include the frame type in the QuicError error message

internal/qerr/error_codes.go

@@ -31,11 +31,20 @@ func (e ErrorCode) isCryptoError() bool {
 
 func (e ErrorCode) Error() string {
 	if e.isCryptoError() {
-		return fmt.Sprintf("%s: %s", e.String(), qtls.Alert(e-0x100).Error())
+		return fmt.Sprintf("%s: %s", e.String(), e.Message())
 	}
 	return e.String()
 }
 
+// Message is a description of the error.
+// It only returns a non-empty string for crypto errors.
+func (e ErrorCode) Message() string {
+	if !e.isCryptoError() {
+		return ""
+	}
+	return qtls.Alert(e - 0x100).Error()
+}
+
 func (e ErrorCode) String() string {
 	switch e {
 	case NoError:

internal/qerr/quic_error.go

@@ -8,6 +8,7 @@ import (
 // A QuicError consists of an error code plus a error reason
 type QuicError struct {
 	ErrorCode          ErrorCode
+	FrameType          uint64 // only valid if this not an application error
 	ErrorMessage       string
 	isTimeout          bool
 	isApplicationError bool
@@ -23,6 +24,15 @@ func Error(errorCode ErrorCode, errorMessage string) *QuicError {
 	}
 }
 
+// ErrorWithFrameType creates a new QuicError instance for a specific frame type
+func ErrorWithFrameType(errorCode ErrorCode, frameType uint64, errorMessage string) *QuicError {
+	return &QuicError{
+		ErrorCode:    errorCode,
+		FrameType:    frameType,
+		ErrorMessage: errorMessage,
+	}
+}
+
 // TimeoutError creates a new QuicError instance for a timeout error
 func TimeoutError(errorMessage string) *QuicError {
 	return &QuicError{
@@ -55,10 +65,18 @@ func (e *QuicError) Error() string {
 		}
 		return fmt.Sprintf("Application error %#x: %s", uint64(e.ErrorCode), e.ErrorMessage)
 	}
-	if len(e.ErrorMessage) == 0 {
-		return e.ErrorCode.Error()
+	str := e.ErrorCode.String()
+	if e.FrameType != 0 {
+		str += fmt.Sprintf(" (frame type: %#x)", e.FrameType)
 	}
-	return fmt.Sprintf("%s: %s", e.ErrorCode.String(), e.ErrorMessage)
+	msg := e.ErrorMessage
+	if len(msg) == 0 {
+		msg = e.ErrorCode.Message()
+	}
+	if len(msg) == 0 {
+		return str
+	}
+	return str + ": " + msg
 }
 
 // IsCryptoError says if this error is a crypto error

internal/qerr/quic_error_test.go

@@ -20,6 +20,16 @@ var _ = Describe("QUIC Transport Errors", func() {
 		Expect(err.Error()).To(Equal("FLOW_CONTROL_ERROR"))
 	})
 
+	It("includes the frame type, for errors without a message", func() {
+		err := ErrorWithFrameType(FlowControlError, 0x1337, "")
+		Expect(err.Error()).To(Equal("FLOW_CONTROL_ERROR (frame type: 0x1337)"))
+	})
+
+	It("includes the frame type, for errors with a message", func() {
+		err := ErrorWithFrameType(FlowControlError, 0x1337, "foobar")
+		Expect(err.Error()).To(Equal("FLOW_CONTROL_ERROR (frame type: 0x1337): foobar"))
+	})
+
 	It("has a string representation for timeout errors", func() {
 		err := TimeoutError("foobar")
 		Expect(err.Timeout()).To(BeTrue())