golang/go · error

invalid format: missing empty line after URLs

Error message

invalid format: missing empty line after URLs

What it means

Raised inside parseUserAuth while collecting URL lines. The loop cuts input on `\n`; if strings.Cut returns ok=false (no more newlines) before an empty line terminates the URL list, the URL section was never closed and parsing aborts with this message.

Solutions

1. Terminate every URL list with a blank line.
2. End each credential block with `\n\n` (URLs, blank, headers, blank).
3. Validate output locally before relying on it: pipe the command's stdout through a parser in a test.

Example fix

// malformed: no blank line after URL
https://example.com
Authorization: Bearer x
// fixed
https://example.com

Authorization: Bearer x

// Ensure the URL list is blank-line-terminated.
func endsURLBlock(s string) bool {
    return strings.Contains(s, "\n\n")
}

When it happens

Trigger: The GOAUTH command output contains URL lines but no terminating blank line, or the input ends mid-URL-list without a final newline.

Common situations: Output written without a trailing `\n\n`; the command emits URLs only and forgets the blank separator; a single block missing its closing empty line.

Related errors

• cannot parse output of GOAUTH command
• invalid format: missing empty line after headers
• could not parse URL
• invalid format: invalid header line
• 'git credential fill' failed for url=

AI-assisted analysis of golang/go@b6b368adc5 (2026-08-12). Data as JSON: /api/errors/c50479d07e2e3765. Report an issue: GitHub.

Appendix: source

Thrown at src/cmd/go/internal/auth/userauth.go:63

	return credentials, nil
}

// parseUserAuth parses the output from a GOAUTH command and
// returns a mapping of prefix → http.Header without the leading "https://"
// or an error if the data does not follow the expected format.
// Returns a nil error and an empty map if the data is empty.
// See the expected format in 'go help goauth'.
func parseUserAuth(data string) (map[string]http.Header, error) {
	credentials := make(map[string]http.Header)
	for data != "" {
		var line string
		var ok bool
		var urls []string
		// Parse URLS first.
		for {
			line, data, ok = strings.Cut(data, "\n")
			if !ok {
				return nil, fmt.Errorf("invalid format: missing empty line after URLs")
			}
			if line == "" {
				break
			}
			u, err := url.ParseRequestURI(line)
			if err != nil {
				return nil, fmt.Errorf("could not parse URL %s: %v", line, err)
			}
			urls = append(urls, u.String())
		}
		// Parse Headers second.
		header := make(http.Header)
		for {
			line, data, ok = strings.Cut(data, "\n")
			if !ok {
				return nil, fmt.Errorf("invalid format: missing empty line after headers")
			}
			if line == "" {

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