// IPv6 with invalid embedded IPv4.
		"::ffff:192.168.140.bad",
		// IPv6 with multiple ellipsis ::.
		"fe80::1::1",
		// IPv6 with invalid non hex/colon character.
		"fe80:1?:1",
		// IPv6 with truncated bytes after single colon.
		"fe80:",
		// IPv6 with 5 zeros in last group
		"0:0:0:0:0:ffff:0:00000",
		// IPv6 with 5 zeros in one group and embedded IPv4
		"0:0:0:0:00000:ffff:127.1.2.3",
	}

	}
	return v.isSecureScheme(u.Scheme)
}

func (v *Cmd) isSecureScheme(scheme string) bool {
	switch v.Cmd {
	case "git":
		// GIT_ALLOW_PROTOCOL is an environment variable defined by Git. It is a
		// colon-separated list of schemes that are allowed to be used with git
		// fetch/clone. Any scheme not mentioned will be considered insecure.
		if allow := os.Getenv("GIT_ALLOW_PROTOCOL"); allow != "" {

	if len(clauses) == 0 {
		return fmt.Errorf("no clauses")
	}
	for _, clause := range clauses {
		elems := strings.Split(clause, ":")
		if len(elems) < 2 {
			return fmt.Errorf("clause %q: expected colon", clause)
		}
		if len(elems) != 2 {
			return fmt.Errorf("clause %q has %d elements, wanted 2", clause,
				len(elems))
		}
		adj, ok := adjStringToVal(elems[0])
		if !ok {

			return m, err
		}
		return m, errors.New("malformed initial line: " + line)
	}

	for {
		kv, err := r.ReadContinuedLine()
		if kv == "" {
			return m, err
		}

		// Key ends at first colon.
		k, v, ok := strings.Cut(kv, ":")
		if !ok {
			return m, errors.New("malformed header line: " + kv)
		}
		key := textproto.CanonicalMIMEHeaderKey(k)

		// Permit empty key, because that is what we did in the past.

// (which can change based on its registration).
type CondUsage struct {
	Summary string // a single-line summary of when the condition is true

	// If Prefix is true, the condition is a prefix and requires a
	// colon-separated suffix (like "[GOOS:linux]" for the "GOOS" condition).
	// The suffix may be the empty string (like "[prefix:]").
	Prefix bool
}

// Execute reads and executes script, writing the output to log.
//

	// under the management of go test.
	if runtime.GOOS == "windows" && len(path) >= 2 {
		letter, colon := path[0], path[1]
		if ('a' <= letter && letter <= 'z' || 'A' <= letter && letter <= 'Z') && colon == ':' {
			// If path starts with a drive letter we're stuck with it regardless.
			return path
		}
	}
	if os.IsPathSeparator(path[0]) {
		return path
	}

		case '\'':
			insertSemi = true
			tok = token.CHAR
			lit = s.scanRune()
		case '`':
			insertSemi = true
			tok = token.STRING
			lit = s.scanRawString()
		case ':':
			tok = s.switch2(token.COLON, token.DEFINE)
		case '.':
			// fractions starting with a '.' are handled by outer switch
			tok = token.PERIOD
			if s.ch == '.' && s.peek() == '.' {
				s.next()
				s.next() // consume last '.'

		}

		// #cgo (nocallback|noescape) <function name>
		if fields := strings.Fields(line); len(fields) == 3 && (fields[1] == "nocallback" || fields[1] == "noescape") {
			continue
		}

		// Split at colon.
		line, argstr, ok := strings.Cut(strings.TrimSpace(line[4:]), ":")
		if !ok {
			return fmt.Errorf("%s: invalid #cgo line: %s", filename, orig)
		}

		// Parse GOOS/GOARCH stuff.
		f := strings.Fields(line)

		{"middle dash", "f-oo.bar.com", ""},
		{"trailing dot", "foo.bar.com.", ""},
		{"prefix dash", "-foo.bar.com", "invalid"},
		{"forward slash separated", "foo/bar/com", "invalid"},
		{"colon separated", "foo:bar:com", "invalid"},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			err := ValidateTrustDomain(tt.in)
			if err == nil && tt.err != "" {

			"Feedback-Type": []string{"abuse"},
			"User-Agent":    []string{"SomeGenerator/1.0"},
			"Version":       []string{"1"},
		},
		body: "",
	},
	{
		// RFC 5322 permits any printable ASCII character,
		// except colon, in a header key. Issue #58862.
		in: `From: ******@****.***
Custom/Header: v

Body
`,
		header: Header{
			"From":          []string{"******@****.***"},
			"Custom/Header": []string{"v"},
		},