diff -r 4f153a23adab -r 6d9efbef00a9 vendor/gopkg.in/yaml.v3/decode.go
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/vendor/gopkg.in/yaml.v3/decode.go	Sun Jul 11 10:35:56 2021 +0200
@@ -0,0 +1,950 @@
+//
+// Copyright (c) 2011-2019 Canonical Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package yaml
+
+import (
+	"encoding"
+	"encoding/base64"
+	"fmt"
+	"io"
+	"math"
+	"reflect"
+	"strconv"
+	"time"
+)
+
+// ----------------------------------------------------------------------------
+// Parser, produces a node tree out of a libyaml event stream.
+
+type parser struct {
+	parser   yaml_parser_t
+	event    yaml_event_t
+	doc      *Node
+	anchors  map[string]*Node
+	doneInit bool
+	textless bool
+}
+
+func newParser(b []byte) *parser {
+	p := parser{}
+	if !yaml_parser_initialize(&p.parser) {
+		panic("failed to initialize YAML emitter")
+	}
+	if len(b) == 0 {
+		b = []byte{'\n'}
+	}
+	yaml_parser_set_input_string(&p.parser, b)
+	return &p
+}
+
+func newParserFromReader(r io.Reader) *parser {
+	p := parser{}
+	if !yaml_parser_initialize(&p.parser) {
+		panic("failed to initialize YAML emitter")
+	}
+	yaml_parser_set_input_reader(&p.parser, r)
+	return &p
+}
+
+func (p *parser) init() {
+	if p.doneInit {
+		return
+	}
+	p.anchors = make(map[string]*Node)
+	p.expect(yaml_STREAM_START_EVENT)
+	p.doneInit = true
+}
+
+func (p *parser) destroy() {
+	if p.event.typ != yaml_NO_EVENT {
+		yaml_event_delete(&p.event)
+	}
+	yaml_parser_delete(&p.parser)
+}
+
+// expect consumes an event from the event stream and
+// checks that it's of the expected type.
+func (p *parser) expect(e yaml_event_type_t) {
+	if p.event.typ == yaml_NO_EVENT {
+		if !yaml_parser_parse(&p.parser, &p.event) {
+			p.fail()
+		}
+	}
+	if p.event.typ == yaml_STREAM_END_EVENT {
+		failf("attempted to go past the end of stream; corrupted value?")
+	}
+	if p.event.typ != e {
+		p.parser.problem = fmt.Sprintf("expected %s event but got %s", e, p.event.typ)
+		p.fail()
+	}
+	yaml_event_delete(&p.event)
+	p.event.typ = yaml_NO_EVENT
+}
+
+// peek peeks at the next event in the event stream,
+// puts the results into p.event and returns the event type.
+func (p *parser) peek() yaml_event_type_t {
+	if p.event.typ != yaml_NO_EVENT {
+		return p.event.typ
+	}
+	if !yaml_parser_parse(&p.parser, &p.event) {
+		p.fail()
+	}
+	return p.event.typ
+}
+
+func (p *parser) fail() {
+	var where string
+	var line int
+	if p.parser.context_mark.line != 0 {
+		line = p.parser.context_mark.line
+		// Scanner errors don't iterate line before returning error
+		if p.parser.error == yaml_SCANNER_ERROR {
+			line++
+		}
+	} else if p.parser.problem_mark.line != 0 {
+		line = p.parser.problem_mark.line
+		// Scanner errors don't iterate line before returning error
+		if p.parser.error == yaml_SCANNER_ERROR {
+			line++
+		}
+	}
+	if line != 0 {
+		where = "line " + strconv.Itoa(line) + ": "
+	}
+	var msg string
+	if len(p.parser.problem) > 0 {
+		msg = p.parser.problem
+	} else {
+		msg = "unknown problem parsing YAML content"
+	}
+	failf("%s%s", where, msg)
+}
+
+func (p *parser) anchor(n *Node, anchor []byte) {
+	if anchor != nil {
+		n.Anchor = string(anchor)
+		p.anchors[n.Anchor] = n
+	}
+}
+
+func (p *parser) parse() *Node {
+	p.init()
+	switch p.peek() {
+	case yaml_SCALAR_EVENT:
+		return p.scalar()
+	case yaml_ALIAS_EVENT:
+		return p.alias()
+	case yaml_MAPPING_START_EVENT:
+		return p.mapping()
+	case yaml_SEQUENCE_START_EVENT:
+		return p.sequence()
+	case yaml_DOCUMENT_START_EVENT:
+		return p.document()
+	case yaml_STREAM_END_EVENT:
+		// Happens when attempting to decode an empty buffer.
