From 872ed736b491e07a04f2cf060049b13cefcbdf5f Mon Sep 17 00:00:00 2001
From: Simon Ser <contact@emersion.fr>
Date: Tue, 21 Sep 2021 11:49:48 +0200
Subject: [PATCH] Workaround lack of net.ErrClosed in WebSocket library

---
 conn.go | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/conn.go b/conn.go
index 5624728..e25f7da 100644
--- a/conn.go
+++ b/conn.go
@@ -74,8 +74,18 @@ func (wic *websocketIRCConn) WriteMessage(msg *irc.Message) error {
 	return wic.conn.Write(ctx, websocket.MessageText, b)
 }
 
+func isErrWebSocketClosed(err error) bool {
+	return err != nil && strings.HasSuffix(err.Error(), "failed to close WebSocket: already wrote close")
+}
+
 func (wic *websocketIRCConn) Close() error {
-	return wic.conn.Close(websocket.StatusNormalClosure, "")
+	err := wic.conn.Close(websocket.StatusNormalClosure, "")
+	// TODO: remove once this PR is merged:
+	// https://github.com/nhooyr/websocket/pull/303
+	if isErrWebSocketClosed(err) {
+		return nil
+	}
+	return err
 }
 
 func (wic *websocketIRCConn) SetReadDeadline(t time.Time) error {