Why is the help displayed despite a flag being present?

[wsw70]

package main

import (
	"fmt"
	"os"
	"time"

	"github.com/rs/zerolog/log"
	"github.com/urfave/cli/v2"
)

func main() {
	app := &cli.App{
		Name:     "syncthing-map",
		Compiled: time.Now(),
		Flags: []cli.Flag{
			&cli.BoolFlag{
				Name:  "version",
				Usage: "show details about syncthing-map",
				Action: func(ctx *cli.Context, isSet bool) error {
					fmt.Printf("version information will be displayed here")
					return nil
				},
			},
		},
	}
	if err := app.Run(os.Args); err != nil {
		log.Fatal().Msgf("error running the application: %v", err)
	}
}

When running the above with

go run . --version

I get

version information will be displayed hereNAME:
   syncthing-map - A new cli application

USAGE:
   syncthing-map [global options] command [command options] [arguments...]

COMMANDS:
   help, h  Shows a list of commands or help for one command

GLOBAL OPTIONS:
   --version   show details about syncthing-map (default: false)
   --help, -h  show help (default: false)

The Action in the flag --version was processed correctly (very first line of the output), and despite this the help was displayed as well. Why?

How can I "break" the execution in a flag Action?

[dearchap]

The Action func of Command or App was designed for this. Flag action func are a recent addition and were supposed to trigger some functionality if flag was set. If you set

App.Action = func(ctx *cli context) error { 
                               return nil 
                       }

Then the help wont be printed