Implement Cobra CLI tooling, Viper config tooling (#336)

* start pulling out + replacing urfave and config

* replace many many instances of config

* move more stuff => viper

* properly remove urfave

* move some flags to root command

* add testrig commands to root

* alias config file keys

* start adding cli parsing tests

* reorder viper init

* remove config path alias

* fmt

* change config file keys to non-nested

* we're more or less in business now

* tidy up the common func

* go fmt

* get tests passing again

* add note about the cliparsing tests

* reorganize

* update docs with changes

* structure cmd dir better

* rename + move some files around

* fix dangling comma

1 files changed, 1308 insertions, 0 deletions

diff --git a/vendor/github.com/pelletier/go-toml/marshal.go b/vendor/github.com/pelletier/go-toml/marshal.go
new file mode 100644
index 000000000..3443c3545
--- /dev/null
+++ b/vendor/github.com/pelletier/go-toml/marshal.go
@@ -0,0 +1,1308 @@
+package toml
+
+import (
+	"bytes"
+	"encoding"
+	"errors"
+	"fmt"
+	"io"
+	"reflect"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const (
+	tagFieldName    = "toml"
+	tagFieldComment = "comment"
+	tagCommented    = "commented"
+	tagMultiline    = "multiline"
+	tagLiteral      = "literal"
+	tagDefault      = "default"
+)
+
+type tomlOpts struct {
+	name         string
+	nameFromTag  bool
+	comment      string
+	commented    bool
+	multiline    bool
+	literal      bool
+	include      bool
+	omitempty    bool
+	defaultValue string
+}
+
+type encOpts struct {
+	quoteMapKeys            bool
+	arraysOneElementPerLine bool
+}
+
+var encOptsDefaults = encOpts{
+	quoteMapKeys: false,
+}
+
+type annotation struct {
+	tag          string
+	comment      string
+	commented    string
+	multiline    string
+	literal      string
+	defaultValue string
+}
+
+var annotationDefault = annotation{
+	tag:          tagFieldName,
+	comment:      tagFieldComment,
+	commented:    tagCommented,
+	multiline:    tagMultiline,
+	literal:      tagLiteral,
+	defaultValue: tagDefault,
+}
+
+type MarshalOrder int
+
+// Orders the Encoder can write the fields to the output stream.
+const (
+	// Sort fields alphabetically.
+	OrderAlphabetical MarshalOrder = iota + 1
+	// Preserve the order the fields are encountered. For example, the order of fields in
+	// a struct.
+	OrderPreserve
+)
+
+var timeType = reflect.TypeOf(time.Time{})
+var marshalerType = reflect.TypeOf(new(Marshaler)).Elem()
+var unmarshalerType = reflect.TypeOf(new(Unmarshaler)).Elem()
+var textMarshalerType = reflect.TypeOf(new(encoding.TextMarshaler)).Elem()
+var textUnmarshalerType = reflect.TypeOf(new(encoding.TextUnmarshaler)).Elem()
+var localDateType = reflect.TypeOf(LocalDate{})
+var localTimeType = reflect.TypeOf(LocalTime{})
+var localDateTimeType = reflect.TypeOf(LocalDateTime{})
+var mapStringInterfaceType = reflect.TypeOf(map[string]interface{}{})
+
+// Check if the given marshal type maps to a Tree primitive
+func isPrimitive(mtype reflect.Type) bool {
+	switch mtype.Kind() {
+	case reflect.Ptr:
+		return isPrimitive(mtype.Elem())
+	case reflect.Bool:
+		return true
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return true
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		return true
+	case reflect.Float32, reflect.Float64:
+		return true
+	case reflect.String:
+		return true
+	case reflect.Struct:
+		return isTimeType(mtype)
+	default:
+		return false
+	}
+}
+
+func isTimeType(mtype reflect.Type) bool {
+	return mtype == timeType || mtype == localDateType || mtype == localDateTimeType || mtype == localTimeType
+}
+
+// Check if the given marshal type maps to a Tree slice or array
+func isTreeSequence(mtype reflect.Type) bool {
+	switch mtype.Kind() {
+	case reflect.Ptr:
+		return isTreeSequence(mtype.Elem())
+	case reflect.Slice, reflect.Array:
+		return isTree(mtype.Elem())
+	default:
+		return false
+	}
+}
+
+// Check if the given marshal type maps to a slice or array of a custom marshaler type
+func isCustomMarshalerSequence(mtype reflect.Type) bool {
+	switch mtype.Kind() {
+	case reflect.Ptr:
+		return isCustomMarshalerSequence(mtype.Elem())
+	case reflect.Slice, reflect.Array:
+		return isCustomMarshaler(mtype.Elem()) || isCustomMarshaler(reflect.New(mtype.Elem()).Type())
+	default:
+		return false
+	}
+}
+
+// Check if the given marshal type maps to a slice or array of a text marshaler type
+func isTextMarshalerSequence(mtype reflect.Type) bool {
+	switch mtype.Kind() {
+	case reflect.Ptr:
+		return isTextMarshalerSequence(mtype.Elem())
+	case reflect.Slice, reflect.Array:
+		return isTextMarshaler(mtype.Elem()) || isTextMarshaler(reflect.New(mtype.Elem()).Type())
+	default:
+		return false
+	}
+}
+
+// Check if the given marshal type maps to a non-Tree slice or array
+func isOtherSequence(mtype reflect.Type) bool {
+	switch mtype.Kind() {
+	case reflect.Ptr:
