wavetermdev/waveterm · error

nil message

Error message

nil message

What it means

EncodeWaveOSCMessageEx serializes an *RpcMessage to JSON and wraps it in an OSC sequence. A nil message pointer cannot be marshalled meaningfully, so the function rejects it explicitly with this sentinel error before touching json.Marshal.

Source

Thrown at pkg/wshutil/wshutil.go:117

	var buf bytes.Buffer
	buf.Write(makeOscPrefix(oscNum))
	escSeq := [6]byte{'\\', 'u', '0', '0', '0', '0'}
	for _, b := range barr {
		if b < 0x20 || b == 0x7f {
			escSeq[4] = HexChars[b>>4]
			escSeq[5] = HexChars[b&0x0f]
			buf.Write(escSeq[:])
		} else {
			buf.WriteByte(b)
		}
	}
	buf.WriteByte(BEL)
	return buf.Bytes(), nil
}

func EncodeWaveOSCMessageEx(oscNum string, msg *RpcMessage) ([]byte, error) {
	if msg == nil {
		return nil, fmt.Errorf("nil message")
	}
	barr, err := json.Marshal(msg)
	if err != nil {
		return nil, fmt.Errorf("error marshalling message to json: %w", err)
	}
	return EncodeWaveOSCBytes(oscNum, barr)
}

var shutdownOnce sync.Once

func DoShutdown(reason string, exitCode int, quiet bool) {
	shutdownOnce.Do(func() {
		defer os.Exit(exitCode)
		if !quiet && reason != "" {
			log.Printf("shutting down: %s\n", reason)
		}
	})
}

View on GitHub (pinned to a4447c1563)

Solutions

1. Construct a valid RpcMessage before calling; never pass a nil pointer.
2. Check the upstream producer for paths that return a nil message.
3. If an empty message is intended, pass &RpcMessage{} with appropriate fields instead.

Example fix

// before
var msg *RpcMessage
barr, err := EncodeWaveOSCMessageEx("1337;", msg) // panics into error
// after
msg := &RpcMessage{Command: "waveclient:getdata", Data: basePayload}
barr, err := EncodeWaveOSCMessageEx("1337;", msg)

if msg == nil {
    return errors.New("cannot encode nil RpcMessage")
}

func hasMessage(m *wshutil.RpcMessage) bool { return m != nil }

if msg == nil { return errors.New("no message to send") }
if _, err := EncodeWaveOSCMessageEx(oscNum, msg); err != nil {
    return fmt.Errorf("encode failed: %w", err)
}

When it happens

Trigger: Calling EncodeWaveOSCMessageEx with msg == nil — e.g. a channel or variable holding a typed-nil *RpcMessage, or an upstream function returning nil on a path the caller didn't check.

Common situations: Uninitialized message variable; an RPC builder that returns (nil, nil) on an edge case; passing a nil pointer through a message queue unchecked.

Related errors

• linePtr is nil
• nil wshrpc passed to wshclient
• file info is required
• invalid AIMessage: %w
• part %d: text type requires non-empty text field

AI-assisted analysis of wavetermdev/waveterm@a4447c1563 (2026-09-01). Data as JSON: /api/errors/65a63d917efd0a08. Report an issue: GitHub.