commit 4f41ff66898913697507fdf8ebb75d811715b81a
from: Stephen Day <stevvooe@users.noreply.github.com>
via: GitHub <noreply@github.com>
date: Fri Aug 12 19:31:16 2016 UTC

Merge pull request #21 from nilium/fix-close-error-race

Fix race-y channel close/error assignment

commit - 87c6cf4550e8bf9dac847f1c6437e453aadef7c8
commit + 4f41ff66898913697507fdf8ebb75d811715b81a
blob - 80b1e9479bb7f916e95e8c9e0734ed4a889ac404
blob + 2c5ec955994e20ddbba22d86b7c3b9c475d23344
--- server.go
+++ server.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"log"
 	"net"
+	"sync"
 	"time"
 
 	"golang.org/x/net/context"
@@ -53,8 +54,10 @@ type conn struct {
 	session Session
 	ch      Channel
 	handler Handler
-	closed  chan struct{}
-	err     error // terminal error for the conn
+
+	once   sync.Once
+	closed chan struct{}
+	err    error // terminal error for the conn
 }
 
 // activeRequest includes information about the active request.
@@ -233,17 +236,14 @@ func (c *conn) Close() error {
 }
 
 func (c *conn) CloseWithError(err error) error {
-	select {
-	case <-c.closed:
-		return c.err
-	default:
-		close(c.closed)
+	c.once.Do(func() {
 		if err == nil {
-			c.err = err
-		} else {
-			c.err = ErrClosed
+			err = ErrClosed
 		}
 
-		return c.err
-	}
+		c.err = err
+		close(c.closed)
+	})
+
+	return c.err
 }