golang/go · error

invalid proxy URL missing scheme: %s

Error message

invalid proxy URL missing scheme: %s

What it means

newProxyRepo rejects a proxy URL whose parsed scheme is empty. The go command needs to know which transport to use (http, https, or file), so a bare hostname or path is not acceptable.

Source

Thrown at src/cmd/go/internal/modfetch/proxy.go:211

	listLatestErr  error
}

func newProxyRepo(baseURL, path string) (Repo, error) {
	// Parse the base proxy URL.
	base, err := url.Parse(baseURL)
	if err != nil {
		return nil, err
	}
	redactedBase := base.Redacted()
	switch base.Scheme {
	case "http", "https":
		// ok
	case "file":
		if *base != (url.URL{Scheme: base.Scheme, Path: base.Path, RawPath: base.RawPath}) {
			return nil, fmt.Errorf("invalid file:// proxy URL with non-path elements: %s", redactedBase)
		}
	case "":
		return nil, fmt.Errorf("invalid proxy URL missing scheme: %s", redactedBase)
	default:
		return nil, fmt.Errorf("invalid proxy URL scheme (must be https, http, file): %s", redactedBase)
	}

	// Append the module path to the URL.
	url := base
	enc, err := module.EscapePath(path)
	if err != nil {
		return nil, err
	}
	url.Path = strings.TrimSuffix(base.Path, "/") + "/" + enc
	url.RawPath = strings.TrimSuffix(base.RawPath, "/") + "/" + pathEscape(enc)

	return &proxyRepo{url, path, redactedBase, sync.Once{}, nil, nil}, nil
}

func (p *proxyRepo) ModulePath() string {
	return p.path

View on GitHub (pinned to b6b368adc5)

Solutions

1. Prefix the entry with https:// (preferred) or http://.
2. For a local directory cache use file:///path.
3. Validate every comma-separated GOPROXY entry has an explicit scheme before running go.

Example fix

// before
//   GOPROXY=proxy.corp.com,direct
// after
//   GOPROXY=https://proxy.corp.com,direct

func validateProxyEntry(s string) error {
    if s == "direct" || s == "off" { return nil }
    u, err := url.Parse(strings.TrimSpace(s))
    if err != nil { return err }
    if u.Scheme == "" { return fmt.Errorf("proxy URL %q missing scheme", s) }
    return nil
}

func hasProxyScheme(s string) bool {
    u, err := url.Parse(strings.TrimSpace(s))
    return err == nil && (u.Scheme == "http" || u.Scheme == "https" || u.Scheme == "file")
}

When it happens

Trigger: GOPROXY entry like `proxy.local` or `/cache` with no scheme. url.Parse succeeds but base.Scheme == "".

Common situations: Typing a hostname without https://; templated GOPROXY that drops the scheme; migrating from a config format that omitted schemes.

Related errors

• invalid proxy URL scheme (must be https, http, file): %s
• invalid file:// proxy URL with non-path elements: %s
• git remote (%s) lookup disabled
• git remote (%s) must not be local directory
• GOPROXY list is not the empty string, but contains no entrie

AI-assisted analysis of golang/go@b6b368adc5 (2026-08-12). Data as JSON: /api/errors/f41952bcd54d4924. Report an issue: GitHub.