Use goreleaser to build and release (#244)

Instead of using gox on one side and an action to release, we can merge
them together with goreleaser which will build for extra targets (arm,
mips if needed in the future) and it also takes care of creating
checksums, a source archive, and a changelog and creating a release with
all the artifacts.

All binaries should respect the old naming convention, so any scripts
out there should still work.

Signed-off-by: Itxaka <igarcia@suse.com>

vendor/github.com/mitchellh/mapstructure/mapstructure.go

@@ -1,10 +1,161 @@
-// Package mapstructure exposes functionality to convert an arbitrary
-// map[string]interface{} into a native Go structure.
+// Package mapstructure exposes functionality to convert one arbitrary
+// Go type into another, typically to convert a map[string]interface{}
+// into a native Go structure.
 //
 // The Go structure can be arbitrarily complex, containing slices,
 // other structs, etc. and the decoder will properly decode nested
 // maps and so on into the proper structures in the native Go struct.
 // See the examples to see what the decoder is capable of.
+//
+// The simplest function to start with is Decode.
+//
+// Field Tags
+//
+// When decoding to a struct, mapstructure will use the field name by
+// default to perform the mapping. For example, if a struct has a field
+// "Username" then mapstructure will look for a key in the source value
+// of "username" (case insensitive).
+//
+//     type User struct {
+//         Username string
+//     }
+//
+// You can change the behavior of mapstructure by using struct tags.
+// The default struct tag that mapstructure looks for is "mapstructure"
+// but you can customize it using DecoderConfig.
+//
+// Renaming Fields
+//
+// To rename the key that mapstructure looks for, use the "mapstructure"
+// tag and set a value directly. For example, to change the "username" example
+// above to "user":
+//
+//     type User struct {
+//         Username string `mapstructure:"user"`
+//     }
+//
+// Embedded Structs and Squashing
+//
+// Embedded structs are treated as if they're another field with that name.
+// By default, the two structs below are equivalent when decoding with
+// mapstructure:
+//
+//     type Person struct {
+//         Name string
+//     }
+//
+//     type Friend struct {
+//         Person
+//     }
+//
+//     type Friend struct {
+//         Person Person
+//     }
+//
+// This would require an input that looks like below:
+//
+//     map[string]interface{}{
+//         "person": map[string]interface{}{"name": "alice"},
+//     }
+//
+// If your "person" value is NOT nested, then you can append ",squash" to
+// your tag value and mapstructure will treat it as if the embedded struct
+// were part of the struct directly. Example:
+//
+//     type Friend struct {
+//         Person `mapstructure:",squash"`
+//     }
+//
+// Now the following input would be accepted:
+//
+//     map[string]interface{}{
+//         "name": "alice",
+//     }
+//
+// When decoding from a struct to a map, the squash tag squashes the struct
+// fields into a single map. Using the example structs from above:
+//
+//     Friend{Person: Person{Name: "alice"}}
+//
+// Will be decoded into a map:
+//
+//     map[string]interface{}{
+//         "name": "alice",
+//     }
+//
+// DecoderConfig has a field that changes the behavior of mapstructure
+// to always squash embedded structs.
+//
+// Remainder Values
+//
+// If there are any unmapped keys in the source value, mapstructure by
+// default will silently ignore them. You can error by setting ErrorUnused
+// in DecoderConfig. If you're using Metadata you can also maintain a slice
+// of the unused keys.
+//
+// You can also use the ",remain" suffix on your tag to collect all unused
+// values in a map. The field with this tag MUST be a map type and should
+// probably be a "map[string]interface{}" or "map[interface{}]interface{}".
+// See example below:
+//
+//     type Friend struct {
+//         Name  string
+//         Other map[string]interface{} `mapstructure:",remain"`
+//     }
+//
+// Given the input below, Other would be populated with the other
+// values that weren't used (everything but "name"):
+//
+//     map[string]interface{}{
+//         "name":    "bob",
+//         "address": "123 Maple St.",
+//     }
+//
+// Omit Empty Values
+//
+// When decoding from a struct to any other value, you may use the
+// ",omitempty" suffix on your tag to omit that value if it equates to
+// the zero value. The zero value of all types is specified in the Go
+// specification.
+//
+// For example, the zero type of a numeric type is zero ("0"). If the struct
+// field value is zero and a numeric type, the field is empty, and it won't
+// be encoded into the destination type.
+//
+//     type Source {
+//         Age int `mapstructure:",omitempty"`
+//     }
+//
+// Unexported fields
+//
+// Since unexported (private) struct fields cannot be set outside the package
+// where they are defined, the decoder will simply skip them.
+//
+// For this output type definition:
+//
+//     type Exported struct {
+//         private string // this unexported field will be skipped
+//         Public string
+//     }
+//
+// Using this map as input:
+//
+//     map[string]interface{}{
+//         "private": "I will be ignored",
+//         "Public":  "I made it through!",
+//     }
+//
+// The following struct will be decoded:
+//
+//     type Exported struct {
+//         private: "" // field is left with an empty string (zero value)
+//         Public: "I made it through!"
+//     }
+//
+// Other Configuration
+//
+// mapstructure is highly configurable. See the DecoderConfig struct
+// for other features and options that are supported.
 package mapstructure
 
