I am trying to hook myself into my application after the default is set but before the resolvers got triggered.
However, when using the env notation, the resolver has populated my structure before the BeforeResolve hook.

Here is an example to trigger:

package main

import (
	"fmt"
	"github.com/alecthomas/kong"
)

type CLI struct {
	Dev bool `env:"DEV"`
}

func (c CLI) BeforeResolve() error {
	fmt.Printf("%+v\n", c)
	return nil
}

func (c CLI) Run() error {
	return nil
}

func main() {
	cli := CLI{}
	ctx := kong.Parse(&cli)

	err := ctx.Run()
	ctx.FatalIfErrorf(err)
}

If I run: DEV=1 go run main.go, the Dev attribute is already populated.

It may be expected, however, the README state that the env annotation is implemented as a resolver.