An alternative way of decoupling?

[mdouchement]

I like your idea of decoupling Cobra from Viper because I use a lot Cobra but I never use Viper which brings lots of dependencies.
But I feel bad to use a fork of an active project so I want to propose an alternative that can do the job in the Cobra projet.

The idea is to use a Viper interface inside Cobra to avoid coupling:

type Viper interface {
	AddConfigPath(string)
	BindPFlag(string, *pflag.Flag) error
	ConfigFileUsed() string
	GetBool(string) bool
	GetString(string) string
	IsSet(string) bool
	Set(string, interface{})
	SetConfigFile(string)
	SetConfigName(string)
	SetConfigType(string)
	SetDefault(string, interface{})
	ReadInConfig() error
}

var viper Viper

func Register(v Viper) {
	viper = v
}

The Cobra's code using Viper can add a condition to check if the variable is not nil like in the following example:

if viper != nil && viper.GetBool("useViper") {
	cobra.CheckErr(goGet("github.com/spf13/viper"))
}

Then developpers who want to use Viper can define the following statement in their programs:

func main() {
	cobra.Register(viper.GetViper())
}