Adding upstream version 1.18.10.upstream/1.18.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2574 insertions, 0 deletions

diff --git a/src/encoding/json/decode_test.go b/src/encoding/json/decode_test.go
new file mode 100644
index 0000000..c2c036b
--- /dev/null
+++ b/src/encoding/json/decode_test.go
@@ -0,0 +1,2574 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package json
+
+import (
+	"bytes"
+	"encoding"
+	"errors"
+	"fmt"
+	"image"
+	"math"
+	"math/big"
+	"net"
+	"reflect"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+)
+
+type T struct {
+	X string
+	Y int
+	Z int `json:"-"`
+}
+
+type U struct {
+	Alphabet string `json:"alpha"`
+}
+
+type V struct {
+	F1 any
+	F2 int32
+	F3 Number
+	F4 *VOuter
+}
+
+type VOuter struct {
+	V V
+}
+
+type W struct {
+	S SS
+}
+
+type P struct {
+	PP PP
+}
+
+type PP struct {
+	T  T
+	Ts []T
+}
+
+type SS string
+
+func (*SS) UnmarshalJSON(data []byte) error {
+	return &UnmarshalTypeError{Value: "number", Type: reflect.TypeOf(SS(""))}
+}
+
+// ifaceNumAsFloat64/ifaceNumAsNumber are used to test unmarshaling with and
+// without UseNumber
+var ifaceNumAsFloat64 = map[string]any{
+	"k1": float64(1),
+	"k2": "s",
+	"k3": []any{float64(1), float64(2.0), float64(3e-3)},
+	"k4": map[string]any{"kk1": "s", "kk2": float64(2)},
+}
+
+var ifaceNumAsNumber = map[string]any{
+	"k1": Number("1"),
+	"k2": "s",
+	"k3": []any{Number("1"), Number("2.0"), Number("3e-3")},
+	"k4": map[string]any{"kk1": "s", "kk2": Number("2")},
+}
+
+type tx struct {
+	x int
+}
+
+type u8 uint8
+
+// A type that can unmarshal itself.
+
+type unmarshaler struct {
+	T bool
+}
+
+func (u *unmarshaler) UnmarshalJSON(b []byte) error {
+	*u = unmarshaler{true} // All we need to see that UnmarshalJSON is called.
+	return nil
+}
+
+type ustruct struct {
+	M unmarshaler
+}
+
+type unmarshalerText struct {
+	A, B string
+}
+
+// needed for re-marshaling tests
+func (u unmarshalerText) MarshalText() ([]byte, error) {
+	return []byte(u.A + ":" + u.B), nil
+}
+
+func (u *unmarshalerText) UnmarshalText(b []byte) error {
+	pos := bytes.IndexByte(b, ':')
+	if pos == -1 {
+		return errors.New("missing separator")
+	}
+	u.A, u.B = string(b[:pos]), string(b[pos+1:])
+	return nil
+}
+
+var _ encoding.TextUnmarshaler = (*unmarshalerText)(nil)
+
+type ustructText struct {
+	M unmarshalerText
+}
+
+// u8marshal is an integer type that can marshal/unmarshal itself.
+type u8marshal uint8
+
+func (u8 u8marshal) MarshalText() ([]byte, error) {
+	return []byte(fmt.Sprintf("u%d", u8)), nil
+}
+
+var errMissingU8Prefix = errors.New("missing 'u' prefix")
+
+func (u8 *u8marshal) UnmarshalText(b []byte) error {
+	if !bytes.HasPrefix(b, []byte{'u'}) {
+		return errMissingU8Prefix
+	}
+	n, err := strconv.Atoi(string(b[1:]))
+	if err != nil {
+		return err
+	}
+	*u8 = u8marshal(n)
+	return nil
+}
+
+var _ encoding.TextUnmarshaler = (*u8marshal)(nil)
+
+var (
+	umtrue   = unmarshaler{true}
+	umslice  = []unmarshaler{{true}}
+	umstruct = ustruct{unmarshaler{true}}
+
+	umtrueXY   = unmarshalerText{"x", "y"}
+	umsliceXY  = []unmarshalerText{{"x", "y"}}
+	umstructXY = ustructText{unmarshalerText{"x", "y"}}
+
+	ummapXY = map[unmarshalerText]bool{{"x", "y"}: true}
+)
+
+// Test data structures for anonymous fields.
+
+type Point struct {
+	Z int
+}
+
+type Top struct {
+	Level0 int
+	Embed0
+	*Embed0a
+	*Embed0b `json:"e,omitempty"` // treated as named
+	Embed0c  `json:"-"`           // ignored
+	Loop
+	Embed0p // has Point with X, Y, used
+	Embed0q // has Point with Z, used
+	embed   // contains exported field
+}
+
+type Embed0 struct {
+	Level1a int // overridden by Embed0a's Level1a with json tag
+	Level1b int // used because Embed0a's Level1b is renamed
+	Level1c int // used because Embed0a's Level1c is ignored
+	Level1d int // annihilated by Embed0a's Level1d
+	Level1e int `json:"x"` // annihilated by Embed0a.Level1e
+}
+
+type Embed0a struct {
+	Level1a int `json:"Level1a,omitempty"`
+	Level1b int `json:"LEVEL1B,omitempty"`
+	Level1c int `json:"-"`
+	Level1d int // annihilated by Embed0's Level1d
+	Level1f int `json:"x"` // annihilated by Embed0's Level1e
+}
+
+type Embed0b Embed0
+
+type Embed0c Embed0
+
+type Embed0p struct {
+	image.Point
+}
+
+type Embed0q struct {
+	Point
+}
+
+type embed struct {
+	Q int
+}
+
+type Loop struct {
+	Loop1 int `json:",omitempty"`
+	Loop2 int `json:",omitempty"`
+	*Loop
+}
+
+// From reflect test:
+// The X in S6 and S7 annihilate, but they also block the X in S8.S9.
+type S5 struct {
+	S6
+	S7
+	S8
+}
+
+type S6 struct {
+	X int
+}
+
+type S7 S6
+
+type S8 struct {
+	S9
+}
+
+type S9 struct {
+	X int
+	Y int
+}
+
+// From reflect test:
+// The X in S11.S6 and S12.S6 annihilate, but they also block the X in S13.S8.S9.
