juanfont/headscale · error · ErrInvalidLocalpart

%w: empty domain in %q

Error message

%w: empty domain in %q

What it means

Error "%w: empty domain in %q" thrown in juanfont/headscale.

Source

Thrown at hscontrol/policy/v2/types.go:3092

	}

	pattern := strings.TrimPrefix(string(u), SSHUserLocalpartPrefix)

	// Must be *@<domain>
	atIdx := strings.LastIndex(pattern, "@")
	if atIdx < 0 {
		return "", fmt.Errorf("%w: missing @ in %q", ErrInvalidLocalpart, u)
	}

	localPart := pattern[:atIdx]
	domain := pattern[atIdx+1:]

	if localPart != "*" {
		return "", fmt.Errorf("%w: local part must be *, got %q in %q", ErrInvalidLocalpart, localPart, u)
	}

	if domain == "" {
		return "", fmt.Errorf("%w: empty domain in %q", ErrInvalidLocalpart, u)
	}

	return domain, nil
}

// MarshalJSON marshals the [SSHUser] to JSON.
func (u SSHUser) MarshalJSON() ([]byte, error) {
	return json.Marshal(string(u))
}

// UnmarshalJSON trims surrounding whitespace per element. A whitespace-
// only entry collapses to `""` and surfaces as `user "" is not valid` in
// the per-rule [Policy.validate] pass.
func (u *SSHUser) UnmarshalJSON(b []byte) error {
	var s string
	if err := json.Unmarshal(b, &s); err != nil { //nolint:noinlineerr
		return err
	}

View on GitHub (pinned to 565fd254d0)

Solutions

1. Inspect the wrapped error for the underlying cause and correct the failing condition (); retry the operation after fixing the input, configuration, or environment.

Example fix

Inspect the wrapped error for the underlying cause and correct the failing condition (); retry the operation after fixing the input, configuration, or environment.

When it happens

Trigger: Thrown at hscontrol/policy/v2/types.go:3092 when the library encounters an invalid state.

Common situations: A localpart entry has an empty domain after '@'. Provide a valid domain, e.g. *@example.com.

AI-assisted analysis of juanfont/headscale@565fd254d0 (2026-08-15). Data as JSON: /api/errors/c371151df1730ac2. Report an issue: GitHub.