From ea0b23e238e529b830d169c005058e26802405ce Mon Sep 17 00:00:00 2001
From: Hussein Ait Lahcen <hussein.aitlahcen@gmail.com>
Date: Mon, 18 Nov 2024 16:39:41 +0100
Subject: [PATCH] fix: mempool reactor

---
 mempool/reactor.go | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/mempool/reactor.go b/mempool/reactor.go
index 73b615dec6e..d9027b3ff9f 100644
--- a/mempool/reactor.go
+++ b/mempool/reactor.go
@@ -191,6 +191,8 @@ type PeerState interface {
 
 // Send new mempool txs to peer.
 func (memR *Reactor) broadcastTxRoutine(peer p2p.Peer) {
+	memR.Logger.Debug("BroadcastTxRoutine start")
+
 	var next *clist.CElement
 
 	// If the node is catching up, don't start this routine immediately.
@@ -216,6 +218,7 @@ func (memR *Reactor) broadcastTxRoutine(peer p2p.Peer) {
 			select {
 			case <-memR.mempool.TxsWaitChan(): // Wait until a tx is available
 				if next = memR.mempool.TxsFront(); next == nil {
+					memR.Logger.Debug("Waiting for transaction")
 					continue
 				}
 			case <-peer.Quit():
@@ -234,6 +237,7 @@ func (memR *Reactor) broadcastTxRoutine(peer p2p.Peer) {
 			// will be initialized before the consensus reactor. We should wait a few
 			// milliseconds and retry.
 			time.Sleep(PeerCatchupSleepIntervalMS * time.Millisecond)
+			memR.Logger.Debug("Invalid peer state, rechecking.")
 			continue
 		}
 
@@ -252,18 +256,24 @@ func (memR *Reactor) broadcastTxRoutine(peer p2p.Peer) {
 		// NOTE: Transaction batching was disabled due to
 		// https://github.com/tendermint/tendermint/issues/5796
 
-		// Do not send this transaction if we receive it from peer.
-		if memTx.isSender(peer.ID()) {
+		// The entry may have been removed from the mempool since it was
+		// chosen at the beginning of the loop. Skip it if that's the case.
+		if !memR.mempool.InMempool(memTx.tx.Key()) {
+			memR.Logger.Debug("Transaction no longer in mempool, skipping.")
+			time.Sleep(PeerCatchupSleepIntervalMS * time.Millisecond)
 			continue
 		}
 
-		success := peer.Send(p2p.Envelope{
-			ChannelID: MempoolChannel,
-			Message:   &protomem.Txs{Txs: [][]byte{memTx.tx}},
-		})
-		if !success {
-			time.Sleep(PeerCatchupSleepIntervalMS * time.Millisecond)
-			continue
+		// Do not send this transaction if we receive it from peer.
+		if !memTx.isSender(peer.ID()) {
+			success := peer.Send(p2p.Envelope{
+				ChannelID: MempoolChannel,
+				Message:   &protomem.Txs{Txs: [][]byte{memTx.tx}},
+			})
+			if !success {
+				time.Sleep(PeerCatchupSleepIntervalMS * time.Millisecond)
+				continue
+			}
 		}
 
 		select {