Hi 👋
First of all, thank you for your awesome work! The Kong is perfect ❤️

What happened

I ran into the following problem. I have an application with no additional commands. Meanwhile, I have a custom config resolver for .env files ("github.com/bluegosolutions/kong-dotenv-go", it's the same as in #156).

Here's a sample of my code:

package main

import (
    // other imports
	"github.com/alecthomas/kong"
	dotenv "github.com/bluegosolutions/kong-dotenv-go"
)

// App defines the service and all its configs
type App struct {
	// You can pass an .env file as a config: <command_name> --env-file=./.env
	EnvFile kong.ConfigFlag `kong:"optional,name=env-file,help='Path to .env file'"`
	// HTTP server configurator
	HTTPServer HTTPServerFlags `kong:"embed"`
}

type HTTPServerFlags struct {
	Address string `kong:"required,group='HTTP Server',name=http-address,env='HTTP_ADDR',default=':8080',help='The HTTP address <host>:<port> of the main server.'"`
}

func main() {
	var app App
	ctx := kong.Parse(&app, kong.Configuration(dotenv.ENVFile))
	ctx.FatalIfErrorf(ctx.Run())
}

When I run the application with environment variables or flags, everything works perfectly.
But when I run the application with the --env-file flag, it crashes with a panic:

go run main.go --env-file=.env

API server listening at: 127.0.0.1:58887
debugserver-@(#)PROGRAM:LLDB  PROJECT:lldb-1300.0.42.3
 for x86_64.
Got a connection, launched process /private/var/folders/df/83mftq9j2rl2tc1z2cxkpxsh0000gq/T/GoLand/___1go_build_gitlab_corp_mail_ru_youla_api_platform_git_v2_cmd_app (pid = 54942).
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x14a402a]

goroutine 1 [running]:
github.com/alecthomas/kong.(*Context).Run(0xc000046c80, {0x0, 0x0, 0x0})
        /Users/d.titusov/go/pkg/mod/github.com/alecthomas/[email protected]/context.go:751 +0x10a
main.main()
        /Users/d.titusov/Projects/youla/platform/cmd/app/main.go:45 +0x15f
Exiting.

My hypothesis as to why this happens

As far as I understand, the issue is that kong is trying to run the application from Node 0, when the 0th node is not ApplicationNode:

The order of the ApplicationNode is changed inside the Resolve method:

How to fix that

First of all, I assume that I could miss something important. There might be a reason why you put original c.Path nodes at the end of the c.Path slice.

Otherwise, If this is a bug, I'd be happy to fix it.

Thanks for your help!