From 1c8903f249731b4da964d766ff2174d68ddd991e Mon Sep 17 00:00:00 2001
From: Andy Wang <cbeuw.andy@gmail.com>
Date: Mon, 20 Apr 2020 23:54:41 +0100
Subject: [PATCH] Log repeat stream closing on Debug level

---
 internal/multiplex/session.go | 3 ++-
 internal/multiplex/stream.go  | 7 ++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/internal/multiplex/session.go b/internal/multiplex/session.go
index 62c2517..cf85b7c 100644
--- a/internal/multiplex/session.go
+++ b/internal/multiplex/session.go
@@ -20,6 +20,7 @@ const (
 
 var ErrBrokenSession = errors.New("broken session")
 var errRepeatSessionClosing = errors.New("trying to close a closed session")
+var errRepeatStreamClosing = errors.New("trying to close a closed stream")
 
 type switchboardStrategy int
 
@@ -145,7 +146,7 @@ func (sesh *Session) Accept() (net.Conn, error) {
 
 func (sesh *Session) closeStream(s *Stream, active bool) error {
 	if atomic.SwapUint32(&s.closed, 1) == 1 {
-		return fmt.Errorf("stream %v is already closed", s.id)
+		return fmt.Errorf("closing stream %v: %w", s.id, errRepeatStreamClosing)
 	}
 	_ = s.recvBuf.Close() // both datagramBuffer and streamBuffer won't return err on Close()
 
diff --git a/internal/multiplex/stream.go b/internal/multiplex/stream.go
index 253cb2b..1e2810b 100644
--- a/internal/multiplex/stream.go
+++ b/internal/multiplex/stream.go
@@ -62,7 +62,12 @@ func (s *Stream) isClosed() bool { return atomic.LoadUint32(&s.closed) == 1 }
 func (s *Stream) writeFrame(frame Frame) error {
 	toBeClosed, err := s.recvBuf.Write(frame)
 	if toBeClosed {
-		return s.passiveClose()
+		err = s.passiveClose()
+		if errors.Is(err, errRepeatStreamClosing) {
+			log.Debug(err)
+			return nil
+		}
+		return err
 	}
 	return err
 }