+		return isOtherSequence(mtype.Elem())
+	case reflect.Slice, reflect.Array:
+		return !isTreeSequence(mtype)
+	default:
+		return false
+	}
+}
+
+// Check if the given marshal type maps to a Tree
+func isTree(mtype reflect.Type) bool {
+	switch mtype.Kind() {
+	case reflect.Ptr:
+		return isTree(mtype.Elem())
+	case reflect.Map:
+		return true
+	case reflect.Struct:
+		return !isPrimitive(mtype)
+	default:
+		return false
+	}
+}
+
+func isCustomMarshaler(mtype reflect.Type) bool {
+	return mtype.Implements(marshalerType)
+}
+
+func callCustomMarshaler(mval reflect.Value) ([]byte, error) {
+	return mval.Interface().(Marshaler).MarshalTOML()
+}
+
+func isTextMarshaler(mtype reflect.Type) bool {
+	return mtype.Implements(textMarshalerType) && !isTimeType(mtype)
+}
+
+func callTextMarshaler(mval reflect.Value) ([]byte, error) {
+	return mval.Interface().(encoding.TextMarshaler).MarshalText()
+}
+
+func isCustomUnmarshaler(mtype reflect.Type) bool {
+	return mtype.Implements(unmarshalerType)
+}
+
+func callCustomUnmarshaler(mval reflect.Value, tval interface{}) error {
+	return mval.Interface().(Unmarshaler).UnmarshalTOML(tval)
+}
+
+func isTextUnmarshaler(mtype reflect.Type) bool {
+	return mtype.Implements(textUnmarshalerType)
+}
+
+func callTextUnmarshaler(mval reflect.Value, text []byte) error {
+	return mval.Interface().(encoding.TextUnmarshaler).UnmarshalText(text)
+}
+
+// Marshaler is the interface implemented by types that
+// can marshal themselves into valid TOML.
+type Marshaler interface {
+	MarshalTOML() ([]byte, error)
+}
+
+// Unmarshaler is the interface implemented by types that
+// can unmarshal a TOML description of themselves.
+type Unmarshaler interface {
+	UnmarshalTOML(interface{}) error
+}
+
+/*
+Marshal returns the TOML encoding of v.  Behavior is similar to the Go json
+encoder, except that there is no concept of a Marshaler interface or MarshalTOML
+function for sub-structs, and currently only definite types can be marshaled
+(i.e. no `interface{}`).
+
+The following struct annotations are supported:
+
+  toml:"Field"      Overrides the field's name to output.
+  omitempty         When set, empty values and groups are not emitted.
+  comment:"comment" Emits a # comment on the same line. This supports new lines.
+  commented:"true"  Emits the value as commented.
+
+Note that pointers are automatically assigned the "omitempty" option, as TOML
+explicitly does not handle null values (saying instead the label should be
+dropped).
+
+Tree structural types and corresponding marshal types:
+
+  *Tree                            (*)struct, (*)map[string]interface{}
+  []*Tree                          (*)[](*)struct, (*)[](*)map[string]interface{}
+  []interface{} (as interface{})   (*)[]primitive, (*)[]([]interface{})
+  interface{}                      (*)primitive
+
+Tree primitive types and corresponding marshal types:
+
+  uint64     uint, uint8-uint64, pointers to same
+  int64      int, int8-uint64, pointers to same
+  float64    float32, float64, pointers to same
+  string     string, pointers to same
+  bool       bool, pointers to same
+  time.LocalTime  time.LocalTime{}, pointers to same
+
+For additional flexibility, use the Encoder API.
+*/
+func Marshal(v interface{}) ([]byte, error) {
+	return NewEncoder(nil).marshal(v)
+}
+
+// Encoder writes TOML values to an output stream.
+type Encoder struct {
+	w io.Writer
+	encOpts
+	annotation
+	line            int
+	col             int
+	order           MarshalOrder
+	promoteAnon     bool
+	compactComments bool
+	indentation     string
+}
+
+// NewEncoder returns a new encoder that writes to w.
+func NewEncoder(w io.Writer) *Encoder {
+	return &Encoder{
+		w:           w,
+		encOpts:     encOptsDefaults,
+		annotation:  annotationDefault,
+		line:        0,
+		col:         1,
+		order:       OrderAlphabetical,
+		indentation: "  ",
+	}
+}
+
+// Encode writes the TOML encoding of v to the stream.
+//
+// See the documentation for Marshal for details.
+func (e *Encoder) Encode(v interface{}) error {
+	b, err := e.marshal(v)
+	if err != nil {
+		return err
+	}
+	if _, err := e.w.Write(b); err != nil {
+		return err
+	}
+	return nil
+}
+
+// QuoteMapKeys sets up the encoder to encode
+// maps with string type keys with quoted TOML keys.
+//
+// This relieves the character limitations on map keys.
+func (e *Encoder) QuoteMapKeys(v bool) *Encoder {
+	e.quoteMapKeys = v
+	return e
+}
+
+// ArraysWithOneElementPerLine sets up the encoder to encode arrays
+// with more than one element on multiple lines instead of one.
+//
+// For example:
+//
+//   A = [1,2,3]
+//
+// Becomes
+//
+//   A = [
+//     1,
+//     2,
+//     3,
+//   ]
+func (e *Encoder) ArraysWithOneElementPerLine(v bool) *Encoder {
+	e.arraysOneElementPerLine = v
+	return e
+}
+
+// Order allows to change in which order fields will be written to the output stream.
+func (e *Encoder) Order(ord MarshalOrder) *Encoder {