+		return nil
+	case yaml_TAIL_COMMENT_EVENT:
+		panic("internal error: unexpected tail comment event (please report)")
+	default:
+		panic("internal error: attempted to parse unknown event (please report): " + p.event.typ.String())
+	}
+}
+
+func (p *parser) node(kind Kind, defaultTag, tag, value string) *Node {
+	var style Style
+	if tag != "" && tag != "!" {
+		tag = shortTag(tag)
+		style = TaggedStyle
+	} else if defaultTag != "" {
+		tag = defaultTag
+	} else if kind == ScalarNode {
+		tag, _ = resolve("", value)
+	}
+	n := &Node{
+		Kind:  kind,
+		Tag:   tag,
+		Value: value,
+		Style: style,
+	}
+	if !p.textless {
+		n.Line = p.event.start_mark.line + 1
+		n.Column = p.event.start_mark.column + 1
+		n.HeadComment = string(p.event.head_comment)
+		n.LineComment = string(p.event.line_comment)
+		n.FootComment = string(p.event.foot_comment)
+	}
+	return n
+}
+
+func (p *parser) parseChild(parent *Node) *Node {
+	child := p.parse()
+	parent.Content = append(parent.Content, child)
+	return child
+}
+
+func (p *parser) document() *Node {
+	n := p.node(DocumentNode, "", "", "")
+	p.doc = n
+	p.expect(yaml_DOCUMENT_START_EVENT)
+	p.parseChild(n)
+	if p.peek() == yaml_DOCUMENT_END_EVENT {
+		n.FootComment = string(p.event.foot_comment)
+	}
+	p.expect(yaml_DOCUMENT_END_EVENT)
+	return n
+}
+
+func (p *parser) alias() *Node {
+	n := p.node(AliasNode, "", "", string(p.event.anchor))
+	n.Alias = p.anchors[n.Value]
+	if n.Alias == nil {
+		failf("unknown anchor '%s' referenced", n.Value)
+	}
+	p.expect(yaml_ALIAS_EVENT)
+	return n
+}
+
+func (p *parser) scalar() *Node {
+	var parsedStyle = p.event.scalar_style()
+	var nodeStyle Style
+	switch {
+	case parsedStyle&yaml_DOUBLE_QUOTED_SCALAR_STYLE != 0:
+		nodeStyle = DoubleQuotedStyle
+	case parsedStyle&yaml_SINGLE_QUOTED_SCALAR_STYLE != 0:
+		nodeStyle = SingleQuotedStyle
+	case parsedStyle&yaml_LITERAL_SCALAR_STYLE != 0:
+		nodeStyle = LiteralStyle
+	case parsedStyle&yaml_FOLDED_SCALAR_STYLE != 0:
+		nodeStyle = FoldedStyle
+	}
+	var nodeValue = string(p.event.value)
+	var nodeTag = string(p.event.tag)
+	var defaultTag string
+	if nodeStyle == 0 {
+		if nodeValue == "<<" {
+			defaultTag = mergeTag
+		}
+	} else {
+		defaultTag = strTag
+	}
+	n := p.node(ScalarNode, defaultTag, nodeTag, nodeValue)
+	n.Style |= nodeStyle
+	p.anchor(n, p.event.anchor)
+	p.expect(yaml_SCALAR_EVENT)
+	return n
+}
+
+func (p *parser) sequence() *Node {
+	n := p.node(SequenceNode, seqTag, string(p.event.tag), "")
+	if p.event.sequence_style()&yaml_FLOW_SEQUENCE_STYLE != 0 {
+		n.Style |= FlowStyle
+	}
+	p.anchor(n, p.event.anchor)
+	p.expect(yaml_SEQUENCE_START_EVENT)
+	for p.peek() != yaml_SEQUENCE_END_EVENT {
+		p.parseChild(n)
+	}
+	n.LineComment = string(p.event.line_comment)
+	n.FootComment = string(p.event.foot_comment)
