From 1e2726ccb1737b6302828f94f2ed2aa839d4db64 Mon Sep 17 00:00:00 2001
From: Franco Testagrossa <franco.testagrossa@iohk.io>
Date: Mon, 23 Sep 2024 13:11:19 +0200
Subject: [PATCH] Try prune /acks on network discrepancy

Remove acks persistency
---
 hydra-node/src/Hydra/Network/Reliability.hs | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/hydra-node/src/Hydra/Network/Reliability.hs b/hydra-node/src/Hydra/Network/Reliability.hs
index 231906b7cf5..af4f34db86e 100644
--- a/hydra-node/src/Hydra/Network/Reliability.hs
+++ b/hydra-node/src/Hydra/Network/Reliability.hs
@@ -221,8 +221,8 @@ withReliability ::
   -- | Underlying network component providing consuming and sending channels.
   NetworkComponent m (Authenticated (ReliableMsg (Heartbeat inbound))) (ReliableMsg (Heartbeat outbound)) a ->
   NetworkComponent m (Authenticated (Heartbeat inbound)) (Heartbeat outbound) a
-withReliability tracer MessagePersistence{saveAcks, loadAcks, appendMessage, loadMessages} me otherParties withRawNetwork callback action = do
-  acksCache <- loadAcks >>= newTVarIO
+withReliability tracer MessagePersistence{appendMessage, loadMessages} me otherParties withRawNetwork callback action = do
+  acksCache <- newTVarIO mempty
   sentMessages <- loadMessages >>= newTVarIO . Seq.fromList
   resendQ <- newTQueueIO
   let ourIndex = fromMaybe (error "This cannot happen because we constructed the list with our party inside.") (findPartyIndex me)
@@ -242,13 +242,11 @@ withReliability tracer MessagePersistence{saveAcks, loadAcks, appendMessage, loa
             case msg of
               Data{} -> do
                 localCounter <- atomically $ cacheMessage msg >> incrementAckCounter
-                saveAcks localCounter
                 appendMessage msg
                 traceWith tracer BroadcastCounter{ourIndex, localCounter}
                 broadcast $ ReliableMsg localCounter msg
               Ping{} -> do
                 localCounter <- readTVarIO acksCache
-                saveAcks localCounter
                 traceWith tracer BroadcastPing{ourIndex, localCounter}
                 broadcast $ ReliableMsg localCounter msg
         }
@@ -288,8 +286,12 @@ withReliability tracer MessagePersistence{saveAcks, loadAcks, appendMessage, loa
                   let newAcks = constructAcks loadedAcks partyIndex
                   lift $ writeTVar acksCache newAcks
                   return (True, partyIndex, newAcks)
-              | otherwise ->
-                  -- other messages are dropped
+              | messageAckForParty <= knownAckForParty ->
+                  -- old messages are dropped
+                  return (False, partyIndex, loadedAcks)
+              | otherwise -> do
+                  -- others
+                  lift $ writeTVar acksCache mempty
                   return (False, partyIndex, loadedAcks)
 
           case eShouldCallbackWithKnownAcks of