+	e.order = ord
+	return e
+}
+
+// Indentation allows to change indentation when marshalling.
+func (e *Encoder) Indentation(indent string) *Encoder {
+	e.indentation = indent
+	return e
+}
+
+// SetTagName allows changing default tag "toml"
+func (e *Encoder) SetTagName(v string) *Encoder {
+	e.tag = v
+	return e
+}
+
+// SetTagComment allows changing default tag "comment"
+func (e *Encoder) SetTagComment(v string) *Encoder {
+	e.comment = v
+	return e
+}
+
+// SetTagCommented allows changing default tag "commented"
+func (e *Encoder) SetTagCommented(v string) *Encoder {
+	e.commented = v
+	return e
+}
+
+// SetTagMultiline allows changing default tag "multiline"
+func (e *Encoder) SetTagMultiline(v string) *Encoder {
+	e.multiline = v
+	return e
+}
+
+// PromoteAnonymous allows to change how anonymous struct fields are marshaled.
+// Usually, they are marshaled as if the inner exported fields were fields in
+// the outer struct. However, if an anonymous struct field is given a name in
+// its TOML tag, it is treated like a regular struct field with that name.
+// rather than being anonymous.
+//
+// In case anonymous promotion is enabled, all anonymous structs are promoted
+// and treated like regular struct fields.
+func (e *Encoder) PromoteAnonymous(promote bool) *Encoder {
+	e.promoteAnon = promote
+	return e
+}
+
+// CompactComments removes the new line before each comment in the tree.
+func (e *Encoder) CompactComments(cc bool) *Encoder {
+	e.compactComments = cc
+	return e
+}
+
+func (e *Encoder) marshal(v interface{}) ([]byte, error) {
+	// Check if indentation is valid
+	for _, char := range e.indentation {
+		if !isSpace(char) {
+			return []byte{}, fmt.Errorf("invalid indentation: must only contains space or tab characters")
+		}
+	}
+
+	mtype := reflect.TypeOf(v)
+	if mtype == nil {
+		return []byte{}, errors.New("nil cannot be marshaled to TOML")
+	}
+
+	switch mtype.Kind() {
+	case reflect.Struct, reflect.Map:
+	case reflect.Ptr:
+		if mtype.Elem().Kind() != reflect.Struct {
+			return []byte{}, errors.New("Only pointer to struct can be marshaled to TOML")
+		}
+		if reflect.ValueOf(v).IsNil() {
+			return []byte{}, errors.New("nil pointer cannot be marshaled to TOML")
+		}
+	default:
+		return []byte{}, errors.New("Only a struct or map can be marshaled to TOML")
+	}
+
+	sval := reflect.ValueOf(v)
+	if isCustomMarshaler(mtype) {
+		return callCustomMarshaler(sval)
+	}
+	if isTextMarshaler(mtype) {
+		return callTextMarshaler(sval)
+	}
+	t, err := e.valueToTree(mtype, sval)
+	if err != nil {
+		return []byte{}, err
+	}
+
+	var buf bytes.Buffer
+	_, err = t.writeToOrdered(&buf, "", "", 0, e.arraysOneElementPerLine, e.order, e.indentation, e.compactComments, false)
+
+	return buf.Bytes(), err
+}
+
+// Create next tree with a position based on Encoder.line
+func (e *Encoder) nextTree() *Tree {
+	return newTreeWithPosition(Position{Line: e.line, Col: 1})
+}
+
+// Convert given marshal struct or map value to toml tree
+func (e *Encoder) valueToTree(mtype reflect.Type, mval reflect.Value) (*Tree, error) {
+	if mtype.Kind() == reflect.Ptr {
+		return e.valueToTree(mtype.Elem(), mval.Elem())
+	}
+	tval := e.nextTree()
+	switch mtype.Kind() {
+	case reflect.Struct:
+		switch mval.Interface().(type) {
+		case Tree:
+			reflect.ValueOf(tval).Elem().Set(mval)
+		default:
+			for i := 0; i < mtype.NumField(); i++ {
+				mtypef, mvalf := mtype.Field(i), mval.Field(i)
+				opts := tomlOptions(mtypef, e.annotation)
+				if opts.include && ((mtypef.Type.Kind() != reflect.Interface && !opts.omitempty) || !isZero(mvalf)) {
+					val, err := e.valueToToml(mtypef.Type, mvalf)
+					if err != nil {
+						return nil, err
+					}
+					if tree, ok := val.(*Tree); ok && mtypef.Anonymous && !opts.nameFromTag && !e.promoteAnon {
+						e.appendTree(tval, tree)
+					} else {
+						val = e.wrapTomlValue(val, tval)
+						tval.SetPathWithOptions([]string{opts.name}, SetOptions{
+							Comment:   opts.comment,
+							Commented: opts.commented,
+							Multiline: opts.multiline,
+							Literal:   opts.literal,
+						}, val)
+					}
+				}
+			}
+		}
+	case reflect.Map:
+		keys := mval.MapKeys()
+		if e.order == OrderPreserve && len(keys) > 0 {
+			// Sorting []reflect.Value is not straight forward.
+			//
+			// OrderPreserve will support deterministic results when string is used
+			// as the key to maps.
+			typ := keys[0].Type()
+			kind := keys[0].Kind()
+			if kind == reflect.String {
+				ikeys := make([]string, len(keys))
+				for i := range keys {
+					ikeys[i] = keys[i].Interface().(string)
+				}
+				sort.Strings(ikeys)
+				for i := range ikeys {
+					keys[i] = reflect.ValueOf(ikeys[i]).Convert(typ)
+				}
+			}
+		}
+		for _, key := range keys {
+			mvalf := mval.MapIndex(key)
+			if (mtype.Elem().Kind() == reflect.Ptr || mtype.Elem().Kind() == reflect.Interface) && mvalf.IsNil() {
+				continue
