From 755d026045bf85e0048d56e05e920d3d2fa0d455 Mon Sep 17 00:00:00 2001
From: Yoshiki Fujikane <40124947+ffjlabo@users.noreply.github.com>
Date: Wed, 5 Jul 2023 22:46:18 +0900
Subject: [PATCH] Output usage only when flag parsing fails #4381 (#4464)

Signed-off-by: Yoshiki Fujikane <ffjlabo@gmail.com>
Signed-off-by: Kenta Kozuka <kenta.kozuka@gmail.com>
---
 pkg/cli/app.go | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/pkg/cli/app.go b/pkg/cli/app.go
index 7afb18bf65..8d578d4a30 100644
--- a/pkg/cli/app.go
+++ b/pkg/cli/app.go
@@ -15,6 +15,7 @@
 package cli
 
 import (
+	"errors"
 	"fmt"
 
 	"github.com/spf13/cobra"
@@ -29,15 +30,23 @@ type App struct {
 	telemetryFlags TelemetryFlags
 }
 
+var FlagParseErr = errors.New("FlagParseErr")
+
 func NewApp(name, desc string) *App {
 	a := &App{
 		rootCmd: &cobra.Command{
 			Use:           name,
 			Short:         desc,
 			SilenceErrors: true,
+			SilenceUsage:  true,
 		},
 		telemetryFlags: defaultTelemetryFlags,
 	}
+	a.rootCmd.SetFlagErrorFunc(func(cmd *cobra.Command, err error) error {
+		cmd.Println(err)
+		cmd.Println(cmd.UsageString())
+		return FlagParseErr
+	})
 	versionCmd := &cobra.Command{
 		Use:   "version",
 		Short: "Print the information of current binary.",