From cb0951dee862613ea978e16a43a0161b78525c72 Mon Sep 17 00:00:00 2001
From: "Brandon McGinty (chatgpt)" <git@bmcginty.us>
Date: Sun, 9 Aug 2026 14:21:35 -0400
Subject: [PATCH] Remove stale reverse channel links

---
 .../gumble/channel_links_regression_test.go   | 27 +++++++++++++++++++
 gumble/gumble/handlers.go                     | 11 +++++---
 2 files changed, 35 insertions(+), 3 deletions(-)
 create mode 100644 gumble/gumble/channel_links_regression_test.go

diff --git a/gumble/gumble/channel_links_regression_test.go b/gumble/gumble/channel_links_regression_test.go
new file mode 100644
index 0000000..49ba088
--- /dev/null
+++ b/gumble/gumble/channel_links_regression_test.go
@@ -0,0 +1,27 @@
+package gumble
+
+import (
+	"testing"
+
+	"git.stormux.org/storm/barnard/gumble/gumble/MumbleProto"
+	"google.golang.org/protobuf/proto"
+)
+
+// Regression: a full channel-link update used to leave the removed peer's
+// reverse link behind, making the client report a link that no longer exists.
+func TestChannelStateFullLinksRemovesReverseLinks(t *testing.T) {
+	c := &Client{Config: NewConfig(), Channels: make(Channels)}
+	a, b, replacement := c.Channels.create(1), c.Channels.create(2), c.Channels.create(3)
+	a.Links[b.ID], b.Links[a.ID] = b, a
+	id := a.ID
+	data, _ := proto.Marshal(&MumbleProto.ChannelState{ChannelId: &id, Links: []uint32{replacement.ID}})
+	if err := c.handleChannelState(data); err != nil {
+		t.Fatal(err)
+	}
+	if _, ok := b.Links[a.ID]; ok {
+		t.Fatal("stale reciprocal link remains")
+	}
+	if replacement.Links[a.ID] != a {
+		t.Fatal("replacement reciprocal link missing")
+	}
+}
diff --git a/gumble/gumble/handlers.go b/gumble/gumble/handlers.go
index 5f33c37..9445314 100644
--- a/gumble/gumble/handlers.go
+++ b/gumble/gumble/handlers.go
@@ -463,11 +463,16 @@ func (c *Client) handleChannelState(buffer []byte) error {
 			channel.Name = *packet.Name
 		}
 		if packet.Links != nil {
-			channel.Links = make(Channels)
+			// A full replacement must also remove our old reciprocal links.
+			for oldID, old := range channel.Links {
+				delete(old.Links, channel.ID)
+				delete(channel.Links, oldID)
+			}
 			event.Type |= ChannelChangeLinks
 			for _, channelID := range packet.Links {
-				if c := c.Channels[channelID]; c != nil {
-					channel.Links[channelID] = c
+				if linked := c.Channels[channelID]; linked != nil {
+					channel.Links[channelID] = linked
+					linked.Links[channel.ID] = channel
 				}
 			}
 		}