+			}
+			val, err := e.valueToToml(mtype.Elem(), mvalf)
+			if err != nil {
+				return nil, err
+			}
+			val = e.wrapTomlValue(val, tval)
+			if e.quoteMapKeys {
+				keyStr, err := tomlValueStringRepresentation(key.String(), "", "", e.order, e.arraysOneElementPerLine)
+				if err != nil {
+					return nil, err
+				}
+				tval.SetPath([]string{keyStr}, val)
+			} else {
+				tval.SetPath([]string{key.String()}, val)
+			}
+		}
+	}
+	return tval, nil
+}
+
+// Convert given marshal slice to slice of Toml trees
+func (e *Encoder) valueToTreeSlice(mtype reflect.Type, mval reflect.Value) ([]*Tree, error) {
+	tval := make([]*Tree, mval.Len(), mval.Len())
+	for i := 0; i < mval.Len(); i++ {
+		val, err := e.valueToTree(mtype.Elem(), mval.Index(i))
+		if err != nil {
+			return nil, err
+		}
+		tval[i] = val
+	}
+	return tval, nil
+}
+
+// Convert given marshal slice to slice of toml values
+func (e *Encoder) valueToOtherSlice(mtype reflect.Type, mval reflect.Value) (interface{}, error) {
+	tval := make([]interface{}, mval.Len(), mval.Len())
+	for i := 0; i < mval.Len(); i++ {
+		val, err := e.valueToToml(mtype.Elem(), mval.Index(i))
+		if err != nil {
+			return nil, err
+		}
+		tval[i] = val
+	}
+	return tval, nil
+}
+
+// Convert given marshal value to toml value
+func (e *Encoder) valueToToml(mtype reflect.Type, mval reflect.Value) (interface{}, error) {
+	if mtype.Kind() == reflect.Ptr {
+		switch {
+		case isCustomMarshaler(mtype):
+			return callCustomMarshaler(mval)
+		case isTextMarshaler(mtype):
+			b, err := callTextMarshaler(mval)
+			return string(b), err
+		default:
+			return e.valueToToml(mtype.Elem(), mval.Elem())
+		}
+	}
+	if mtype.Kind() == reflect.Interface {
+		return e.valueToToml(mval.Elem().Type(), mval.Elem())
+	}
+	switch {
+	case isCustomMarshaler(mtype):
+		return callCustomMarshaler(mval)
+	case isTextMarshaler(mtype):
+		b, err := callTextMarshaler(mval)
+		return string(b), err
+	case isTree(mtype):
+		return e.valueToTree(mtype, mval)
+	case isOtherSequence(mtype), isCustomMarshalerSequence(mtype), isTextMarshalerSequence(mtype):
+		return e.valueToOtherSlice(mtype, mval)
+	case isTreeSequence(mtype):
+		return e.valueToTreeSlice(mtype, mval)
+	default:
+		switch mtype.Kind() {
+		case reflect.Bool:
+			return mval.Bool(), nil
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+			if mtype.Kind() == reflect.Int64 && mtype == reflect.TypeOf(time.Duration(1)) {
+				return fmt.Sprint(mval), nil
+			}
+			return mval.Int(), nil
+		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+			return mval.Uint(), nil
+		case reflect.Float32, reflect.Float64:
+			return mval.Float(), nil
+		case reflect.String:
+			return mval.String(), nil
+		case reflect.Struct:
+			return mval.Interface(), nil
+		default:
+			return nil, fmt.Errorf("Marshal can't handle %v(%v)", mtype, mtype.Kind())
+		}
+	}
+}
+
+func (e *Encoder) appendTree(t, o *Tree) error {
+	for key, value := range o.values {
+		if _, ok := t.values[key]; ok {
+			continue
+		}
+		if tomlValue, ok := value.(*tomlValue); ok {
+			tomlValue.position.Col = t.position.Col
+		}
+		t.values[key] = value
+	}
+	return nil
+}
+
+// Create a toml value with the current line number as the position line
+func (e *Encoder) wrapTomlValue(val interface{}, parent *Tree) interface{} {
+	_, isTree := val.(*Tree)
+	_, isTreeS := val.([]*Tree)
+	if isTree || isTreeS {
+		e.line++
+		return val
+	}
+
+	ret := &tomlValue{
+		value: val,
+		position: Position{
+			e.line,
+			parent.position.Col,
+		},
+	}
+	e.line++
+	return ret
+}
+
+// Unmarshal attempts to unmarshal the Tree into a Go struct pointed by v.
+// Neither Unmarshaler interfaces nor UnmarshalTOML functions are supported for
+// sub-structs, and only definite types can be unmarshaled.
+func (t *Tree) Unmarshal(v interface{}) error {
+	d := Decoder{tval: t, tagName: tagFieldName}
+	return d.unmarshal(v)
+}
+
+// Marshal returns the TOML encoding of Tree.
+// See Marshal() documentation for types mapping table.
+func (t *Tree) Marshal() ([]byte, error) {
+	var buf bytes.Buffer
+	_, err := t.WriteTo(&buf)
+	if err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
+// Unmarshal parses the TOML-encoded data and stores the result in the value
+// pointed to by v. Behavior is similar to the Go json encoder, except that there
+// is no concept of an Unmarshaler interface or UnmarshalTOML function for
+// sub-structs, and currently only definite types can be unmarshaled to (i.e. no
+// `interface{}`).
+//
+// The following struct annotations are supported:
+//
+//   toml:"Field" Overrides the field's name to map to.
+//   default:"foo" Provides a default value.
+//
+// For default values, only fields of the following types are supported:
+//   * string
+//   * bool
+//   * int
+//   * int64
+//   * float64
+//
+// See Marshal() documentation for types mapping table.
+func Unmarshal(data []byte, v interface{}) error {
