if let Some(output) = self.watched_outputs.remove(&input.previous_output) {
+                                       self.outputs_spends_pending_threshold_conf.push((ctx.tx.txid(), ctx.block_height, input.previous_output, output));
+                               }
                        }
                }
        }
+
+       pub fn prune_output_spends(&mut self, cur_height: u32) {
+               self.outputs_spends_pending_threshold_conf.retain(|(_, conf_height, _, _)| {
+                       cur_height < conf_height + ANTI_REORG_DELAY - 1
+               });
+       }
 }
 
 
@@ -104,6 +128,7 @@ impl FilterQueue {
 #[derive(Debug)]
 pub(crate) struct ConfirmedTx {
        pub tx: Transaction,
+       pub txid: Txid,
        pub block_header: Header,
        pub block_height: u32,
        pub pos: usize,