handle remote errors in Stream Write

stream.go

@@ -163,6 +163,9 @@ func (s *stream) Write(p []byte) (int, error) {
 		s.windowUpdateCond.L.Lock()
 		remainingBytesInWindow := int64(s.flowControlWindow) - int64(s.writeOffset)
 		for ; remainingBytesInWindow == 0; remainingBytesInWindow = int64(s.flowControlWindow) - int64(s.writeOffset) {
+			if s.remoteErr != nil {
+				return 0, s.remoteErr
+			}
 			s.windowUpdateCond.Wait()
 		}
 		s.windowUpdateCond.L.Unlock()
@@ -206,6 +209,7 @@ func (s *stream) AddStreamFrame(frame *frames.StreamFrame) error {
 func (s *stream) RegisterError(err error) {
 	s.remoteErr = err
 	s.streamFrames <- nil
+	s.windowUpdateCond.Broadcast()
 }
 
 func (s *stream) finishedReading() bool {

stream_test.go

@@ -305,6 +305,23 @@ var _ = Describe("Stream", func() {
 				Expect(n).To(Equal(2))
 				Expect(err).ToNot(HaveOccurred())
 			})
+
+			It("immediately returns on remote errors", func() {
+				var b bool
+				str.flowControlWindow = 1
+
+				testErr := errors.New("test error")
+
+				go func() {
+					time.Sleep(time.Millisecond)
+					b = true
+					str.RegisterError(testErr)
+				}()
+
+				_, err := str.Write([]byte{0xDE, 0xCA, 0xFB, 0xAD})
+				Expect(b).To(BeTrue())
+				Expect(err).To(Equal(testErr))
+			})
 		})
 	})