Merge branch 'main' into disableMarkPersistentRequiredFlagForHelpAndComp

.github/labeler.yml

@@ -1,17 +1,24 @@
 # changes to documentation generation
-"area/docs-generation": doc/**/*
+"area/docs-generation": 
+- changed-files:
+  - any-glob-to-any-file: 'doc/**'
 
 # changes to the core cobra command
 "area/cobra-command":
-- any: ['./cobra.go', './cobra_test.go', './*command*.go']
+- changed-files:
+  - any-glob-to-any-file: ['./cobra.go', './cobra_test.go', './*command*.go']
 
 # changes made to command flags/args
-"area/flags": ./args*.go
+"area/flags":
+- changed-files:
+  - any-glob-to-any-file: './args*.go'
 
 # changes to Github workflows
-"area/github": .github/**/*
+"area/github":
+- changed-files:
+  - any-glob-to-any-file: '.github/**'
 
 # changes to shell completions
 "area/shell-completion":
-  - ./*completions*
-
+- changed-files:
+  - any-glob-to-any-file: './*completions*'

.github/workflows/labeler.yml

@@ -12,7 +12,7 @@ jobs:
       pull-requests: write  # for actions/labeler to add labels to PRs
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/labeler@v4
+    - uses: actions/labeler@v5
       with:
         repo-token: "${{ github.token }}"
 

.github/workflows/test.yml

@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
 
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - run: >-
           docker run
@@ -39,17 +39,15 @@ jobs:
     runs-on: ubuntu-latest
     steps:
 
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
-      - uses: actions/setup-go@v3
+      - uses: actions/setup-go@v5
         with:
-          go-version: '^1.20'
+          go-version: '^1.22'
           check-latest: true
           cache: true
 
-      - uses: actions/checkout@v3
-
-      - uses: golangci/golangci-lint-action@v3.6.0
+      - uses: golangci/golangci-lint-action@v4.0.0
         with:
           version: latest
           args: --verbose
@@ -67,13 +65,15 @@ jobs:
         - 18
         - 19
         - 20
+        - 21
+        - 22
     name: '${{ matrix.platform }} | 1.${{ matrix.go }}.x'
     runs-on: ${{ matrix.platform }}-latest
     steps:
 
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
 
-    - uses: actions/setup-go@v3
+    - uses: actions/setup-go@v5
       with:
         go-version: 1.${{ matrix.go }}.x
         cache: true
@@ -107,9 +107,9 @@ jobs:
           unzip
           mingw-w64-x86_64-go
 
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
 
-    - uses: actions/cache@v3
+    - uses: actions/cache@v4
       with:
         path: ~/go/pkg/mod
         key: ${{ runner.os }}-${{ matrix.go }}-${{ hashFiles('**/go.sum') }}

.golangci.yml

@@ -19,7 +19,7 @@ linters:
   disable-all: true
   enable:
     #- bodyclose
-    - deadcode
+    # - deadcode ! deprecated since v1.49.0; replaced by 'unused'
     #- depguard
     #- dogsled
     #- dupl
@@ -29,20 +29,17 @@ linters:
     - gas
     #- gochecknoinits
     - goconst
-    #- gocritic
+    - gocritic
     #- gocyclo
     #- gofmt
     - goimports
-    - golint
     #- gomnd
     #- goprintffuncname
     #- gosec
-    #- gosimple
+    - gosimple
     - govet
     - ineffassign
-    - interfacer
     #- lll
-    - maligned
     - megacheck
     #- misspell
     #- nakedret
@@ -51,12 +48,12 @@ linters:
     #- rowserrcheck
     #- scopelint
     #- staticcheck
-    - structcheck
-    #- stylecheck
+    #- structcheck ! deprecated since v1.49.0; replaced by 'unused'
+    - stylecheck
     #- typecheck
     - unconvert
     #- unparam
-    #- unused
-    - varcheck
+    - unused
+    # - varcheck ! deprecated since v1.49.0; replaced by 'unused'
     #- whitespace
   fast: false

active_help.go

@@ -17,15 +17,14 @@ package cobra
 import (
 	"fmt"
 	"os"
-	"strings"
 )
 
 const (
 	activeHelpMarker = "_activeHelp_ "
 	// The below values should not be changed: programs will be using them explicitly
 	// in their user documentation, and users will be using them explicitly.
-	activeHelpEnvVarSuffix  = "_ACTIVE_HELP"
-	activeHelpGlobalEnvVar  = "COBRA_ACTIVE_HELP"
+	activeHelpEnvVarSuffix  = "ACTIVE_HELP"
+	activeHelpGlobalEnvVar  = configEnvVarGlobalPrefix + "_" + activeHelpEnvVarSuffix
 	activeHelpGlobalDisable = "0"
 )
 
@@ -42,7 +41,7 @@ func AppendActiveHelp(compArray []string, activeHelpStr string) []string {
 
 // GetActiveHelpConfig returns the value of the ActiveHelp environment variable
 // <PROGRAM>_ACTIVE_HELP where <PROGRAM> is the name of the root command in upper
-// case, with all - replaced by _.
+// case, with all non-ASCII-alphanumeric characters replaced by `_`.
 // It will always return "0" if the global environment variable COBRA_ACTIVE_HELP
 // is set to "0".
 func GetActiveHelpConfig(cmd *Command) string {
@@ -55,9 +54,7 @@ func GetActiveHelpConfig(cmd *Command) string {
 
 // activeHelpEnvVar returns the name of the program-specific ActiveHelp environment
 // variable.  It has the format <PROGRAM>_ACTIVE_HELP where <PROGRAM> is the name of the
-// root command in upper case, with all - replaced by _.
+// root command in upper case, with all non-ASCII-alphanumeric characters replaced by `_`.
 func activeHelpEnvVar(name string) string {
-	// This format should not be changed: users will be using it explicitly.
-	activeHelpEnvVar := strings.ToUpper(fmt.Sprintf("%s%s", name, activeHelpEnvVarSuffix))
-	return strings.ReplaceAll(activeHelpEnvVar, "-", "_")
+	return configEnvVar(name, activeHelpEnvVarSuffix)
 }

args.go

@@ -52,9 +52,9 @@ func OnlyValidArgs(cmd *Command, args []string) error {
 	if len(cmd.ValidArgs) > 0 {
 		// Remove any description that may be included in ValidArgs.
 		// A description is following a tab character.
-		var validArgs []string
+		validArgs := make([]string, 0, len(cmd.ValidArgs))
 		for _, v := range cmd.ValidArgs {
-			validArgs = append(validArgs, strings.Split(v, "\t")[0])
+			validArgs = append(validArgs, strings.SplitN(v, "\t", 2)[0])
 		}
 		for _, v := range args {
 			if !stringInSlice(v, validArgs) {

bash_completions.go

@@ -597,9 +597,7 @@ func writeRequiredFlag(buf io.StringWriter, cmd *Command) {
 		if nonCompletableFlag(flag) {
 			return
 		}
-		for key := range flag.Annotations {
-			switch key {
-			case BashCompOneRequiredFlag:
+		if _, ok := flag.Annotations[BashCompOneRequiredFlag]; ok {
 			format := "    must_have_one_flag+=(\"--%s"
 			if flag.Value.Type() != "bool" {
 				format += "="
@@ -611,7 +609,6 @@ func writeRequiredFlag(buf io.StringWriter, cmd *Command) {
 				WriteStringAndCheck(buf, fmt.Sprintf("    must_have_one_flag+=(\"-%s"+cbn, flag.Shorthand))
 			}
 		}
-		}
 	})
 }
 
@@ -621,7 +618,7 @@ func writeRequiredNouns(buf io.StringWriter, cmd *Command) {
 	for _, value := range cmd.ValidArgs {
 		// Remove any description that may be included following a tab character.
 		// Descriptions are not supported by bash completion.
-		value = strings.Split(value, "\t")[0]
+		value = strings.SplitN(value, "\t", 2)[0]
 		WriteStringAndCheck(buf, fmt.Sprintf("    must_have_one_noun+=(%q)\n", value))
 	}
 	if cmd.ValidArgsFunction != nil {

cobra.go

@@ -46,6 +46,7 @@ const (
 	defaultPrefixMatching   = false
 	defaultCommandSorting   = true
 	defaultCaseInsensitive  = false
+	defaultTraverseRunHooks = false
 )
 
 // EnablePrefixMatching allows setting automatic prefix matching. Automatic prefix matching can be a dangerous thing
@@ -60,6 +61,10 @@ var EnableCommandSorting = defaultCommandSorting
 // EnableCaseInsensitive allows case-insensitive commands names. (case sensitive by default)
 var EnableCaseInsensitive = defaultCaseInsensitive
 
+// EnableTraverseRunHooks executes persistent pre-run and post-run hooks from all parents.
+// By default this is disabled, which means only the first run hook to be found is executed.
+var EnableTraverseRunHooks = defaultTraverseRunHooks
+
 // MousetrapHelpText enables an information splash screen on Windows
 // if the CLI is started from explorer.exe.
 // To disable the mousetrap, just set this variable to blank string ("").
@@ -188,8 +193,6 @@ func ld(s, t string, ignoreCase bool) int {
 	d := make([][]int, len(s)+1)
 	for i := range d {
 		d[i] = make([]int, len(t)+1)
-	}
-	for i := range d {
 		d[i][0] = i
 	}
 	for j := range d[0] {

cobra_test.go

@@ -40,3 +40,185 @@ func TestAddTemplateFunctions(t *testing.T) {
 		t.Errorf("Expected UsageString: %v\nGot: %v", expected, got)
 	}
 }
+
+func TestLevenshteinDistance(t *testing.T) {
+	tests := []struct {
+		name       string
+		s          string
+		t          string
+		ignoreCase bool
+		expected   int
+	}{
+		{
+			name:       "Equal strings (case-sensitive)",
+			s:          "hello",
+			t:          "hello",
+			ignoreCase: false,
+			expected:   0,
+		},
+		{
+			name:       "Equal strings (case-insensitive)",
+			s:          "Hello",
+			t:          "hello",
+			ignoreCase: true,
+			expected:   0,
+		},
+		{
+			name:       "Different strings (case-sensitive)",
+			s:          "kitten",
+			t:          "sitting",
+			ignoreCase: false,
+			expected:   3,
+		},
+		{
+			name:       "Different strings (case-insensitive)",
+			s:          "Kitten",
+			t:          "Sitting",
+			ignoreCase: true,
+			expected:   3,
+		},
+		{
+			name:       "Empty strings",
+			s:          "",
+			t:          "",
+			ignoreCase: false,
+			expected:   0,
+		},
+		{
+			name:       "One empty string",
+			s:          "abc",
+			t:          "",
+			ignoreCase: false,
+			expected:   3,
+		},
+		{
+			name:       "Both empty strings",
+			s:          "",
+			t:          "",
+			ignoreCase: true,
+			expected:   0,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Act
+			got := ld(tt.s, tt.t, tt.ignoreCase)
+
+			// Assert
+			if got != tt.expected {
+				t.Errorf("Expected ld: %v\nGot: %v", tt.expected, got)
+			}
+		})
+	}
+}
+
+func TestStringInSlice(t *testing.T) {
+	tests := []struct {
+		name     string
+		a        string
+		list     []string
+		expected bool
+	}{
+		{
+			name:     "String in slice (case-sensitive)",
+			a:        "apple",
+			list:     []string{"orange", "banana", "apple", "grape"},
+			expected: true,
+		},
+		{
+			name:     "String not in slice (case-sensitive)",
+			a:        "pear",
+			list:     []string{"orange", "banana", "apple", "grape"},
+			expected: false,
+		},
+		{
+			name:     "String in slice (case-insensitive)",
+			a:        "APPLE",
+			list:     []string{"orange", "banana", "apple", "grape"},
+			expected: false,
+		},
+		{
+			name:     "Empty slice",
+			a:        "apple",
+			list:     []string{},
+			expected: false,
+		},
+		{
+			name:     "Empty string",
+			a:        "",
+			list:     []string{"orange", "banana", "apple", "grape"},
+			expected: false,
+		},
+		{
+			name:     "Empty strings match",
+			a:        "",
+			list:     []string{"orange", ""},
+			expected: true,
+		},
+		{
+			name:     "Empty string in empty slice",
+			a:        "",
+			list:     []string{},
+			expected: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Act
+			got := stringInSlice(tt.a, tt.list)
+
+			// Assert
+			if got != tt.expected {
+				t.Errorf("Expected stringInSlice: %v\nGot: %v", tt.expected, got)
+			}
+		})
+	}
+}
+
+func TestRpad(t *testing.T) {
+	tests := []struct {
+		name        string
+		inputString string
+		padding     int
+		expected    string
+	}{
+		{
+			name:        "Padding required",
+			inputString: "Hello",
+			padding:     10,
+			expected:    "Hello     ",
+		},
+		{
+			name:        "No padding required",
+			inputString: "World",
+			padding:     5,
+			expected:    "World",
+		},
+		{
+			name:        "Empty string",
+			inputString: "",
+			padding:     8,
+			expected:    "        ",
+		},
+		{
+			name:        "Zero padding",
+			inputString: "cobra",
+			padding:     0,
+			expected:    "cobra",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Act
+			got := rpad(tt.inputString, tt.padding)
+
+			// Assert
+			if got != tt.expected {
+				t.Errorf("Expected rpad: %v\nGot: %v", tt.expected, got)
+			}
+		})
+	}
+}

command.go

@@ -32,6 +32,7 @@ import (
 
 const (
 	FlagSetByCobraAnnotation     = "cobra_annotation_flag_set_by_cobra"
+	CommandDisplayNameAnnotation = "cobra_annotation_command_display_name"
 	trueString                   = "true"
 )
 