+	p.expect(yaml_SEQUENCE_END_EVENT)
+	return n
+}
+
+func (p *parser) mapping() *Node {
+	n := p.node(MappingNode, mapTag, string(p.event.tag), "")
+	block := true
+	if p.event.mapping_style()&yaml_FLOW_MAPPING_STYLE != 0 {
+		block = false
+		n.Style |= FlowStyle
+	}
+	p.anchor(n, p.event.anchor)
+	p.expect(yaml_MAPPING_START_EVENT)
+	for p.peek() != yaml_MAPPING_END_EVENT {
+		k := p.parseChild(n)
+		if block && k.FootComment != "" {
+			// Must be a foot comment for the prior value when being dedented.
+			if len(n.Content) > 2 {
+				n.Content[len(n.Content)-3].FootComment = k.FootComment
+				k.FootComment = ""
+			}
+		}
+		v := p.parseChild(n)
+		if k.FootComment == "" && v.FootComment != "" {
+			k.FootComment = v.FootComment
+			v.FootComment = ""
+		}
+		if p.peek() == yaml_TAIL_COMMENT_EVENT {
+			if k.FootComment == "" {
+				k.FootComment = string(p.event.foot_comment)
+			}
+			p.expect(yaml_TAIL_COMMENT_EVENT)
+		}
+	}
+	n.LineComment = string(p.event.line_comment)
+	n.FootComment = string(p.event.foot_comment)
+	if n.Style&FlowStyle == 0 && n.FootComment != "" && len(n.Content) > 1 {
+		n.Content[len(n.Content)-2].FootComment = n.FootComment
+		n.FootComment = ""
+	}
+	p.expect(yaml_MAPPING_END_EVENT)
+	return n
+}
+
+// ----------------------------------------------------------------------------
+// Decoder, unmarshals a node into a provided value.
+
+type decoder struct {
+	doc     *Node
+	aliases map[*Node]bool
+	terrors []string
+
+	stringMapType  reflect.Type
+	generalMapType reflect.Type
+
+	knownFields bool
+	uniqueKeys  bool
+	decodeCount int
+	aliasCount  int
+	aliasDepth  int
+}
+
+var (
+	nodeType       = reflect.TypeOf(Node{})
+	durationType   = reflect.TypeOf(time.Duration(0))
+	stringMapType  = reflect.TypeOf(map[string]interface{}{})
+	generalMapType = reflect.TypeOf(map[interface{}]interface{}{})
+	ifaceType      = generalMapType.Elem()
+	timeType       = reflect.TypeOf(time.Time{})
+	ptrTimeType    = reflect.TypeOf(&time.Time{})
+)
+
+func newDecoder() *decoder {
+	d := &decoder{
+		stringMapType:  stringMapType,
+		generalMapType: generalMapType,
+		uniqueKeys:     true,
+	}
+	d.aliases = make(map[*Node]bool)
+	return d
+}
+
+func (d *decoder) terror(n *Node, tag string, out reflect.Value) {
+	if n.Tag != "" {
+		tag = n.Tag
+	}
+	value := n.Value
+	if tag != seqTag && tag != mapTag {
+		if len(value) > 10 {
+			value = " `" + value[:7] + "...`"
+		} else {
+			value = " `" + value + "`"
+		}
+	}
+	d.terrors = append(d.terrors, fmt.Sprintf("line %d: cannot unmarshal %s%s into %s", n.Line, shortTag(tag), value, out.Type()))
+}
+
+func (d *decoder) callUnmarshaler(n *Node, u Unmarshaler) (good bool) {
+	err := u.UnmarshalYAML(n)
+	if e, ok := err.(*TypeError); ok {
+		d.terrors = append(d.terrors, e.Errors...)