 import (
@@ -21,10 +172,11 @@ import (
 // data transformations. See "DecodeHook" in the DecoderConfig
 // struct.
 //
-// The type should be DecodeHookFuncType or DecodeHookFuncKind.
-// Either is accepted. Types are a superset of Kinds (Types can return
-// Kinds) and are generally a richer thing to use, but Kinds are simpler
-// if you only need those.
+// The type must be one of DecodeHookFuncType, DecodeHookFuncKind, or
+// DecodeHookFuncValue.
+// Values are a superset of Types (Values can return types), and Types are a
+// superset of Kinds (Types can return Kinds) and are generally a richer thing
+// to use, but Kinds are simpler if you only need those.
 //
 // The reason DecodeHookFunc is multi-typed is for backwards compatibility:
 // we started with Kinds and then realized Types were the better solution,
@@ -40,15 +192,22 @@ type DecodeHookFuncType func(reflect.Type, reflect.Type, interface{}) (interface
 // source and target types.
 type DecodeHookFuncKind func(reflect.Kind, reflect.Kind, interface{}) (interface{}, error)
 
+// DecodeHookFuncRaw is a DecodeHookFunc which has complete access to both the source and target
+// values.
+type DecodeHookFuncValue func(from reflect.Value, to reflect.Value) (interface{}, error)
+
 // DecoderConfig is the configuration that is used to create a new decoder
 // and allows customization of various aspects of decoding.
 type DecoderConfig struct {
 	// DecodeHook, if set, will be called before any decoding and any
 	// type conversion (if WeaklyTypedInput is on). This lets you modify
-	// the values before they're set down onto the resulting struct.
+	// the values before they're set down onto the resulting struct. The
+	// DecodeHook is called for every map and value in the input. This means
+	// that if a struct has embedded fields with squash tags the decode hook
+	// is called only once with all of the input data, not once for each
+	// embedded struct.
 	//
-	// If an error is returned, the entire decode will fail with that
-	// error.
+	// If an error is returned, the entire decode will fail with that error.
 	DecodeHook DecodeHookFunc
 
 	// If ErrorUnused is true, then it is an error for there to exist
@@ -80,6 +239,14 @@ type DecoderConfig struct {
 	//
 	WeaklyTypedInput bool
 
