AppHelpTemplate does not work under having required Flag and not having subcommand

[yyamanoi1222]

My urfave/cli version is

v2.23.5

Checklist

• Are you running the latest v2 release? The list of releases is here.
• Did you check the manual for your release? The v2 manual is here
• Did you perform a search about this problem? Here's the GitHub guide about searching.

Dependency Management

• My project is using go modules.

Describe the bug

My apologies if this is an existing issue.
AppHelpTemplate does not work under having required Flag and not having subcommand

To reproduce

main.go

package main

import (
  "github.com/urfave/cli/v2"
  "os"
  "fmt"
)

func main() {
  cli.AppHelpTemplate = ``
  app := cli.App{
    Name: "test app",
    Action: func(ctx *cli.Context) error {
      return nil
    },
    Flags: []cli.Flag{
      &cli.StringFlag{
        Name: "test",
        Required: true,
      },
    },
  }
  if err := app.Run(os.Args); err != nil {
    fmt.Printf("error %s", err)
  }
}

Observed behavior

$ go run main.go
NAME:
   test app - A new cli application

USAGE:
   test app command [command options] [arguments...]

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

OPTIONS:
   --test value  
   --help, -h    show help (default: false)
error Required flag "test" not set%                                                                                                                                                                                                                                                                                          
yamaoni% go run main.go                                                                                                                                                                                                                                                             [HEAD ~/ghq/github.com/yamanoi/cli-test]
NAME:
   test app - A new cli application

USAGE:
   test app command [command options] [arguments...]

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

OPTIONS:
   --test value  
   --help, -h    show help (default: false)
error Required flag "test" not set%

Expected behavior

$ go run main.go
error Required flag "test" not set%

Additional context

If I putsgo run main.go -h, the output is expected behavior

$ go run main.go -h

Want to fix this yourself?

yes

Run go version and paste its output here

go version go1.18.4 linux/amd64

[dearchap]

Duplicate of #1247

[dearchap]

@yyamanoi1222 Would you like to submit a fix for this ?

[yyamanoi1222]

@dearchap Sorry, I must have missed it.
I'd like to submit a PR

[yyamanoi1222]

@dearchap
I think that my issue is slightly different from issue #1247.
I think that issue #1247 is caused by checkHelp slipping through when executing the help command.
My issue is that when executing the root command not a executing help, a SubcommandHelpTemplate is drawn instead of the AppHelpTemplate if a required parameter is missing.

If my perception is different, feel free to tell me.

[yyamanoi1222]

so I think that the thing i have to is that changing
this method call to drawing appropriate help template by ctx

[dearchap]

@yyamanoi1222 Can you check if the PR fixes your issue ?