@@ -102,7 +103,7 @@ type Command struct {
 	Deprecated string
 
 	// Annotations are key/value pairs that can be used by applications to identify or
-	// group commands.
+	// group commands or set special options.
 	Annotations map[string]string
 
 	// Version defines the version for this command. If this value is non-empty and the command does not
@@ -118,6 +119,8 @@ type Command struct {
 	//   * PostRun()
 	//   * PersistentPostRun()
 	// All functions get the same args, the arguments after the command name.
+	// The *PreRun and *PostRun functions will only be executed if the Run function of the current
+	// command has been declared.
 	//
 	// PersistentPreRun: children of this command will inherit and execute.
 	PersistentPreRun func(cmd *Command, args []string)
@@ -152,8 +155,10 @@ type Command struct {
 	// pflags contains persistent flags.
 	pflags *flag.FlagSet
 	// lflags contains local flags.
+	// This field does not represent internal state, it's used as a cache to optimise LocalFlags function call
 	lflags *flag.FlagSet
 	// iflags contains inherited flags.
+	// This field does not represent internal state, it's used as a cache to optimise InheritedFlags function call
 	iflags *flag.FlagSet
 	// parentsPflags is all persistent flags of cmd's parents.
 	parentsPflags *flag.FlagSet
@@ -184,6 +189,9 @@ type Command struct {
 	// versionTemplate is the version template defined by user.
 	versionTemplate string
 
+	// errPrefix is the error message prefix defined by user.
+	errPrefix string
+
 	// inReader is a reader defined by the user that replaces stdin
 	inReader io.Reader
 	// outWriter is a writer defined by the user that replaces stdout
@@ -349,6 +357,11 @@ func (c *Command) SetVersionTemplate(s string) {
 	c.versionTemplate = s
 }
 
+// SetErrPrefix sets error message prefix to be used. Application can use it to set custom prefix.
+func (c *Command) SetErrPrefix(s string) {
+	c.errPrefix = s
+}
+
 // SetGlobalNormalizationFunc sets a normalization function to all flag sets and also to child commands.
 // The user should not have a cyclic dependency on commands.
 func (c *Command) SetGlobalNormalizationFunc(n func(f *flag.FlagSet, name string) flag.NormalizedName) {
@@ -598,6 +611,18 @@ func (c *Command) VersionTemplate() string {
 `
 }
 
+// ErrPrefix return error message prefix for the command
+func (c *Command) ErrPrefix() string {
+	if c.errPrefix != "" {
+		return c.errPrefix
+	}
+
+	if c.HasParent() {
+		return c.parent.ErrPrefix()
+	}
+	return "Error:"
+}
+
 func hasNoOptDefVal(name string, fs *flag.FlagSet) bool {
 	flag := fs.Lookup(name)
 	if flag == nil {
@@ -684,7 +709,7 @@ Loop:
 			// This is not a flag or a flag value. Check to see if it matches what we're looking for, and if so,
 			// return the args, excluding the one at this position.
 			if s == x {
-				ret := []string{}
+				ret := make([]string, 0, len(args)-1)
 				ret = append(ret, args[:pos]...)
 				ret = append(ret, args[pos+1:]...)
 				return ret
@@ -732,14 +757,14 @@ func (c *Command) findSuggestions(arg string) string {
 	if c.SuggestionsMinimumDistance <= 0 {
 		c.SuggestionsMinimumDistance = 2
 	}
-	suggestionsString := ""
+	var sb strings.Builder
 	if suggestions := c.SuggestionsFor(arg); len(suggestions) > 0 {
-		suggestionsString += "\n\nDid you mean this?\n"
+		sb.WriteString("\n\nDid you mean this?\n")
 		for _, s := range suggestions {
-			suggestionsString += fmt.Sprintf("\t%v\n", s)
+			_, _ = fmt.Fprintf(&sb, "\t%v\n", s)
 		}
 	}
-	return suggestionsString
+	return sb.String()
 }
 
 func (c *Command) findNext(next string) *Command {
@@ -755,7 +780,9 @@ func (c *Command) findNext(next string) *Command {
 	}
 
 	if len(matches) == 1 {
-		return matches[0]
+		// Temporarily disable gosec G602, which produces a false positive.
+		// See https://github.com/securego/gosec/issues/1005.
+		return matches[0] // #nosec G602
 	}
 
 	return nil
@@ -849,7 +876,7 @@ func (c *Command) ArgsLenAtDash() int {
 
 func (c *Command) execute(a []string) (err error) {
 	if c == nil {
-		return fmt.Errorf("Called Execute() on a nil Command")
+		return fmt.Errorf("called Execute() on a nil Command")
 	}
 
 	if len(c.Deprecated) > 0 {
@@ -913,17 +940,33 @@ func (c *Command) execute(a []string) (err error) {
 		return err
 	}
 
+	parents := make([]*Command, 0, 5)
 	for p := c; p != nil; p = p.Parent() {
+		if EnableTraverseRunHooks {
+			// When EnableTraverseRunHooks is set:
+			// - Execute all persistent pre-runs from the root parent till this command.
+			// - Execute all persistent post-runs from this command till the root parent.
+			parents = append([]*Command{p}, parents...)
+		} else {
+			// Otherwise, execute only the first found persistent hook.
+			parents = append(parents, p)
+		}
+	}
+	for _, p := range parents {
 		if p.PersistentPreRunE != nil {
 			if err := p.PersistentPreRunE(c, argWoFlags); err != nil {
 				return err
 			}
+			if !EnableTraverseRunHooks {
 				break
+			}
 		} else if p.PersistentPreRun != nil {
 			p.PersistentPreRun(c, argWoFlags)
+			if !EnableTraverseRunHooks {
 				break
 			}
 		}
+	}
 	if c.PreRunE != nil {
 		if err := c.PreRunE(c, argWoFlags); err != nil {
 			return err
@@ -958,12 +1001,16 @@ func (c *Command) execute(a []string) (err error) {
 			if err := p.PersistentPostRunE(c, argWoFlags); err != nil {
 				return err
 			}
+			if !EnableTraverseRunHooks {
 				break
+			}
 		} else if p.PersistentPostRun != nil {
 			p.PersistentPostRun(c, argWoFlags)
+			if !EnableTraverseRunHooks {
 				break
 			}
 		}
+	}
 
 	return nil
 }
@@ -1051,7 +1098,7 @@ func (c *Command) ExecuteC() (cmd *Command, err error) {
 			c = cmd
 		}
 		if !c.SilenceErrors {
-			c.PrintErrln("Error:", err.Error())
+			c.PrintErrln(c.ErrPrefix(), err.Error())
 			c.PrintErrf("Run '%v --help' for usage.\n", c.CommandPath())
 		}
 		return c, err
@@ -1080,7 +1127,7 @@ func (c *Command) ExecuteC() (cmd *Command, err error) {
 		// If root command has SilenceErrors flagged,
 		// all subcommands should respect it
 		if !cmd.SilenceErrors && !c.SilenceErrors {
-			c.PrintErrln("Error:", err.Error())
+			c.PrintErrln(cmd.ErrPrefix(), err.Error())
 		}
 
 		// If root command has SilenceUsage flagged,
@@ -1143,10 +1190,11 @@ func (c *Command) InitDefaultHelpFlag() {
 	c.mergePersistentFlags()
 	if c.Flags().Lookup("help") == nil {
 		usage := "help for "
-		if c.Name() == "" {
+		name := c.displayName()
+		if name == "" {
 			usage += "this command"
 		} else {
-			usage += c.Name()
+			usage += name
 		}
 		c.Flags().BoolP("help", "h", false, usage)
 		_ = c.Flags().SetAnnotation("help", FlagSetByCobraAnnotation, []string{trueString})
@@ -1192,7 +1240,7 @@ func (c *Command) InitDefaultHelpCmd() {
 			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.`,
+Simply type ` + c.displayName() + ` help [path to command] for full details.`,
 			ValidArgsFunction: func(c *Command, args []string, toComplete string) ([]string, ShellCompDirective) {
 				var completions []string
 				cmd, _, e := c.Root().Find(args)
@@ -1400,16 +1448,24 @@ func (c *Command) CommandPath() string {
 	if c.HasParent() {
 		return c.Parent().CommandPath() + " " + c.Name()
 	}
+	return c.displayName()
+}
+
+func (c *Command) displayName() string {
+	if displayName, ok := c.Annotations[CommandDisplayNameAnnotation]; ok {
+		return displayName
+	}
 	return c.Name()
 }
 
 // UseLine puts out the full usage for a given command (including parents).
 func (c *Command) UseLine() string {
 	var useline string
+	use := strings.Replace(c.Use, c.Name(), c.displayName(), 1)
 	if c.HasParent() {
-		useline = c.parent.CommandPath() + " " + c.Use
+		useline = c.parent.CommandPath() + " " + use
 	} else {
-		useline = c.Use
+		useline = use
 	}
 	if c.DisableFlagsInUseLine {
 		return useline
@@ -1422,6 +1478,7 @@ func (c *Command) UseLine() string {
 
 // DebugFlags used to determine which flags have been assigned to which commands
 // and which persist.
+// nolint:goconst
 func (c *Command) DebugFlags() {
 	c.Println("DebugFlags called on", c.Name())
 	var debugflags func(*Command)
@@ -1611,7 +1668,7 @@ func (c *Command) GlobalNormalizationFunc() func(f *flag.FlagSet, name string) f
 // to this command (local and persistent declared here and by all parents).
 func (c *Command) Flags() *flag.FlagSet {
 	if c.flags == nil {
-		c.flags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
+		c.flags = flag.NewFlagSet(c.displayName(), flag.ContinueOnError)
 		if c.flagErrorBuf == nil {
 			c.flagErrorBuf = new(bytes.Buffer)
 		}
@@ -1622,10 +1679,11 @@ func (c *Command) Flags() *flag.FlagSet {
 }
 
 // LocalNonPersistentFlags are flags specific to this command which will NOT persist to subcommands.
+// This function does not modify the flags of the current command, it's purpose is to return the current state.
 func (c *Command) LocalNonPersistentFlags() *flag.FlagSet {
 	persistentFlags := c.PersistentFlags()
 
-	out := flag.NewFlagSet(c.Name(), flag.ContinueOnError)
+	out := flag.NewFlagSet(c.displayName(), flag.ContinueOnError)
 	c.LocalFlags().VisitAll(func(f *flag.Flag) {
 		if persistentFlags.Lookup(f.Name) == nil {
 			out.AddFlag(f)
@@ -1635,11 +1693,12 @@ func (c *Command) LocalNonPersistentFlags() *flag.FlagSet {
 }
 
 // LocalFlags returns the local FlagSet specifically set in the current command.
+// This function does not modify the flags of the current command, it's purpose is to return the current state.
 func (c *Command) LocalFlags() *flag.FlagSet {
 	c.mergePersistentFlags()
 
 	if c.lflags == nil {
-		c.lflags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
+		c.lflags = flag.NewFlagSet(c.displayName(), flag.ContinueOnError)
 		if c.flagErrorBuf == nil {
 			c.flagErrorBuf = new(bytes.Buffer)
 		}
@@ -1662,11 +1721,12 @@ func (c *Command) LocalFlags() *flag.FlagSet {
 }
 