+	t, err := LoadReader(bytes.NewReader(data))
+	if err != nil {
+		return err
+	}
+	return t.Unmarshal(v)
+}
+
+// Decoder reads and decodes TOML values from an input stream.
+type Decoder struct {
+	r    io.Reader
+	tval *Tree
+	encOpts
+	tagName string
+	strict  bool
+	visitor visitorState
+}
+
+// NewDecoder returns a new decoder that reads from r.
+func NewDecoder(r io.Reader) *Decoder {
+	return &Decoder{
+		r:       r,
+		encOpts: encOptsDefaults,
+		tagName: tagFieldName,
+	}
+}
+
+// Decode reads a TOML-encoded value from it's input
+// and unmarshals it in the value pointed at by v.
+//
+// See the documentation for Marshal for details.
+func (d *Decoder) Decode(v interface{}) error {
+	var err error
+	d.tval, err = LoadReader(d.r)
+	if err != nil {
+		return err
+	}
+	return d.unmarshal(v)
+}
+
+// SetTagName allows changing default tag "toml"
+func (d *Decoder) SetTagName(v string) *Decoder {
+	d.tagName = v
+	return d
+}
+
+// Strict allows changing to strict decoding. Any fields that are found in the
+// input data and do not have a corresponding struct member cause an error.
+func (d *Decoder) Strict(strict bool) *Decoder {
+	d.strict = strict
+	return d
+}
+
+func (d *Decoder) unmarshal(v interface{}) error {
+	mtype := reflect.TypeOf(v)
+	if mtype == nil {
+		return errors.New("nil cannot be unmarshaled from TOML")
+	}
+	if mtype.Kind() != reflect.Ptr {
+		return errors.New("only a pointer to struct or map can be unmarshaled from TOML")
+	}
+
+	elem := mtype.Elem()
+
+	switch elem.Kind() {
+	case reflect.Struct, reflect.Map:
+	case reflect.Interface:
+		elem = mapStringInterfaceType
+	default:
+		return errors.New("only a pointer to struct or map can be unmarshaled from TOML")
+	}
+
+	if reflect.ValueOf(v).IsNil() {
+		return errors.New("nil pointer cannot be unmarshaled from TOML")
+	}
+
+	vv := reflect.ValueOf(v).Elem()
+
+	if d.strict {
+		d.visitor = newVisitorState(d.tval)
+	}
+
+	sval, err := d.valueFromTree(elem, d.tval, &vv)
+	if err != nil {
+		return err
+	}
+	if err := d.visitor.validate(); err != nil {
+		return err
+	}
+	reflect.ValueOf(v).Elem().Set(sval)
+	return nil
+}
+
+// Convert toml tree to marshal struct or map, using marshal type. When mval1
+// is non-nil, merge fields into the given value instead of allocating a new one.
+func (d *Decoder) valueFromTree(mtype reflect.Type, tval *Tree, mval1 *reflect.Value) (reflect.Value, error) {
+	if mtype.Kind() == reflect.Ptr {
+		return d.unwrapPointer(mtype, tval, mval1)
+	}
+
+	// Check if pointer to value implements the Unmarshaler interface.
+	if mvalPtr := reflect.New(mtype); isCustomUnmarshaler(mvalPtr.Type()) {
+		d.visitor.visitAll()
+
+		if tval == nil {
+			return mvalPtr.Elem(), nil
+		}
+
+		if err := callCustomUnmarshaler(mvalPtr, tval.ToMap()); err != nil {
+			return reflect.ValueOf(nil), fmt.Errorf("unmarshal toml: %v", err)
+		}
+		return mvalPtr.Elem(), nil
+	}
+
+	var mval reflect.Value
+	switch mtype.Kind() {
+	case reflect.Struct:
+		if mval1 != nil {
+			mval = *mval1
+		} else {
+			mval = reflect.New(mtype).Elem()
+		}
+
+		switch mval.Interface().(type) {
+		case Tree:
+			mval.Set(reflect.ValueOf(tval).Elem())
+		default:
+			for i := 0; i < mtype.NumField(); i++ {
+				mtypef := mtype.Field(i)
+				an := annotation{tag: d.tagName}
+				opts := tomlOptions(mtypef, an)
+				if !opts.include {
+					continue
+				}
+				baseKey := opts.name
+				keysToTry := []string{
+					baseKey,
+					strings.ToLower(baseKey),
+					strings.ToTitle(baseKey),
+					strings.ToLower(string(baseKey[0])) + baseKey[1:],
+				}
+
+				found := false
+				if tval != nil {
+					for _, key := range keysToTry {
+						exists := tval.HasPath([]string{key})
+						if !exists {
+							continue
+						}
+
+						d.visitor.push(key)
+						val := tval.GetPath([]string{key})
+						fval := mval.Field(i)
+						mvalf, err := d.valueFromToml(mtypef.Type, val, &fval)
+						if err != nil {
+							return mval, formatError(err, tval.GetPositionPath([]string{key}))
+						}
+						mval.Field(i).Set(mvalf)
+						found = true
+						d.visitor.pop()
+						break
+					}
+				}
+
+				if !found && opts.defaultValue != "" {
+					mvalf := mval.Field(i)
+					var val interface{}
+					var err error
+					switch mvalf.Kind() {
+					case reflect.String:
+						val = opts.defaultValue
+					case reflect.Bool:
+						val, err = strconv.ParseBool(opts.defaultValue)
+					case reflect.Uint:
+						val, err = strconv.ParseUint(opts.defaultValue, 10, 0)
+					case reflect.Uint8:
+						val, err = strconv.ParseUint(opts.defaultValue, 10, 8)
+					case reflect.Uint16:
+						val, err = strconv.ParseUint(opts.defaultValue, 10, 16)
+					case reflect.Uint32:
+						val, err = strconv.ParseUint(opts.defaultValue, 10, 32)
+					case reflect.Uint64:
+						val, err = strconv.ParseUint(opts.defaultValue, 10, 64)
+					case reflect.Int:
