fix(server/v2): return ErrHelp (backport #22399) (#22400)

Co-authored-by: Matt Kocubinski <mkocubinski@gmail.com>
Co-authored-by: Julien Robert <julien@rbrt.fr>

simapp/v2/simdv2/cmd/root_di.go

@@ -1,7 +1,10 @@
 package cmd
 
 import (
+	"errors"
+
 	"github.com/spf13/cobra"
+	"github.com/spf13/pflag"
 
 	autocliv1 "cosmossdk.io/api/cosmos/autocli/v1"
 	"cosmossdk.io/client/v2/autocli"
@@ -38,6 +41,9 @@ func NewRootCmd[T transaction.Tx](
 
 	subCommand, configMap, logger, err := factory.ParseCommand(rootCommand, args)
 	if err != nil {
+		if errors.Is(err, pflag.ErrHelp) {
+			return rootCommand, nil
+		}
 		return nil, err
 	}
 

simapp/v2/simdv2/cmd/root_test.go

@@ -1,6 +1,7 @@
 package cmd_test
 
 import (
+	"bytes"
 	"fmt"
 	"testing"
 
@@ -42,3 +43,25 @@ func TestHomeFlagRegistration(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, result, homeDir)
 }
+
+func TestHelpRequested(t *testing.T) {
+	argz := [][]string{
+		{"query", "--help"},
+		{"query", "tx", "-h"},
+		{"--help"},
+		{"start", "-h"},
+	}
+
+	for _, args := range argz {
+		rootCmd, err := cmd.NewRootCmd[transaction.Tx](args...)
+		require.NoError(t, err)
+
+		var out bytes.Buffer
+		rootCmd.SetArgs(args)
+		rootCmd.SetOut(&out)
+		require.NoError(t, rootCmd.Execute())
+		require.Contains(t, out.String(), args[0])
+		require.Contains(t, out.String(), "--help")
+		require.Contains(t, out.String(), "Usage:")
+	}
+}