 // InheritedFlags returns all flags which were inherited from parent commands.
+// This function does not modify the flags of the current command, it's purpose is to return the current state.
 func (c *Command) InheritedFlags() *flag.FlagSet {
 	c.mergePersistentFlags()
 
 	if c.iflags == nil {
-		c.iflags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
+		c.iflags = flag.NewFlagSet(c.displayName(), flag.ContinueOnError)
 		if c.flagErrorBuf == nil {
 			c.flagErrorBuf = new(bytes.Buffer)
 		}
@@ -1687,6 +1747,7 @@ func (c *Command) InheritedFlags() *flag.FlagSet {
 }
 
 // NonInheritedFlags returns all flags which were not inherited from parent commands.
+// This function does not modify the flags of the current command, it's purpose is to return the current state.
 func (c *Command) NonInheritedFlags() *flag.FlagSet {
 	return c.LocalFlags()
 }
@@ -1694,7 +1755,7 @@ func (c *Command) NonInheritedFlags() *flag.FlagSet {
 // PersistentFlags returns the persistent FlagSet specifically set in the current command.
 func (c *Command) PersistentFlags() *flag.FlagSet {
 	if c.pflags == nil {
-		c.pflags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
+		c.pflags = flag.NewFlagSet(c.displayName(), flag.ContinueOnError)
 		if c.flagErrorBuf == nil {
 			c.flagErrorBuf = new(bytes.Buffer)
 		}
@@ -1707,9 +1768,9 @@ func (c *Command) PersistentFlags() *flag.FlagSet {
 func (c *Command) ResetFlags() {
 	c.flagErrorBuf = new(bytes.Buffer)
 	c.flagErrorBuf.Reset()
-	c.flags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
+	c.flags = flag.NewFlagSet(c.displayName(), flag.ContinueOnError)
 	c.flags.SetOutput(c.flagErrorBuf)
-	c.pflags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
+	c.pflags = flag.NewFlagSet(c.displayName(), flag.ContinueOnError)
 	c.pflags.SetOutput(c.flagErrorBuf)
 
 	c.lflags = nil
@@ -1826,7 +1887,7 @@ func (c *Command) mergePersistentFlags() {
 // If c.parentsPflags == nil, it makes new.
 func (c *Command) updateParentsPflags() {
 	if c.parentsPflags == nil {
-		c.parentsPflags = flag.NewFlagSet(c.Name(), flag.ContinueOnError)
+		c.parentsPflags = flag.NewFlagSet(c.displayName(), flag.ContinueOnError)
 		c.parentsPflags.SetOutput(c.flagErrorBuf)
 		c.parentsPflags.SortFlags = false
 	}

command_test.go

@@ -18,7 +18,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"os"
 	"reflect"
 	"strings"
@@ -366,6 +366,67 @@ func TestAliasPrefixMatching(t *testing.T) {
 	EnablePrefixMatching = defaultPrefixMatching
 }
 
+// TestPlugin checks usage as plugin for another command such as kubectl.  The
+// executable is `kubectl-plugin`, but we run it as `kubectl plugin`. The help
+// text should reflect the way we run the command.
+func TestPlugin(t *testing.T) {
+	cmd := &Command{
+		Use:  "kubectl-plugin",
+		Args: NoArgs,
+		Annotations: map[string]string{
+			CommandDisplayNameAnnotation: "kubectl plugin",
+		},
+		Run: emptyRun,
+	}
+
+	cmdHelp, err := executeCommand(cmd, "-h")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	checkStringContains(t, cmdHelp, "kubectl plugin [flags]")
+	checkStringContains(t, cmdHelp, "help for kubectl plugin")
+}
+
+// TestPlugin checks usage as plugin with sub commands.
+func TestPluginWithSubCommands(t *testing.T) {
+	rootCmd := &Command{
+		Use:  "kubectl-plugin",
+		Args: NoArgs,
+		Annotations: map[string]string{
+			CommandDisplayNameAnnotation: "kubectl plugin",
+		},
+	}
+
+	subCmd := &Command{Use: "sub [flags]", Args: NoArgs, Run: emptyRun}
+	rootCmd.AddCommand(subCmd)
+
+	rootHelp, err := executeCommand(rootCmd, "-h")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	checkStringContains(t, rootHelp, "kubectl plugin [command]")
+	checkStringContains(t, rootHelp, "help for kubectl plugin")
+	checkStringContains(t, rootHelp, "kubectl plugin [command] --help")
+
+	childHelp, err := executeCommand(rootCmd, "sub", "-h")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	checkStringContains(t, childHelp, "kubectl plugin sub [flags]")
+	checkStringContains(t, childHelp, "help for sub")
+
+	helpHelp, err := executeCommand(rootCmd, "help", "-h")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	checkStringContains(t, helpHelp, "kubectl plugin help [path to command]")
+	checkStringContains(t, helpHelp, "kubectl plugin help [command]")
+}
+
 // TestChildSameName checks the correct behaviour of cobra in cases,
 // when an application with name "foo" and with subcommand "foo"
 // is executed with args "foo foo".
@@ -438,7 +499,7 @@ func TestFlagLong(t *testing.T) {
 
 	output, err := executeCommand(c, "--intf=7", "--sf=abc", "one", "--", "two")
 	if output != "" {
-		t.Errorf("Unexpected output: %v", err)
+		t.Errorf("Unexpected output: %v", output)
 	}
 	if err != nil {
 		t.Errorf("Unexpected error: %v", err)
@@ -475,7 +536,7 @@ func TestFlagShort(t *testing.T) {
 
 	output, err := executeCommand(c, "-i", "7", "-sabc", "one", "two")
 	if output != "" {
-		t.Errorf("Unexpected output: %v", err)
+		t.Errorf("Unexpected output: %v", output)
 	}
 	if err != nil {
 		t.Errorf("Unexpected error: %v", err)
@@ -504,7 +565,7 @@ func TestChildFlag(t *testing.T) {
 
 	output, err := executeCommand(rootCmd, "child", "-i7")
 	if output != "" {
-		t.Errorf("Unexpected output: %v", err)
+		t.Errorf("Unexpected output: %v", output)
 	}
 	if err != nil {
 		t.Errorf("Unexpected error: %v", err)
@@ -1111,6 +1172,39 @@ func TestShorthandVersionTemplate(t *testing.T) {
 	checkStringContains(t, output, "customized version: 1.0.0")
 }
 
+func TestRootErrPrefixExecutedOnSubcommand(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	rootCmd.SetErrPrefix("root error prefix:")
+	rootCmd.AddCommand(&Command{Use: "sub", Run: emptyRun})
+
+	output, err := executeCommand(rootCmd, "sub", "--unknown-flag")
+	if err == nil {
+		t.Errorf("Expected error")
+	}
+
+	checkStringContains(t, output, "root error prefix: unknown flag: --unknown-flag")
+}
+
+func TestRootAndSubErrPrefix(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	subCmd := &Command{Use: "sub", Run: emptyRun}
+	rootCmd.AddCommand(subCmd)
+	rootCmd.SetErrPrefix("root error prefix:")
+	subCmd.SetErrPrefix("sub error prefix:")
+
+	if output, err := executeCommand(rootCmd, "--unknown-root-flag"); err == nil {
+		t.Errorf("Expected error")
+	} else {
+		checkStringContains(t, output, "root error prefix: unknown flag: --unknown-root-flag")
+	}
+
+	if output, err := executeCommand(rootCmd, "sub", "--unknown-sub-flag"); err == nil {
+		t.Errorf("Expected error")
+	} else {
+		checkStringContains(t, output, "sub error prefix: unknown flag: --unknown-sub-flag")
+	}
+}
+
 func TestVersionFlagExecutedOnSubcommand(t *testing.T) {
 	rootCmd := &Command{Use: "root", Version: "1.0.0"}
 	rootCmd.AddCommand(&Command{Use: "sub", Run: emptyRun})
@@ -1509,57 +1603,73 @@ func TestHooks(t *testing.T) {
 }
 
 func TestPersistentHooks(t *testing.T) {
-	var (
-		parentPersPreArgs  string
-		parentPreArgs      string
-		parentRunArgs      string
-		parentPostArgs     string
-		parentPersPostArgs string
-	)
+	EnableTraverseRunHooks = true
+	testPersistentHooks(t, []string{
+		"parent PersistentPreRun",
+		"child PersistentPreRun",
+		"child PreRun",
+		"child Run",
+		"child PostRun",
+		"child PersistentPostRun",
+		"parent PersistentPostRun",
+	})
 
-	var (
-		childPersPreArgs  string
-		childPreArgs      string
-		childRunArgs      string
-		childPostArgs     string
-		childPersPostArgs string
-	)
+	EnableTraverseRunHooks = false
+	testPersistentHooks(t, []string{
+		"child PersistentPreRun",
+		"child PreRun",
+		"child Run",
+		"child PostRun",
+		"child PersistentPostRun",
+	})
+}
+
+func testPersistentHooks(t *testing.T, expectedHookRunOrder []string) {
+	var hookRunOrder []string
+
+	validateHook := func(args []string, hookName string) {
+		hookRunOrder = append(hookRunOrder, hookName)
+		got := strings.Join(args, " ")
+		if onetwo != got {
+			t.Errorf("Expected %s %q, got %q", hookName, onetwo, got)
+		}
+	}
 
 	parentCmd := &Command{
 		Use: "parent",
 		PersistentPreRun: func(_ *Command, args []string) {
-			parentPersPreArgs = strings.Join(args, " ")
+			validateHook(args, "parent PersistentPreRun")
 		},
 		PreRun: func(_ *Command, args []string) {
-			parentPreArgs = strings.Join(args, " ")
+			validateHook(args, "parent PreRun")
 		},
 		Run: func(_ *Command, args []string) {
-			parentRunArgs = strings.Join(args, " ")
+			validateHook(args, "parent Run")
 		},
 		PostRun: func(_ *Command, args []string) {
-			parentPostArgs = strings.Join(args, " ")
+			validateHook(args, "parent PostRun")
 		},
 		PersistentPostRun: func(_ *Command, args []string) {
-			parentPersPostArgs = strings.Join(args, " ")
+			validateHook(args, "parent PersistentPostRun")
 		},
 	}
 
 	childCmd := &Command{
 		Use: "child",
 		PersistentPreRun: func(_ *Command, args []string) {
-			childPersPreArgs = strings.Join(args, " ")
+			validateHook(args, "child PersistentPreRun")
 		},
 		PreRun: func(_ *Command, args []string) {
-			childPreArgs = strings.Join(args, " ")
+			validateHook(args, "child PreRun")
 		},
 		Run: func(_ *Command, args []string) {
-			childRunArgs = strings.Join(args, " ")
+			validateHook(args, "child Run")
 		},
 		PostRun: func(_ *Command, args []string) {
-			childPostArgs = strings.Join(args, " ")
+			validateHook(args, "child PostRun")
 		},
 		PersistentPostRun: func(_ *Command, args []string) {
-			childPersPostArgs = strings.Join(args, " ")
+			validateHook(args, "child PersistentPostRun")
 		},
 	}
 	parentCmd.AddCommand(childCmd)
@@ -1572,41 +1682,13 @@ func TestPersistentHooks(t *testing.T) {
 		t.Errorf("Unexpected error: %v", err)
 	}
 
