go-flags doesn't work with go's flag package

[subtleseeker]

package main

import (
    "flag"
    "log"
    "github.com/jessevdk/go-flags"
)

var f = flag.Bool("a", false, "yeyey")

type A struct {
    X string `long:"tf" description:"testflag" default:"def_val" env:"TF"`
}

func main() {
    flag.Parse()
    a := &A{}
    parser := flags.NewParser(a, flags.IgnoreUnknown|flags.HelpFlag|flags.PrintErrors)
    _, err := parser.Parse()
    if err != nil {
        log.Fatal(err)
    }
    println(*f)
    println((*a).X)
}

$ go run flagtest.go --tf bc
flag provided but not defined: -tf
Usage of /tmp/go-build245317497/b001/exe/flagtest:
  -a    yeyey
exit status 2

After commenting the line, flag.Parse():

$ go run flagtest.go --tf bc
false
bc

The use-case occurs when you import a package which is using go's flag package and my package uses go-flags. In that case, go-flags are shadowed by the go's flag library.
Was this a thought out decision while designing? Are there any ways to use both of them together?

[FrankDMartinez]

I have run into this as well just now. As much as I enjoy the go-flags package, it's interfering with my use of glog, which is also very convenient.

[jessevdk]

This is not a use case that go-flags was designed for. The error that you're getting is from the flag package from what I can see. I don't think it make much sense to use multiple flags parsers at the same time. You could try passing the "rest" arguments returned from Parse from go-flags to the CommandLine.Parse from go flag and see if that works for you. Otherwise this is simply not a goal for go-flags to support.