From 8e5ae65837e395430c1c202eb9274f3af335e83c Mon Sep 17 00:00:00 2001
From: Matt Joiner <anacrolix@gmail.com>
Date: Fri, 19 Nov 2021 13:02:42 +1100
Subject: [PATCH] Quote peer extension names to expvar

---
 peerconn.go | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/peerconn.go b/peerconn.go
index 4dcf71e8..06469461 100644
--- a/peerconn.go
+++ b/peerconn.go
@@ -1257,7 +1257,11 @@ func (c *PeerConn) onReadExtendedMsg(id pp.ExtensionNumber, payload []byte) (err
 		c.PeerPrefersEncryption = d.Encryption
 		for name, id := range d.M {
 			if _, ok := c.PeerExtensionIDs[name]; !ok {
-				peersSupportingExtension.Add(string(name), 1)
+				peersSupportingExtension.Add(
+					// expvar.Var.String must produce valid JSON. "ut_payme\xeet_address" was being
+					// entered here which caused problems later when unmarshalling.
+					strconv.Quote(string(name)),
+					1)
 			}
 			c.PeerExtensionIDs[name] = id
 		}
-- 
2.48.1