-	for _, v := range []struct {
-		name string
-		got  string
-	}{
-		// TODO: currently PersistentPreRun* defined in parent does not
-		// run if the matching child subcommand has PersistentPreRun.
-		// If the behavior changes (https://github.com/spf13/cobra/issues/252)
-		// this test must be fixed.
-		{"parentPersPreArgs", parentPersPreArgs},
-		{"parentPreArgs", parentPreArgs},
-		{"parentRunArgs", parentRunArgs},
-		{"parentPostArgs", parentPostArgs},
-		// TODO: currently PersistentPostRun* defined in parent does not
-		// run if the matching child subcommand has PersistentPostRun.
-		// If the behavior changes (https://github.com/spf13/cobra/issues/252)
-		// this test must be fixed.
-		{"parentPersPostArgs", parentPersPostArgs},
-	} {
-		if v.got != "" {
-			t.Errorf("Expected blank %s, got %q", v.name, v.got)
+	for idx, exp := range expectedHookRunOrder {
+		if len(hookRunOrder) > idx {
+			if act := hookRunOrder[idx]; act != exp {
+				t.Errorf("Expected %q at %d, got %q", exp, idx, act)
 			}
-	}
-
-	for _, v := range []struct {
-		name string
-		got  string
-	}{
-		{"childPersPreArgs", childPersPreArgs},
-		{"childPreArgs", childPreArgs},
-		{"childRunArgs", childRunArgs},
-		{"childPostArgs", childPostArgs},
-		{"childPersPostArgs", childPersPostArgs},
-	} {
-		if v.got != onetwo {
-			t.Errorf("Expected %s %q, got %q", v.name, onetwo, v.got)
+		} else {
+			t.Errorf("Expected %q at %d, got nothing", exp, idx)
 		}
 	}
 }
@@ -2041,12 +2123,12 @@ func TestCommandPrintRedirection(t *testing.T) {
 		t.Error(err)
 	}
 
-	gotErrBytes, err := ioutil.ReadAll(errBuff)
+	gotErrBytes, err := io.ReadAll(errBuff)
 	if err != nil {
 		t.Error(err)
 	}
 
-	gotOutBytes, err := ioutil.ReadAll(outBuff)
+	gotOutBytes, err := io.ReadAll(outBuff)
 	if err != nil {
 		t.Error(err)
 	}
@@ -2726,7 +2808,7 @@ func TestFind(t *testing.T) {
 
 func TestUnknownFlagShouldReturnSameErrorRegardlessOfArgPosition(t *testing.T) {
 	testCases := [][]string{
-		//{"--unknown", "--namespace", "foo", "child", "--bar"}, // FIXME: This test case fails, returning the error `unknown command "foo" for "root"` instead of the expected error `unknown flag: --unknown`
+		// {"--unknown", "--namespace", "foo", "child", "--bar"}, // FIXME: This test case fails, returning the error `unknown command "foo" for "root"` instead of the expected error `unknown flag: --unknown`
 		{"--namespace", "foo", "--unknown", "child", "--bar"},
 		{"--namespace", "foo", "child", "--unknown", "--bar"},
 		{"--namespace", "foo", "child", "--bar", "--unknown"},

completions.go

@@ -17,6 +17,8 @@ package cobra
 import (
 	"fmt"
 	"os"
+	"regexp"
+	"strconv"
 	"strings"
 	"sync"
 
@@ -145,6 +147,20 @@ func (c *Command) RegisterFlagCompletionFunc(flagName string, f func(cmd *Comman
 	return nil
 }
 
+// GetFlagCompletionFunc returns the completion function for the given flag of the command, if available.
+func (c *Command) GetFlagCompletionFunc(flagName string) (func(*Command, []string, string) ([]string, ShellCompDirective), bool) {
+	flag := c.Flag(flagName)
+	if flag == nil {
+		return nil, false
+	}
+
+	flagCompletionMutex.RLock()
+	defer flagCompletionMutex.RUnlock()
+
+	completionFunc, exists := flagCompletionFunctions[flag]
+	return completionFunc, exists
+}
+
 // Returns a string listing the different directive enabled in the specified parameter
 func (d ShellCompDirective) string() string {
 	var directives []string
@@ -197,24 +213,29 @@ func (c *Command) initCompleteCmd(args []string) {
 				// 2- Even without completions, we need to print the directive
 			}
 
-			noDescriptions := (cmd.CalledAs() == ShellCompNoDescRequestCmd)
-			for _, comp := range completions {
-				if GetActiveHelpConfig(finalCmd) == activeHelpGlobalDisable {
-					// Remove all activeHelp entries in this case
-					if strings.HasPrefix(comp, activeHelpMarker) {
-						continue
+			noDescriptions := cmd.CalledAs() == ShellCompNoDescRequestCmd
+			if !noDescriptions {
+				if doDescriptions, err := strconv.ParseBool(getEnvConfig(cmd, configEnvVarSuffixDescriptions)); err == nil {
+					noDescriptions = !doDescriptions
 				}
 			}
+			noActiveHelp := GetActiveHelpConfig(finalCmd) == activeHelpGlobalDisable
+			out := finalCmd.OutOrStdout()
+			for _, comp := range completions {
+				if noActiveHelp && strings.HasPrefix(comp, activeHelpMarker) {
+					// Remove all activeHelp entries if it's disabled.
+					continue
+				}
 				if noDescriptions {
 					// Remove any description that may be included following a tab character.
-					comp = strings.Split(comp, "\t")[0]
+					comp = strings.SplitN(comp, "\t", 2)[0]
 				}
 
 				// Make sure we only write the first line to the output.
 				// This is needed if a description contains a linebreak.
 				// Otherwise the shell scripts will interpret the other lines as new flags
 				// and could therefore provide a wrong completion.
-				comp = strings.Split(comp, "\n")[0]
+				comp = strings.SplitN(comp, "\n", 2)[0]
 
 				// Finally trim the completion.  This is especially important to get rid
 				// of a trailing tab when there are no description following it.
@@ -223,14 +244,14 @@ func (c *Command) initCompleteCmd(args []string) {
 				// although there is no description).
 				comp = strings.TrimSpace(comp)
 
-				// Print each possible completion to stdout for the completion script to consume.
-				fmt.Fprintln(finalCmd.OutOrStdout(), comp)
+				// Print each possible completion to the output for the completion script to consume.
+				fmt.Fprintln(out, comp)
 			}
 
 			// As the last printout, print the completion directive for the completion script to parse.
 			// The directive integer must be that last character following a single colon (:).
 			// The completion script expects :<directive>
-			fmt.Fprintf(finalCmd.OutOrStdout(), ":%d\n", directive)
+			fmt.Fprintf(out, ":%d\n", directive)
 
 			// Print some helpful info to stderr for the user to understand.
 			// Output from stderr must be ignored by the completion script.
@@ -277,15 +298,19 @@ func (c *Command) getCompletions(args []string) (*Command, []string, ShellCompDi
 	}
 	if err != nil {
 		// Unable to find the real command. E.g., <program> someInvalidCmd <TAB>
-		return c, []string{}, ShellCompDirectiveDefault, fmt.Errorf("Unable to find a command for arguments: %v", trimmedArgs)
+		return c, []string{}, ShellCompDirectiveDefault, fmt.Errorf("unable to find a command for arguments: %v", trimmedArgs)
 	}
 	finalCmd.ctx = c.ctx
 
 	// These flags are normally added when `execute()` is called on `finalCmd`,
 	// however, when doing completion, we don't call `finalCmd.execute()`.
-	// Let's add the --help and --version flag ourselves.
+	// Let's add the --help and --version flag ourselves but only if the finalCmd
+	// has not disabled flag parsing; if flag parsing is disabled, it is up to the
+	// finalCmd itself to handle the completion of *all* flags.
+	if !finalCmd.DisableFlagParsing {
 		finalCmd.InitDefaultHelpFlag()
 		finalCmd.InitDefaultVersionFlag()
+	}
 
 	// Check if we are doing flag value completion before parsing the flags.
 	// This is important because if we are completing a flag value, we need to also
@@ -389,6 +414,11 @@ func (c *Command) getCompletions(args []string) (*Command, []string, ShellCompDi
 			finalCmd.InheritedFlags().VisitAll(func(flag *pflag.Flag) {
 				doCompleteFlags(flag)
 			})
+			// Try to complete non-inherited flags even if DisableFlagParsing==true.
+			// This allows programs to tell Cobra about flags for completion even
+			// if the actual parsing of flags is not done by Cobra.
+			// For instance, Helm uses this to provide flag name completion for
+			// some of its plugins.
 			finalCmd.NonInheritedFlags().VisitAll(func(flag *pflag.Flag) {
 				doCompleteFlags(flag)
 			})
@@ -893,3 +923,34 @@ func CompError(msg string) {
 func CompErrorln(msg string) {
 	CompError(fmt.Sprintf("%s\n", msg))
 }
+
+// These values should not be changed: users will be using them explicitly.
+const (
+	configEnvVarGlobalPrefix       = "COBRA"
+	configEnvVarSuffixDescriptions = "COMPLETION_DESCRIPTIONS"
+)
+
+var configEnvVarPrefixSubstRegexp = regexp.MustCompile(`[^A-Z0-9_]`)
+
+// configEnvVar returns the name of the program-specific configuration environment
+// variable.  It has the format <PROGRAM>_<SUFFIX> where <PROGRAM> is the name of the
+// root command in upper case, with all non-ASCII-alphanumeric characters replaced by `_`.
+func configEnvVar(name, suffix string) string {
+	// This format should not be changed: users will be using it explicitly.
+	v := strings.ToUpper(fmt.Sprintf("%s_%s", name, suffix))
+	v = configEnvVarPrefixSubstRegexp.ReplaceAllString(v, "_")
+	return v
+}
+
+// getEnvConfig returns the value of the configuration environment variable
+// <PROGRAM>_<SUFFIX> where <PROGRAM> is the name of the root command in upper
+// case, with all non-ASCII-alphanumeric characters replaced by `_`.
+// If the value is empty or not set, the value of the environment variable
+// COBRA_<SUFFIX> is returned instead.
+func getEnvConfig(cmd *Command, suffix string) string {
+	v := os.Getenv(configEnvVar(cmd.Root().Name(), suffix))
+	if v == "" {
+		v = os.Getenv(configEnvVar(configEnvVarGlobalPrefix, suffix))
+	}
+	return v
+}

completions_test.go

@@ -17,7 +17,10 @@ package cobra
 import (
 	"bytes"
 	"context"
+	"fmt"
+	"os"
 	"strings"
+	"sync"
 	"testing"
 )
 
@@ -2040,6 +2043,114 @@ func TestFlagCompletionWorksRootCommandAddedAfterFlags(t *testing.T) {
 	}
 }
 
+func TestFlagCompletionForPersistentFlagsCalledFromSubCmd(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	rootCmd.PersistentFlags().String("string", "", "test string flag")
+	_ = rootCmd.RegisterFlagCompletionFunc("string", func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective) {
+		return []string{"myval"}, ShellCompDirectiveDefault
+	})
+
+	childCmd := &Command{
+		Use: "child",
+		Run: emptyRun,
+		ValidArgsFunction: func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective) {
+			return []string{"--validarg", "test"}, ShellCompDirectiveDefault
+		},
+	}
+	childCmd.Flags().Bool("bool", false, "test bool flag")
+	rootCmd.AddCommand(childCmd)
+
+	// Test that persistent flag completion works for the subcmd
+	output, err := executeCommand(rootCmd, ShellCompRequestCmd, "child", "--string", "")
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
+	expected := strings.Join([]string{
+		"myval",
+		":0",
+		"Completion ended with directive: ShellCompDirectiveDefault", ""}, "\n")
+
+	if output != expected {
+		t.Errorf("expected: %q, got: %q", expected, output)
+	}
+}
+
+// This test tries to register flag completion concurrently to make sure the
+// code handles concurrency properly.
+// This was reported as a problem when tests are run concurrently:
+// https://github.com/spf13/cobra/issues/1320
+//
+// NOTE: this test can sometimes pass even if the code were to not handle
+// concurrency properly. This is not great but the important part is that
+// it should never fail.  Therefore, if the tests fails sometimes, we will
+// still be able to know there is a problem.
+func TestFlagCompletionConcurrentRegistration(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+	const maxFlags = 50
+	for i := 1; i < maxFlags; i += 2 {
+		flagName := fmt.Sprintf("flag%d", i)
+		rootCmd.Flags().String(flagName, "", fmt.Sprintf("test %s flag on root", flagName))
+	}
+
+	childCmd := &Command{
+		Use: "child",
+		Run: emptyRun,
+	}
+	for i := 2; i <= maxFlags; i += 2 {
+		flagName := fmt.Sprintf("flag%d", i)
+		childCmd.Flags().String(flagName, "", fmt.Sprintf("test %s flag on child", flagName))
+	}
+
+	rootCmd.AddCommand(childCmd)
+
+	// Register completion in different threads to test concurrency.
+	var wg sync.WaitGroup
+	for i := 1; i <= maxFlags; i++ {
+		index := i
+		flagName := fmt.Sprintf("flag%d", i)
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			cmd := rootCmd
+			if index%2 == 0 {
+				cmd = childCmd
+			}
+			_ = cmd.RegisterFlagCompletionFunc(flagName, func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective) {
+				return []string{fmt.Sprintf("flag%d", index)}, ShellCompDirectiveDefault
+			})
+		}()
+	}
+
+	wg.Wait()
+
+	// Test that flag completion works for each flag
+	for i := 1; i <= 6; i++ {
+		var output string
+		var err error
+		flagName := fmt.Sprintf("flag%d", i)
+
+		if i%2 == 1 {
+			output, err = executeCommand(rootCmd, ShellCompRequestCmd, "--"+flagName, "")
+		} else {
+			output, err = executeCommand(rootCmd, ShellCompRequestCmd, "child", "--"+flagName, "")
+		}
+
+		if err != nil {
+			t.Errorf("Unexpected error: %v", err)
+		}
+
+		expected := strings.Join([]string{
+			flagName,
+			":0",
+			"Completion ended with directive: ShellCompDirectiveDefault", ""}, "\n")
+
+		if output != expected {
+			t.Errorf("expected: %q, got: %q", expected, output)
+		}
+	}
+}
+
 func TestFlagCompletionInGoWithDesc(t *testing.T) {
 	rootCmd := &Command{
 		Use: "root",
@@ -2658,8 +2769,6 @@ func TestCompleteWithDisableFlagParsing(t *testing.T) {
 	expected := strings.Join([]string{
 		"--persistent",
 		"-p",
-		"--help",
-		"-h",
 		"--nonPersistent",
 		"-n",
 		"--flag",
@@ -2866,6 +2975,104 @@ func TestCompletionForGroupedFlags(t *testing.T) {
 	}
 }
 
