gorilla/mux · error

mux: route doesn't have a path

Error message

mux: route doesn't have a path

What it means

Returned by Route.URLPath (route.go:676-681) when building a URL but the route has no path matcher (r.regexp.path == nil). URLPath constructs only the path, so a path matcher is mandatory. Route.URL() without a path returns a URL with an empty Path.

Source

Thrown at route.go:681

	u := &url.URL{
		Scheme: "http",
		Host:   host,
	}
	if r.buildScheme != "" {
		u.Scheme = r.buildScheme
	}
	return u, nil
}

// URLPath builds the path part of the URL for a route. See Route.URL().
//
// The route must have a path defined.
func (r *Route) URLPath(pairs ...string) (*url.URL, error) {
	if r.err != nil {
		return nil, r.err
	}
	if r.regexp.path == nil {
		return nil, errors.New("mux: route doesn't have a path")
	}
	values, err := r.prepareVars(pairs...)
	if err != nil {
		return nil, err
	}
	path, err := r.regexp.path.url(values)
	if err != nil {
		return nil, err
	}
	return &url.URL{
		Path: path,
	}, nil
}

// GetPathTemplate returns the template used to build the
// route match.
// This is useful for building simple REST API documentation and for instrumentation
// against third-party services.

View on GitHub (pinned to db9d1d0073)

Solutions

1. Add .Path(...) to the route if you want to build paths.
2. Use Route.URL() if you need host-only output.
3. Probe with GetPathTemplate() first.

Example fix

// before
u, err := r.Get("x").URLPath() // route has no Path

// after
u, err := r.Get("x").URL()

if _, err := rt.GetPathTemplate(); err != nil {
    return rt.URL(pairs...)
}

func hasPath(rt *mux.Route) bool { _, err := rt.GetPathTemplate(); return err == nil }

u, err := rt.URLPath(pairs...)
if err != nil { u, err = rt.URL(pairs...) }

When it happens

Trigger: r.NewRoute().Host("{s}.com").Name("x"); then r.Get("x").URLPath(...) is called but Path() was never invoked on the route.

Common situations: Host-only routes used for URL building; refactor that removed a path; BuildOnly routes used for host links.

Related errors

• mux: route doesn't have a host
• key not found in metadata
• mux: duplicated route variable %q
• mux: number of parameters must be multiple of 2, got %v
• mux: route already has name %q, can't set %q

AI-assisted analysis of gorilla/mux@db9d1d0073 (2026-08-04). Data as JSON: /data/errors/aa7e03b288c6adeb.json. Report an issue: GitHub.