+						val, err = strconv.ParseInt(opts.defaultValue, 10, 0)
+					case reflect.Int8:
+						val, err = strconv.ParseInt(opts.defaultValue, 10, 8)
+					case reflect.Int16:
+						val, err = strconv.ParseInt(opts.defaultValue, 10, 16)
+					case reflect.Int32:
+						val, err = strconv.ParseInt(opts.defaultValue, 10, 32)
+					case reflect.Int64:
+						// Check if the provided number has a non-numeric extension.
+						var hasExtension bool
+						if len(opts.defaultValue) > 0 {
+							lastChar := opts.defaultValue[len(opts.defaultValue)-1]
+							if lastChar < '0' || lastChar > '9' {
+								hasExtension = true
+							}
+						}
+						// If the value is a time.Duration with extension, parse as duration.
+						// If the value is an int64 or a time.Duration without extension, parse as number.
+						if hasExtension && mvalf.Type().String() == "time.Duration" {
+							val, err = time.ParseDuration(opts.defaultValue)
+						} else {
+							val, err = strconv.ParseInt(opts.defaultValue, 10, 64)
+						}
+					case reflect.Float32:
+						val, err = strconv.ParseFloat(opts.defaultValue, 32)
+					case reflect.Float64:
+						val, err = strconv.ParseFloat(opts.defaultValue, 64)
+					default:
+						return mvalf, fmt.Errorf("unsupported field type for default option")
+					}
+
+					if err != nil {
+						return mvalf, err
+					}
+					mvalf.Set(reflect.ValueOf(val).Convert(mvalf.Type()))
+				}
+
+				// save the old behavior above and try to check structs
+				if !found && opts.defaultValue == "" && mtypef.Type.Kind() == reflect.Struct {
+					tmpTval := tval
+					if !mtypef.Anonymous {
+						tmpTval = nil
+					}
+					fval := mval.Field(i)
+					v, err := d.valueFromTree(mtypef.Type, tmpTval, &fval)
+					if err != nil {
+						return v, err
+					}
+					mval.Field(i).Set(v)
+				}
+			}
+		}
+	case reflect.Map:
+		mval = reflect.MakeMap(mtype)
+		for _, key := range tval.Keys() {
+			d.visitor.push(key)
+			// TODO: path splits key
+			val := tval.GetPath([]string{key})
+			mvalf, err := d.valueFromToml(mtype.Elem(), val, nil)
+			if err != nil {
+				return mval, formatError(err, tval.GetPositionPath([]string{key}))
+			}
+			mval.SetMapIndex(reflect.ValueOf(key).Convert(mtype.Key()), mvalf)
+			d.visitor.pop()
+		}
+	}
+	return mval, nil
+}
+
+// Convert toml value to marshal struct/map slice, using marshal type
+func (d *Decoder) valueFromTreeSlice(mtype reflect.Type, tval []*Tree) (reflect.Value, error) {
+	mval, err := makeSliceOrArray(mtype, len(tval))
+	if err != nil {
+		return mval, err
+	}
+
+	for i := 0; i < len(tval); i++ {
+		d.visitor.push(strconv.Itoa(i))
+		val, err := d.valueFromTree(mtype.Elem(), tval[i], nil)
+		if err != nil {
+			return mval, err
+		}
+		mval.Index(i).Set(val)
+		d.visitor.pop()
+	}
+	return mval, nil
+}
+
+// Convert toml value to marshal primitive slice, using marshal type
+func (d *Decoder) valueFromOtherSlice(mtype reflect.Type, tval []interface{}) (reflect.Value, error) {
+	mval, err := makeSliceOrArray(mtype, len(tval))
+	if err != nil {
+		return mval, err
+	}
+
+	for i := 0; i < len(tval); i++ {
+		val, err := d.valueFromToml(mtype.Elem(), tval[i], nil)
+		if err != nil {
+			return mval, err
+		}
+		mval.Index(i).Set(val)
+	}
+	return mval, nil
+}
+
+// Convert toml value to marshal primitive slice, using marshal type
+func (d *Decoder) valueFromOtherSliceI(mtype reflect.Type, tval interface{}) (reflect.Value, error) {
+	val := reflect.ValueOf(tval)
+	length := val.Len()
+
+	mval, err := makeSliceOrArray(mtype, length)
+	if err != nil {
+		return mval, err
+	}
+
+	for i := 0; i < length; i++ {
+		val, err := d.valueFromToml(mtype.Elem(), val.Index(i).Interface(), nil)
+		if err != nil {
+			return mval, err
+		}
+		mval.Index(i).Set(val)
+	}
+	return mval, nil
+}
+
+// Create a new slice or a new array with specified length
+func makeSliceOrArray(mtype reflect.Type, tLength int) (reflect.Value, error) {
+	var mval reflect.Value
+	switch mtype.Kind() {
+	case reflect.Slice:
+		mval = reflect.MakeSlice(mtype, tLength, tLength)
+	case reflect.Array:
+		mval = reflect.New(reflect.ArrayOf(mtype.Len(), mtype.Elem())).Elem()
+		if tLength > mtype.Len() {
+			return mval, fmt.Errorf("unmarshal: TOML array length (%v) exceeds destination array length (%v)", tLength, mtype.Len())
+		}
+	}
+	return mval, nil
+}
+
+// Convert toml value to marshal value, using marshal type. When mval1 is non-nil
+// and the given type is a struct value, merge fields into it.
+func (d *Decoder) valueFromToml(mtype reflect.Type, tval interface{}, mval1 *reflect.Value) (reflect.Value, error) {
+	if mtype.Kind() == reflect.Ptr {
+		return d.unwrapPointer(mtype, tval, mval1)
+	}
+
+	switch t := tval.(type) {
+	case *Tree:
+		var mval11 *reflect.Value
+		if mtype.Kind() == reflect.Struct {
+			mval11 = mval1
+		}
+
+		if isTree(mtype) {
+			return d.valueFromTree(mtype, t, mval11)
+		}
+
