From 20040f2e9b566b48cd568b0849f58d106a360315 Mon Sep 17 00:00:00 2001
From: Prem Chaitanya Prathi <chaitanyaprem@gmail.com>
Date: Sat, 5 Aug 2023 08:03:19 +0530
Subject: [PATCH] fix: data race in filter unsubscribe

---
 waku/v2/protocol/filter/client.go | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/waku/v2/protocol/filter/client.go b/waku/v2/protocol/filter/client.go
index 39b8d65a..ca7977b5 100644
--- a/waku/v2/protocol/filter/client.go
+++ b/waku/v2/protocol/filter/client.go
@@ -407,11 +407,14 @@ func (wf *WakuFilterLightnode) UnsubscribeAll(ctx context.Context, opts ...Filte
 
 	localWg := sync.WaitGroup{}
 	resultChan := make(chan WakuFilterPushResult, len(wf.subscriptions.items))
+	var peersUnsubscribed []peer.ID
 
 	for peerID := range wf.subscriptions.items {
 		if params.selectedPeer != "" && peerID != params.selectedPeer {
 			continue
 		}
+		peersUnsubscribed = append(peersUnsubscribed, peerID)
+
 		localWg.Add(1)
 		go func(peerID peer.ID) {
 			defer localWg.Done()
@@ -423,9 +426,6 @@ func (wf *WakuFilterLightnode) UnsubscribeAll(ctx context.Context, opts ...Filte
 			if err != nil {
 				wf.log.Error("could not unsubscribe from peer", logging.HostID("peerID", peerID), zap.Error(err))
 			}
-
-			delete(wf.subscriptions.items, peerID)
-
 			resultChan <- WakuFilterPushResult{
 				Err:    err,
 				PeerID: peerID,
@@ -435,6 +435,10 @@ func (wf *WakuFilterLightnode) UnsubscribeAll(ctx context.Context, opts ...Filte
 
 	localWg.Wait()
 	close(resultChan)
-
+	for _, peerID := range peersUnsubscribed {
+		if len(wf.subscriptions.items[peerID].subscriptionsPerTopic) == 0 {
+			delete(wf.subscriptions.items, peerID)
+		}
+	}
 	return resultChan, nil
 }