CustomHelpTemplate is ignored with --help flag

[feedmeapples]

My urfave/cli version is

2.25.0

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.
• My project is automatically downloading the latest version.

Describe the bug

While cli top-level-command help respects CustomHelpTemplate when printing help, cli top-level-command --help ignores it and prints SubcommandHelpTemplate instead.

Is this intentional? What is the purpose of SubcommandHelpTemplate?

If this is not intentional i can send a PR switching to CustomHelpTemplate

To reproduce

app := cli.NewApp()
	app.Name = "testapp"
        app.Commands = []*cli.Command{
		        {
			        Name:   "top-level-command",
			        Action: func(c *cli.Context) error { return nil },
			        CustomHelpTemplate: "TESTING",
			 }
}

go run ./cmd/app top-level-command --help

Observed behavior

It prints SubcommandHelpTemplate

Expected behavior

go run ./cmd/app top-level-command --help should print CustomHelpTemplate

Additional context

temporalio/cli#153

Want to fix this yourself?

Yes

Run go version and paste its output here

go version

Run go env and paste its output here

[dearchap]

@feedmeapples Can you post your whole main.go file here. ? I want to double check some things. The behaviour is really really tricky to get right.

[jojje]

Here's a small main.go that reproduces the issue.

package main

import (
	"log"
	"os"

	"github.com/urfave/cli/v2"
)

func main() {
	app := &cli.App{
		Name: "myapp",
		Commands: []*cli.Command{
			{
				Name:               "subcmd",
				CustomHelpTemplate: "My template",
				// HideHelpCommand:    true,
				Action: func(c *cli.Context) error {
					return nil
				},
			},
		},
	}
	if err := app.Run(os.Args); err != nil {
		log.Fatal(err)
	}
}

This code has the right behavior,

$ go run main.go subcmd -h
My template

But if you comment in the HideHelpCommand line, the custom template is not used, but the default hard-coded one.

$ go run main.go subcmd -h
NAME:
   myapp subcmd

USAGE:
   myapp subcmd command [command options] [arguments...]

OPTIONS:
   --help, -h  show help

The problem seems to be here, where the fall-through results in the hard coded template being used.