+func TestCompletionForOneRequiredGroupFlags(t *testing.T) {
+	getCmd := func() *Command {
+		rootCmd := &Command{
+			Use: "root",
+			Run: emptyRun,
+		}
+		childCmd := &Command{
+			Use: "child",
+			ValidArgsFunction: func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective) {
+				return []string{"subArg"}, ShellCompDirectiveNoFileComp
+			},
+			Run: emptyRun,
+		}
+		rootCmd.AddCommand(childCmd)
+
+		rootCmd.PersistentFlags().Int("ingroup1", -1, "ingroup1")
+		rootCmd.PersistentFlags().String("ingroup2", "", "ingroup2")
+
+		childCmd.Flags().Bool("ingroup3", false, "ingroup3")
+		childCmd.Flags().Bool("nogroup", false, "nogroup")
+
+		// Add flags to a group
+		childCmd.MarkFlagsOneRequired("ingroup1", "ingroup2", "ingroup3")
+
+		return rootCmd
+	}
+
+	// Each test case uses a unique command from the function above.
+	testcases := []struct {
+		desc           string
+		args           []string
+		expectedOutput string
+	}{
+		{
+			desc: "flags in group suggested without - prefix",
+			args: []string{"child", ""},
+			expectedOutput: strings.Join([]string{
+				"--ingroup1",
+				"--ingroup2",
+				"--ingroup3",
+				"subArg",
+				":4",
+				"Completion ended with directive: ShellCompDirectiveNoFileComp", ""}, "\n"),
+		},
+		{
+			desc: "flags in group suggested with - prefix",
+			args: []string{"child", "-"},
+			expectedOutput: strings.Join([]string{
+				"--ingroup1",
+				"--ingroup2",
+				"--ingroup3",
+				":4",
+				"Completion ended with directive: ShellCompDirectiveNoFileComp", ""}, "\n"),
+		},
+		{
+			desc: "when any flag in group present, other flags in group not suggested without - prefix",
+			args: []string{"child", "--ingroup2", "value", ""},
+			expectedOutput: strings.Join([]string{
+				"subArg",
+				":4",
+				"Completion ended with directive: ShellCompDirectiveNoFileComp", ""}, "\n"),
+		},
+		{
+			desc: "when all flags in group present, flags not suggested without - prefix",
+			args: []string{"child", "--ingroup1", "8", "--ingroup2", "value2", "--ingroup3", ""},
+			expectedOutput: strings.Join([]string{
+				"subArg",
+				":4",
+				"Completion ended with directive: ShellCompDirectiveNoFileComp", ""}, "\n"),
+		},
+		{
+			desc: "group ignored if some flags not applicable",
+			args: []string{"--ingroup2", "value", ""},
+			expectedOutput: strings.Join([]string{
+				"child",
+				"completion",
+				"help",
+				":4",
+				"Completion ended with directive: ShellCompDirectiveNoFileComp", ""}, "\n"),
+		},
+	}
+
+	for _, tc := range testcases {
+		t.Run(tc.desc, func(t *testing.T) {
+			c := getCmd()
+			args := []string{ShellCompNoDescRequestCmd}
+			args = append(args, tc.args...)
+			output, err := executeCommand(c, args...)
+			switch {
+			case err == nil && output != tc.expectedOutput:
+				t.Errorf("expected: %q, got: %q", tc.expectedOutput, output)
+			case err != nil:
+				t.Errorf("Unexpected error %q", err)
+			}
+		})
+	}
+}
+
 func TestCompletionForMutuallyExclusiveFlags(t *testing.T) {
 	getCmd := func() *Command {
 		rootCmd := &Command{
@@ -2991,8 +3198,26 @@ func TestCompletionCobraFlags(t *testing.T) {
 				return []string{"extra3"}, ShellCompDirectiveNoFileComp
 			},
 		}
+		childCmd4 := &Command{
+			Use:     "child4",
+			Version: "1.1.1",
+			Run:     emptyRun,
+			ValidArgsFunction: func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective) {
+				return []string{"extra4"}, ShellCompDirectiveNoFileComp
+			},
+			DisableFlagParsing: true,
+		}
+		childCmd5 := &Command{
+			Use:     "child5",
+			Version: "1.1.1",
+			Run:     emptyRun,
+			ValidArgsFunction: func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective) {
+				return []string{"extra5"}, ShellCompDirectiveNoFileComp
+			},
+			DisableFlagParsing: true,
+		}
 
-		rootCmd.AddCommand(childCmd, childCmd2, childCmd3)
+		rootCmd.AddCommand(childCmd, childCmd2, childCmd3, childCmd4, childCmd5)
 
 		_ = childCmd.Flags().Bool("bool", false, "A bool flag")
 		_ = childCmd.MarkFlagRequired("bool")
@@ -3004,6 +3229,10 @@ func TestCompletionCobraFlags(t *testing.T) {
 		// Have a command that only adds its own -v flag
 		_ = childCmd3.Flags().BoolP("verbose", "v", false, "Not a version flag")
 
+		// Have a command that DisablesFlagParsing but that also adds its own help and version flags
+		_ = childCmd5.Flags().BoolP("help", "h", false, "My own help")
+		_ = childCmd5.Flags().BoolP("version", "v", false, "My own version")
+
 		return rootCmd
 	}
 
@@ -3134,6 +3363,26 @@ func TestCompletionCobraFlags(t *testing.T) {
 				":4",
 				"Completion ended with directive: ShellCompDirectiveNoFileComp", ""}, "\n"),
 		},
+		{
+			desc: "no completion for --help/-h and --version/-v flags when DisableFlagParsing=true",
+			args: []string{"child4", "-"},
+			expectedOutput: strings.Join([]string{
+				"extra4",
+				":4",
+				"Completion ended with directive: ShellCompDirectiveNoFileComp", ""}, "\n"),
+		},
+		{
+			desc: "completions for program-defined --help/-h and --version/-v flags even when DisableFlagParsing=true",
+			args: []string{"child5", "-"},
+			expectedOutput: strings.Join([]string{
+				"--help",
+				"-h",
+				"--version",
+				"-v",
+				"extra5",
+				":4",
+				"Completion ended with directive: ShellCompDirectiveNoFileComp", ""}, "\n"),
+		},
 	}
 
