src/pkg/encoding/line/line.go      |  3 +++
 src/pkg/encoding/line/line_test.go | 23 +++++++++++++++++++++++

diff --git a/src/pkg/encoding/line/line.go b/src/pkg/encoding/line/line.go
index 779b5758adde09cad0a818197a063d73982f7fdb..f46ce1c83a05711c4a0eb87d3ed241eaf94f600f 100644
--- a/src/pkg/encoding/line/line.go
+++ b/src/pkg/encoding/line/line.go
@@ -105,6 +105,9 @@ 		n, readErr := l.in.Read(l.buf[oldLen:])
 		l.buf = l.buf[:oldLen+n]
 		if readErr != nil {
 			l.err = readErr
+			if len(l.buf) == 0 {
+				return nil, false, readErr
+			}
 		}
 	}
 	panic("unreachable")
diff --git a/src/pkg/encoding/line/line_test.go b/src/pkg/encoding/line/line_test.go
index ff16d10c709d7cbab1cda4050f8dc4eb359e5205..ff3d51669b54326646975bd1a9ce2fa12e69a7e6 100644
--- a/src/pkg/encoding/line/line_test.go
+++ b/src/pkg/encoding/line/line_test.go
@@ -7,6 +7,7 @@
 import (
 	"bytes"
 	"io"
+	"io/ioutil"
 	"os"
 	"testing"
 )
@@ -108,3 +109,25 @@ 	if outbuf.String() != restData {
 		t.Errorf("bad result for Read: got %q; expected %q", outbuf.String(), restData)
 	}
 }
+
+func TestReadEmptyBuffer(t *testing.T) {
+	l := NewReader(bytes.NewBuffer(nil), 10)
+	line, isPrefix, err := l.ReadLine()
+	if err != os.EOF {
+		t.Errorf("expected EOF from ReadLine, got '%s' %t %s", line, isPrefix, err)
+	}
+}
+
+func TestLinesAfterRead(t *testing.T) {
+	l := NewReader(bytes.NewBuffer([]byte("foo")), 10)
+	_, err := ioutil.ReadAll(l)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	line, isPrefix, err := l.ReadLine()
+	if err != os.EOF {
+		t.Errorf("expected EOF from ReadLine, got '%s' %t %s", line, isPrefix, err)
+	}
+}