+	// Squash will squash embedded structs.  A squash tag may also be
+	// added to an individual struct field using a tag.  For example:
+	//
+	//  type Parent struct {
+	//      Child `mapstructure:",squash"`
+	//  }
+	Squash bool
+
 	// Metadata is the struct that will contain extra metadata about
 	// the decoding. If this is nil, then no metadata will be tracked.
 	Metadata *Metadata
@@ -261,9 +428,7 @@ func (d *Decoder) decode(name string, input interface{}, outVal reflect.Value) e
 	if d.config.DecodeHook != nil {
 		// We have a DecodeHook, so let's pre-process the input.
 		var err error
-		input, err = DecodeHookExec(
-			d.config.DecodeHook,
-			inputVal.Type(), outVal.Type(), input)
+		input, err = DecodeHookExec(d.config.DecodeHook, inputVal, outVal)
 		if err != nil {
 			return fmt.Errorf("error decoding '%s': %s", name, err)
 		}
@@ -271,6 +436,7 @@ func (d *Decoder) decode(name string, input interface{}, outVal reflect.Value) e
 
 	var err error
 	outputKind := getKind(outVal)
+	addMetaKey := true
 	switch outputKind {
 	case reflect.Bool:
 		err = d.decodeBool(name, input, outVal)
@@ -289,7 +455,7 @@ func (d *Decoder) decode(name string, input interface{}, outVal reflect.Value) e
 	case reflect.Map:
 		err = d.decodeMap(name, input, outVal)
 	case reflect.Ptr:
-		err = d.decodePtr(name, input, outVal)
+		addMetaKey, err = d.decodePtr(name, input, outVal)
 	case reflect.Slice:
 		err = d.decodeSlice(name, input, outVal)
 	case reflect.Array:
@@ -303,7 +469,7 @@ func (d *Decoder) decode(name string, input interface{}, outVal reflect.Value) e
 
 	// If we reached here, then we successfully decoded SOMETHING, so
 	// mark the key as used if we're tracking metainput.
-	if d.config.Metadata != nil && name != "" {
+	if addMetaKey && d.config.Metadata != nil && name != "" {
 		d.config.Metadata.Keys = append(d.config.Metadata.Keys, name)
 	}
 
@@ -314,7 +480,34 @@ func (d *Decoder) decode(name string, input interface{}, outVal reflect.Value) e
 // value to "data" of that type.
 func (d *Decoder) decodeBasic(name string, data interface{}, val reflect.Value) error {
 	if val.IsValid() && val.Elem().IsValid() {
-		return d.decode(name, data, val.Elem())
+		elem := val.Elem()
+
+		// If we can't address this element, then its not writable. Instead,
+		// we make a copy of the value (which is a pointer and therefore
+		// writable), decode into that, and replace the whole value.
+		copied := false
+		if !elem.CanAddr() {
+			copied = true
+
+			// Make *T
+			copy := reflect.New(elem.Type())
+
+			// *T = elem
+			copy.Elem().Set(elem)
+
+			// Set elem so we decode into it
+			elem = copy
+		}
+
+		// Decode. If we have an error then return. We also return right
+		// away if we're not a copy because that means we decoded directly.
+		if err := d.decode(name, data, elem); err != nil || !copied {
+			return err
+		}
+
+		// If we're a copy, we need to set te final result
+		val.Set(elem.Elem())
+		return nil
 	}
 
 	dataVal := reflect.ValueOf(data)
@@ -386,8 +579,8 @@ func (d *Decoder) decodeString(name string, data interface{}, val reflect.Value)
 
 	if !converted {
 		return fmt.Errorf(
-			"'%s' expected type '%s', got unconvertible type '%s'",
-			name, val.Type(), dataVal.Type())
+			"'%s' expected type '%s', got unconvertible type '%s', value: '%v'",
+			name, val.Type(), dataVal.Type(), data)
 	}
 