+		return false
+	}
+	if err != nil {
+		fail(err)
+	}
+	return true
+}
+
+func (d *decoder) callObsoleteUnmarshaler(n *Node, u obsoleteUnmarshaler) (good bool) {
+	terrlen := len(d.terrors)
+	err := u.UnmarshalYAML(func(v interface{}) (err error) {
+		defer handleErr(&err)
+		d.unmarshal(n, reflect.ValueOf(v))
+		if len(d.terrors) > terrlen {
+			issues := d.terrors[terrlen:]
+			d.terrors = d.terrors[:terrlen]
+			return &TypeError{issues}
+		}
+		return nil
+	})
+	if e, ok := err.(*TypeError); ok {
+		d.terrors = append(d.terrors, e.Errors...)
+		return false
+	}
+	if err != nil {
+		fail(err)
+	}
+	return true
+}
+
+// d.prepare initializes and dereferences pointers and calls UnmarshalYAML
+// if a value is found to implement it.
+// It returns the initialized and dereferenced out value, whether
+// unmarshalling was already done by UnmarshalYAML, and if so whether
+// its types unmarshalled appropriately.
+//
+// If n holds a null value, prepare returns before doing anything.
+func (d *decoder) prepare(n *Node, out reflect.Value) (newout reflect.Value, unmarshaled, good bool) {
+	if n.ShortTag() == nullTag {
+		return out, false, false
+	}
+	again := true
+	for again {
+		again = false
+		if out.Kind() == reflect.Ptr {
+			if out.IsNil() {
+				out.Set(reflect.New(out.Type().Elem()))
+			}
+			out = out.Elem()
+			again = true
+		}
+		if out.CanAddr() {
+			outi := out.Addr().Interface()
+			if u, ok := outi.(Unmarshaler); ok {
+				good = d.callUnmarshaler(n, u)
+				return out, true, good
+			}
+			if u, ok := outi.(obsoleteUnmarshaler); ok {
+				good = d.callObsoleteUnmarshaler(n, u)
+				return out, true, good
+			}
+		}
+	}
+	return out, false, false
+}
+
+func (d *decoder) fieldByIndex(n *Node, v reflect.Value, index []int) (field reflect.Value) {
+	if n.ShortTag() == nullTag {
+		return reflect.Value{}
+	}
+	for _, num := range index {
+		for {
+			if v.Kind() == reflect.Ptr {
+				if v.IsNil() {
+					v.Set(reflect.New(v.Type().Elem()))
+				}
+				v = v.Elem()
+				continue
+			}
+			break
+		}
+		v = v.Field(num)
+	}
+	return v
+}
+
+const (
+	// 400,000 decode operations is ~500kb of dense object declarations, or
+	// ~5kb of dense object declarations with 10000% alias expansion
+	alias_ratio_range_low = 400000
+
+	// 4,000,000 decode operations is ~5MB of dense object declarations, or
+	// ~4.5MB of dense object declarations with 10% alias expansion
+	alias_ratio_range_high = 4000000
+
+	// alias_ratio_range is the range over which we scale allowed alias ratios
+	alias_ratio_range = float64(alias_ratio_range_high - alias_ratio_range_low)
+)
+
+func allowedAliasRatio(decodeCount int) float64 {
+	switch {
+	case decodeCount <= alias_ratio_range_low:
+		// allow 99% to come from alias expansion for small-to-medium documents
+		return 0.99
+	case decodeCount >= alias_ratio_range_high:
+		// allow 10% to come from alias expansion for very large documents
+		return 0.10
+	default:
+		// scale smoothly from 99% down to 10% over the range.
