PR #673 broke my code. The nested structures don't get the default values correctly

[flw-cn]

I wrote a short example to illustrate the problem.

package main

import (
	"fmt"

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

type Config struct {
	Foo struct {
		Bar string
	}
}

func main() {
	config := &Config{}
	cmdRoot := &cobra.Command{
		Run: func(*cobra.Command, []string) {
			viper.Unmarshal(config)
		},
	}
	flags := cmdRoot.PersistentFlags()
	flags.String("foo.bar", "hello-world", "test default value fo foo.bar")
	viper.BindPFlags(flags)
	cmdRoot.Execute()
	fmt.Printf("foo.bar: [%v]\n", config.Foo.Bar)
}

The above code I expected to get the output is:

foo.bar: [hello-world]

This has worked very well in the past. But since PR #673, it can't work properly, it will output:

foo.bar: []

I checked the contents of the PR #673 , I can't fully understand the changes. But I believe the changes blocked my previous usage.

How should I modify my code to fit the new version of viper?

[sagikazarmark]

@flw-cn Thanks for opening this PR. It seems that the linked PR indeed introduced a regression.

[inkychris]

It looks like this only affects flags? The new keyComponents function should always return as many components as possible, ie: it will favour [foo bar] over [foo.bar]. For some reason, it is not seeing foo when it is only set by a flag value so it then sets foo.bar as the last resort which then doesn't get unmarshalled correctly.

[sagikazarmark]

I explained in #673 why that's the case. Defaults and explicit sets are also affected. Basically everything that's not a nested structure (config files, key value stores)

[inkychris]

I'm not seeing the same behaviour for SetDefault or Set...

package viper

import (
	"github.com/spf13/pflag"
	"github.com/stretchr/testify/assert"
	"testing"
)

type Config struct {
	Foo struct {
		Bar string
	}
}

func Test673_PFlags(t *testing.T) {
	v := New()
	flags := pflag.NewFlagSet("test", pflag.ContinueOnError)
	flags.String("foo.bar", "cobra_flag", "")
	assert.NoError(t, v.BindPFlags(flags))

	config := &Config{}
	assert.NoError(t, v.Unmarshal(config))
	assert.Equal(t, "cobra_flag", config.Foo.Bar)
}

func Test673_Default(t *testing.T) {
	v := New()
	config := &Config{}
	v.SetDefault("foo.bar", "default")
	assert.NoError(t, v.Unmarshal(config))
	assert.Equal(t, "default", config.Foo.Bar)
}

func Test673_Set(t *testing.T) {
	v := New()
	config := &Config{}
	v.SetDefault("foo.bar", "default")
	v.Set("foo.bar", "override")
	assert.NoError(t, v.Unmarshal(config))
	assert.Equal(t, "override", config.Foo.Bar)
}

Currently for me, the PFlags test is failing but the other two are okay; am I testing the right thing here?