 	return nil
@@ -412,7 +605,12 @@ func (d *Decoder) decodeInt(name string, data interface{}, val reflect.Value) er
 			val.SetInt(0)
 		}
 	case dataKind == reflect.String && d.config.WeaklyTypedInput:
-		i, err := strconv.ParseInt(dataVal.String(), 0, val.Type().Bits())
+		str := dataVal.String()
+		if str == "" {
+			str = "0"
+		}
+
+		i, err := strconv.ParseInt(str, 0, val.Type().Bits())
 		if err == nil {
 			val.SetInt(i)
 		} else {
@@ -428,8 +626,8 @@ func (d *Decoder) decodeInt(name string, data interface{}, val reflect.Value) er
 		val.SetInt(i)
 	default:
 		return fmt.Errorf(
-			"'%s' expected type '%s', got unconvertible type '%s'",
-			name, val.Type(), dataVal.Type())
+			"'%s' expected type '%s', got unconvertible type '%s', value: '%v'",
+			name, val.Type(), dataVal.Type(), data)
 	}
 
 	return nil
@@ -438,6 +636,7 @@ func (d *Decoder) decodeInt(name string, data interface{}, val reflect.Value) er
 func (d *Decoder) decodeUint(name string, data interface{}, val reflect.Value) error {
 	dataVal := reflect.Indirect(reflect.ValueOf(data))
 	dataKind := getKind(dataVal)
+	dataType := dataVal.Type()
 
 	switch {
 	case dataKind == reflect.Int:
@@ -463,16 +662,33 @@ func (d *Decoder) decodeUint(name string, data interface{}, val reflect.Value) e
 			val.SetUint(0)
 		}
 	case dataKind == reflect.String && d.config.WeaklyTypedInput:
-		i, err := strconv.ParseUint(dataVal.String(), 0, val.Type().Bits())
+		str := dataVal.String()
+		if str == "" {
+			str = "0"
+		}
+
+		i, err := strconv.ParseUint(str, 0, val.Type().Bits())
 		if err == nil {
 			val.SetUint(i)
 		} else {
 			return fmt.Errorf("cannot parse '%s' as uint: %s", name, err)
 		}
+	case dataType.PkgPath() == "encoding/json" && dataType.Name() == "Number":
+		jn := data.(json.Number)
+		i, err := jn.Int64()
+		if err != nil {
+			return fmt.Errorf(
+				"error decoding json.Number into %s: %s", name, err)
+		}
+		if i < 0 && !d.config.WeaklyTypedInput {
+			return fmt.Errorf("cannot parse '%s', %d overflows uint",
+				name, i)
+		}
+		val.SetUint(uint64(i))
 	default:
 		return fmt.Errorf(
-			"'%s' expected type '%s', got unconvertible type '%s'",
-			name, val.Type(), dataVal.Type())
+			"'%s' expected type '%s', got unconvertible type '%s', value: '%v'",
+			name, val.Type(), dataVal.Type(), data)
 	}
 
 	return nil
@@ -502,8 +718,8 @@ func (d *Decoder) decodeBool(name string, data interface{}, val reflect.Value) e
 		}
 	default:
 		return fmt.Errorf(
-			"'%s' expected type '%s', got unconvertible type '%s'",
-			name, val.Type(), dataVal.Type())
+			"'%s' expected type '%s', got unconvertible type '%s', value: '%v'",
+			name, val.Type(), dataVal.Type(), data)
 	}
 
 	return nil
@@ -528,7 +744,12 @@ func (d *Decoder) decodeFloat(name string, data interface{}, val reflect.Value)
 			val.SetFloat(0)
 		}
 	case dataKind == reflect.String && d.config.WeaklyTypedInput:
-		f, err := strconv.ParseFloat(dataVal.String(), val.Type().Bits())
+		str := dataVal.String()
+		if str == "" {
+			str = "0"
+		}
+
+		f, err := strconv.ParseFloat(str, val.Type().Bits())
 		if err == nil {
 			val.SetFloat(f)
 		} else {
@@ -544,8 +765,8 @@ func (d *Decoder) decodeFloat(name string, data interface{}, val reflect.Value)
 		val.SetFloat(i)
 	default:
 		return fmt.Errorf(
-			"'%s' expected type '%s', got unconvertible type '%s'",
-			name, val.Type(), dataVal.Type())
+			"'%s' expected type '%s', got unconvertible type '%s', value: '%v'",
+			name, val.Type(), dataVal.Type(), data)
 	}
 
