What causes "request URL is missing" in JuliusBrussee/caveman?

Pass the request's parsed URL: ValidateRequestPath(r.URL) on a non-nil *http.Request.

request URL is missing

Error message

request URL is missing

What it means

Thrown by ValidateRequestPath when it is called with a nil *url.URL. This pre-adapter validation gate rejects ambiguous path encodings before adapter selection; a nil URL means the caller has no request path to validate, so it fails closed instead of skipping validation.

Source

Thrown at proxy/providers/openaicompat/openaicompat.go:251

		return nil, err
	}
	if !strings.HasPrefix(req.URL.Path, a.prefix+"/") {
		return nil, fmt.Errorf("compat route %q does not match prefix %q", req.URL.Path, a.prefix+"/")
	}
	path := strings.TrimPrefix(req.URL.Path, a.prefix)
	base.Path = joinCompatPath(base.Path, path)
	base.RawPath = ""
	base.RawQuery = joinCompatQuery(base.RawQuery, req.URL.RawQuery)
	return base, nil
}

// ValidateRequestPath rejects ambiguous path encodings before adapter selection.
// Gateways call this with the original URL (including RawPath), while the
// adapter MatchRoute/ResolveUpstreamURL checks provide a second fail-closed
// boundary for direct callers.
func ValidateRequestPath(u *url.URL) error {
	if u == nil {
		return fmt.Errorf("request URL is missing")
	}
	if !strings.HasPrefix(u.Path, "/compat/") {
		return nil
	}
	return validateCompatPath(u.Path, u.RawPath)
}

func validateCompatPath(path, rawPath string) error {
	if !strings.HasPrefix(path, "/compat/") {
		return nil
	}
	if err := validatePathComponents(path, rawPath); err != nil {
		return fmt.Errorf("compat route path rejected: %w", err)
	}
	return nil
}

func validatePathComponents(path, rawPath string) error {

View on GitHub (pinned to 27d5a3981a)

Solutions

Pass the request's parsed URL: ValidateRequestPath(r.URL) on a non-nil *http.Request.
Add a nil check at the call site and reject the request earlier (400/502) if the URL could not be established.
In tests, build the URL with url.Parse or httptest.NewRequest rather than leaving it nil.

Example fix

// before
if err := ValidateRequestPath(maybeNilURL); err != nil { ... }

// after
if r == nil || r.URL == nil {
    http.Error(w, "bad request", http.StatusBadRequest)
    return
}
if err := ValidateRequestPath(r.URL); err != nil { ... }

Defensive patterns

Strategy: validation

Validate before calling

if r == nil || r.URL == nil {
    http.Error(w, "request URL missing", http.StatusBadRequest)
    return
}
if err := openaicompat.ValidateRequestPath(r.URL); err != nil {
    http.Error(w, err.Error(), http.StatusBadRequest)
    return
}

Try / catch

Handle as a 400/500 boundary error and stop; no retry. Log where the nil URL came from if reachable.

Prevention

Never call ValidateRequestPath with a value that wasn't obtained from a parsed *http.Request.
Guard request middleware against nil r.URL before any handler runs.
Unit-test the exported validator with both nil and valid URLs to lock the contract.

When it happens

Trigger: ValidateRequestPath(nil) — a gateway or direct caller passing a nil URL because the request failed to parse upstream, or test code exercising the validation boundary without constructing a URL.

Common situations: Middleware that forwards r.URL after a parsing step that can return nil; tests calling the exported validator directly; refactoring that changed the call site from r.URL to a variable that can be nil.

Related errors

AI-assisted analysis of JuliusBrussee/caveman@27d5a3981a (2026-08-15). Data as JSON: /api/errors/fb3c13ffda048dd2. Report an issue: GitHub.