fix(cli/clibase): don't error on required flags with --help (#12181)

cli/clibase/cmd.go

@@ -383,7 +383,8 @@ func (inv *Invocation) run(state *runState) error {
 			missing = append(missing, opt.Flag)
 		}
 	}
-	if len(missing) > 0 {
+	// Don't error for missing flags if `--help` was supplied.
+	if len(missing) > 0 && !errors.Is(state.flagParseErr, pflag.ErrHelp) {
 		return xerrors.Errorf("Missing values for the required flags: %s", strings.Join(missing, ", "))
 	}
 

cli/clibase/cmd_test.go

@@ -79,6 +79,10 @@ func TestCommand(t *testing.T) {
 							Required: true,
 						},
 					},
+					HelpHandler: func(i *clibase.Invocation) error {
+						_, _ = i.Stdout.Write([]byte("help text.png"))
+						return nil
+					},
 					Handler: func(i *clibase.Invocation) error {
 						_, _ = i.Stdout.Write([]byte(fmt.Sprintf("%s-%t", reqStr, reqBool)))
 						return nil
@@ -255,6 +259,18 @@ func TestCommand(t *testing.T) {
 		require.ErrorContains(t, err, "Missing values")
 	})
 
+	t.Run("RequiredFlagsMissingWithHelp", func(t *testing.T) {
+		t.Parallel()
+		i := cmd().Invoke(
+			"required-flag",
+			"--help",
+		)
+		fio := fakeIO(i)
+		err := i.Run()
+		require.NoError(t, err)
+		require.Contains(t, fio.Stdout.String(), "help text.png")
+	})
+
 	t.Run("RequiredFlagsMissingBool", func(t *testing.T) {
 		t.Parallel()
 		i := cmd().Invoke(