feat(i18n): implement localization using gettext files

- Recipe to extract new translations from the Go code: `make i18n_extract`
- Embedded `MO` files
- Detect language from environment variables
- Some strings were pluralized

Makefile

@@ -21,7 +21,7 @@ lint:
 
 test: install_deps
 	$(info ******************** running tests ********************)
-	go test -v ./...
+	LANGUAGE="en" go test -v ./...
 
 richtest: install_deps
 	$(info ******************** running tests with kyoh86/richgo ********************)
@@ -33,3 +33,7 @@ install_deps:
 
 clean:
 	rm -rf $(BIN)
+
+i18n_extract:
+	$(info ******************** extracting translation files ********************)
+	xgotext -v -in . -out locales

args.go

@@ -16,6 +16,7 @@ package cobra
 
 import (
 	"fmt"
+	"github.com/leonelquinteros/gotext"
 	"strings"
 )
 
@@ -33,15 +34,15 @@ func legacyArgs(cmd *Command, args []string) error {
 
 	// root command with subcommands, do subcommand checking.
 	if !cmd.HasParent() && len(args) > 0 {
-		return fmt.Errorf("unknown command %q for %q%s", args[0], cmd.CommandPath(), cmd.findSuggestions(args[0]))
+		return fmt.Errorf(gotext.Get("LegacyArgsValidationError"), args[0], cmd.CommandPath(), cmd.findSuggestions(args[0]))
 	}
 	return nil
 }
 
 // NoArgs returns an error if any args are included.
 func NoArgs(cmd *Command, args []string) error {
 	if len(args) > 0 {
-		return fmt.Errorf("unknown command %q for %q", args[0], cmd.CommandPath())
+		return fmt.Errorf(gotext.Get("NoArgsValidationError"), args[0], cmd.CommandPath())
 	}
 	return nil
 }
@@ -58,7 +59,7 @@ func OnlyValidArgs(cmd *Command, args []string) error {
 		}
 		for _, v := range args {
 			if !stringInSlice(v, validArgs) {
-				return fmt.Errorf("invalid argument %q for %q%s", v, cmd.CommandPath(), cmd.findSuggestions(args[0]))
+				return fmt.Errorf(gotext.Get("OnlyValidArgsValidationError"), v, cmd.CommandPath(), cmd.findSuggestions(args[0]))
 			}
 		}
 	}
@@ -74,7 +75,7 @@ func ArbitraryArgs(cmd *Command, args []string) error {
 func MinimumNArgs(n int) PositionalArgs {
 	return func(cmd *Command, args []string) error {
 		if len(args) < n {
-			return fmt.Errorf("requires at least %d arg(s), only received %d", n, len(args))
+			return fmt.Errorf(gotext.GetN("MinimumNArgsValidationError", "MinimumNArgsValidationErrorPlural", n), n, len(args))
 		}
 		return nil
 	}
@@ -84,7 +85,7 @@ func MinimumNArgs(n int) PositionalArgs {
 func MaximumNArgs(n int) PositionalArgs {
 	return func(cmd *Command, args []string) error {
 		if len(args) > n {
-			return fmt.Errorf("accepts at most %d arg(s), received %d", n, len(args))
+			return fmt.Errorf(gotext.GetN("MaximumNArgsValidationError", "MaximumNArgsValidationErrorPlural", n), n, len(args))
 		}
 		return nil
 	}
@@ -94,7 +95,7 @@ func MaximumNArgs(n int) PositionalArgs {
 func ExactArgs(n int) PositionalArgs {
 	return func(cmd *Command, args []string) error {
 		if len(args) != n {
-			return fmt.Errorf("accepts %d arg(s), received %d", n, len(args))
+			return fmt.Errorf(gotext.GetN("ExactArgsValidationError", "ExactArgsValidationErrorPlural", n), n, len(args))
 		}
 		return nil
 	}
@@ -104,7 +105,7 @@ func ExactArgs(n int) PositionalArgs {
 func RangeArgs(min int, max int) PositionalArgs {
 	return func(cmd *Command, args []string) error {
 		if len(args) < min || len(args) > max {
-			return fmt.Errorf("accepts between %d and %d arg(s), received %d", min, max, len(args))
+			return fmt.Errorf(gotext.GetN("RangeArgsValidationError", "RangeArgsValidationErrorPlural", max), min, max, len(args))
 		}
 		return nil
 	}