+		// this maps to 396,000 - 400,000 allowed alias-driven decodes over the range.
+		// 400,000 decode operations is ~100MB of allocations in worst-case scenarios (single-item maps).
+		return 0.99 - 0.89*(float64(decodeCount-alias_ratio_range_low)/alias_ratio_range)
+	}
+}
+
+func (d *decoder) unmarshal(n *Node, out reflect.Value) (good bool) {
+	d.decodeCount++
+	if d.aliasDepth > 0 {
+		d.aliasCount++
+	}
+	if d.aliasCount > 100 && d.decodeCount > 1000 && float64(d.aliasCount)/float64(d.decodeCount) > allowedAliasRatio(d.decodeCount) {
+		failf("document contains excessive aliasing")
+	}
+	if out.Type() == nodeType {
+		out.Set(reflect.ValueOf(n).Elem())
+		return true
+	}
+	switch n.Kind {
+	case DocumentNode:
+		return d.document(n, out)
+	case AliasNode:
+		return d.alias(n, out)
+	}
+	out, unmarshaled, good := d.prepare(n, out)
+	if unmarshaled {
+		return good
+	}
+	switch n.Kind {
+	case ScalarNode:
+		good = d.scalar(n, out)
+	case MappingNode:
+		good = d.mapping(n, out)
+	case SequenceNode:
+		good = d.sequence(n, out)
+	case 0:
+		if n.IsZero() {
+			return d.null(out)
+		}
+		fallthrough
+	default:
+		failf("cannot decode node with unknown kind %d", n.Kind)
+	}
+	return good
+}
+
+func (d *decoder) document(n *Node, out reflect.Value) (good bool) {
+	if len(n.Content) == 1 {
+		d.doc = n
+		d.unmarshal(n.Content[0], out)
+		return true
+	}
+	return false
+}
+
+func (d *decoder) alias(n *Node, out reflect.Value) (good bool) {
+	if d.aliases[n] {
+		// TODO this could actually be allowed in some circumstances.
+		failf("anchor '%s' value contains itself", n.Value)
+	}
+	d.aliases[n] = true
+	d.aliasDepth++
+	good = d.unmarshal(n.Alias, out)
+	d.aliasDepth--
+	delete(d.aliases, n)
+	return good
+}
+
+var zeroValue reflect.Value
+
+func resetMap(out reflect.Value) {
+	for _, k := range out.MapKeys() {
+		out.SetMapIndex(k, zeroValue)
+	}
+}
+
+func (d *decoder) null(out reflect.Value) bool {
+	if out.CanAddr() {
+		switch out.Kind() {
+		case reflect.Interface, reflect.Ptr, reflect.Map, reflect.Slice:
+			out.Set(reflect.Zero(out.Type()))
+			return true
+		}
+	}
+	return false
+}
+
+func (d *decoder) scalar(n *Node, out reflect.Value) bool {
+	var tag string
+	var resolved interface{}
+	if n.indicatedString() {
+		tag = strTag
+		resolved = n.Value
+	} else {
+		tag, resolved = resolve(n.Tag, n.Value)
+		if tag == binaryTag {
+			data, err := base64.StdEncoding.DecodeString(resolved.(string))
+			if err != nil {
+				failf("!!binary value contains invalid base64 data")
+			}
+			resolved = string(data)
+		}
+	}
+	if resolved == nil {
+		return d.null(out)
+	}
+	if resolvedv := reflect.ValueOf(resolved); out.Type() == resolvedv.Type() {
+		// We've resolved to exactly the type we want, so use that.
+		out.Set(resolvedv)
+		return true
+	}
+	// Perhaps we can use the value as a TextUnmarshaler to
+	// set its value.