 	for _, tc := range testcases {
@@ -3215,3 +3464,284 @@ Completion ended with directive: ShellCompDirectiveNoFileComp
 		})
 	}
 }
+
+func TestGetFlagCompletion(t *testing.T) {
+	rootCmd := &Command{Use: "root", Run: emptyRun}
+
+	rootCmd.Flags().String("rootflag", "", "root flag")
+	_ = rootCmd.RegisterFlagCompletionFunc("rootflag", func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective) {
+		return []string{"rootvalue"}, ShellCompDirectiveKeepOrder
+	})
+
+	rootCmd.PersistentFlags().String("persistentflag", "", "persistent flag")
+	_ = rootCmd.RegisterFlagCompletionFunc("persistentflag", func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective) {
+		return []string{"persistentvalue"}, ShellCompDirectiveDefault
+	})
+
+	childCmd := &Command{Use: "child", Run: emptyRun}
+
+	childCmd.Flags().String("childflag", "", "child flag")
+	_ = childCmd.RegisterFlagCompletionFunc("childflag", func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective) {
+		return []string{"childvalue"}, ShellCompDirectiveNoFileComp | ShellCompDirectiveNoSpace
+	})
+
+	rootCmd.AddCommand(childCmd)
+
+	testcases := []struct {
+		desc      string
+		cmd       *Command
+		flagName  string
+		exists    bool
+		comps     []string
+		directive ShellCompDirective
+	}{
+		{
+			desc:      "get flag completion function for command",
+			cmd:       rootCmd,
+			flagName:  "rootflag",
+			exists:    true,
+			comps:     []string{"rootvalue"},
+			directive: ShellCompDirectiveKeepOrder,
+		},
+		{
+			desc:      "get persistent flag completion function for command",
+			cmd:       rootCmd,
+			flagName:  "persistentflag",
+			exists:    true,
+			comps:     []string{"persistentvalue"},
+			directive: ShellCompDirectiveDefault,
+		},
+		{
+			desc:      "get flag completion function for child command",
+			cmd:       childCmd,
+			flagName:  "childflag",
+			exists:    true,
+			comps:     []string{"childvalue"},
+			directive: ShellCompDirectiveNoFileComp | ShellCompDirectiveNoSpace,
+		},
+		{
+			desc:      "get persistent flag completion function for child command",
+			cmd:       childCmd,
+			flagName:  "persistentflag",
+			exists:    true,
+			comps:     []string{"persistentvalue"},
+			directive: ShellCompDirectiveDefault,
+		},
+		{
+			desc:     "cannot get flag completion function for local parent flag",
+			cmd:      childCmd,
+			flagName: "rootflag",
+			exists:   false,
+		},
+	}
+
+	for _, tc := range testcases {
+		t.Run(tc.desc, func(t *testing.T) {
+			compFunc, exists := tc.cmd.GetFlagCompletionFunc(tc.flagName)
+			if tc.exists != exists {
+				t.Errorf("Unexpected result looking for flag completion function")
+			}
+
+			if exists {
+				comps, directive := compFunc(tc.cmd, []string{}, "")
+				if strings.Join(tc.comps, " ") != strings.Join(comps, " ") {
+					t.Errorf("Unexpected completions %q", comps)
+				}
+				if tc.directive != directive {
+					t.Errorf("Unexpected directive %q", directive)
+				}
+			}
+		})
+	}
+}
+
+func TestGetEnvConfig(t *testing.T) {
+	testCases := []struct {
+		desc      string
+		use       string
+		suffix    string
+		cmdVar    string
+		globalVar string
+		cmdVal    string
+		globalVal string
+		expected  string
+	}{
+		{
+			desc:      "Command envvar overrides global",
+			use:       "root",
+			suffix:    "test",
+			cmdVar:    "ROOT_TEST",
+			globalVar: "COBRA_TEST",
+			cmdVal:    "cmd",
+			globalVal: "global",
+			expected:  "cmd",
+		},
+		{
+			desc:      "Missing/empty command envvar falls back to global",
+			use:       "root",
+			suffix:    "test",
+			cmdVar:    "ROOT_TEST",
+			globalVar: "COBRA_TEST",
+			cmdVal:    "",
+			globalVal: "global",
+			expected:  "global",
+		},
+		{
+			desc:      "Missing/empty command and global envvars fall back to empty",
+			use:       "root",
+			suffix:    "test",
+			cmdVar:    "ROOT_TEST",
+			globalVar: "COBRA_TEST",
+			cmdVal:    "",
+			globalVal: "",
+			expected:  "",
+		},
+		{
+			desc:      "Periods in command use transform to underscores in env var name",
+			use:       "foo.bar",
+			suffix:    "test",
+			cmdVar:    "FOO_BAR_TEST",
+			globalVar: "COBRA_TEST",
+			cmdVal:    "cmd",
+			globalVal: "global",
+			expected:  "cmd",
+		},
+		{
+			desc:      "Dashes in command use transform to underscores in env var name",
+			use:       "quux-BAZ",
+			suffix:    "test",
+			cmdVar:    "QUUX_BAZ_TEST",
+			globalVar: "COBRA_TEST",
+			cmdVal:    "cmd",
+			globalVal: "global",
+			expected:  "cmd",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.desc, func(t *testing.T) {
+			// Could make env handling cleaner with t.Setenv with Go >= 1.17
+			err := os.Setenv(tc.cmdVar, tc.cmdVal)
+			defer func() {
+				assertNoErr(t, os.Unsetenv(tc.cmdVar))
+			}()
+			assertNoErr(t, err)
+			err = os.Setenv(tc.globalVar, tc.globalVal)
+			defer func() {
+				assertNoErr(t, os.Unsetenv(tc.globalVar))
+			}()
+			assertNoErr(t, err)
+			cmd := &Command{Use: tc.use}
+			got := getEnvConfig(cmd, tc.suffix)
+			if got != tc.expected {
+				t.Errorf("expected: %q, got: %q", tc.expected, got)
+			}
+		})
+	}
+}
+
+func TestDisableDescriptions(t *testing.T) {
+	rootCmd := &Command{
+		Use: "root",
+		Run: emptyRun,
+	}
+
+	childCmd := &Command{
+		Use:   "thechild",
+		Short: "The child command",
+		Run:   emptyRun,
+	}
+	rootCmd.AddCommand(childCmd)
+
+	specificDescriptionsEnvVar := configEnvVar(rootCmd.Name(), configEnvVarSuffixDescriptions)
+	globalDescriptionsEnvVar := configEnvVar(configEnvVarGlobalPrefix, configEnvVarSuffixDescriptions)
+
+	const (
+		descLineWithDescription    = "first\tdescription"
+		descLineWithoutDescription = "first"
+	)
+	childCmd.ValidArgsFunction = func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective) {
+		comps := []string{descLineWithDescription}
+		return comps, ShellCompDirectiveDefault
+	}
+
+	testCases := []struct {
+		desc             string
+		globalEnvValue   string
+		specificEnvValue string
+		expectedLine     string
+	}{
+		{
+			"No env variables set",
+			"",
+			"",
+			descLineWithDescription,
+		},
+		{
+			"Global value false",
+			"false",
+			"",
+			descLineWithoutDescription,
+		},
+		{
+			"Specific value false",
+			"",
+			"false",
+			descLineWithoutDescription,
+		},
+		{
+			"Both values false",
+			"false",
+			"false",
+			descLineWithoutDescription,
+		},
+		{
+			"Both values true",
+			"true",
+			"true",
+			descLineWithDescription,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.desc, func(t *testing.T) {
+			if err := os.Setenv(specificDescriptionsEnvVar, tc.specificEnvValue); err != nil {
+				t.Errorf("Unexpected error setting %s: %v", specificDescriptionsEnvVar, err)
+			}
+			if err := os.Setenv(globalDescriptionsEnvVar, tc.globalEnvValue); err != nil {
+				t.Errorf("Unexpected error setting %s: %v", globalDescriptionsEnvVar, err)
+			}
+
+			var run = func() {
+				output, err := executeCommand(rootCmd, ShellCompRequestCmd, "thechild", "")
+				if err != nil {
+					t.Errorf("Unexpected error: %v", err)
+				}
+
+				expected := strings.Join([]string{
+					tc.expectedLine,
+					":0",
+					"Completion ended with directive: ShellCompDirectiveDefault", ""}, "\n")
+				if output != expected {
+					t.Errorf("expected: %q, got: %q", expected, output)
+				}
+			}
+
+			run()
+
+			// For empty cases, test also unset state
+			if tc.specificEnvValue == "" {
+				if err := os.Unsetenv(specificDescriptionsEnvVar); err != nil {
+					t.Errorf("Unexpected error unsetting %s: %v", specificDescriptionsEnvVar, err)
+				}
+				run()
+			}
+			if tc.globalEnvValue == "" {
+				if err := os.Unsetenv(globalDescriptionsEnvVar); err != nil {
+					t.Errorf("Unexpected error unsetting %s: %v", globalDescriptionsEnvVar, err)
+				}
+				run()
+			}
+		})
+	}
+}

doc/man_docs.go

@@ -133,7 +133,7 @@ func fillHeader(header *GenManHeader, name string, disableAutoGen bool) error {
 		}
 		header.Date = &now
 	}
-	header.date = (*header.Date).Format("Jan 2006")
+	header.date = header.Date.Format("Jan 2006")
 	if header.Source == "" && !disableAutoGen {
 		header.Source = "Auto generated by spf13/cobra"
 	}

doc/man_docs_test.go

@@ -150,7 +150,7 @@ func TestGenManSeeAlso(t *testing.T) {
 	}
 }
 
-func TestManPrintFlagsHidesShortDeperecated(t *testing.T) {
+func TestManPrintFlagsHidesShortDeprecated(t *testing.T) {
 	c := &cobra.Command{}
 	c.Flags().StringP("foo", "f", "default", "Foo flag")
 	assertNoErr(t, c.Flags().MarkShorthandDeprecated("foo", "don't use it no more"))

doc/md_docs.go

@@ -27,6 +27,8 @@ import (
 	"github.com/spf13/cobra"
 )
 
+const markdownExtension = ".md"
+
 func printOptions(buf *bytes.Buffer, cmd *cobra.Command, name string) error {
 	flags := cmd.NonInheritedFlags()
 	flags.SetOutput(buf)
@@ -83,7 +85,7 @@ func GenMarkdownCustom(cmd *cobra.Command, w io.Writer, linkHandler func(string)
 		if cmd.HasParent() {
 			parent := cmd.Parent()
 			pname := parent.CommandPath()
-			link := pname + ".md"
+			link := pname + markdownExtension
 			link = strings.ReplaceAll(link, " ", "_")
 			buf.WriteString(fmt.Sprintf("* [%s](%s)\t - %s\n", pname, linkHandler(link), parent.Short))
 			cmd.VisitParents(func(c *cobra.Command) {
@@ -101,7 +103,7 @@ func GenMarkdownCustom(cmd *cobra.Command, w io.Writer, linkHandler func(string)
 				continue
 			}
 			cname := name + " " + child.Name()
-			link := cname + ".md"
+			link := cname + markdownExtension
 			link = strings.ReplaceAll(link, " ", "_")
 			buf.WriteString(fmt.Sprintf("* [%s](%s)\t - %s\n", cname, linkHandler(link), child.Short))
 		}
@@ -126,7 +128,7 @@ func GenMarkdownTree(cmd *cobra.Command, dir string) error {
 	return GenMarkdownTreeCustom(cmd, dir, emptyStr, identity)
 }
 
-// GenMarkdownTreeCustom is the the same as GenMarkdownTree, but
+// GenMarkdownTreeCustom is the same as GenMarkdownTree, but
 // with custom filePrepender and linkHandler.
 func GenMarkdownTreeCustom(cmd *cobra.Command, dir string, filePrepender, linkHandler func(string) string) error {
 	for _, c := range cmd.Commands() {
@@ -138,7 +140,7 @@ func GenMarkdownTreeCustom(cmd *cobra.Command, dir string, filePrepender, linkHa
 		}
 	}
 
-	basename := strings.ReplaceAll(cmd.CommandPath(), " ", "_") + ".md"
+	basename := strings.ReplaceAll(cmd.CommandPath(), " ", "_") + markdownExtension
 	filename := filepath.Join(dir, basename)
 	f, err := os.Create(filename)
 	if err != nil {

doc/rest_docs.go

@@ -140,7 +140,7 @@ func GenReSTTree(cmd *cobra.Command, dir string) error {
 	return GenReSTTreeCustom(cmd, dir, emptyStr, defaultLinkHandler)
 }
 
-// GenReSTTreeCustom is the the same as GenReSTTree, but
+// GenReSTTreeCustom is the same as GenReSTTree, but
 // with custom filePrepender and linkHandler.
 func GenReSTTreeCustom(cmd *cobra.Command, dir string, filePrepender func(string) string, linkHandler func(string, string) string) error {
 	for _, c := range cmd.Commands() {

doc/util.go

@@ -40,7 +40,7 @@ func hasSeeAlso(cmd *cobra.Command) bool {
 // that do not contain \n.
 func forceMultiLine(s string) string {
 	if len(s) > 60 && !strings.Contains(s, "\n") {
-		s = s + "\n"
+		s += "\n"
 	}
 	return s
 }

flag_groups.go

@@ -23,8 +23,9 @@ import (
 )
 
 const (
-	requiredAsGroup   = "cobra_annotation_required_if_others_set"
-	mutuallyExclusive = "cobra_annotation_mutually_exclusive"
+	requiredAsGroupAnnotation   = "cobra_annotation_required_if_others_set"
+	oneRequiredAnnotation       = "cobra_annotation_one_required"
+	mutuallyExclusiveAnnotation = "cobra_annotation_mutually_exclusive"
 )
 
 // MarkFlagsRequiredTogether marks the given flags with annotations so that Cobra errors
@@ -36,7 +37,23 @@ func (c *Command) MarkFlagsRequiredTogether(flagNames ...string) {
 		if f == nil {
 			panic(fmt.Sprintf("Failed to find flag %q and mark it as being required in a flag group", v))
 		}
-		if err := c.Flags().SetAnnotation(v, requiredAsGroup, append(f.Annotations[requiredAsGroup], strings.Join(flagNames, " "))); err != nil {
+		if err := c.Flags().SetAnnotation(v, requiredAsGroupAnnotation, append(f.Annotations[requiredAsGroupAnnotation], strings.Join(flagNames, " "))); err != nil {
+			// Only errs if the flag isn't found.
+			panic(err)
+		}
+	}
+}
+
+// MarkFlagsOneRequired marks the given flags with annotations so that Cobra errors
+// if the command is invoked without at least one flag from the given set of flags.
+func (c *Command) MarkFlagsOneRequired(flagNames ...string) {
+	c.mergePersistentFlags()
+	for _, v := range flagNames {
+		f := c.Flags().Lookup(v)
+		if f == nil {
+			panic(fmt.Sprintf("Failed to find flag %q and mark it as being in a one-required flag group", v))
+		}
+		if err := c.Flags().SetAnnotation(v, oneRequiredAnnotation, append(f.Annotations[oneRequiredAnnotation], strings.Join(flagNames, " "))); err != nil {
 			// Only errs if the flag isn't found.
 			panic(err)
 		}
@@ -53,13 +70,13 @@ func (c *Command) MarkFlagsMutuallyExclusive(flagNames ...string) {
 			panic(fmt.Sprintf("Failed to find flag %q and mark it as being in a mutually exclusive flag group", v))
 		}
 		// Each time this is called is a single new entry; this allows it to be a member of multiple groups if needed.
-		if err := c.Flags().SetAnnotation(v, mutuallyExclusive, append(f.Annotations[mutuallyExclusive], strings.Join(flagNames, " "))); err != nil {
+		if err := c.Flags().SetAnnotation(v, mutuallyExclusiveAnnotation, append(f.Annotations[mutuallyExclusiveAnnotation], strings.Join(flagNames, " "))); err != nil {
 			panic(err)
 		}
 	}
 }
 
