From 36255f1b38e77d02e96c6893e7cd7dd3e68e6921 Mon Sep 17 00:00:00 2001
From: Maxime Piraux <maxime.piraux@uclouvain.be>
Date: Tue, 15 Mar 2022 17:05:42 +0100
Subject: [PATCH] Fixes unregistering a channel on a possibly closed stream
 data broadcaster

---
 agents/http3_agent.go | 6 +++++-
 utils.go              | 8 ++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/agents/http3_agent.go b/agents/http3_agent.go
index ecdd0b4..59b77ab 100644
--- a/agents/http3_agent.go
+++ b/agents/http3_agent.go
@@ -251,7 +251,11 @@ func (a *HTTP3Agent) SendRequest(path, method, authority string, headers map[str
 	a.responseBuffer[streamID] = response
 
 	go func() { // Pipes the data from the response stream to the agent
-		defer stream.ReadChan.Unregister(streamChan)
+		defer func() {
+			if !stream.ReadChan.IsClosed() {
+				stream.ReadChan.Unregister(streamChan)
+			}
+		}()
 		for {
 			select {
 			case i := <-streamChan:
diff --git a/utils.go b/utils.go
index e3b8e1b..580597f 100644
--- a/utils.go
+++ b/utils.go
@@ -5,6 +5,7 @@ import "github.com/dustin/go-broadcast"
 type Broadcaster struct {
 	broadcast.Broadcaster
 	channels []chan interface{}
+	isClosed bool
 }
 
 func NewBroadcaster(buflen int) Broadcaster {
@@ -19,8 +20,15 @@ func (b *Broadcaster) RegisterNewChan(size int) chan interface{} {
 }
 
 func (b *Broadcaster) Close() error {
+	if b.isClosed {
+		return nil
+	}
+	b.isClosed = true
 	for _, c := range b.channels {
 		close(c)
 	}
 	return b.Broadcaster.Close()
+}
+func (b *Broadcaster) IsClosed() bool {
+	return b.isClosed
 }
\ No newline at end of file