+	if out.CanAddr() {
+		u, ok := out.Addr().Interface().(encoding.TextUnmarshaler)
+		if ok {
+			var text []byte
+			if tag == binaryTag {
+				text = []byte(resolved.(string))
+			} else {
+				// We let any value be unmarshaled into TextUnmarshaler.
+				// That might be more lax than we'd like, but the
+				// TextUnmarshaler itself should bowl out any dubious values.
+				text = []byte(n.Value)
+			}
+			err := u.UnmarshalText(text)
+			if err != nil {
+				fail(err)
+			}
+			return true
+		}
+	}
+	switch out.Kind() {
+	case reflect.String:
+		if tag == binaryTag {
+			out.SetString(resolved.(string))
+			return true
+		}
+		out.SetString(n.Value)
+		return true
+	case reflect.Interface:
+		out.Set(reflect.ValueOf(resolved))
+		return true
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		// This used to work in v2, but it's very unfriendly.
+		isDuration := out.Type() == durationType
+
+		switch resolved := resolved.(type) {
+		case int:
+			if !isDuration && !out.OverflowInt(int64(resolved)) {
+				out.SetInt(int64(resolved))
+				return true
+			}
+		case int64:
+			if !isDuration && !out.OverflowInt(resolved) {
+				out.SetInt(resolved)
+				return true
+			}
+		case uint64:
+			if !isDuration && resolved <= math.MaxInt64 && !out.OverflowInt(int64(resolved)) {
+				out.SetInt(int64(resolved))
+				return true
+			}
+		case float64:
+			if !isDuration && resolved <= math.MaxInt64 && !out.OverflowInt(int64(resolved)) {
+				out.SetInt(int64(resolved))
+				return true
+			}
+		case string:
+			if out.Type() == durationType {
+				d, err := time.ParseDuration(resolved)
+				if err == nil {
+					out.SetInt(int64(d))
+					return true
+				}
+			}
+		}
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		switch resolved := resolved.(type) {
+		case int:
+			if resolved >= 0 && !out.OverflowUint(uint64(resolved)) {
+				out.SetUint(uint64(resolved))
+				return true
+			}
+		case int64:
+			if resolved >= 0 && !out.OverflowUint(uint64(resolved)) {
+				out.SetUint(uint64(resolved))
+				return true
+			}
+		case uint64:
+			if !out.OverflowUint(uint64(resolved)) {
+				out.SetUint(uint64(resolved))
+				return true
+			}
+		case float64:
+			if resolved <= math.MaxUint64 && !out.OverflowUint(uint64(resolved)) {
+				out.SetUint(uint64(resolved))
+				return true
+			}
+		}
+	case reflect.Bool:
+		switch resolved := resolved.(type) {
+		case bool:
+			out.SetBool(resolved)
+			return true
+		case string:
+			// This offers some compatibility with the 1.1 spec (https://yaml.org/type/bool.html).
+			// It only works if explicitly attempting to unmarshal into a typed bool value.
+			switch resolved {
+			case "y", "Y", "yes", "Yes", "YES", "on", "On", "ON":
+				out.SetBool(true)
+				return true
+			case "n", "N", "no", "No", "NO", "off", "Off", "OFF":
+				out.SetBool(false)
+				return true
+			}
+		}
+	case reflect.Float32, reflect.Float64:
+		switch resolved := resolved.(type) {
+		case int:
+			out.SetFloat(float64(resolved))
+			return true
+		case int64:
+			out.SetFloat(float64(resolved))
+			return true
+		case uint64:
+			out.SetFloat(float64(resolved))
+			return true
+		case float64:
+			out.SetFloat(resolved)
+			return true
+		}
+	case reflect.Struct:
+		if resolvedv := reflect.ValueOf(resolved); out.Type() == resolvedv.Type() {
+			out.Set(resolvedv)
+			return true
+		}
+	case reflect.Ptr:
+		panic("yaml internal error: please report the issue")
+	}
+	d.terror(n, tag, out)
+	return false
+}
+
+func settableValueOf(i interface{}) reflect.Value {
+	v := reflect.ValueOf(i)
+	sv := reflect.New(v.Type()).Elem()
+	sv.Set(v)
+	return sv
+}
+
+func (d *decoder) sequence(n *Node, out reflect.Value) (good bool) {
+	l := len(n.Content)
+
+	var iface reflect.Value
+	switch out.Kind() {
+	case reflect.Slice:
+		out.Set(reflect.MakeSlice(out.Type(), l, l))
+	case reflect.Array:
+		if l != out.Len() {
+			failf("invalid array: want %d elements but got %d", out.Len(), l)
+		}
+	case reflect.Interface:
+		// No type hints. Will have to use a generic sequence.