+type S10 struct {
+	S11
+	S12
+	S13
+}
+
+type S11 struct {
+	S6
+}
+
+type S12 struct {
+	S6
+}
+
+type S13 struct {
+	S8
+}
+
+type Ambig struct {
+	// Given "hello", the first match should win.
+	First  int `json:"HELLO"`
+	Second int `json:"Hello"`
+}
+
+type XYZ struct {
+	X any
+	Y any
+	Z any
+}
+
+type unexportedWithMethods struct{}
+
+func (unexportedWithMethods) F() {}
+
+type byteWithMarshalJSON byte
+
+func (b byteWithMarshalJSON) MarshalJSON() ([]byte, error) {
+	return []byte(fmt.Sprintf(`"Z%.2x"`, byte(b))), nil
+}
+
+func (b *byteWithMarshalJSON) UnmarshalJSON(data []byte) error {
+	if len(data) != 5 || data[0] != '"' || data[1] != 'Z' || data[4] != '"' {
+		return fmt.Errorf("bad quoted string")
+	}
+	i, err := strconv.ParseInt(string(data[2:4]), 16, 8)
+	if err != nil {
+		return fmt.Errorf("bad hex")
+	}
+	*b = byteWithMarshalJSON(i)
+	return nil
+}
+
+type byteWithPtrMarshalJSON byte
+
+func (b *byteWithPtrMarshalJSON) MarshalJSON() ([]byte, error) {
+	return byteWithMarshalJSON(*b).MarshalJSON()
+}
+
+func (b *byteWithPtrMarshalJSON) UnmarshalJSON(data []byte) error {
+	return (*byteWithMarshalJSON)(b).UnmarshalJSON(data)
+}
+
+type byteWithMarshalText byte
+
+func (b byteWithMarshalText) MarshalText() ([]byte, error) {
+	return []byte(fmt.Sprintf(`Z%.2x`, byte(b))), nil
+}
+
+func (b *byteWithMarshalText) UnmarshalText(data []byte) error {
+	if len(data) != 3 || data[0] != 'Z' {
+		return fmt.Errorf("bad quoted string")
+	}
+	i, err := strconv.ParseInt(string(data[1:3]), 16, 8)
+	if err != nil {
+		return fmt.Errorf("bad hex")
+	}
+	*b = byteWithMarshalText(i)
+	return nil
+}
+
+type byteWithPtrMarshalText byte
+
+func (b *byteWithPtrMarshalText) MarshalText() ([]byte, error) {
+	return byteWithMarshalText(*b).MarshalText()
+}
+
+func (b *byteWithPtrMarshalText) UnmarshalText(data []byte) error {
+	return (*byteWithMarshalText)(b).UnmarshalText(data)
+}
+
+type intWithMarshalJSON int
+
+func (b intWithMarshalJSON) MarshalJSON() ([]byte, error) {
+	return []byte(fmt.Sprintf(`"Z%.2x"`, int(b))), nil
+}
+
+func (b *intWithMarshalJSON) UnmarshalJSON(data []byte) error {
+	if len(data) != 5 || data[0] != '"' || data[1] != 'Z' || data[4] != '"' {
+		return fmt.Errorf("bad quoted string")
+	}
+	i, err := strconv.ParseInt(string(data[2:4]), 16, 8)
+	if err != nil {
+		return fmt.Errorf("bad hex")
+	}
+	*b = intWithMarshalJSON(i)
+	return nil
+}
+
+type intWithPtrMarshalJSON int
+
+func (b *intWithPtrMarshalJSON) MarshalJSON() ([]byte, error) {
+	return intWithMarshalJSON(*b).MarshalJSON()
+}
+
+func (b *intWithPtrMarshalJSON) UnmarshalJSON(data []byte) error {
+	return (*intWithMarshalJSON)(b).UnmarshalJSON(data)
+}
+
+type intWithMarshalText int
+
+func (b intWithMarshalText) MarshalText() ([]byte, error) {
+	return []byte(fmt.Sprintf(`Z%.2x`, int(b))), nil
+}
+
+func (b *intWithMarshalText) UnmarshalText(data []byte) error {
+	if len(data) != 3 || data[0] != 'Z' {
+		return fmt.Errorf("bad quoted string")
+	}
+	i, err := strconv.ParseInt(string(data[1:3]), 16, 8)
+	if err != nil {
+		return fmt.Errorf("bad hex")
+	}
+	*b = intWithMarshalText(i)
+	return nil
+}
+
+type intWithPtrMarshalText int
+
+func (b *intWithPtrMarshalText) MarshalText() ([]byte, error) {
+	return intWithMarshalText(*b).MarshalText()
+}
+
+func (b *intWithPtrMarshalText) UnmarshalText(data []byte) error {
+	return (*intWithMarshalText)(b).UnmarshalText(data)
+}
+
+type mapStringToStringData struct {
+	Data map[string]string `json:"data"`
+}
+
+type unmarshalTest struct {
+	in                    string
+	ptr                   any // new(type)
+	out                   any
+	err                   error
+	useNumber             bool
+	golden                bool
+	disallowUnknownFields bool
+}
+
+type B struct {
+	B bool `json:",string"`
+}
+
+type DoublePtr struct {
+	I **int
+	J **int
+}
+
+var unmarshalTests = []unmarshalTest{
+	// basic types
+	{in: `true`, ptr: new(bool), out: true},
+	{in: `1`, ptr: new(int), out: 1},
+	{in: `1.2`, ptr: new(float64), out: 1.2},
+	{in: `-5`, ptr: new(int16), out: int16(-5)},
+	{in: `2`, ptr: new(Number), out: Number("2"), useNumber: true},
+	{in: `2`, ptr: new(Number), out: Number("2")},
+	{in: `2`, ptr: new(any), out: float64(2.0)},
+	{in: `2`, ptr: new(any), out: Number("2"), useNumber: true},
+	{in: `"a\u1234"`, ptr: new(string), out: "a\u1234"},
+	{in: `"http:\/\/"`, ptr: new(string), out: "http://"},
+	{in: `"g-clef: \uD834\uDD1E"`, ptr: new(string), out: "g-clef: \U0001D11E"},
+	{in: `"invalid: \uD834x\uDD1E"`, ptr: new(string), out: "invalid: \uFFFDx\uFFFD"},
