From 803daaa8b7dd2dbabea2192c6b734251c30dc841 Mon Sep 17 00:00:00 2001
From: Hugo Dutka <hugo@coder.com>
Date: Thu, 18 Jun 2026 10:28:17 +0200
Subject: [PATCH] fix(coderd/x/chatd): deflake
 TestStreamPartsDialerDialsPartsEndpoint (#26504)

Closes https://github.com/coder/internal/issues/1601. Fixes a stream
parts WebSocket close race. If the peer closed first, the session read
loop could close the connection before `StreamPartsSession.Close()` ran,
causing cleanup to return a wrapped `net.ErrClosed`. The fix treats
expected transport close errors as successful cleanup.
---
 coderd/x/chatd/stream_parts_transport.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/coderd/x/chatd/stream_parts_transport.go b/coderd/x/chatd/stream_parts_transport.go
index 461a950f6b..04544cf741 100644
--- a/coderd/x/chatd/stream_parts_transport.go
+++ b/coderd/x/chatd/stream_parts_transport.go
@@ -214,6 +214,9 @@ func (s *streamPartsTransportSession) Close() error {
 	s.closeOnce.Do(func() {
 		s.cancel()
 		s.closeErr = s.transport.Close()
+		if streamPartsExpectedTransportClose(s.closeErr) {
+			s.closeErr = nil
+		}
 	})
 	return s.closeErr
 }