+		if mtype.Kind() == reflect.Interface {
+			if mval1 == nil || mval1.IsNil() {
+				return d.valueFromTree(reflect.TypeOf(map[string]interface{}{}), t, nil)
+			} else {
+				return d.valueFromToml(mval1.Elem().Type(), t, nil)
+			}
+		}
+
+		return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to a tree", tval, tval)
+	case []*Tree:
+		if isTreeSequence(mtype) {
+			return d.valueFromTreeSlice(mtype, t)
+		}
+		if mtype.Kind() == reflect.Interface {
+			if mval1 == nil || mval1.IsNil() {
+				return d.valueFromTreeSlice(reflect.TypeOf([]map[string]interface{}{}), t)
+			} else {
+				ival := mval1.Elem()
+				return d.valueFromToml(mval1.Elem().Type(), t, &ival)
+			}
+		}
+		return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to trees", tval, tval)
+	case []interface{}:
+		d.visitor.visit()
+		if isOtherSequence(mtype) {
+			return d.valueFromOtherSlice(mtype, t)
+		}
+		if mtype.Kind() == reflect.Interface {
+			if mval1 == nil || mval1.IsNil() {
+				return d.valueFromOtherSlice(reflect.TypeOf([]interface{}{}), t)
+			} else {
+				ival := mval1.Elem()
+				return d.valueFromToml(mval1.Elem().Type(), t, &ival)
+			}
+		}
+		return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to a slice", tval, tval)
+	default:
+		d.visitor.visit()
+		mvalPtr := reflect.New(mtype)
+
+		// Check if pointer to value implements the Unmarshaler interface.
+		if isCustomUnmarshaler(mvalPtr.Type()) {
+			if err := callCustomUnmarshaler(mvalPtr, tval); err != nil {
+				return reflect.ValueOf(nil), fmt.Errorf("unmarshal toml: %v", err)
+			}
+			return mvalPtr.Elem(), nil
+		}
+
+		// Check if pointer to value implements the encoding.TextUnmarshaler.
+		if isTextUnmarshaler(mvalPtr.Type()) && !isTimeType(mtype) {
+			if err := d.unmarshalText(tval, mvalPtr); err != nil {
+				return reflect.ValueOf(nil), fmt.Errorf("unmarshal text: %v", err)
+			}
+			return mvalPtr.Elem(), nil
+		}
+
+		switch mtype.Kind() {
+		case reflect.Bool, reflect.Struct:
+			val := reflect.ValueOf(tval)
+
+			switch val.Type() {
+			case localDateType:
+				localDate := val.Interface().(LocalDate)
+				switch mtype {
+				case timeType:
+					return reflect.ValueOf(time.Date(localDate.Year, localDate.Month, localDate.Day, 0, 0, 0, 0, time.Local)), nil
+				}
+			case localDateTimeType:
+				localDateTime := val.Interface().(LocalDateTime)
+				switch mtype {
+				case timeType:
+					return reflect.ValueOf(time.Date(
+						localDateTime.Date.Year,
+						localDateTime.Date.Month,
+						localDateTime.Date.Day,
+						localDateTime.Time.Hour,
+						localDateTime.Time.Minute,
+						localDateTime.Time.Second,
+						localDateTime.Time.Nanosecond,
+						time.Local)), nil
+				}
+			}
+
+			// if this passes for when mtype is reflect.Struct, tval is a time.LocalTime
+			if !val.Type().ConvertibleTo(mtype) {
+				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to %v", tval, tval, mtype.String())
+			}
+
+			return val.Convert(mtype), nil
+		case reflect.String:
+			val := reflect.ValueOf(tval)
+			// stupidly, int64 is convertible to string. So special case this.
+			if !val.Type().ConvertibleTo(mtype) || val.Kind() == reflect.Int64 {
+				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to %v", tval, tval, mtype.String())
+			}
+
+			return val.Convert(mtype), nil
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+			val := reflect.ValueOf(tval)
+			if mtype.Kind() == reflect.Int64 && mtype == reflect.TypeOf(time.Duration(1)) && val.Kind() == reflect.String {
+				d, err := time.ParseDuration(val.String())
+				if err != nil {
+					return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to %v. %s", tval, tval, mtype.String(), err)
+				}
+				return reflect.ValueOf(d), nil
+			}
+			if !val.Type().ConvertibleTo(mtype) || val.Kind() == reflect.Float64 {
+				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to %v", tval, tval, mtype.String())
+			}
+			if reflect.Indirect(reflect.New(mtype)).OverflowInt(val.Convert(reflect.TypeOf(int64(0))).Int()) {
+				return reflect.ValueOf(nil), fmt.Errorf("%v(%T) would overflow %v", tval, tval, mtype.String())
+			}
+
+			return val.Convert(mtype), nil
+		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+			val := reflect.ValueOf(tval)
+			if !val.Type().ConvertibleTo(mtype) || val.Kind() == reflect.Float64 {
+				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to %v", tval, tval, mtype.String())
+			}
+
+			if val.Convert(reflect.TypeOf(int(1))).Int() < 0 {
+				return reflect.ValueOf(nil), fmt.Errorf("%v(%T) is negative so does not fit in %v", tval, tval, mtype.String())
+			}
+			if reflect.Indirect(reflect.New(mtype)).OverflowUint(val.Convert(reflect.TypeOf(uint64(0))).Uint()) {
+				return reflect.ValueOf(nil), fmt.Errorf("%v(%T) would overflow %v", tval, tval, mtype.String())
+			}
+
+			return val.Convert(mtype), nil
+		case reflect.Float32, reflect.Float64:
+			val := reflect.ValueOf(tval)