args_test.go

@@ -68,7 +68,7 @@ func minimumNArgsWithLessArgs(err error, t *testing.T) {
 		t.Fatal("Expected an error")
 	}
 	got := err.Error()
-	expected := "requires at least 2 arg(s), only received 1"
+	expected := "requires at least 2 args, only received 1"
 	if got != expected {
 		t.Fatalf("Expected %q, got %q", expected, got)
 	}
@@ -79,7 +79,7 @@ func maximumNArgsWithMoreArgs(err error, t *testing.T) {
 		t.Fatal("Expected an error")
 	}
 	got := err.Error()
-	expected := "accepts at most 2 arg(s), received 3"
+	expected := "accepts at most 2 args, received 3"
 	if got != expected {
 		t.Fatalf("Expected %q, got %q", expected, got)
 	}
@@ -90,7 +90,7 @@ func exactArgsWithInvalidCount(err error, t *testing.T) {
 		t.Fatal("Expected an error")
 	}
 	got := err.Error()
-	expected := "accepts 2 arg(s), received 3"
+	expected := "accepts 2 args, received 3"
 	if got != expected {
 		t.Fatalf("Expected %q, got %q", expected, got)
 	}
@@ -101,7 +101,7 @@ func rangeArgsWithInvalidCount(err error, t *testing.T) {
 		t.Fatal("Expected an error")
 	}
 	got := err.Error()
-	expected := "accepts between 2 and 4 arg(s), received 1"
+	expected := "accepts between 2 and 4 args, received 1"
 	if got != expected {
 		t.Fatalf("Expected %q, got %q", expected, got)
 	}

cobra.go

@@ -19,6 +19,7 @@ package cobra
 
 import (
 	"fmt"
+	"github.com/leonelquinteros/gotext"
 	"io"
 	"os"
 	"reflect"
@@ -230,7 +231,7 @@ func stringInSlice(a string, list []string) bool {
 // CheckErr prints the msg with the prefix 'Error:' and exits with error code 1. If the msg is nil, it does nothing.
 func CheckErr(msg interface{}) {
 	if msg != nil {
-		fmt.Fprintln(os.Stderr, "Error:", msg)
+		fmt.Fprintln(os.Stderr, gotext.Get("Error")+":", msg)
 		os.Exit(1)
 	}
 }

command.go

@@ -21,6 +21,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"github.com/leonelquinteros/gotext"
 	"io"
 	"os"
 	"path/filepath"
@@ -432,7 +433,11 @@ func (c *Command) UsageFunc() (f func(*Command) error) {
 	}
 	return func(c *Command) error {
 		c.mergePersistentFlags()
-		err := tmpl(c.OutOrStderr(), c.UsageTemplate(), c)
+		data := CommandUsageTemplateData{
+			Command: c,
+			I18n:    getCommandGlossary(),
+		}
+		err := tmpl(c.OutOrStderr(), c.UsageTemplate(), data)
 		if err != nil {
 			c.PrintErrln(err)
 		}
@@ -549,35 +554,35 @@ func (c *Command) UsageTemplate() string {
 	if c.HasParent() {
 		return c.parent.UsageTemplate()
 	}
-	return `Usage:{{if .Runnable}}
+	return `{{.I18n.SectionUsage}}:{{if .Runnable}}
   {{.UseLine}}{{end}}{{if .HasAvailableSubCommands}}
   {{.CommandPath}} [command]{{end}}{{if gt (len .Aliases) 0}}
 
-Aliases:
+{{.I18n.SectionAliases}}:
   {{.NameAndAliases}}{{end}}{{if .HasExample}}
 
-Examples:
+{{.I18n.SectionExamples}}:
 {{.Example}}{{end}}{{if .HasAvailableSubCommands}}{{$cmds := .Commands}}{{if eq (len .Groups) 0}}
 
-Available Commands:{{range $cmds}}{{if (or .IsAvailableCommand (eq .Name "help"))}}
+{{.I18n.SectionAvailableCommands}}:{{range $cmds}}{{if (or .IsAvailableCommand (eq .Name "help"))}}
   {{rpad .Name .NamePadding }} {{.Short}}{{end}}{{end}}{{else}}{{range $group := .Groups}}
 
 {{.Title}}{{range $cmds}}{{if (and (eq .GroupID $group.ID) (or .IsAvailableCommand (eq .Name "help")))}}
   {{rpad .Name .NamePadding }} {{.Short}}{{end}}{{end}}{{end}}{{if not .AllChildCommandsHaveGroup}}
 
-Additional Commands:{{range $cmds}}{{if (and (eq .GroupID "") (or .IsAvailableCommand (eq .Name "help")))}}
+{{.I18n.SectionAdditionalCommands}}:{{range $cmds}}{{if (and (eq .GroupID "") (or .IsAvailableCommand (eq .Name "help")))}}
   {{rpad .Name .NamePadding }} {{.Short}}{{end}}{{end}}{{end}}{{end}}{{end}}{{if .HasAvailableLocalFlags}}
 
