refactor: keeping the same Stderr method

pty.go

@@ -13,6 +13,8 @@ func NewPtyWriter(w io.Writer) io.Writer {
 	}
 }
 
+var _ io.Writer = ptyWriter{}
+
 type ptyWriter struct {
 	w io.Writer
 }
@@ -29,3 +31,27 @@ func (w ptyWriter) Write(p []byte) (int, error) {
 	}
 	return n, err
 }
+
+// NewPtyReadWriter return an io.ReadWriter that delegates the read to the
+// given io.ReadWriter, and the writes to a ptyWriter.
+func NewPtyReadWriter(rw io.ReadWriter) io.ReadWriter {
+	return readWriterDelegate{
+		w: NewPtyWriter(rw),
+		r: rw,
+	}
+}
+
+var _ io.ReadWriter = readWriterDelegate{}
+
+type readWriterDelegate struct {
+	w io.Writer
+	r io.Reader
+}
+
+func (rw readWriterDelegate) Read(p []byte) (n int, err error) {
+	return rw.r.Read(p)
+}
+
+func (rw readWriterDelegate) Write(p []byte) (n int, err error) {
+	return rw.w.Write(p)
+}

session.go

@@ -83,9 +83,11 @@ type Session interface {
 	// During the time that no channel is registered, breaks are ignored.
 	Break(c chan<- bool)
 
-	// SafeStderr returns the Stderr io.Writer that handles replacing \n with
-	// \r\n when there's an active Pty.
-	SafeStderr() io.Writer
+	// Stderr returns an io.ReadWriter that writes to this channel
+	// with the extended data type set to stderr. Stderr may
+	// safely be read and written from a different goroutine than
+	// Read and Write respectively.
+	Stderr() io.ReadWriter
 }
 
 // maxSigBufSize is how many signals will be buffered
@@ -131,11 +133,11 @@ type session struct {
 	breakCh           chan<- bool
 }
 
-func (sess *session) SafeStderr() io.Writer {
+func (sess *session) Stderr() io.ReadWriter {
 	if sess.pty != nil {
-		return NewPtyWriter(sess.Stderr())
+		return NewPtyReadWriter(sess.Channel.Stderr())
 	}
-	return sess.Stderr()
+	return sess.Channel.Stderr()
 }
 
 func (sess *session) Write(p []byte) (int, error) {

session_test.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"net"
 	"testing"
+	"time"
 
 	gossh "golang.org/x/crypto/ssh"
 )
@@ -236,7 +237,8 @@ func TestPtyWriter(t *testing.T) {
 	session, _, cleanup := newTestSession(t, &Server{
 		Handler: func(s Session) {
 			_, _ = fmt.Fprintln(s, "foo\nbar")
-			_, _ = fmt.Fprintln(s.SafeStderr(), "many\nerrors")
+			time.Sleep(10 * time.Millisecond)
+			_, _ = fmt.Fprintln(s.Stderr(), "many\nerrors")
 			_ = s.Exit(0)
 		},
 	}, nil)