+	{in: "null", ptr: new(any), out: nil},
+	{in: `{"X": [1,2,3], "Y": 4}`, ptr: new(T), out: T{Y: 4}, err: &UnmarshalTypeError{"array", reflect.TypeOf(""), 7, "T", "X"}},
+	{in: `{"X": 23}`, ptr: new(T), out: T{}, err: &UnmarshalTypeError{"number", reflect.TypeOf(""), 8, "T", "X"}}, {in: `{"x": 1}`, ptr: new(tx), out: tx{}},
+	{in: `{"x": 1}`, ptr: new(tx), out: tx{}},
+	{in: `{"x": 1}`, ptr: new(tx), err: fmt.Errorf("json: unknown field \"x\""), disallowUnknownFields: true},
+	{in: `{"S": 23}`, ptr: new(W), out: W{}, err: &UnmarshalTypeError{"number", reflect.TypeOf(SS("")), 0, "W", "S"}},
+	{in: `{"F1":1,"F2":2,"F3":3}`, ptr: new(V), out: V{F1: float64(1), F2: int32(2), F3: Number("3")}},
+	{in: `{"F1":1,"F2":2,"F3":3}`, ptr: new(V), out: V{F1: Number("1"), F2: int32(2), F3: Number("3")}, useNumber: true},
+	{in: `{"k1":1,"k2":"s","k3":[1,2.0,3e-3],"k4":{"kk1":"s","kk2":2}}`, ptr: new(any), out: ifaceNumAsFloat64},
+	{in: `{"k1":1,"k2":"s","k3":[1,2.0,3e-3],"k4":{"kk1":"s","kk2":2}}`, ptr: new(any), out: ifaceNumAsNumber, useNumber: true},
+
+	// raw values with whitespace
+	{in: "\n true ", ptr: new(bool), out: true},
+	{in: "\t 1 ", ptr: new(int), out: 1},
+	{in: "\r 1.2 ", ptr: new(float64), out: 1.2},
+	{in: "\t -5 \n", ptr: new(int16), out: int16(-5)},
+	{in: "\t \"a\\u1234\" \n", ptr: new(string), out: "a\u1234"},
+
+	// Z has a "-" tag.
+	{in: `{"Y": 1, "Z": 2}`, ptr: new(T), out: T{Y: 1}},
+	{in: `{"Y": 1, "Z": 2}`, ptr: new(T), err: fmt.Errorf("json: unknown field \"Z\""), disallowUnknownFields: true},
+
+	{in: `{"alpha": "abc", "alphabet": "xyz"}`, ptr: new(U), out: U{Alphabet: "abc"}},
+	{in: `{"alpha": "abc", "alphabet": "xyz"}`, ptr: new(U), err: fmt.Errorf("json: unknown field \"alphabet\""), disallowUnknownFields: true},
+	{in: `{"alpha": "abc"}`, ptr: new(U), out: U{Alphabet: "abc"}},
+	{in: `{"alphabet": "xyz"}`, ptr: new(U), out: U{}},
+	{in: `{"alphabet": "xyz"}`, ptr: new(U), err: fmt.Errorf("json: unknown field \"alphabet\""), disallowUnknownFields: true},
+
+	// syntax errors
+	{in: `{"X": "foo", "Y"}`, err: &SyntaxError{"invalid character '}' after object key", 17}},
+	{in: `[1, 2, 3+]`, err: &SyntaxError{"invalid character '+' after array element", 9}},
+	{in: `{"X":12x}`, err: &SyntaxError{"invalid character 'x' after object key:value pair", 8}, useNumber: true},
+	{in: `[2, 3`, err: &SyntaxError{msg: "unexpected end of JSON input", Offset: 5}},
+	{in: `{"F3": -}`, ptr: new(V), out: V{F3: Number("-")}, err: &SyntaxError{msg: "invalid character '}' in numeric literal", Offset: 9}},
+
+	// raw value errors
+	{in: "\x01 42", err: &SyntaxError{"invalid character '\\x01' looking for beginning of value", 1}},
+	{in: " 42 \x01", err: &SyntaxError{"invalid character '\\x01' after top-level value", 5}},
+	{in: "\x01 true", err: &SyntaxError{"invalid character '\\x01' looking for beginning of value", 1}},
+	{in: " false \x01", err: &SyntaxError{"invalid character '\\x01' after top-level value", 8}},
+	{in: "\x01 1.2", err: &SyntaxError{"invalid character '\\x01' looking for beginning of value", 1}},
+	{in: " 3.4 \x01", err: &SyntaxError{"invalid character '\\x01' after top-level value", 6}},
+	{in: "\x01 \"string\"", err: &SyntaxError{"invalid character '\\x01' looking for beginning of value", 1}},
+	{in: " \"string\" \x01", err: &SyntaxError{"invalid character '\\x01' after top-level value", 11}},
+
+	// array tests
+	{in: `[1, 2, 3]`, ptr: new([3]int), out: [3]int{1, 2, 3}},
+	{in: `[1, 2, 3]`, ptr: new([1]int), out: [1]int{1}},
+	{in: `[1, 2, 3]`, ptr: new([5]int), out: [5]int{1, 2, 3, 0, 0}},
+	{in: `[1, 2, 3]`, ptr: new(MustNotUnmarshalJSON), err: errors.New("MustNotUnmarshalJSON was used")},
+
+	// empty array to interface test
+	{in: `[]`, ptr: new([]any), out: []any{}},
+	{in: `null`, ptr: new([]any), out: []any(nil)},
+	{in: `{"T":[]}`, ptr: new(map[string]any), out: map[string]any{"T": []any{}}},
+	{in: `{"T":null}`, ptr: new(map[string]any), out: map[string]any{"T": any(nil)}},
+
+	// composite tests
+	{in: allValueIndent, ptr: new(All), out: allValue},
+	{in: allValueCompact, ptr: new(All), out: allValue},
+	{in: allValueIndent, ptr: new(*All), out: &allValue},
+	{in: allValueCompact, ptr: new(*All), out: &allValue},
+	{in: pallValueIndent, ptr: new(All), out: pallValue},
+	{in: pallValueCompact, ptr: new(All), out: pallValue},
+	{in: pallValueIndent, ptr: new(*All), out: &pallValue},
+	{in: pallValueCompact, ptr: new(*All), out: &pallValue},
+
+	// unmarshal interface test
+	{in: `{"T":false}`, ptr: new(unmarshaler), out: umtrue}, // use "false" so test will fail if custom unmarshaler is not called
