Walk-up-from-cwd to find project-scoped config

byob-config.1 config

Problem: project-scoped config files need to work from any subdirectory, not just the project root. Users expect to run mytool anywhere inside their project and have it find the right config.

Idea: starting from os.Getwd(), walk upward toward the filesystem root looking for a config file (mytool.toml, .mytoolrc, etc). The first match wins. If none is found before hitting root, fall back to ~/.config/mytool/ or a pure-defaults config.

Tradeoffs: one filesystem stat per ancestor directory. Negligible for depths seen in practice. Same UX users already expect from git, cargo, and direnv. Avoid: searching XDG dirs before the walk — project config must always win.

Design

func FindConfigUp(name string) (string, error) {
    dir, err := os.Getwd()
    if err != nil { return "", err }
    for {
        p := filepath.Join(dir, name)
        if _, err := os.Stat(p); err == nil {
            return p, nil
        }
        parent := filepath.Dir(dir)
        if parent == dir { // reached filesystem root
            return "", fs.ErrNotExist
        }
        dir = parent
    }
}