+			if !val.Type().ConvertibleTo(mtype) || val.Kind() == reflect.Int64 {
+				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to %v", tval, tval, mtype.String())
+			}
+			if reflect.Indirect(reflect.New(mtype)).OverflowFloat(val.Convert(reflect.TypeOf(float64(0))).Float()) {
+				return reflect.ValueOf(nil), fmt.Errorf("%v(%T) would overflow %v", tval, tval, mtype.String())
+			}
+
+			return val.Convert(mtype), nil
+		case reflect.Interface:
+			if mval1 == nil || mval1.IsNil() {
+				return reflect.ValueOf(tval), nil
+			} else {
+				ival := mval1.Elem()
+				return d.valueFromToml(mval1.Elem().Type(), t, &ival)
+			}
+		case reflect.Slice, reflect.Array:
+			if isOtherSequence(mtype) && isOtherSequence(reflect.TypeOf(t)) {
+				return d.valueFromOtherSliceI(mtype, t)
+			}
+			return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to %v(%v)", tval, tval, mtype, mtype.Kind())
+		default:
+			return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to %v(%v)", tval, tval, mtype, mtype.Kind())
+		}
+	}
+}
+
+func (d *Decoder) unwrapPointer(mtype reflect.Type, tval interface{}, mval1 *reflect.Value) (reflect.Value, error) {
+	var melem *reflect.Value
+
+	if mval1 != nil && !mval1.IsNil() && (mtype.Elem().Kind() == reflect.Struct || mtype.Elem().Kind() == reflect.Interface) {
+		elem := mval1.Elem()
+		melem = &elem
+	}
+
+	val, err := d.valueFromToml(mtype.Elem(), tval, melem)
+	if err != nil {
+		return reflect.ValueOf(nil), err
+	}
+	mval := reflect.New(mtype.Elem())
+	mval.Elem().Set(val)
+	return mval, nil
+}
+
+func (d *Decoder) unmarshalText(tval interface{}, mval reflect.Value) error {
+	var buf bytes.Buffer
+	fmt.Fprint(&buf, tval)
+	return callTextUnmarshaler(mval, buf.Bytes())
+}
+
+func tomlOptions(vf reflect.StructField, an annotation) tomlOpts {
+	tag := vf.Tag.Get(an.tag)
+	parse := strings.Split(tag, ",")
+	var comment string
+	if c := vf.Tag.Get(an.comment); c != "" {
+		comment = c
+	}
+	commented, _ := strconv.ParseBool(vf.Tag.Get(an.commented))
+	multiline, _ := strconv.ParseBool(vf.Tag.Get(an.multiline))
+	literal, _ := strconv.ParseBool(vf.Tag.Get(an.literal))
+	defaultValue := vf.Tag.Get(tagDefault)
+	result := tomlOpts{
+		name:         vf.Name,
+		nameFromTag:  false,
+		comment:      comment,
+		commented:    commented,
+		multiline:    multiline,
+		literal:      literal,
+		include:      true,
+		omitempty:    false,
+		defaultValue: defaultValue,
+	}
+	if parse[0] != "" {
+		if parse[0] == "-" && len(parse) == 1 {
+			result.include = false
+		} else {
+			result.name = strings.Trim(parse[0], " ")
+			result.nameFromTag = true
+		}
+	}
+	if vf.PkgPath != "" {
+		result.include = false
+	}
+	if len(parse) > 1 && strings.Trim(parse[1], " ") == "omitempty" {
+		result.omitempty = true
+	}
+	if vf.Type.Kind() == reflect.Ptr {
+		result.omitempty = true
+	}
+	return result
+}
+
+func isZero(val reflect.Value) bool {
+	switch val.Type().Kind() {
+	case reflect.Slice, reflect.Array, reflect.Map:
+		return val.Len() == 0
+	default:
+		return reflect.DeepEqual(val.Interface(), reflect.Zero(val.Type()).Interface())
+	}
+}
+
+func formatError(err error, pos Position) error {
+	if err.Error()[0] == '(' { // Error already contains position information
+		return err
+	}
+	return fmt.Errorf("%s: %s", pos, err)
+}
+
+// visitorState keeps track of which keys were unmarshaled.
+type visitorState struct {
+	tree   *Tree
+	path   []string
+	keys   map[string]struct{}
+	active bool
+}
+
+func newVisitorState(tree *Tree) visitorState {
+	path, result := []string{}, map[string]struct{}{}
+	insertKeys(path, result, tree)
+	return visitorState{
+		tree:   tree,
+		path:   path[:0],
+		keys:   result,
+		active: true,
+	}
+}
+
+func (s *visitorState) push(key string) {
+	if s.active {
+		s.path = append(s.path, key)
+	}
+}
+
+func (s *visitorState) pop() {
+	if s.active {
+		s.path = s.path[:len(s.path)-1]
+	}
+}
+
+func (s *visitorState) visit() {
+	if s.active {
+		delete(s.keys, strings.Join(s.path, "."))
+	}
+}
+
+func (s *visitorState) visitAll() {
+	if s.active {
+		for k := range s.keys {
+			if strings.HasPrefix(k, strings.Join(s.path, ".")) {
+				delete(s.keys, k)
+			}
+		}
+	}
+}
+
+func (s *visitorState) validate() error {
+	if !s.active {
+		return nil
+	}
+	undecoded := make([]string, 0, len(s.keys))
+	for key := range s.keys {
+		undecoded = append(undecoded, key)
+	}
+	sort.Strings(undecoded)
+	if len(undecoded) > 0 {
+		return fmt.Errorf("undecoded keys: %q", undecoded)
+	}
+	return nil
+}
+
+func insertKeys(path []string, m map[string]struct{}, tree *Tree) {
+	for k, v := range tree.values {
+		switch node := v.(type) {
+		case []*Tree:
+			for i, item := range node {
+				insertKeys(append(path, k, strconv.Itoa(i)), m, item)
+			}
+		case *Tree:
+			insertKeys(append(path, k), m, node)
+		case *tomlValue:
+			m[strings.Join(append(path, k), ".")] = struct{}{}
+		}
+	}
+}