viper_unmarshal_bug.go

package main

import (
	"fmt"

	"github.com/spf13/pflag"
	"github.com/spf13/viper"
)

type config struct {
	Foo bool
}

var (
	c config
)

func main() {
	flag := pflag.Bool("Foo", false, "Test flag.")
	viper.BindPFlag("Foo", pflag.Lookup("Foo"))
	pflag.Parse()

	// Unmarshal without an explicit viper default
	viper.Unmarshal(&c)
	lookedup := viper.GetBool("Foo")
	fmt.Printf("foo unmarshals as: %v\n", c.Foo)
	fmt.Printf("foo is looked up as: %v\n", lookedup)
	fmt.Printf("foo is actually: %v\n", *flag)

	// Do it again with the redundant default
	viper.SetDefault("Foo", false)
	viper.Unmarshal(&c)
	fmt.Printf("foo now unmarshals as: %v\n", c.Foo)
}