-Flags:
+{{.I18n.SectionFlags}}:
 {{.LocalFlags.FlagUsages | trimTrailingWhitespaces}}{{end}}{{if .HasAvailableInheritedFlags}}
 
-Global Flags:
+{{.I18n.SectionGlobalFlags}}:
 {{.InheritedFlags.FlagUsages | trimTrailingWhitespaces}}{{end}}{{if .HasHelpSubCommands}}
 
-Additional help topics:{{range .Commands}}{{if .IsAdditionalHelpTopicCommand}}
+{{.I18n.SectionAdditionalHelpTopics}}:{{range .Commands}}{{if .IsAdditionalHelpTopicCommand}}
   {{rpad .CommandPath .CommandPathPadding}} {{.Short}}{{end}}{{end}}{{end}}{{if .HasAvailableSubCommands}}
 
-Use "{{.CommandPath}} [command] --help" for more information about a command.{{end}}
+{{.I18n.Use}} "{{.CommandPath}} [command] --help" {{.I18n.ForInfoAboutCommand}}.{{end}}
 `
 }
 
@@ -756,7 +761,7 @@ func (c *Command) findSuggestions(arg string) string {
 	}
 	var sb strings.Builder
 	if suggestions := c.SuggestionsFor(arg); len(suggestions) > 0 {
-		sb.WriteString("\n\nDid you mean this?\n")
+		sb.WriteString("\n\n" + gotext.Get("DidYouMeanThis") + "\n")
 		for _, s := range suggestions {
 			_, _ = fmt.Fprintf(&sb, "\t%v\n", s)
 		}
@@ -877,7 +882,7 @@ func (c *Command) execute(a []string) (err error) {
 	}
 
 	if len(c.Deprecated) > 0 {
-		c.Printf("Command %q is deprecated, %s\n", c.Name(), c.Deprecated)
+		c.Printf(gotext.Get("CommandDeprecatedWarning")+"\n", c.Name(), c.Deprecated)
 	}
 
 	// initialize help and version flag at the last point possible to allow for user
@@ -1096,7 +1101,7 @@ func (c *Command) ExecuteC() (cmd *Command, err error) {
 		}
 		if !c.SilenceErrors {
 			c.PrintErrln(c.ErrPrefix(), err.Error())
-			c.PrintErrf("Run '%v --help' for usage.\n", c.CommandPath())
+			c.PrintErrf(gotext.Get("RunHelpTip")+"\n", c.CommandPath())
 		}
 		return c, err
 	}
@@ -1162,7 +1167,7 @@ func (c *Command) ValidateRequiredFlags() error {
 	})
 
 	if len(missingFlagNames) > 0 {
-		return fmt.Errorf(`required flag(s) "%s" not set`, strings.Join(missingFlagNames, `", "`))
+		return fmt.Errorf(gotext.GetN("FlagNotSetError", "FlagNotSetErrorPlural", len(missingFlagNames)), strings.Join(missingFlagNames, `", "`))
 	}
 	return nil
 }
@@ -1186,9 +1191,9 @@ func (c *Command) checkCommandGroups() {
 func (c *Command) InitDefaultHelpFlag() {
 	c.mergePersistentFlags()
 	if c.Flags().Lookup("help") == nil {
-		usage := "help for "
+		usage := gotext.Get("HelpFor") + " "
 		if c.Name() == "" {
-			usage += "this command"
+			usage += gotext.Get("ThisCommand")
 		} else {
 			usage += c.Name()
 		}
@@ -1208,9 +1213,9 @@ func (c *Command) InitDefaultVersionFlag() {
 
 	c.mergePersistentFlags()
 	if c.Flags().Lookup("version") == nil {
-		usage := "version for "
+		usage := gotext.Get("VersionFor") + " "
 		if c.Name() == "" {
-			usage += "this command"
+			usage += gotext.Get("ThisCommand")
 		} else {
 			usage += c.Name()
 		}
@@ -1233,10 +1238,9 @@ func (c *Command) InitDefaultHelpCmd() {
 
 	if c.helpCommand == nil {
 		c.helpCommand = &Command{
-			Use:   "help [command]",
-			Short: "Help about any command",
-			Long: `Help provides help for any command in the application.
-Simply type ` + c.Name() + ` help [path to command] for full details.`,
+			Use:   fmt.Sprintf("help [%s]", gotext.Get("command")),
+			Short: gotext.Get("CommandHelpShort"),
+			Long:  fmt.Sprintf(gotext.Get("CommandHelpLong"), c.Name()+fmt.Sprintf(" help [%s]", gotext.Get("command"))),
 			ValidArgsFunction: func(c *Command, args []string, toComplete string) ([]string, ShellCompDirective) {
 				var completions []string
 				cmd, _, e := c.Root().Find(args)
@@ -1259,7 +1263,7 @@ Simply type ` + c.Name() + ` help [path to command] for full details.`,
 			Run: func(c *Command, args []string) {
 				cmd, _, e := c.Root().Find(args)
 				if cmd == nil || e != nil {
-					c.Printf("Unknown help topic %#q\n", args)
+					c.Printf(gotext.Get("CommandHelpUnknownTopicError")+"\n", args)
 					CheckErr(c.Root().Usage())
 				} else {
 					cmd.InitDefaultHelpFlag()    // make possible 'help' flag to be shown