-// ValidateFlagGroups validates the mutuallyExclusive/requiredAsGroup logic and returns the
+// ValidateFlagGroups validates the mutuallyExclusive/oneRequired/requiredAsGroup logic and returns the
 // first error encountered.
 func (c *Command) ValidateFlagGroups() error {
 	if c.DisableFlagParsing {
@@ -71,15 +88,20 @@ func (c *Command) ValidateFlagGroups() error {
 	// groupStatus format is the list of flags as a unique ID,
 	// then a map of each flag name and whether it is set or not.
 	groupStatus := map[string]map[string]bool{}
+	oneRequiredGroupStatus := map[string]map[string]bool{}
 	mutuallyExclusiveGroupStatus := map[string]map[string]bool{}
 	flags.VisitAll(func(pflag *flag.Flag) {
-		processFlagForGroupAnnotation(flags, pflag, requiredAsGroup, groupStatus)
-		processFlagForGroupAnnotation(flags, pflag, mutuallyExclusive, mutuallyExclusiveGroupStatus)
+		processFlagForGroupAnnotation(flags, pflag, requiredAsGroupAnnotation, groupStatus)
+		processFlagForGroupAnnotation(flags, pflag, oneRequiredAnnotation, oneRequiredGroupStatus)
+		processFlagForGroupAnnotation(flags, pflag, mutuallyExclusiveAnnotation, mutuallyExclusiveGroupStatus)
 	})
 
 	if err := validateRequiredFlagGroups(groupStatus); err != nil {
 		return err
 	}
+	if err := validateOneRequiredFlagGroups(oneRequiredGroupStatus); err != nil {
+		return err
+	}
 	if err := validateExclusiveFlagGroups(mutuallyExclusiveGroupStatus); err != nil {
 		return err
 	}
@@ -108,7 +130,7 @@ func processFlagForGroupAnnotation(flags *flag.FlagSet, pflag *flag.Flag, annota
 					continue
 				}
 
-				groupStatus[group] = map[string]bool{}
+				groupStatus[group] = make(map[string]bool, len(flagnames))
 				for _, name := range flagnames {
 					groupStatus[group][name] = false
 				}
@@ -142,6 +164,27 @@ func validateRequiredFlagGroups(data map[string]map[string]bool) error {
 	return nil
 }
 
+func validateOneRequiredFlagGroups(data map[string]map[string]bool) error {
+	keys := sortedKeys(data)
+	for _, flagList := range keys {
+		flagnameAndStatus := data[flagList]
+		var set []string
+		for flagname, isSet := range flagnameAndStatus {
+			if isSet {
+				set = append(set, flagname)
+			}
+		}
+		if len(set) >= 1 {
+			continue
+		}
+
+		// Sort values, so they can be tested/scripted against consistently.
+		sort.Strings(set)
+		return fmt.Errorf("at least one of the flags in the group [%v] is required", flagList)
+	}
+	return nil
+}
+
 func validateExclusiveFlagGroups(data map[string]map[string]bool) error {
 	keys := sortedKeys(data)
 	for _, flagList := range keys {
@@ -176,6 +219,7 @@ func sortedKeys(m map[string]map[string]bool) []string {
 
 // enforceFlagGroupsForCompletion will do the following:
 // - when a flag in a group is present, other flags in the group will be marked required
+// - when none of the flags in a one-required group are present, all flags in the group will be marked required
 // - when a flag in a mutually exclusive group is present, other flags in the group will be marked as hidden
 // This allows the standard completion logic to behave appropriately for flag groups
 func (c *Command) enforceFlagGroupsForCompletion() {
@@ -185,10 +229,12 @@ func (c *Command) enforceFlagGroupsForCompletion() {
 
 	flags := c.Flags()
 	groupStatus := map[string]map[string]bool{}
+	oneRequiredGroupStatus := map[string]map[string]bool{}
 	mutuallyExclusiveGroupStatus := map[string]map[string]bool{}
 	c.Flags().VisitAll(func(pflag *flag.Flag) {
-		processFlagForGroupAnnotation(flags, pflag, requiredAsGroup, groupStatus)
-		processFlagForGroupAnnotation(flags, pflag, mutuallyExclusive, mutuallyExclusiveGroupStatus)
+		processFlagForGroupAnnotation(flags, pflag, requiredAsGroupAnnotation, groupStatus)
+		processFlagForGroupAnnotation(flags, pflag, oneRequiredAnnotation, oneRequiredGroupStatus)
+		processFlagForGroupAnnotation(flags, pflag, mutuallyExclusiveAnnotation, mutuallyExclusiveGroupStatus)
 	})
 
 	// If a flag that is part of a group is present, we make all the other flags
@@ -204,6 +250,26 @@ func (c *Command) enforceFlagGroupsForCompletion() {
 		}
 	}
 
+	// If none of the flags of a one-required group are present, we make all the flags
+	// of that group required so that the shell completion suggests them automatically
+	for flagList, flagnameAndStatus := range oneRequiredGroupStatus {
+		isSet := false
+
+		for _, isSet = range flagnameAndStatus {
+			if isSet {
+				break
+			}
+		}
+
+		// None of the flags of the group are set, mark all flags in the group
+		// as required
+		if !isSet {
+			for _, fName := range strings.Split(flagList, " ") {
+				_ = c.MarkFlagRequired(fName)
+			}
+		}
+	}
+
 	// If a flag that is mutually exclusive to others is present, we hide the other
 	// flags of that group so the shell completion does not suggest them
 	for flagList, flagnameAndStatus := range mutuallyExclusiveGroupStatus {

flag_groups_test.go

@@ -45,8 +45,10 @@ func TestValidateFlagGroups(t *testing.T) {
 	testcases := []struct {
 		desc                        string
 		flagGroupsRequired          []string
+		flagGroupsOneRequired       []string
 		flagGroupsExclusive         []string
 		subCmdFlagGroupsRequired    []string
+		subCmdFlagGroupsOneRequired []string
 		subCmdFlagGroupsExclusive   []string
 		args                        []string
 		expectErr                   string
@@ -62,6 +64,11 @@ func TestValidateFlagGroups(t *testing.T) {
 			flagGroupsRequired: []string{"a b c"},
 			args:               []string{"--a=foo"},
 			expectErr:          "if any flags in the group [a b c] are set they must all be set; missing [b c]",
+		}, {
+			desc:                  "One-required flag group not satisfied",
+			flagGroupsOneRequired: []string{"a b"},
+			args:                  []string{"--c=foo"},
+			expectErr:             "at least one of the flags in the group [a b] is required",
 		}, {
 			desc:                "Exclusive flag group not satisfied",
 			flagGroupsExclusive: []string{"a b c"},
@@ -72,6 +79,11 @@ func TestValidateFlagGroups(t *testing.T) {
 			flagGroupsRequired: []string{"a b c", "a d"},
 			args:               []string{"--c=foo", "--d=foo"},
 			expectErr:          `if any flags in the group [a b c] are set they must all be set; missing [a b]`,
+		}, {
+			desc:                  "Multiple one-required flag group not satisfied returns first error",
+			flagGroupsOneRequired: []string{"a b", "d e"},
+			args:                  []string{"--c=foo", "--f=foo"},
+			expectErr:             `at least one of the flags in the group [a b] is required`,
 		}, {
 			desc:                "Multiple exclusive flag group not satisfied returns first error",
 			flagGroupsExclusive: []string{"a b c", "a d"},
@@ -82,32 +94,57 @@ func TestValidateFlagGroups(t *testing.T) {
 			flagGroupsRequired: []string{"a d", "a b", "a c"},
 			args:               []string{"--a=foo"},
 			expectErr:          `if any flags in the group [a b] are set they must all be set; missing [b]`,
+		}, {
+			desc:                  "Validation of one-required groups occurs on groups in sorted order",
+			flagGroupsOneRequired: []string{"d e", "a b", "f g"},
+			args:                  []string{"--c=foo"},
+			expectErr:             `at least one of the flags in the group [a b] is required`,
 		}, {
 			desc:                "Validation of exclusive groups occurs on groups in sorted order",
 			flagGroupsExclusive: []string{"a d", "a b", "a c"},
 			args:                []string{"--a=foo", "--b=foo", "--c=foo"},
 			expectErr:           `if any flags in the group [a b] are set none of the others can be; [a b] were all set`,
 		}, {
-			desc:                "Persistent flags utilize both features and can fail required groups",
+			desc:                "Persistent flags utilize required and exclusive groups and can fail required groups",
 			flagGroupsRequired:  []string{"a e", "e f"},
 			flagGroupsExclusive: []string{"f g"},
 			args:                []string{"--a=foo", "--f=foo", "--g=foo"},
 			expectErr:           `if any flags in the group [a e] are set they must all be set; missing [e]`,
 		}, {
-			desc:                "Persistent flags utilize both features and can fail mutually exclusive groups",
+			desc:                  "Persistent flags utilize one-required and exclusive groups and can fail one-required groups",
+			flagGroupsOneRequired: []string{"a b", "e f"},
+			flagGroupsExclusive:   []string{"e f"},
+			args:                  []string{"--e=foo"},
+			expectErr:             `at least one of the flags in the group [a b] is required`,
+		}, {
+			desc:                "Persistent flags utilize required and exclusive groups and can fail mutually exclusive groups",
 			flagGroupsRequired:  []string{"a e", "e f"},
 			flagGroupsExclusive: []string{"f g"},
 			args:                []string{"--a=foo", "--e=foo", "--f=foo", "--g=foo"},
 			expectErr:           `if any flags in the group [f g] are set none of the others can be; [f g] were all set`,
 		}, {
-			desc:                "Persistent flags utilize both features and can pass",
+			desc:                "Persistent flags utilize required and exclusive groups and can pass",
 			flagGroupsRequired:  []string{"a e", "e f"},
 			flagGroupsExclusive: []string{"f g"},
 			args:                []string{"--a=foo", "--e=foo", "--f=foo"},
+		}, {
+			desc:                  "Persistent flags utilize one-required and exclusive groups and can pass",
+			flagGroupsOneRequired: []string{"a e", "e f"},
+			flagGroupsExclusive:   []string{"f g"},
+			args:                  []string{"--a=foo", "--e=foo", "--f=foo"},
 		}, {
 			desc:                     "Subcmds can use required groups using inherited flags",
 			subCmdFlagGroupsRequired: []string{"e subonly"},
 			args:                     []string{"subcmd", "--e=foo", "--subonly=foo"},
+		}, {
+			desc:                        "Subcmds can use one-required groups using inherited flags",
+			subCmdFlagGroupsOneRequired: []string{"e subonly"},
+			args:                        []string{"subcmd", "--e=foo", "--subonly=foo"},
+		}, {
+			desc:                        "Subcmds can use one-required groups using inherited flags and fail one-required groups",
+			subCmdFlagGroupsOneRequired: []string{"e subonly"},
+			args:                        []string{"subcmd"},
+			expectErr:                   "at least one of the flags in the group [e subonly] is required",
 		}, {
 			desc:                      "Subcmds can use exclusive groups using inherited flags",
 			subCmdFlagGroupsExclusive: []string{"e subonly"},
@@ -130,12 +167,18 @@ func TestValidateFlagGroups(t *testing.T) {
 			for _, flagGroup := range tc.flagGroupsRequired {
 				c.MarkFlagsRequiredTogether(strings.Split(flagGroup, " ")...)
 			}
+			for _, flagGroup := range tc.flagGroupsOneRequired {
+				c.MarkFlagsOneRequired(strings.Split(flagGroup, " ")...)
+			}
 			for _, flagGroup := range tc.flagGroupsExclusive {
 				c.MarkFlagsMutuallyExclusive(strings.Split(flagGroup, " ")...)
 			}
 			for _, flagGroup := range tc.subCmdFlagGroupsRequired {
 				sub.MarkFlagsRequiredTogether(strings.Split(flagGroup, " ")...)
 			}
+			for _, flagGroup := range tc.subCmdFlagGroupsOneRequired {
+				sub.MarkFlagsOneRequired(strings.Split(flagGroup, " ")...)
+			}
 			for _, flagGroup := range tc.subCmdFlagGroupsExclusive {
 				sub.MarkFlagsMutuallyExclusive(strings.Split(flagGroup, " ")...)
 			}

go.mod

@@ -3,7 +3,7 @@ module github.com/spf13/cobra
 go 1.15
 
 require (
-	github.com/cpuguy83/go-md2man/v2 v2.0.2
+	github.com/cpuguy83/go-md2man/v2 v2.0.4
 	github.com/inconshreveable/mousetrap v1.1.0
 	github.com/spf13/pflag v1.0.5
 	gopkg.in/yaml.v3 v3.0.1

go.sum

@@ -1,5 +1,5 @@
-github.com/cpuguy83/go-md2man/v2 v2.0.2 h1:p1EgwI/C7NhT0JmVkwCD2ZBK8j4aeHQX2pMHHBfMQ6w=
-github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
+github.com/cpuguy83/go-md2man/v2 v2.0.4 h1:wfIWP927BUkWJb2NmU/kNDYIBTh/ziUX91+lVfRxZq4=
+github.com/cpuguy83/go-md2man/v2 v2.0.4/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/russross/blackfriday/v2 v2.1.0 h1:JIOH55/0cWyOuilr9/qlrm0BSXldqnqwMsf35Ld67mk=

powershell_completions.go

@@ -28,8 +28,8 @@ import (
 func genPowerShellComp(buf io.StringWriter, name string, includeDesc bool) {
 	// Variables should not contain a '-' or ':' character
 	nameForVar := name
-	nameForVar = strings.Replace(nameForVar, "-", "_", -1)
-	nameForVar = strings.Replace(nameForVar, ":", "_", -1)
+	nameForVar = strings.ReplaceAll(nameForVar, "-", "_")
+	nameForVar = strings.ReplaceAll(nameForVar, ":", "_")
 
 	compCmd := ShellCompRequestCmd
 	if !includeDesc {

site/content/active_help.md

@@ -92,7 +92,7 @@ Allowing to configure Active Help is entirely optional; you can use Active Help
 
 The way to configure Active Help is to use the program's Active Help environment
 variable.  That variable is named `<PROGRAM>_ACTIVE_HELP` where `<PROGRAM>` is the name of your 
-program in uppercase with any `-` replaced by an `_`.  The variable should be set by the user to whatever
+program in uppercase with any non-ASCII-alphanumeric characters replaced by an `_`.  The variable should be set by the user to whatever
 Active Help configuration values are supported by the program.
 