+		iface = out
+		out = settableValueOf(make([]interface{}, l))
+	default:
+		d.terror(n, seqTag, out)
+		return false
+	}
+	et := out.Type().Elem()
+
+	j := 0
+	for i := 0; i < l; i++ {
+		e := reflect.New(et).Elem()
+		if ok := d.unmarshal(n.Content[i], e); ok {
+			out.Index(j).Set(e)
+			j++
+		}
+	}
+	if out.Kind() != reflect.Array {
+		out.Set(out.Slice(0, j))
+	}
+	if iface.IsValid() {
+		iface.Set(out)
+	}
+	return true
+}
+
+func (d *decoder) mapping(n *Node, out reflect.Value) (good bool) {
+	l := len(n.Content)
+	if d.uniqueKeys {
+		nerrs := len(d.terrors)
+		for i := 0; i < l; i += 2 {
+			ni := n.Content[i]
+			for j := i + 2; j < l; j += 2 {
+				nj := n.Content[j]
+				if ni.Kind == nj.Kind && ni.Value == nj.Value {
+					d.terrors = append(d.terrors, fmt.Sprintf("line %d: mapping key %#v already defined at line %d", nj.Line, nj.Value, ni.Line))
+				}
+			}
+		}
+		if len(d.terrors) > nerrs {
+			return false
+		}
+	}
+	switch out.Kind() {
+	case reflect.Struct:
+		return d.mappingStruct(n, out)
+	case reflect.Map:
+		// okay
+	case reflect.Interface:
+		iface := out
+		if isStringMap(n) {
+			out = reflect.MakeMap(d.stringMapType)
+		} else {
+			out = reflect.MakeMap(d.generalMapType)
+		}
+		iface.Set(out)
+	default:
+		d.terror(n, mapTag, out)
+		return false
+	}
+
+	outt := out.Type()
+	kt := outt.Key()
+	et := outt.Elem()
+
+	stringMapType := d.stringMapType
+	generalMapType := d.generalMapType
+	if outt.Elem() == ifaceType {
+		if outt.Key().Kind() == reflect.String {
+			d.stringMapType = outt
+		} else if outt.Key() == ifaceType {
+			d.generalMapType = outt
+		}
+	}
+
+	mapIsNew := false
+	if out.IsNil() {
+		out.Set(reflect.MakeMap(outt))
+		mapIsNew = true
+	}
+	for i := 0; i < l; i += 2 {
+		if isMerge(n.Content[i]) {
+			d.merge(n.Content[i+1], out)
+			continue
+		}
+		k := reflect.New(kt).Elem()
+		if d.unmarshal(n.Content[i], k) {
+			kkind := k.Kind()
+			if kkind == reflect.Interface {
+				kkind = k.Elem().Kind()
+			}
+			if kkind == reflect.Map || kkind == reflect.Slice {
+				failf("invalid map key: %#v", k.Interface())
+			}
+			e := reflect.New(et).Elem()
+			if d.unmarshal(n.Content[i+1], e) || n.Content[i+1].ShortTag() == nullTag && (mapIsNew || !out.MapIndex(k).IsValid()) {
+				out.SetMapIndex(k, e)
+			}
+		}
+	}
+	d.stringMapType = stringMapType
+	d.generalMapType = generalMapType
+	return true
+}
+
+func isStringMap(n *Node) bool {
+	if n.Kind != MappingNode {
+		return false
+	}
+	l := len(n.Content)
+	for i := 0; i < l; i += 2 {
+		if n.Content[i].ShortTag() != strTag {
+			return false
+		}
+	}
+	return true
+}
+
