benbjohnson/litestream · error

marshal lock file: %w

Error message

marshal lock file: %w

What it means

json.Marshal of the litestream.Lease struct failed inside writeLease. This should be unreachable for well-formed Lease values; it indicates an unmarshalable field (e.g. a channel or func injected programmatically) rather than a runtime condition.

Source

Thrown at s3/leaser.go:236

	if err := json.NewDecoder(out.Body).Decode(&lease); err != nil {
		return nil, "", fmt.Errorf("decode lock file: %w", err)
	}

	etag := ""
	if out.ETag != nil {
		etag = *out.ETag
	}
	lease.ETag = etag

	return &lease, etag, nil
}

func (l *Leaser) writeLease(ctx context.Context, lease *litestream.Lease, etag string) (string, error) {
	key := l.lockKey()

	data, err := json.Marshal(lease)
	if err != nil {
		return "", fmt.Errorf("marshal lock file: %w", err)
	}

	input := &s3.PutObjectInput{
		Bucket:      aws.String(l.Bucket),
		Key:         aws.String(key),
		Body:        bytes.NewReader(data),
		ContentType: aws.String("application/json"),
	}

	if etag == "" {
		input.IfNoneMatch = aws.String("*")
	} else {
		input.IfMatch = aws.String(etag)
	}

	out, err := l.s3.PutObject(ctx, input)
	if err != nil {
		if isPreconditionFailed(err) {

View on GitHub (pinned to 4ed7a308f6)

Solutions

1. Inspect the Lease struct for unsupported field types
2. Report as a bug if it occurs with normal lease data

When it happens

Trigger: Thrown at s3/leaser.go:236 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of benbjohnson/litestream@4ed7a308f6 (2026-09-06). Data as JSON: /api/errors/5feed24e3fc6d7e0. Report an issue: GitHub.