 For example, say `helm` has chosen to support three levels for Active Help: `on`, `off`, `local`.  Then a user
@@ -140,7 +140,7 @@ details for your users.
 
 Debugging your Active Help code is done in the same way as debugging your dynamic completion code, which is with Cobra's hidden `__complete` command.  Please refer to [debugging shell completion](shell_completions.md#debugging) for details.
 
-When debugging with the `__complete` command, if you want to specify different Active Help configurations, you should use the active help environment variable.  That variable is named `<PROGRAM>_ACTIVE_HELP` where any `-` is replaced by an `_`.  For example, we can test deactivating some Active Help as shown below:
+When debugging with the `__complete` command, if you want to specify different Active Help configurations, you should use the active help environment variable.  That variable is named `<PROGRAM>_ACTIVE_HELP` where any non-ASCII-alphanumeric characters are replaced by an `_`.  For example, we can test deactivating some Active Help as shown below:
 ```
 $ HELM_ACTIVE_HELP=1 bin/helm __complete install wordpress bitnami/h<ENTER>
 bitnami/haproxy

site/content/completions/_index.md

@@ -393,6 +393,9 @@ $ source <(helm completion bash --no-descriptions)
 $ helm completion [tab][tab]
 bash        fish        powershell  zsh
 ```
+
+Setting the `<PROGRAM>_COMPLETION_DESCRIPTIONS` environment variable (falling back to `COBRA_COMPLETION_DESCRIPTIONS` if empty or not set) to a [falsey value](https://pkg.go.dev/strconv#ParseBool) achieves the same. `<PROGRAM>` is the name of your program with all non-ASCII-alphanumeric characters replaced by `_`.
+
 ## Bash completions
 
 ### Dependencies

site/content/projects_using_cobra.md

@@ -12,6 +12,7 @@
 - [Datree](https://github.com/datreeio/datree)
 - [Delve](https://github.com/derekparker/delve)
 - [Docker (distribution)](https://github.com/docker/distribution)
+- [Encore](https://encore.dev)
 - [Etcd](https://etcd.io/)
 - [Gardener](https://github.com/gardener/gardenctl)
 - [Giant Swarm's gsctl](https://github.com/giantswarm/gsctl)
@@ -23,6 +24,7 @@
 - [GoReleaser](https://goreleaser.com)
 - [Helm](https://helm.sh)
 - [Hugo](https://gohugo.io)
+- [Incus](https://linuxcontainers.org/incus/)
 - [Infracost](https://github.com/infracost/infracost)
 - [Istio](https://istio.io)
 - [Kool](https://github.com/kool-dev/kool)
@@ -30,6 +32,7 @@
 - [Kubescape](https://github.com/kubescape/kubescape)
 - [KubeVirt](https://github.com/kubevirt/kubevirt)
 - [Linkerd](https://linkerd.io/)
+- [LXC](https://github.com/canonical/lxd)
 - [Mattermost-server](https://github.com/mattermost/mattermost-server)
 - [Mercure](https://mercure.rocks/)
 - [Meroxa CLI](https://github.com/meroxa/cli)
@@ -55,10 +58,12 @@
 - [Scaleway CLI](https://github.com/scaleway/scaleway-cli)
 - [Sia](https://github.com/SiaFoundation/siad)
 - [Skaffold](https://skaffold.dev/)
+- [Taikun](https://taikun.cloud/)
 - [Tendermint](https://github.com/tendermint/tendermint)
 - [Twitch CLI](https://github.com/twitchdev/twitch-cli)
 - [UpCloud CLI (`upctl`)](https://github.com/UpCloudLtd/upcloud-cli)
 - [Vitess](https://vitess.io)
 - VMware's [Tanzu Community Edition](https://github.com/vmware-tanzu/community-edition) & [Tanzu Framework](https://github.com/vmware-tanzu/tanzu-framework)
 - [Werf](https://werf.io/)
+- [Zarf](https://github.com/defenseunicorns/zarf)
 - [ZITADEL](https://github.com/zitadel/zitadel)

site/content/user_guide.md

@@ -3,7 +3,7 @@
 While you are welcome to provide your own organization, typically a Cobra-based
 application will follow the following organizational structure:
 
-```
+```test
   ▾ appName/
     ▾ cmd/
         add.go
@@ -301,6 +301,7 @@ command := cobra.Command{
 ### Bind Flags with Config
 
 You can also bind your flags with [viper](https://github.com/spf13/viper):
+
 ```go
 var author string
 
@@ -320,12 +321,14 @@ More in [viper documentation](https://github.com/spf13/viper#working-with-flags)
 
 Flags are optional by default. If instead you wish your command to report an error
 when a flag has not been set, mark it as required:
+
 ```go
 rootCmd.Flags().StringVarP(&Region, "region", "r", "", "AWS region (required)")
 rootCmd.MarkFlagRequired("region")
 ```
 
 Or, for persistent flags:
+
 ```go
 rootCmd.PersistentFlags().StringVarP(&Region, "region", "r", "", "AWS region (required)")
 rootCmd.MarkPersistentFlagRequired("region")
@@ -335,6 +338,7 @@ rootCmd.MarkPersistentFlagRequired("region")
 
 If you have different flags that must be provided together (e.g. if they provide the `--username` flag they MUST provide the `--password` flag as well) then
 Cobra can enforce that requirement:
+
 ```go
 rootCmd.Flags().StringVarP(&u, "username", "u", "", "Username (required if password is set)")
 rootCmd.Flags().StringVarP(&pw, "password", "p", "", "Password (required if username is set)")
@@ -343,13 +347,24 @@ rootCmd.MarkFlagsRequiredTogether("username", "password")
 
 You can also prevent different flags from being provided together if they represent mutually
 exclusive options such as specifying an output format as either `--json` or `--yaml` but never both:
+
 ```go
 rootCmd.Flags().BoolVar(&ofJson, "json", false, "Output in JSON")
 rootCmd.Flags().BoolVar(&ofYaml, "yaml", false, "Output in YAML")
 rootCmd.MarkFlagsMutuallyExclusive("json", "yaml")
 ```
 
-In both of these cases:
+If you want to require at least one flag from a group to be present, you can use `MarkFlagsOneRequired`.
+This can be combined with `MarkFlagsMutuallyExclusive` to enforce exactly one flag from a given group:
+
+```go
+rootCmd.Flags().BoolVar(&ofJson, "json", false, "Output in JSON")
+rootCmd.Flags().BoolVar(&ofYaml, "yaml", false, "Output in YAML")
+rootCmd.MarkFlagsOneRequired("json", "yaml")
+rootCmd.MarkFlagsMutuallyExclusive("json", "yaml")
+```
+
+In these cases:
   - both local and persistent flags can be used
     - **NOTE:** the group is only enforced on commands where every flag is defined
   - a flag may appear in multiple groups
@@ -419,7 +434,7 @@ by not providing a 'Run' for the 'rootCmd'.
 
 We have only defined one flag for a single command.
 
-More documentation about flags is available at https://github.com/spf13/pflag
+More documentation about flags is available at https://github.com/spf13/pflag.
 
 ```go
 package main
@@ -587,9 +602,15 @@ Running an application with the '--version' flag will print the version to stdou
 the version template. The template can be customized using the
 `cmd.SetVersionTemplate(s string)` function.
 
+## Error Message Prefix
+
+Cobra prints an error message when receiving a non-nil error value.
+The default error message is `Error: <error contents>`.
+The Prefix, `Error:` can be customized using the `cmd.SetErrPrefix(s string)` function.
+
 ## PreRun and PostRun Hooks
 
-It is possible to run functions before or after the main `Run` function of your command. The `PersistentPreRun` and `PreRun` functions will be executed before `Run`. `PersistentPostRun` and `PostRun` will be executed after `Run`.  The `Persistent*Run` functions will be inherited by children if they do not declare their own.  These functions are run in the following order:
+It is possible to run functions before or after the main `Run` function of your command. The `PersistentPreRun` and `PreRun` functions will be executed before `Run`. `PersistentPostRun` and `PostRun` will be executed after `Run`.  The `Persistent*Run` functions will be inherited by children if they do not declare their own.  The `*PreRun` and `*PostRun` functions will only be executed if the `Run` function of the current command has been declared.  These functions are run in the following order:
 
 - `PersistentPreRun`
 - `PreRun`
@@ -672,6 +693,10 @@ Inside subCmd PostRun with args: [arg1 arg2]
 Inside subCmd PersistentPostRun with args: [arg1 arg2]
 ```
 
+By default, only the first persistent hook found in the command chain is executed.
+That is why in the above output, the `rootCmd PersistentPostRun` was not called for a child command.
+Set `EnableTraverseRunHooks` global variable to `true` if you want to execute all parents' persistent hooks.
+
 ## Suggestions when "unknown command" happens
 
 Cobra will print automatic suggestions when "unknown command" errors happen. This allows Cobra to behave similarly to the `git` command when a typo happens. For example:
@@ -703,7 +728,7 @@ command.SuggestionsMinimumDistance = 1
 You can also explicitly set names for which a given command will be suggested using the `SuggestFor` attribute. This allows suggestions for strings that are not close in terms of string distance, but make sense in your set of commands but for which
 you don't want aliases. Example:
 
-```
+```bash
 $ kubectl remove
 Error: unknown command "remove" for "kubectl"
 
@@ -729,3 +754,57 @@ Read more about it in [Shell Completions](completions/_index.md).
 Cobra makes use of the shell-completion system to define a framework allowing you to provide Active Help to your users.
 Active Help are messages (hints, warnings, etc) printed as the program is being used.
 Read more about it in [Active Help](active_help.md).
+
+## Creating a plugin
+
+When creating a plugin for tools like *kubectl*, the executable is named
+`kubectl-myplugin`, but it is used as `kubectl myplugin`. To fix help
+messages and completions, annotate the root command with the
+`cobra.CommandDisplayNameAnnotation` annotation.
+
+### Example kubectl plugin
+
+```go
+package main
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+)
+
+func main() {
+	rootCmd := &cobra.Command{
+		Use: "kubectl-myplugin",
+		Annotations: map[string]string{
+			cobra.CommandDisplayNameAnnotation: "kubectl myplugin",
+		},
+	}
+	subCmd := &cobra.Command{
+		Use: "subcmd",
+		Run: func(cmd *cobra.Command, args []string) {
+			fmt.Println("kubectl myplugin subcmd")
+		},
+	}
+	rootCmd.AddCommand(subCmd)
+	rootCmd.Execute()
+}
+```
+
+Example run as a kubectl plugin:
+
+```bash
+$ kubectl myplugin
+Usage:
+  kubectl myplugin [command]
+
+Available Commands:
+  completion  Generate the autocompletion script for the specified shell
+  help        Help about any command
+  subcmd
+
+Flags:
+  -h, --help   help for kubectl myplugin
+
+Use "kubectl myplugin [command] --help" for more information about a command.
+```