+	{in: `{"T":false}`, ptr: new(*unmarshaler), out: &umtrue},
+	{in: `[{"T":false}]`, ptr: new([]unmarshaler), out: umslice},
+	{in: `[{"T":false}]`, ptr: new(*[]unmarshaler), out: &umslice},
+	{in: `{"M":{"T":"x:y"}}`, ptr: new(ustruct), out: umstruct},
+
+	// UnmarshalText interface test
+	{in: `"x:y"`, ptr: new(unmarshalerText), out: umtrueXY},
+	{in: `"x:y"`, ptr: new(*unmarshalerText), out: &umtrueXY},
+	{in: `["x:y"]`, ptr: new([]unmarshalerText), out: umsliceXY},
+	{in: `["x:y"]`, ptr: new(*[]unmarshalerText), out: &umsliceXY},
+	{in: `{"M":"x:y"}`, ptr: new(ustructText), out: umstructXY},
+
+	// integer-keyed map test
+	{
+		in:  `{"-1":"a","0":"b","1":"c"}`,
+		ptr: new(map[int]string),
+		out: map[int]string{-1: "a", 0: "b", 1: "c"},
+	},
+	{
+		in:  `{"0":"a","10":"c","9":"b"}`,
+		ptr: new(map[u8]string),
+		out: map[u8]string{0: "a", 9: "b", 10: "c"},
+	},
+	{
+		in:  `{"-9223372036854775808":"min","9223372036854775807":"max"}`,
+		ptr: new(map[int64]string),
+		out: map[int64]string{math.MinInt64: "min", math.MaxInt64: "max"},
+	},
+	{
+		in:  `{"18446744073709551615":"max"}`,
+		ptr: new(map[uint64]string),
+		out: map[uint64]string{math.MaxUint64: "max"},
+	},
+	{
+		in:  `{"0":false,"10":true}`,
+		ptr: new(map[uintptr]bool),
+		out: map[uintptr]bool{0: false, 10: true},
+	},
+
+	// Check that MarshalText and UnmarshalText take precedence
+	// over default integer handling in map keys.
+	{
+		in:  `{"u2":4}`,
+		ptr: new(map[u8marshal]int),
+		out: map[u8marshal]int{2: 4},
+	},
+	{
+		in:  `{"2":4}`,
+		ptr: new(map[u8marshal]int),
+		err: errMissingU8Prefix,
+	},
+
+	// integer-keyed map errors
+	{
+		in:  `{"abc":"abc"}`,
+		ptr: new(map[int]string),
+		err: &UnmarshalTypeError{Value: "number abc", Type: reflect.TypeOf(0), Offset: 2},
+	},
+	{
+		in:  `{"256":"abc"}`,
+		ptr: new(map[uint8]string),
+		err: &UnmarshalTypeError{Value: "number 256", Type: reflect.TypeOf(uint8(0)), Offset: 2},
+	},
+	{
+		in:  `{"128":"abc"}`,
+		ptr: new(map[int8]string),
+		err: &UnmarshalTypeError{Value: "number 128", Type: reflect.TypeOf(int8(0)), Offset: 2},
+	},
+	{
+		in:  `{"-1":"abc"}`,
+		ptr: new(map[uint8]string),
+		err: &UnmarshalTypeError{Value: "number -1", Type: reflect.TypeOf(uint8(0)), Offset: 2},
+	},
+	{
+		in:  `{"F":{"a":2,"3":4}}`,
+		ptr: new(map[string]map[int]int),
+		err: &UnmarshalTypeError{Value: "number a", Type: reflect.TypeOf(int(0)), Offset: 7},
+	},
+	{
+		in:  `{"F":{"a":2,"3":4}}`,
+		ptr: new(map[string]map[uint]int),
+		err: &UnmarshalTypeError{Value: "number a", Type: reflect.TypeOf(uint(0)), Offset: 7},
+	},
+
+	// Map keys can be encoding.TextUnmarshalers.
+	{in: `{"x:y":true}`, ptr: new(map[unmarshalerText]bool), out: ummapXY},
+	// If multiple values for the same key exists, only the most recent value is used.
+	{in: `{"x:y":false,"x:y":true}`, ptr: new(map[unmarshalerText]bool), out: ummapXY},
+
+	{
+		in: `{
+			"Level0": 1,
+			"Level1b": 2,
+			"Level1c": 3,
+			"x": 4,
+			"Level1a": 5,
+			"LEVEL1B": 6,
+			"e": {
+				"Level1a": 8,
+				"Level1b": 9,
+				"Level1c": 10,
+				"Level1d": 11,
+				"x": 12
+			},
+			"Loop1": 13,
+			"Loop2": 14,
+			"X": 15,
+			"Y": 16,
+			"Z": 17,
+			"Q": 18
+		}`,
+		ptr: new(Top),
+		out: Top{
+			Level0: 1,
+			Embed0: Embed0{
+				Level1b: 2,
+				Level1c: 3,
+			},
+			Embed0a: &Embed0a{
+				Level1a: 5,
+				Level1b: 6,
+			},
+			Embed0b: &Embed0b{
+				Level1a: 8,
+				Level1b: 9,
+				Level1c: 10,
+				Level1d: 11,
+				Level1e: 12,
+			},
+			Loop: Loop{
+				Loop1: 13,
+				Loop2: 14,
+			},
+			Embed0p: Embed0p{
+				Point: image.Point{X: 15, Y: 16},
+			},
+			Embed0q: Embed0q{
+				Point: Point{Z: 17},
+			},
+			embed: embed{
+				Q: 18,
+			},
+		},
+	},
+	{
+		in:  `{"hello": 1}`,
+		ptr: new(Ambig),
+		out: Ambig{First: 1},
+	},
+
+	{
+		in:  `{"X": 1,"Y":2}`,
+		ptr: new(S5),
+		out: S5{S8: S8{S9: S9{Y: 2}}},
+	},
+	{
+		in:                    `{"X": 1,"Y":2}`,
+		ptr:                   new(S5),
+		err:                   fmt.Errorf("json: unknown field \"X\""),
+		disallowUnknownFields: true,
+	},
+	{
+		in:  `{"X": 1,"Y":2}`,
+		ptr: new(S10),
+		out: S10{S13: S13{S8: S8{S9: S9{Y: 2}}}},
+	},
+	{
+		in:                    `{"X": 1,"Y":2}`,
+		ptr:                   new(S10),
+		err:                   fmt.Errorf("json: unknown field \"X\""),
+		disallowUnknownFields: true,
+	},
+	{
+		in:  `{"I": 0, "I": null, "J": null}`,
+		ptr: new(DoublePtr),
+		out: DoublePtr{I: nil, J: nil},
+	},
+
+	// invalid UTF-8 is coerced to valid UTF-8.
