fix(config): fix config marshaling producing unreadable config file

There are two practical changes when the config gets updated:
- The `forgetoption` and `configoption` bug is now gone
- Superfluous config keys no longer get written out

internal/backend.go

@@ -14,19 +14,19 @@ import (
 )
 
 type BackendRest struct {
-	User     string `mapstructure:"user,omitempty"`
-	Password string `mapstructure:"password,omitempty"`
+	User     string `mapstructure:"user,omitempty" yaml:"user,omitempty"`
+	Password string `mapstructure:"password,omitempty" yaml:"password,omitempty"`
 }
 
 type Backend struct {
 	name       string
-	Type       string            `mapstructure:"type,omitempty"`
-	Path       string            `mapstructure:"path,omitempty"`
-	Key        string            `mapstructure:"key,omitempty"`
-	RequireKey bool              `mapstructure:"requireKey,omitempty"`
-	Env        map[string]string `mapstructure:"env,omitempty"`
-	Rest       BackendRest       `mapstructure:"rest,omitempty"`
-	Options    Options           `mapstructure:"options,omitempty"`
+	Type       string            `mapstructure:"type,omitempty" yaml:"type,omitempty"`
+	Path       string            `mapstructure:"path,omitempty" yaml:"path,omitempty"`
+	Key        string            `mapstructure:"key,omitempty" yaml:"key,omitempty"`
+	RequireKey bool              `mapstructure:"requireKey,omitempty" yaml:"requireKey,omitempty"`
+	Env        map[string]string `mapstructure:"env,omitempty" yaml:"env,omitempty"`
+	Rest       BackendRest       `mapstructure:"rest,omitempty" yaml:"rest,omitempty"`
+	Options    Options           `mapstructure:"options,omitempty" yaml:"options,omitempty"`
 }
 
 func GetBackend(name string) (Backend, bool) {

internal/config.go

@@ -23,11 +23,11 @@ type OptionMap map[string][]interface{}
 type Options map[string]OptionMap
 
 type Config struct {
-	Version   string              `mapstructure:"version"`
-	Extras    interface{}         `mapstructure:"extras"`
-	Locations map[string]Location `mapstructure:"locations"`
-	Backends  map[string]Backend  `mapstructure:"backends"`
-	Global    Options             `mapstructure:"global"`
+	Version   string              `mapstructure:"version" yaml:"version"`
+	Extras    interface{}         `mapstructure:"extras" yaml:"extras"`
+	Locations map[string]Location `mapstructure:"locations" yaml:"locations"`
+	Backends  map[string]Backend  `mapstructure:"backends" yaml:"backends"`
+	Global    Options             `mapstructure:"global" yaml:"global"`
 }
 
 var once sync.Once

internal/config_test.go

@@ -1,10 +1,15 @@
 package internal
 
 import (
+	"path"
 	"reflect"
 	"strconv"
 	"strings"
+	"sync"
 	"testing"
+
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestOptionToString(t *testing.T) {
@@ -143,6 +148,48 @@ func TestGetOptionsMultipleKeys(t *testing.T) {
 	reflect.DeepEqual(result, expected)
 }
 
+func TestSaveConfigProducesReadableConfig(t *testing.T) {
+	workDir := t.TempDir()
+	viper.SetConfigFile(path.Join(workDir, ".autorestic.yml"))
+
+	// Required to appease the config reader
+	viper.Set("version", 2)
+
+	c := Config{
+		Version: "2",
+		Locations: map[string]Location{
+			"test": {
+				Type: "local",
+				name: "test",
+				From: []string{"in-dir"},
+				To:   []string{"test"},
+				// ForgetOption & ConfigOption have previously marshalled in a way that
+				// can't get read correctly
+				ForgetOption: "foo",
+				CopyOption:   map[string][]string{"foo": {"bar"}},
+			},
+		},
+		Backends: map[string]Backend{
+			"test": {
+				name: "test",
+				Type: "local",
+				Path: "backup-target",
+				Key:  "supersecret",
+			},
+		},
+	}
+
+	err := c.SaveConfig()
+	assert.NoError(t, err)
+
+	// Ensure we the config reading logic actually runs
+	config = nil
+	once = sync.Once{}
+	readConfig := GetConfig()
+	assert.NotNil(t, readConfig)
+	assert.Equal(t, c, *readConfig)
+}
+
 func assertEqual[T comparable](t testing.TB, result, expected T) {
 	t.Helper()
 

internal/location.go

@@ -33,26 +33,26 @@ const (
 )
 
 type Hooks struct {
-	Dir         string    `mapstructure:"dir"`
-	PreValidate HookArray `mapstructure:"prevalidate,omitempty"`
-	Before      HookArray `mapstructure:"before,omitempty"`
-	After       HookArray `mapstructure:"after,omitempty"`
-	Success     HookArray `mapstructure:"success,omitempty"`
-	Failure     HookArray `mapstructure:"failure,omitempty"`
+	Dir         string    `mapstructure:"dir" yaml:"dir"`
+	PreValidate HookArray `mapstructure:"prevalidate,omitempty" yaml:"prevalidate,omitempty"`
+	Before      HookArray `mapstructure:"before,omitempty" yaml:"before,omitempty"`
+	After       HookArray `mapstructure:"after,omitempty" yaml:"after,omitempty"`
+	Success     HookArray `mapstructure:"success,omitempty" yaml:"success,omitempty"`
+	Failure     HookArray `mapstructure:"failure,omitempty" yaml:"failure,omitempty"`
 }
 
 type LocationCopy = map[string][]string
 
 type Location struct {
-	name         string               `mapstructure:",omitempty"`
-	From         []string             `mapstructure:"from,omitempty"`
-	Type         string               `mapstructure:"type,omitempty"`
-	To           []string             `mapstructure:"to,omitempty"`
-	Hooks        Hooks                `mapstructure:"hooks,omitempty"`
-	Cron         string               `mapstructure:"cron,omitempty"`
-	Options      Options              `mapstructure:"options,omitempty"`
-	ForgetOption LocationForgetOption `mapstructure:"forget,omitempty"`
-	CopyOption   LocationCopy         `mapstructure:"copy,omitempty"`
+	name         string               `mapstructure:",omitempty" yaml:",omitempty"`
+	From         []string             `mapstructure:"from,omitempty" yaml:"from,omitempty"`
+	Type         string               `mapstructure:"type,omitempty" yaml:"type,omitempty"`
+	To           []string             `mapstructure:"to,omitempty" yaml:"to,omitempty"`
+	Hooks        Hooks                `mapstructure:"hooks,omitempty" yaml:"hooks,omitempty"`
+	Cron         string               `mapstructure:"cron,omitempty" yaml:"cron,omitempty"`
+	Options      Options              `mapstructure:"options,omitempty" yaml:"options,omitempty"`
+	ForgetOption LocationForgetOption `mapstructure:"forget,omitempty" yaml:"forget,omitempty"`
+	CopyOption   LocationCopy         `mapstructure:"copy,omitempty" yaml:"copy,omitempty"`
 }
 
 func GetLocation(name string) (Location, bool) {