From 52de95f21f01083b851fac9bd09186380ff19210 Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Thu, 19 May 2016 13:15:47 +0700
Subject: [PATCH] don't ignore queued control frames when packing a packet

---
 packet_packer.go      | 2 +-
 packet_packer_test.go | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/packet_packer.go b/packet_packer.go
index 698d15741..5d9b4c350 100644
--- a/packet_packer.go
+++ b/packet_packer.go
@@ -66,7 +66,7 @@ func (p *packetPacker) AddBlocked(streamID protocol.StreamID, byteOffset protoco
 
 func (p *packetPacker) PackPacket(stopWaitingFrame *frames.StopWaitingFrame, controlFrames []frames.Frame, includeStreamFrames bool) (*packedPacket, error) {
 	// don't send out packets that only contain a StopWaitingFrame
-	if len(controlFrames) == 0 && (p.streamFrameQueue.Len() == 0 || !includeStreamFrames) {
+	if len(p.controlFrames) == 0 && len(controlFrames) == 0 && (p.streamFrameQueue.Len() == 0 || !includeStreamFrames) {
 		return nil, nil
 	}
 
diff --git a/packet_packer_test.go b/packet_packer_test.go
index 3d35e99b2..0de39e5ba 100644
--- a/packet_packer_test.go
+++ b/packet_packer_test.go
@@ -114,6 +114,13 @@ var _ = Describe("Packet packer", func() {
 		Expect(err).ToNot(HaveOccurred())
 	})
 
+	It("packs a packet if it has queued control frames, but no new control frames", func() {
+		packer.controlFrames = []frames.Frame{&frames.BlockedFrame{StreamID: 0}}
+		p, err := packer.PackPacket(nil, []frames.Frame{}, false)
+		Expect(err).ToNot(HaveOccurred())
+		Expect(p).ToNot(BeNil())
+	})
+
 	It("packs many control frames into 1 packets", func() {
 		f := &frames.AckFrame{LargestObserved: 1}
 		b := &bytes.Buffer{}