bytes.Buffer: Fix bug in UnreadByte.

Error check was inverted.

Fixes #1396.

R=rsc, adg
CC=golang-dev
https://golang.org/cl/3851042

diff --git a/src/pkg/bytes/buffer.go b/src/pkg/bytes/buffer.go
index 55d313386856f9b9c0b0cc77d5587aac680ebf67..2574b4f4329852383f2212d51b8ea8e3fb79090c 100644 (file)
--- a/src/pkg/bytes/buffer.go
+++ b/src/pkg/bytes/buffer.go
@@ -291,7 +291,7 @@ func (b *Buffer) UnreadRune() os.Error {
 // read operation.  If write has happened since the last read, UnreadByte
 // returns an error.
 func (b *Buffer) UnreadByte() os.Error {
-       if b.lastRead == opReadRune || b.lastRead == opRead {
+       if b.lastRead != opReadRune && b.lastRead != opRead {
                return os.ErrorString("bytes.Buffer: UnreadByte: previous operation was not a read")
        }
        b.lastRead = opInvalid