 	return nil
@@ -596,7 +817,7 @@ func (d *Decoder) decodeMapFromSlice(name string, dataVal reflect.Value, val ref
 
 	for i := 0; i < dataVal.Len(); i++ {
 		err := d.decode(
-			fmt.Sprintf("%s[%d]", name, i),
+			name+"["+strconv.Itoa(i)+"]",
 			dataVal.Index(i).Interface(), val)
 		if err != nil {
 			return err
@@ -629,7 +850,7 @@ func (d *Decoder) decodeMapFromMap(name string, dataVal reflect.Value, val refle
 	}
 
 	for _, k := range dataVal.MapKeys() {
-		fieldName := fmt.Sprintf("%s[%s]", name, k)
+		fieldName := name + "[" + k.String() + "]"
 
 		// First decode the key into the proper type
 		currentKey := reflect.Indirect(reflect.New(valKeyType))
@@ -678,27 +899,40 @@ func (d *Decoder) decodeMapFromStruct(name string, dataVal reflect.Value, val re
 		}
 
 		tagValue := f.Tag.Get(d.config.TagName)
-		tagParts := strings.Split(tagValue, ",")
+		keyName := f.Name
+
+		// If Squash is set in the config, we squash the field down.
+		squash := d.config.Squash && v.Kind() == reflect.Struct && f.Anonymous
 
 		// Determine the name of the key in the map
-		keyName := f.Name
-		if tagParts[0] != "" {
-			if tagParts[0] == "-" {
+		if index := strings.Index(tagValue, ","); index != -1 {
+			if tagValue[:index] == "-" {
 				continue
 			}
-			keyName = tagParts[0]
-		}
-
-		// If "squash" is specified in the tag, we squash the field down.
-		squash := false
-		for _, tag := range tagParts[1:] {
-			if tag == "squash" {
-				squash = true
-				break
+			// If "omitempty" is specified in the tag, it ignores empty values.
+			if strings.Index(tagValue[index+1:], "omitempty") != -1 && isEmptyValue(v) {
+				continue
 			}
-		}
-		if squash && v.Kind() != reflect.Struct {
-			return fmt.Errorf("cannot squash non-struct type '%s'", v.Type())
+
+			// If "squash" is specified in the tag, we squash the field down.
+			squash = !squash && strings.Index(tagValue[index+1:], "squash") != -1
+			if squash {
+				// When squashing, the embedded type can be a pointer to a struct.
+				if v.Kind() == reflect.Ptr && v.Elem().Kind() == reflect.Struct {
+					v = v.Elem()
+				}
+
+				// The final type must be a struct
+				if v.Kind() != reflect.Struct {
+					return fmt.Errorf("cannot squash non-struct type '%s'", v.Type())
+				}
+			}
+			keyName = tagValue[:index]
+		} else if len(tagValue) > 0 {
+			if tagValue == "-" {
+				continue
+			}
+			keyName = tagValue
 		}
 
 		switch v.Kind() {
@@ -713,11 +947,22 @@ func (d *Decoder) decodeMapFromStruct(name string, dataVal reflect.Value, val re
 			mType := reflect.MapOf(vKeyType, vElemType)
 			vMap := reflect.MakeMap(mType)
 
-			err := d.decode(keyName, x.Interface(), vMap)
+			// Creating a pointer to a map so that other methods can completely
+			// overwrite the map if need be (looking at you decodeMapFromMap). The
+			// indirection allows the underlying map to be settable (CanSet() == true)
+			// where as reflect.MakeMap returns an unsettable map.
+			addrVal := reflect.New(vMap.Type())
+			reflect.Indirect(addrVal).Set(vMap)
+
+			err := d.decode(keyName, x.Interface(), reflect.Indirect(addrVal))
 			if err != nil {
 				return err
 			}
 