+func (d *decoder) mappingStruct(n *Node, out reflect.Value) (good bool) {
+	sinfo, err := getStructInfo(out.Type())
+	if err != nil {
+		panic(err)
+	}
+
+	var inlineMap reflect.Value
+	var elemType reflect.Type
+	if sinfo.InlineMap != -1 {
+		inlineMap = out.Field(sinfo.InlineMap)
+		inlineMap.Set(reflect.New(inlineMap.Type()).Elem())
+		elemType = inlineMap.Type().Elem()
+	}
+
+	for _, index := range sinfo.InlineUnmarshalers {
+		field := d.fieldByIndex(n, out, index)
+		d.prepare(n, field)
+	}
+
+	var doneFields []bool
+	if d.uniqueKeys {
+		doneFields = make([]bool, len(sinfo.FieldsList))
+	}
+	name := settableValueOf("")
+	l := len(n.Content)
+	for i := 0; i < l; i += 2 {
+		ni := n.Content[i]
+		if isMerge(ni) {
+			d.merge(n.Content[i+1], out)
+			continue
+		}
+		if !d.unmarshal(ni, name) {
+			continue
+		}
+		if info, ok := sinfo.FieldsMap[name.String()]; ok {
+			if d.uniqueKeys {
+				if doneFields[info.Id] {
+					d.terrors = append(d.terrors, fmt.Sprintf("line %d: field %s already set in type %s", ni.Line, name.String(), out.Type()))
+					continue
+				}
+				doneFields[info.Id] = true
+			}
+			var field reflect.Value
+			if info.Inline == nil {
+				field = out.Field(info.Num)
+			} else {
+				field = d.fieldByIndex(n, out, info.Inline)
+			}
+			d.unmarshal(n.Content[i+1], field)
+		} else if sinfo.InlineMap != -1 {
+			if inlineMap.IsNil() {
+				inlineMap.Set(reflect.MakeMap(inlineMap.Type()))
+			}
+			value := reflect.New(elemType).Elem()
+			d.unmarshal(n.Content[i+1], value)
+			inlineMap.SetMapIndex(name, value)
+		} else if d.knownFields {
+			d.terrors = append(d.terrors, fmt.Sprintf("line %d: field %s not found in type %s", ni.Line, name.String(), out.Type()))
+		}
+	}
+	return true
+}
+
+func failWantMap() {
+	failf("map merge requires map or sequence of maps as the value")
+}
+
+func (d *decoder) merge(n *Node, out reflect.Value) {
+	switch n.Kind {
+	case MappingNode:
+		d.unmarshal(n, out)
+	case AliasNode:
+		if n.Alias != nil && n.Alias.Kind != MappingNode {
+			failWantMap()
+		}
+		d.unmarshal(n, out)
+	case SequenceNode:
+		// Step backwards as earlier nodes take precedence.
+		for i := len(n.Content) - 1; i >= 0; i-- {
+			ni := n.Content[i]
+			if ni.Kind == AliasNode {
+				if ni.Alias != nil && ni.Alias.Kind != MappingNode {
+					failWantMap()
+				}
+			} else if ni.Kind != MappingNode {
+				failWantMap()
+			}
+			d.unmarshal(ni, out)
+		}
+	default:
+		failWantMap()
+	}
+}
+
+func isMerge(n *Node) bool {
+	return n.Kind == ScalarNode && n.Value == "<<" && (n.Tag == "" || n.Tag == "!" || shortTag(n.Tag) == mergeTag)
+}