+	{
+		in:  "\"hello\xffworld\"",
+		ptr: new(string),
+		out: "hello\ufffdworld",
+	},
+	{
+		in:  "\"hello\xc2\xc2world\"",
+		ptr: new(string),
+		out: "hello\ufffd\ufffdworld",
+	},
+	{
+		in:  "\"hello\xc2\xffworld\"",
+		ptr: new(string),
+		out: "hello\ufffd\ufffdworld",
+	},
+	{
+		in:  "\"hello\\ud800world\"",
+		ptr: new(string),
+		out: "hello\ufffdworld",
+	},
+	{
+		in:  "\"hello\\ud800\\ud800world\"",
+		ptr: new(string),
+		out: "hello\ufffd\ufffdworld",
+	},
+	{
+		in:  "\"hello\\ud800\\ud800world\"",
+		ptr: new(string),
+		out: "hello\ufffd\ufffdworld",
+	},
+	{
+		in:  "\"hello\xed\xa0\x80\xed\xb0\x80world\"",
+		ptr: new(string),
+		out: "hello\ufffd\ufffd\ufffd\ufffd\ufffd\ufffdworld",
+	},
+
+	// Used to be issue 8305, but time.Time implements encoding.TextUnmarshaler so this works now.
+	{
+		in:  `{"2009-11-10T23:00:00Z": "hello world"}`,
+		ptr: new(map[time.Time]string),
+		out: map[time.Time]string{time.Date(2009, 11, 10, 23, 0, 0, 0, time.UTC): "hello world"},
+	},
+
+	// issue 8305
+	{
+		in:  `{"2009-11-10T23:00:00Z": "hello world"}`,
+		ptr: new(map[Point]string),
+		err: &UnmarshalTypeError{Value: "object", Type: reflect.TypeOf(map[Point]string{}), Offset: 1},
+	},
+	{
+		in:  `{"asdf": "hello world"}`,
+		ptr: new(map[unmarshaler]string),
+		err: &UnmarshalTypeError{Value: "object", Type: reflect.TypeOf(map[unmarshaler]string{}), Offset: 1},
+	},
+
+	// related to issue 13783.
+	// Go 1.7 changed marshaling a slice of typed byte to use the methods on the byte type,
+	// similar to marshaling a slice of typed int.
+	// These tests check that, assuming the byte type also has valid decoding methods,
+	// either the old base64 string encoding or the new per-element encoding can be
+	// successfully unmarshaled. The custom unmarshalers were accessible in earlier
+	// versions of Go, even though the custom marshaler was not.
+	{
+		in:  `"AQID"`,
+		ptr: new([]byteWithMarshalJSON),
+		out: []byteWithMarshalJSON{1, 2, 3},
+	},
+	{
+		in:     `["Z01","Z02","Z03"]`,
+		ptr:    new([]byteWithMarshalJSON),
+		out:    []byteWithMarshalJSON{1, 2, 3},
+		golden: true,
+	},
+	{
+		in:  `"AQID"`,
+		ptr: new([]byteWithMarshalText),
+		out: []byteWithMarshalText{1, 2, 3},
+	},
+	{
+		in:     `["Z01","Z02","Z03"]`,
+		ptr:    new([]byteWithMarshalText),
+		out:    []byteWithMarshalText{1, 2, 3},
+		golden: true,
+	},
+	{
+		in:  `"AQID"`,
+		ptr: new([]byteWithPtrMarshalJSON),
+		out: []byteWithPtrMarshalJSON{1, 2, 3},
+	},
+	{
+		in:     `["Z01","Z02","Z03"]`,
+		ptr:    new([]byteWithPtrMarshalJSON),
+		out:    []byteWithPtrMarshalJSON{1, 2, 3},
+		golden: true,
+	},
+	{
+		in:  `"AQID"`,
+		ptr: new([]byteWithPtrMarshalText),
+		out: []byteWithPtrMarshalText{1, 2, 3},
+	},
+	{
+		in:     `["Z01","Z02","Z03"]`,
+		ptr:    new([]byteWithPtrMarshalText),
+		out:    []byteWithPtrMarshalText{1, 2, 3},
+		golden: true,
+	},
+
+	// ints work with the marshaler but not the base64 []byte case
+	{
+		in:     `["Z01","Z02","Z03"]`,
+		ptr:    new([]intWithMarshalJSON),
+		out:    []intWithMarshalJSON{1, 2, 3},
+		golden: true,
+	},
+	{
+		in:     `["Z01","Z02","Z03"]`,
+		ptr:    new([]intWithMarshalText),
+		out:    []intWithMarshalText{1, 2, 3},
+		golden: true,
+	},
+	{
+		in:     `["Z01","Z02","Z03"]`,
+		ptr:    new([]intWithPtrMarshalJSON),
+		out:    []intWithPtrMarshalJSON{1, 2, 3},
+		golden: true,
+	},
+	{
+		in:     `["Z01","Z02","Z03"]`,
+		ptr:    new([]intWithPtrMarshalText),
+		out:    []intWithPtrMarshalText{1, 2, 3},
+		golden: true,
+	},
+
+	{in: `0.000001`, ptr: new(float64), out: 0.000001, golden: true},
+	{in: `1e-7`, ptr: new(float64), out: 1e-7, golden: true},
+	{in: `100000000000000000000`, ptr: new(float64), out: 100000000000000000000.0, golden: true},
+	{in: `1e+21`, ptr: new(float64), out: 1e21, golden: true},
+	{in: `-0.000001`, ptr: new(float64), out: -0.000001, golden: true},
+	{in: `-1e-7`, ptr: new(float64), out: -1e-7, golden: true},
+	{in: `-100000000000000000000`, ptr: new(float64), out: -100000000000000000000.0, golden: true},
+	{in: `-1e+21`, ptr: new(float64), out: -1e21, golden: true},
+	{in: `999999999999999900000`, ptr: new(float64), out: 999999999999999900000.0, golden: true},
+	{in: `9007199254740992`, ptr: new(float64), out: 9007199254740992.0, golden: true},
+	{in: `9007199254740993`, ptr: new(float64), out: 9007199254740992.0, golden: false},
+
+	{
+		in:  `{"V": {"F2": "hello"}}`,
+		ptr: new(VOuter),
+		err: &UnmarshalTypeError{
+			Value:  "string",
+			Struct: "V",
+			Field:  "V.F2",
+			Type:   reflect.TypeOf(int32(0)),
+			Offset: 20,
+		},
+	},
+	{
+		in:  `{"V": {"F4": {}, "F2": "hello"}}`,
+		ptr: new(VOuter),
+		err: &UnmarshalTypeError{
+			Value:  "string",
+			Struct: "V",
+			Field:  "V.F2",
+			Type:   reflect.TypeOf(int32(0)),
+			Offset: 30,
+		},
+	},
+
+	// issue 15146.
