Don't complete --help flag when flag parsing disabled

Fixes #2060

When a command sets `DisableFlagParsing = true` it requests the
responsibility of doing all the flag parsing. Therefore even the
`--help/-f/--version/-v` flags should not be automatically completed
by Cobra in such a case.

Without this change the `--help/-h/--version/-v` flags can end up being
completed twice for plugins: one time from cobra and one time from the
plugin (which has set `DisableFlagParsing = true`).

Signed-off-by: Marc Khouzam <marc.khouzam@gmail.com>

completions.go

@@ -302,9 +302,13 @@ func (c *Command) getCompletions(args []string) (*Command, []string, ShellCompDi
 
 	// 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.
-	finalCmd.InitDefaultHelpFlag()
-	finalCmd.InitDefaultVersionFlag()
+	// 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
@@ -408,6 +412,11 @@ 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)
 			})

completions_test.go

@@ -2622,8 +2622,6 @@ func TestCompleteWithDisableFlagParsing(t *testing.T) {
 	expected := strings.Join([]string{
 		"--persistent",
 		"-p",
-		"--help",
-		"-h",
 		"--nonPersistent",
 		"-n",
 		"--flag",
@@ -3053,8 +3051,26 @@ 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")
@@ -3066,6 +3082,10 @@ 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
 	}
 
@@ -3196,6 +3216,26 @@ 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 {