command_test.go

@@ -815,6 +815,21 @@ func TestPersistentFlagsOnChild(t *testing.T) {
 	}
 }
 
+func TestRequiredFlag(t *testing.T) {
+	c := &Command{Use: "c", Run: emptyRun}
+	c.Flags().String("foo1", "", "")
+	assertNoErr(t, c.MarkFlagRequired("foo1"))
+
+	expected := fmt.Sprintf("required flag %q is not set", "foo1")
+
+	_, err := executeCommand(c)
+	got := err.Error()
+
+	if got != expected {
+		t.Errorf("Expected error: %q, got: %q", expected, got)
+	}
+}
+
 func TestRequiredFlags(t *testing.T) {
 	c := &Command{Use: "c", Run: emptyRun}
 	c.Flags().String("foo1", "", "")
@@ -823,7 +838,7 @@ func TestRequiredFlags(t *testing.T) {
 	assertNoErr(t, c.MarkFlagRequired("foo2"))
 	c.Flags().String("bar", "", "")
 
-	expected := fmt.Sprintf("required flag(s) %q, %q not set", "foo1", "foo2")
+	expected := fmt.Sprintf("required flags %q, %q are not set", "foo1", "foo2")
 
 	_, err := executeCommand(c)
 	got := err.Error()
@@ -850,7 +865,7 @@ func TestPersistentRequiredFlags(t *testing.T) {
 
 	parent.AddCommand(child)
 
-	expected := fmt.Sprintf("required flag(s) %q, %q, %q, %q not set", "bar1", "bar2", "foo1", "foo2")
+	expected := fmt.Sprintf("required flags %q, %q, %q, %q are not set", "bar1", "bar2", "foo1", "foo2")
 
 	_, err := executeCommand(parent, "child")
 	if err.Error() != expected {

flag_groups.go

@@ -16,6 +16,7 @@ package cobra
 
 import (
 	"fmt"
+	"github.com/leonelquinteros/gotext"
 	"sort"
 	"strings"
 
@@ -201,7 +202,7 @@ func validateExclusiveFlagGroups(data map[string]map[string]bool) error {
 
 		// Sort values, so they can be tested/scripted against consistently.
 		sort.Strings(set)
-		return fmt.Errorf("if any flags in the group [%v] are set none of the others can be; %v were all set", flagList, set)
+		return fmt.Errorf(gotext.Get("ExclusiveFlagsValidationError"), flagList, set)
 	}
 	return nil
 }

go.mod

@@ -1,10 +1,12 @@
 module github.com/spf13/cobra
 
-go 1.15
+go 1.16
 
 require (
 	github.com/cpuguy83/go-md2man/v2 v2.0.3
 	github.com/inconshreveable/mousetrap v1.1.0
+	github.com/leonelquinteros/gotext v1.5.3-0.20231003122255-12a99145a351
 	github.com/spf13/pflag v1.0.5
+	golang.org/x/text v0.4.0
 	gopkg.in/yaml.v3 v3.0.1
 )

go.sum

@@ -2,10 +2,37 @@ github.com/cpuguy83/go-md2man/v2 v2.0.3 h1:qMCsGGgs+MAzDFyp9LpAe1Lqy/fY/qCovCm0q
 github.com/cpuguy83/go-md2man/v2 v2.0.3/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
+github.com/leonelquinteros/gotext v1.5.3-0.20231003122255-12a99145a351 h1:Rk+RkO4xEZMkEok69CbeA6cgXKyVCsgF3qGGGR46pd8=
+github.com/leonelquinteros/gotext v1.5.3-0.20231003122255-12a99145a351/go.mod h1:qQRISjoonXYFdRGrTG1LARQ38Gpibad0IPeB4hpvyyM=
 github.com/russross/blackfriday/v2 v2.1.0 h1:JIOH55/0cWyOuilr9/qlrm0BSXldqnqwMsf35Ld67mk=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
 github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
+github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
+golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
+golang.org/x/text v0.4.0 h1:BrVqGRd7+k1DiOgtnFvAkoQEWQvBc25ouMJM6429SFg=
+golang.org/x/text v0.4.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=