+			// the underlying map may have been completely overwritten so pull
+			// it indirectly out of the enclosing value.
+			vMap = reflect.Indirect(addrVal)
+
 			if squash {
 				for _, k := range vMap.MapKeys() {
 					valMap.SetMapIndex(k, vMap.MapIndex(k))
@@ -738,7 +983,7 @@ func (d *Decoder) decodeMapFromStruct(name string, dataVal reflect.Value, val re
 	return nil
 }
 
-func (d *Decoder) decodePtr(name string, data interface{}, val reflect.Value) error {
+func (d *Decoder) decodePtr(name string, data interface{}, val reflect.Value) (bool, error) {
 	// If the input data is nil, then we want to just set the output
 	// pointer to be nil as well.
 	isNil := data == nil
@@ -759,7 +1004,7 @@ func (d *Decoder) decodePtr(name string, data interface{}, val reflect.Value) er
 			val.Set(nilValue)
 		}
 
-		return nil
+		return true, nil
 	}
 
 	// Create an element of the concrete (non pointer) type and decode
@@ -773,16 +1018,16 @@ func (d *Decoder) decodePtr(name string, data interface{}, val reflect.Value) er
 		}
 
 		if err := d.decode(name, data, reflect.Indirect(realVal)); err != nil {
-			return err
+			return false, err
 		}
 
 		val.Set(realVal)
 	} else {
 		if err := d.decode(name, data, reflect.Indirect(val)); err != nil {
-			return err
+			return false, err
 		}
 	}
-	return nil
+	return false, nil
 }
 
 func (d *Decoder) decodeFunc(name string, data interface{}, val reflect.Value) error {
@@ -791,8 +1036,8 @@ func (d *Decoder) decodeFunc(name string, data interface{}, val reflect.Value) e
 	dataVal := reflect.Indirect(reflect.ValueOf(data))
 	if val.Type() != dataVal.Type() {
 		return fmt.Errorf(
-			"'%s' expected type '%s', got unconvertible type '%s'",
-			name, val.Type(), dataVal.Type())
+			"'%s' expected type '%s', got unconvertible type '%s', value: '%v'",
+			name, val.Type(), dataVal.Type(), data)
 	}
 	val.Set(dataVal)
 	return nil
@@ -805,8 +1050,8 @@ func (d *Decoder) decodeSlice(name string, data interface{}, val reflect.Value)
 	valElemType := valType.Elem()
 	sliceType := reflect.SliceOf(valElemType)
 
-	valSlice := val
-	if valSlice.IsNil() || d.config.ZeroFields {
+	// If we have a non array/slice type then we first attempt to convert.
+	if dataValKind != reflect.Array && dataValKind != reflect.Slice {
 		if d.config.WeaklyTypedInput {
 			switch {
 			// Slice and array we use the normal logic
@@ -833,18 +1078,17 @@ func (d *Decoder) decodeSlice(name string, data interface{}, val reflect.Value)
 			}
 		}
 
-		// Check input type
-		if dataValKind != reflect.Array && dataValKind != reflect.Slice {
-			return fmt.Errorf(
-				"'%s': source data must be an array or slice, got %s", name, dataValKind)
+		return fmt.Errorf(
+			"'%s': source data must be an array or slice, got %s", name, dataValKind)
+	}
 
-		}
-
-		// If the input value is empty, then don't allocate since non-nil != nil
-		if dataVal.Len() == 0 {
-			return nil
-		}
+	// If the input value is nil, then don't allocate since empty != nil
+	if dataVal.IsNil() {
+		return nil
+	}
 
+	valSlice := val
+	if valSlice.IsNil() || d.config.ZeroFields {
 		// Make a new slice to hold our result, same size as the original data.
 		valSlice = reflect.MakeSlice(sliceType, dataVal.Len(), dataVal.Len())
 	}
@@ -859,7 +1103,7 @@ func (d *Decoder) decodeSlice(name string, data interface{}, val reflect.Value)
 		}
 		currentField := valSlice.Index(i)
 