+	// invalid inputs in wrongStringTests below.
+	{in: `{"B":"true"}`, ptr: new(B), out: B{true}, golden: true},
+	{in: `{"B":"false"}`, ptr: new(B), out: B{false}, golden: true},
+	{in: `{"B": "maybe"}`, ptr: new(B), err: errors.New(`json: invalid use of ,string struct tag, trying to unmarshal "maybe" into bool`)},
+	{in: `{"B": "tru"}`, ptr: new(B), err: errors.New(`json: invalid use of ,string struct tag, trying to unmarshal "tru" into bool`)},
+	{in: `{"B": "False"}`, ptr: new(B), err: errors.New(`json: invalid use of ,string struct tag, trying to unmarshal "False" into bool`)},
+	{in: `{"B": "null"}`, ptr: new(B), out: B{false}},
+	{in: `{"B": "nul"}`, ptr: new(B), err: errors.New(`json: invalid use of ,string struct tag, trying to unmarshal "nul" into bool`)},
+	{in: `{"B": [2, 3]}`, ptr: new(B), err: errors.New(`json: invalid use of ,string struct tag, trying to unmarshal unquoted value into bool`)},
+
+	// additional tests for disallowUnknownFields
+	{
+		in: `{
+			"Level0": 1,
+			"Level1b": 2,
+			"Level1c": 3,
+			"x": 4,
+			"Level1a": 5,
+			"LEVEL1B": 6,
+			"e": {
+				"Level1a": 8,
+				"Level1b": 9,
+				"Level1c": 10,
+				"Level1d": 11,
+				"x": 12
+			},
+			"Loop1": 13,
+			"Loop2": 14,
+			"X": 15,
+			"Y": 16,
+			"Z": 17,
+			"Q": 18,
+			"extra": true
+		}`,
+		ptr:                   new(Top),
+		err:                   fmt.Errorf("json: unknown field \"extra\""),
+		disallowUnknownFields: true,
+	},
+	{
+		in: `{
+			"Level0": 1,
+			"Level1b": 2,
+			"Level1c": 3,
+			"x": 4,
+			"Level1a": 5,
+			"LEVEL1B": 6,
+			"e": {
+				"Level1a": 8,
+				"Level1b": 9,
+				"Level1c": 10,
+				"Level1d": 11,
+				"x": 12,
+				"extra": null
+			},
+			"Loop1": 13,
+			"Loop2": 14,
+			"X": 15,
+			"Y": 16,
+			"Z": 17,
+			"Q": 18
+		}`,
+		ptr:                   new(Top),
+		err:                   fmt.Errorf("json: unknown field \"extra\""),
+		disallowUnknownFields: true,
+	},
+	// issue 26444
+	// UnmarshalTypeError without field & struct values
+	{
+		in:  `{"data":{"test1": "bob", "test2": 123}}`,
+		ptr: new(mapStringToStringData),
+		err: &UnmarshalTypeError{Value: "number", Type: reflect.TypeOf(""), Offset: 37, Struct: "mapStringToStringData", Field: "data"},
+	},
+	{
+		in:  `{"data":{"test1": 123, "test2": "bob"}}`,
+		ptr: new(mapStringToStringData),
+		err: &UnmarshalTypeError{Value: "number", Type: reflect.TypeOf(""), Offset: 21, Struct: "mapStringToStringData", Field: "data"},
+	},
+
+	// trying to decode JSON arrays or objects via TextUnmarshaler
+	{
+		in:  `[1, 2, 3]`,
+		ptr: new(MustNotUnmarshalText),
+		err: &UnmarshalTypeError{Value: "array", Type: reflect.TypeOf(&MustNotUnmarshalText{}), Offset: 1},
+	},
+	{
+		in:  `{"foo": "bar"}`,
+		ptr: new(MustNotUnmarshalText),
+		err: &UnmarshalTypeError{Value: "object", Type: reflect.TypeOf(&MustNotUnmarshalText{}), Offset: 1},
+	},
+	// #22369
+	{
+		in:  `{"PP": {"T": {"Y": "bad-type"}}}`,
+		ptr: new(P),
+		err: &UnmarshalTypeError{
+			Value:  "string",
+			Struct: "T",
+			Field:  "PP.T.Y",
+			Type:   reflect.TypeOf(int(0)),
+			Offset: 29,
+		},
+	},
+	{
+		in:  `{"Ts": [{"Y": 1}, {"Y": 2}, {"Y": "bad-type"}]}`,
+		ptr: new(PP),
+		err: &UnmarshalTypeError{
+			Value:  "string",
+			Struct: "T",
+			Field:  "Ts.Y",
+			Type:   reflect.TypeOf(int(0)),
+			Offset: 29,
+		},
+	},
+	// #14702
+	{
+		in:  `invalid`,
+		ptr: new(Number),
+		err: &SyntaxError{
+			msg:    "invalid character 'i' looking for beginning of value",
+			Offset: 1,
+		},
+	},
+	{
+		in:  `"invalid"`,
+		ptr: new(Number),
+		err: fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number", `"invalid"`),
+	},
+	{
+		in:  `{"A":"invalid"}`,
+		ptr: new(struct{ A Number }),
+		err: fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number", `"invalid"`),
+	},
+	{
+		in: `{"A":"invalid"}`,
+		ptr: new(struct {
+			A Number `json:",string"`
+		}),
+		err: fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into json.Number", `invalid`),
+	},
+	{
+		in:  `{"A":"invalid"}`,
+		ptr: new(map[string]Number),
