What causes "db: CountForPrefix: prefix must not be empty" in gastownhall/beads?

Supply a non-empty prefix (e.g. "bd") before calling

db: CountForPrefix: prefix must not be empty

Error message

db: CountForPrefix: prefix must not be empty

What it means

CountForPrefix() counts issues whose ids share a given prefix; a blank prefix has no meaning and would match nothing or everything depending on the LIKE pattern, so the repository rejects it explicitly. It is an input-validation guard before the COUNT query.

Source

Thrown at internal/storage/domain/db/issue.go:623

		return false, errors.New("db: Exists: id must not be empty")
	}
	table := pickIssueTable(opts.UseWispsTable)
	//nolint:gosec // G201: table is one of two hardcoded constants
	row := r.runner.QueryRowContext(ctx, fmt.Sprintf("SELECT 1 FROM %s WHERE id = ? LIMIT 1", table), id)
	var one int
	err := row.Scan(&one)
	if errors.Is(err, sql.ErrNoRows) {
		return false, nil
	}
	if err != nil {
		return false, fmt.Errorf("db: Exists %s: %w", id, err)
	}
	return true, nil
}

func (r *issueSQLRepositoryImpl) CountForPrefix(ctx context.Context, prefix string, opts domain.IssueTableOpts) (int, error) {
	if prefix == "" {
		return 0, errors.New("db: CountForPrefix: prefix must not be empty")
	}
	table := pickIssueTable(opts.UseWispsTable)
	var count int
	//nolint:gosec // G201: table is one of two hardcoded constants
	err := r.runner.QueryRowContext(ctx, fmt.Sprintf(`
		SELECT COUNT(*)
		FROM %s
		WHERE id LIKE CONCAT(?, '-%%')
		  AND INSTR(SUBSTRING(id, LENGTH(?) + 2), '.') = 0
	`, table), prefix, prefix).Scan(&count)
	if err != nil {
		return 0, fmt.Errorf("db: CountForPrefix %s: %w", prefix, err)
	}
	return count, nil
}

func (r *issueSQLRepositoryImpl) NextCounterID(ctx context.Context, prefix string) (int, error) {
	if prefix == "" {

View on GitHub (pinned to 71377f2769)

Solutions

Supply a non-empty prefix (e.g. "bd") before calling
If empty prefix is a valid 'count all' intent, call a list-all/count-all API instead
Log/validate configuration at startup so empty prefixes fail early

Example fix

// before
n, err := repo.CountForPrefix(ctx, cfg.IDPrefix, opts)
// after
if cfg.IDPrefix == "" {
    return errors.New("id prefix not configured")
}
n, err := repo.CountForPrefix(ctx, cfg.IDPrefix, opts)

Defensive patterns

Strategy: validation

Validate before calling

if prefix == "" {
    return errors.New("prefix must be configured before counting issues")
}

Type guard

func validPrefix(p string) bool { return strings.TrimSpace(p) != "" }

Try / catch

n, err := repo.CountForPrefix(ctx, prefix, opts)
if err != nil {
    return fmt.Errorf("count prefix %q: %w", prefix, err)
}

Prevention

Validate the configured ID prefix at application startup
Default the prefix (e.g. "bd") when config is empty rather than passing it through
Centralize prefix derivation in one function that enforces non-empty output

When it happens

Trigger: Calling issueSQLRepositoryImpl.CountForPrefix(ctx, "", opts) — e.g. a prefix derived from config, CLI flag, or an issue-ID parse that came back empty.

Common situations: Missing or empty --prefix style configuration; computing a prefix from a partially parsed ID; a metadata.json field left blank.

Related errors

AI-assisted analysis of gastownhall/beads@71377f2769 (2026-08-30). Data as JSON: /api/errors/d0111616ed3ab364. Report an issue: GitHub.