-		fieldName := fmt.Sprintf("%s[%d]", name, i)
+		fieldName := name + "[" + strconv.Itoa(i) + "]"
 		if err := d.decode(fieldName, currentData, currentField); err != nil {
 			errors = appendErrors(errors, err)
 		}
@@ -926,7 +1170,7 @@ func (d *Decoder) decodeArray(name string, data interface{}, val reflect.Value)
 		currentData := dataVal.Index(i).Interface()
 		currentField := valArray.Index(i)
 
-		fieldName := fmt.Sprintf("%s[%d]", name, i)
+		fieldName := name + "[" + strconv.Itoa(i) + "]"
 		if err := d.decode(fieldName, currentData, currentField); err != nil {
 			errors = appendErrors(errors, err)
 		}
@@ -962,13 +1206,23 @@ func (d *Decoder) decodeStruct(name string, data interface{}, val reflect.Value)
 		// Not the most efficient way to do this but we can optimize later if
 		// we want to. To convert from struct to struct we go to map first
 		// as an intermediary.
-		m := make(map[string]interface{})
-		mval := reflect.Indirect(reflect.ValueOf(&m))
-		if err := d.decodeMapFromStruct(name, dataVal, mval, mval); err != nil {
+
+		// Make a new map to hold our result
+		mapType := reflect.TypeOf((map[string]interface{})(nil))
+		mval := reflect.MakeMap(mapType)
+
+		// Creating a pointer to a map so that other methods can completely
+		// overwrite the map if need be (looking at you decodeMapFromMap). The
+		// indirection allows the underlying map to be settable (CanSet() == true)
+		// where as reflect.MakeMap returns an unsettable map.
+		addrVal := reflect.New(mval.Type())
+
+		reflect.Indirect(addrVal).Set(mval)
+		if err := d.decodeMapFromStruct(name, dataVal, reflect.Indirect(addrVal), mval); err != nil {
 			return err
 		}
 
-		result := d.decodeStructFromMap(name, mval, val)
+		result := d.decodeStructFromMap(name, reflect.Indirect(addrVal), val)
 		return result
 
 	default:
@@ -1005,6 +1259,11 @@ func (d *Decoder) decodeStructFromMap(name string, dataVal, val reflect.Value) e
 		field reflect.StructField
 		val   reflect.Value
 	}
+
+	// remainField is set to a valid field set with the "remain" tag if
+	// we are keeping track of remaining values.
+	var remainField *field
+
 	fields := []field{}
 	for len(structs) > 0 {
 		structVal := structs[0]
@@ -1014,30 +1273,47 @@ func (d *Decoder) decodeStructFromMap(name string, dataVal, val reflect.Value) e
 
 		for i := 0; i < structType.NumField(); i++ {
 			fieldType := structType.Field(i)
-			fieldKind := fieldType.Type.Kind()
+			fieldVal := structVal.Field(i)
+			if fieldVal.Kind() == reflect.Ptr && fieldVal.Elem().Kind() == reflect.Struct {
+				// Handle embedded struct pointers as embedded structs.
+				fieldVal = fieldVal.Elem()
+			}
 
 			// If "squash" is specified in the tag, we squash the field down.
-			squash := false
+			squash := d.config.Squash && fieldVal.Kind() == reflect.Struct && fieldType.Anonymous
+			remain := false
+
+			// We always parse the tags cause we're looking for other tags too
 			tagParts := strings.Split(fieldType.Tag.Get(d.config.TagName), ",")
 			for _, tag := range tagParts[1:] {
 				if tag == "squash" {
 					squash = true
 					break
 				}
+
+				if tag == "remain" {
+					remain = true
+					break
+				}
 			}
 
 			if squash {
-				if fieldKind != reflect.Struct {
+				if fieldVal.Kind() != reflect.Struct {
 					errors = appendErrors(errors,
-						fmt.Errorf("%s: unsupported type for squash: %s", fieldType.Name, fieldKind))
+						fmt.Errorf("%s: unsupported type for squash: %s", fieldType.Name, fieldVal.Kind()))
 				} else {
-					structs = append(structs, structVal.FieldByName(fieldType.Name))
+					structs = append(structs, fieldVal)
 				}
 				continue
 			}
 