+		err: fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number", `"invalid"`),
+	},
+}
+
+func TestMarshal(t *testing.T) {
+	b, err := Marshal(allValue)
+	if err != nil {
+		t.Fatalf("Marshal allValue: %v", err)
+	}
+	if string(b) != allValueCompact {
+		t.Errorf("Marshal allValueCompact")
+		diff(t, b, []byte(allValueCompact))
+		return
+	}
+
+	b, err = Marshal(pallValue)
+	if err != nil {
+		t.Fatalf("Marshal pallValue: %v", err)
+	}
+	if string(b) != pallValueCompact {
+		t.Errorf("Marshal pallValueCompact")
+		diff(t, b, []byte(pallValueCompact))
+		return
+	}
+}
+
+var badUTF8 = []struct {
+	in, out string
+}{
+	{"hello\xffworld", `"hello\ufffdworld"`},
+	{"", `""`},
+	{"\xff", `"\ufffd"`},
+	{"\xff\xff", `"\ufffd\ufffd"`},
+	{"a\xffb", `"a\ufffdb"`},
+	{"\xe6\x97\xa5\xe6\x9c\xac\xff\xaa\x9e", `"日本\ufffd\ufffd\ufffd"`},
+}
+
+func TestMarshalBadUTF8(t *testing.T) {
+	for _, tt := range badUTF8 {
+		b, err := Marshal(tt.in)
+		if string(b) != tt.out || err != nil {
+			t.Errorf("Marshal(%q) = %#q, %v, want %#q, nil", tt.in, b, err, tt.out)
+		}
+	}
+}
+
+func TestMarshalNumberZeroVal(t *testing.T) {
+	var n Number
+	out, err := Marshal(n)
+	if err != nil {
+		t.Fatal(err)
+	}
+	outStr := string(out)
+	if outStr != "0" {
+		t.Fatalf("Invalid zero val for Number: %q", outStr)
+	}
+}
+
+func TestMarshalEmbeds(t *testing.T) {
+	top := &Top{
+		Level0: 1,
+		Embed0: Embed0{
+			Level1b: 2,
+			Level1c: 3,
+		},
+		Embed0a: &Embed0a{
+			Level1a: 5,
+			Level1b: 6,
+		},
+		Embed0b: &Embed0b{
+			Level1a: 8,
+			Level1b: 9,
+			Level1c: 10,
+			Level1d: 11,
+			Level1e: 12,
+		},
+		Loop: Loop{
+			Loop1: 13,
+			Loop2: 14,
+		},
+		Embed0p: Embed0p{
+			Point: image.Point{X: 15, Y: 16},
+		},
+		Embed0q: Embed0q{
+			Point: Point{Z: 17},
+		},
+		embed: embed{
+			Q: 18,
+		},
+	}
+	b, err := Marshal(top)
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := "{\"Level0\":1,\"Level1b\":2,\"Level1c\":3,\"Level1a\":5,\"LEVEL1B\":6,\"e\":{\"Level1a\":8,\"Level1b\":9,\"Level1c\":10,\"Level1d\":11,\"x\":12},\"Loop1\":13,\"Loop2\":14,\"X\":15,\"Y\":16,\"Z\":17,\"Q\":18}"
+	if string(b) != want {
+		t.Errorf("Wrong marshal result.\n got: %q\nwant: %q", b, want)
+	}
+}
+
+func equalError(a, b error) bool {
+	if a == nil {
+		return b == nil
+	}
+	if b == nil {
+		return a == nil
+	}
+	return a.Error() == b.Error()
+}
+
+func TestUnmarshal(t *testing.T) {
+	for i, tt := range unmarshalTests {
+		var scan scanner
+		in := []byte(tt.in)
+		if err := checkValid(in, &scan); err != nil {
+			if !equalError(err, tt.err) {
+				t.Errorf("#%d: checkValid: %#v", i, err)
+				continue
+			}
+		}
+		if tt.ptr == nil {
+			continue
+		}
+
+		typ := reflect.TypeOf(tt.ptr)
+		if typ.Kind() != reflect.Pointer {
+			t.Errorf("#%d: unmarshalTest.ptr %T is not a pointer type", i, tt.ptr)
+			continue
+		}
+		typ = typ.Elem()
+
+		// v = new(right-type)
+		v := reflect.New(typ)
+
+		if !reflect.DeepEqual(tt.ptr, v.Interface()) {
+			// There's no reason for ptr to point to non-zero data,
+			// as we decode into new(right-type), so the data is
+			// discarded.
+			// This can easily mean tests that silently don't test
+			// what they should. To test decoding into existing
+			// data, see TestPrefilled.
+			t.Errorf("#%d: unmarshalTest.ptr %#v is not a pointer to a zero value", i, tt.ptr)
+			continue
+		}
+
+		dec := NewDecoder(bytes.NewReader(in))
+		if tt.useNumber {
+			dec.UseNumber()
+		}
+		if tt.disallowUnknownFields {
+			dec.DisallowUnknownFields()
+		}
+		if err := dec.Decode(v.Interface()); !equalError(err, tt.err) {
+			t.Errorf("#%d: %v, want %v", i, err, tt.err)
+			continue
+		} else if err != nil {
+			continue
+		}
+		if !reflect.DeepEqual(v.Elem().Interface(), tt.out) {
+			t.Errorf("#%d: mismatch\nhave: %#+v\nwant: %#+v", i, v.Elem().Interface(), tt.out)
+			data, _ := Marshal(v.Elem().Interface())
+			println(string(data))
+			data, _ = Marshal(tt.out)
+			println(string(data))
+			continue
+		}
+
+		// Check round trip also decodes correctly.
