}

	if len(chains) > 0 {
		err = nil
	}
	if len(chains) == 0 && err == nil {
		err = UnknownAuthorityError{c, hintErr, hintCert}
	}

	return
}

func validHostnamePattern(host string) bool { return validHostname(host, true) }
func validHostnameInput(host string) bool   { return validHostname(host, false) }

// validHostname reports whether host is a valid hostname that can be matched or

		{host: "exa_mple.com", validInput: true, validPattern: true},
		{host: "foo,bar"},
		{host: "project-dev:us-central1:main"},
	}
	for _, tt := range tests {
		if got := validHostnamePattern(tt.host); got != tt.validPattern {
			t.Errorf("validHostnamePattern(%q) = %v, want %v", tt.host, got, tt.validPattern)
		}
		if got := validHostnameInput(tt.host); got != tt.validInput {