-			// Normal struct field, store it away
-			fields = append(fields, field{fieldType, structVal.Field(i)})
+			// Build our field
+			if remain {
+				remainField = &field{fieldType, fieldVal}
+			} else {
+				// Normal struct field, store it away
+				fields = append(fields, field{fieldType, fieldVal})
+			}
 		}
 	}
 
@@ -1078,9 +1354,6 @@ func (d *Decoder) decodeStructFromMap(name string, dataVal, val reflect.Value) e
 			}
 		}
 
-		// Delete the key we're using from the unused map so we stop tracking
-		delete(dataValKeysUnused, rawMapKey.Interface())
-
 		if !fieldValue.IsValid() {
 			// This should never happen
 			panic("field is not valid")
@@ -1092,10 +1365,13 @@ func (d *Decoder) decodeStructFromMap(name string, dataVal, val reflect.Value) e
 			continue
 		}
 
+		// Delete the key we're using from the unused map so we stop tracking
+		delete(dataValKeysUnused, rawMapKey.Interface())
+
 		// If the name is empty string, then we're at the root, and we
 		// don't dot-join the fields.
 		if name != "" {
-			fieldName = fmt.Sprintf("%s.%s", name, fieldName)
+			fieldName = name + "." + fieldName
 		}
 
 		if err := d.decode(fieldName, rawMapVal.Interface(), fieldValue); err != nil {
@@ -1103,6 +1379,25 @@ func (d *Decoder) decodeStructFromMap(name string, dataVal, val reflect.Value) e
 		}
 	}
 
+	// If we have a "remain"-tagged field and we have unused keys then
+	// we put the unused keys directly into the remain field.
+	if remainField != nil && len(dataValKeysUnused) > 0 {
+		// Build a map of only the unused values
+		remain := map[interface{}]interface{}{}
+		for key := range dataValKeysUnused {
+			remain[key] = dataVal.MapIndex(reflect.ValueOf(key)).Interface()
+		}
+
+		// Decode it as-if we were just decoding this map onto our map.
+		if err := d.decodeMap(name, remain, remainField.val); err != nil {
+			errors = appendErrors(errors, err)
+		}
+
+		// Set the map to nil so we have none so that the next check will
+		// not error (ErrorUnused)
+		dataValKeysUnused = nil
+	}
+
 	if d.config.ErrorUnused && len(dataValKeysUnused) > 0 {
 		keys := make([]string, 0, len(dataValKeysUnused))
 		for rawKey := range dataValKeysUnused {
@@ -1123,7 +1418,7 @@ func (d *Decoder) decodeStructFromMap(name string, dataVal, val reflect.Value) e
 		for rawKey := range dataValKeysUnused {
 			key := rawKey.(string)
 			if name != "" {
-				key = fmt.Sprintf("%s.%s", name, key)
+				key = name + "." + key
 			}
 
 			d.config.Metadata.Unused = append(d.config.Metadata.Unused, key)
@@ -1133,6 +1428,24 @@ func (d *Decoder) decodeStructFromMap(name string, dataVal, val reflect.Value) e
 	return nil
 }
 
+func isEmptyValue(v reflect.Value) bool {
+	switch getKind(v) {
+	case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
+		return v.Len() == 0
+	case reflect.Bool:
+		return !v.Bool()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return v.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return v.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return v.Float() == 0
+	case reflect.Interface, reflect.Ptr:
+		return v.IsNil()
+	}
+	return false
+}
+
 func getKind(val reflect.Value) reflect.Kind {
 	kind := val.Kind()