Add env variable to suppress completion descriptions on create (#1938)

COBRA_COMPLETION_DESCRIPTIONS=0 
or 
<PROGRAM>_COMPLETION_DESCRIPTIONS=0
can now be used to disable shell completion descriptions.

active_help.go

@@ -17,21 +17,17 @@ package cobra
 import (
 	"fmt"
 	"os"
-	"regexp"
-	"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"
 )
 
-var activeHelpEnvVarPrefixSubstRegexp = regexp.MustCompile(`[^A-Z0-9_]`)
-
 // AppendActiveHelp adds the specified string to the specified array to be used as ActiveHelp.
 // Such strings will be processed by the completion script and will be shown as ActiveHelp
 // to the user.
@@ -60,8 +56,5 @@ func GetActiveHelpConfig(cmd *Command) string {
 // variable.  It has the format <PROGRAM>_ACTIVE_HELP where <PROGRAM> is the name of the
 // 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))
-	activeHelpEnvVar = activeHelpEnvVarPrefixSubstRegexp.ReplaceAllString(activeHelpEnvVar, "_")
-	return activeHelpEnvVar
+	return configEnvVar(name, activeHelpEnvVarSuffix)
 }

completions.go

@@ -17,6 +17,8 @@ package cobra
 import (
 	"fmt"
 	"os"
+	"regexp"
+	"strconv"
 	"strings"
 	"sync"
 
@@ -211,7 +213,12 @@ func (c *Command) initCompleteCmd(args []string) {
 				// 2- Even without completions, we need to print the directive
 			}
 
-			noDescriptions := (cmd.CalledAs() == ShellCompNoDescRequestCmd)
+			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 {
@@ -899,3 +906,34 @@ 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

@@ -18,6 +18,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"os"
 	"strings"
 	"sync"
 	"testing"
@@ -3517,3 +3518,194 @@ func TestGetFlagCompletion(t *testing.T) {
 		})
 	}
 }
+
+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()
+			}
+		})
+	}
+}

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