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.

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 == "" {

View on GitHub (pinned to b6b368adc5)

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 %s: %v
• invalid format: missing empty line after headers
• could not parse URL %s: %v
• invalid format: invalid header line
• 'git credential fill' failed for url=%s, could not parse url

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