gh auth login: add git protocol flag (#5158)

Co-authored-by: Mislav Marohnić <mislav@github.com>

pkg/cmd/auth/login/login.go

@@ -27,10 +27,11 @@ type LoginOptions struct {
 
 	Interactive bool
 
-	Hostname string
-	Scopes   []string
-	Token    string
-	Web      bool
+	Hostname    string
+	Scopes      []string
+	Token       string
+	Web         bool
+	GitProtocol string
 }
 
 func NewCmdLogin(f *cmdutil.Factory, runF func(*LoginOptions) error) *cobra.Command {
@@ -54,8 +55,8 @@ func NewCmdLogin(f *cmdutil.Factory, runF func(*LoginOptions) error) *cobra.Comm
 			Alternatively, pass in a token on standard input by using %[1]s--with-token%[1]s.
 			The minimum required scopes for the token are: "repo", "read:org".
 
-			The --scopes flag accepts a comma separated list of scopes you want your gh credentials to have. If
-			absent, this command ensures that gh has access to a minimum set of scopes.
+			The %[1]s--scopes%[1]s flag accepts a comma separated list of scopes you want your gh credentials to
+			have. If absent, this command ensures that gh has access to a minimum set of scopes.
 		`, "`"),
 		Example: heredoc.Doc(`
 			# start interactive setup
@@ -64,7 +65,7 @@ func NewCmdLogin(f *cmdutil.Factory, runF func(*LoginOptions) error) *cobra.Comm
 			# authenticate against github.com by reading the token from a file
 			$ gh auth login --with-token < mytoken.txt
 
-			# authenticate with a specific GitHub Enterprise Server instance
+			# authenticate with a specific GitHub instance
 			$ gh auth login --hostname enterprise.internal
 		`),
 		RunE: func(cmd *cobra.Command, args []string) error {
@@ -111,6 +112,7 @@ func NewCmdLogin(f *cmdutil.Factory, runF func(*LoginOptions) error) *cobra.Comm
 	cmd.Flags().StringSliceVarP(&opts.Scopes, "scopes", "s", nil, "Additional authentication scopes for gh to have")
 	cmd.Flags().BoolVar(&tokenStdin, "with-token", false, "Read token from standard input")
 	cmd.Flags().BoolVarP(&opts.Web, "web", "w", false, "Open a browser to authenticate")
+	cmdutil.StringEnumFlag(cmd, &opts.GitProtocol, "git-protocol", "p", "", []string{"ssh", "https"}, "The protocol to use for git operations")
 
 	return cmd
 }
@@ -186,6 +188,7 @@ func loginRun(opts *LoginOptions) error {
 		Web:         opts.Web,
 		Scopes:      opts.Scopes,
 		Executable:  opts.MainExecutable,
+		GitProtocol: opts.GitProtocol,
 	})
 }
 

pkg/cmd/auth/shared/login_flow.go

@@ -29,6 +29,7 @@ type LoginOptions struct {
 	Web         bool
 	Scopes      []string
 	Executable  string
+	GitProtocol string
 
 	sshContext sshContext
 }
@@ -39,8 +40,8 @@ func Login(opts *LoginOptions) error {
 	httpClient := opts.HTTPClient
 	cs := opts.IO.ColorScheme()
 
-	var gitProtocol string
-	if opts.Interactive {
+	gitProtocol := strings.ToLower(opts.GitProtocol)
+	if opts.Interactive && gitProtocol == "" {
 		var proto string
 		err := prompt.SurveyAskOne(&survey.Select{
 			Message: "What is your preferred protocol for Git operations?",

pkg/cmdutil/flags.go

@@ -1,7 +1,9 @@
 package cmdutil
 
 import (
+	"fmt"
 	"strconv"
+	"strings"
 
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
@@ -21,6 +23,20 @@ func NilBoolFlag(cmd *cobra.Command, p **bool, name string, shorthand string, us
 	return f
 }
 
+// StringEnumFlag defines a new string flag that only allows values listed in options.
+func StringEnumFlag(cmd *cobra.Command, p *string, name, shorthand, defaultValue string, options []string, usage string) *pflag.Flag {
+	val := &enumValue{string: p, options: options}
+	f := cmd.Flags().VarPF(val, name, shorthand, fmt.Sprintf("%s: %s", usage, formatValuesForUsageDocs(options)))
+	_ = cmd.RegisterFlagCompletionFunc(name, func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+		return options, cobra.ShellCompDirectiveNoFileComp
+	})
+	return f
+}
+
+func formatValuesForUsageDocs(values []string) string {
+	return fmt.Sprintf("{%s}", strings.Join(values, "|"))
+}
+
 type stringValue struct {
 	string **string
 }
@@ -75,3 +91,31 @@ func (b *boolValue) Type() string {
 func (b *boolValue) IsBoolFlag() bool {
 	return true
 }
+
+type enumValue struct {
+	string  *string
+	options []string
+}
+
+func (e *enumValue) Set(value string) error {
+	found := false
+	for _, opt := range e.options {
+		if strings.EqualFold(opt, value) {
+			found = true
+			break
+		}
+	}
+	if !found {
+		return fmt.Errorf("valid values are %s", formatValuesForUsageDocs(e.options))
+	}
+	*e.string = value
+	return nil
+}
+
+func (e *enumValue) String() string {
+	return *e.string
+}
+
+func (e *enumValue) Type() string {
+	return "string"
+}