+		if tt.err == nil {
+			enc, err := Marshal(v.Interface())
+			if err != nil {
+				t.Errorf("#%d: error re-marshaling: %v", i, err)
+				continue
+			}
+			if tt.golden && !bytes.Equal(enc, in) {
+				t.Errorf("#%d: remarshal mismatch:\nhave: %s\nwant: %s", i, enc, in)
+			}
+			vv := reflect.New(reflect.TypeOf(tt.ptr).Elem())
+			dec = NewDecoder(bytes.NewReader(enc))
+			if tt.useNumber {
+				dec.UseNumber()
+			}
+			if err := dec.Decode(vv.Interface()); err != nil {
+				t.Errorf("#%d: error re-unmarshaling %#q: %v", i, enc, err)
+				continue
+			}
+			if !reflect.DeepEqual(v.Elem().Interface(), vv.Elem().Interface()) {
+				t.Errorf("#%d: mismatch\nhave: %#+v\nwant: %#+v", i, v.Elem().Interface(), vv.Elem().Interface())
+				t.Errorf("     In: %q", strings.Map(noSpace, string(in)))
+				t.Errorf("Marshal: %q", strings.Map(noSpace, string(enc)))
+				continue
+			}
+		}
+	}
+}
+
+func TestUnmarshalMarshal(t *testing.T) {
+	initBig()
+	var v any
+	if err := Unmarshal(jsonBig, &v); err != nil {
+		t.Fatalf("Unmarshal: %v", err)
+	}
+	b, err := Marshal(v)
+	if err != nil {
+		t.Fatalf("Marshal: %v", err)
+	}
+	if !bytes.Equal(jsonBig, b) {
+		t.Errorf("Marshal jsonBig")
+		diff(t, b, jsonBig)
+		return
+	}
+}
+
+var numberTests = []struct {
+	in       string
+	i        int64
+	intErr   string
+	f        float64
+	floatErr string
+}{
+	{in: "-1.23e1", intErr: "strconv.ParseInt: parsing \"-1.23e1\": invalid syntax", f: -1.23e1},
+	{in: "-12", i: -12, f: -12.0},
+	{in: "1e1000", intErr: "strconv.ParseInt: parsing \"1e1000\": invalid syntax", floatErr: "strconv.ParseFloat: parsing \"1e1000\": value out of range"},
+}
+
+// Independent of Decode, basic coverage of the accessors in Number
+func TestNumberAccessors(t *testing.T) {
+	for _, tt := range numberTests {
+		n := Number(tt.in)
+		if s := n.String(); s != tt.in {
+			t.Errorf("Number(%q).String() is %q", tt.in, s)
+		}
+		if i, err := n.Int64(); err == nil && tt.intErr == "" && i != tt.i {
+			t.Errorf("Number(%q).Int64() is %d", tt.in, i)
+		} else if (err == nil && tt.intErr != "") || (err != nil && err.Error() != tt.intErr) {
+			t.Errorf("Number(%q).Int64() wanted error %q but got: %v", tt.in, tt.intErr, err)
+		}
+		if f, err := n.Float64(); err == nil && tt.floatErr == "" && f != tt.f {
+			t.Errorf("Number(%q).Float64() is %g", tt.in, f)
+		} else if (err == nil && tt.floatErr != "") || (err != nil && err.Error() != tt.floatErr) {
+			t.Errorf("Number(%q).Float64() wanted error %q but got: %v", tt.in, tt.floatErr, err)
+		}
+	}
+}
+
+func TestLargeByteSlice(t *testing.T) {
+	s0 := make([]byte, 2000)
+	for i := range s0 {
+		s0[i] = byte(i)
+	}
+	b, err := Marshal(s0)
+	if err != nil {
+		t.Fatalf("Marshal: %v", err)
+	}
+	var s1 []byte
+	if err := Unmarshal(b, &s1); err != nil {
+		t.Fatalf("Unmarshal: %v", err)
+	}
+	if !bytes.Equal(s0, s1) {
+		t.Errorf("Marshal large byte slice")
+		diff(t, s0, s1)
+	}
+}
+
+type Xint struct {
+	X int
+}
+
+func TestUnmarshalInterface(t *testing.T) {
+	var xint Xint
+	var i any = &xint
+	if err := Unmarshal([]byte(`{"X":1}`), &i); err != nil {
+		t.Fatalf("Unmarshal: %v", err)
+	}
+	if xint.X != 1 {
+		t.Fatalf("Did not write to xint")
+	}
+}
+
+func TestUnmarshalPtrPtr(t *testing.T) {
+	var xint Xint
+	pxint := &xint
+	if err := Unmarshal([]byte(`{"X":1}`), &pxint); err != nil {
+		t.Fatalf("Unmarshal: %v", err)
+	}
+	if xint.X != 1 {
+		t.Fatalf("Did not write to xint")
+	}
+}
+
+func TestEscape(t *testing.T) {
+	const input = `"foobar"<html>` + " [\u2028 \u2029]"
+	const expected = `"\"foobar\"\u003chtml\u003e [\u2028 \u2029]"`
+	b, err := Marshal(input)
+	if err != nil {
+		t.Fatalf("Marshal error: %v", err)
+	}
+	if s := string(b); s != expected {
+		t.Errorf("Encoding of [%s]:\n got [%s]\nwant [%s]", input, s, expected)
+	}
+}
+
+// WrongString is a struct that's misusing the ,string modifier.
+type WrongString struct {
+	Message string `json:"result,string"`
+}
+
+type wrongStringTest struct {
+	in, err string
+}
+
+var wrongStringTests = []wrongStringTest{
+	{`{"result":"x"}`, `json: invalid use of ,string struct tag, trying to unmarshal "x" into string`},
+	{`{"result":"foo"}`, `json: invalid use of ,string struct tag, trying to unmarshal "foo" into string`},
+	{`{"result":"123"}`, `json: invalid use of ,string struct tag, trying to unmarshal "123" into string`},
+	{`{"result":123}`, `json: invalid use of ,string struct tag, trying to unmarshal unquoted value into string`},
+	{`{"result":"\""}`, `json: invalid use of ,string struct tag, trying to unmarshal "\"" into string`},
+	{`{"result":"\"foo"}`, `json: invalid use of ,string struct tag, trying to unmarshal "\"foo" into string`},
+}
+
+// If people misuse the ,string modifier, the error message should be
+// helpful, telling the user that they're doing it wrong.
+func TestErrorMessageFromMisusedString(t *testing.T) {
+	for n, tt := range wrongStringTests {
+		r := strings.NewReader(tt.in)
+		var s WrongString
+		err := NewDecoder(r).Decode(&s)
+		got := fmt.Sprintf("%v", err)
+		if got != tt.err {
+			t.Errorf("%d. got err = %q, want %q", n, got, tt.err)
+		}
+	}
+}
+
+func noSpace(c rune) rune {
+	if isSpace(byte(c)) { //only used for ascii
+		return -1
+	}
+	return c
+}
+
+type All struct {
+	Bool    bool
+	Int     int
+	Int8    int8
+	Int16   int16
+	Int32   int32
+	Int64   int64
+	Uint    uint
+	Uint8   uint8
+	Uint16  uint16
+	Uint32  uint32
+	Uint64  uint64
+	Uintptr uintptr
+	Float32 float32
+	Float64 float64
+
+	Foo  string `json:"bar"`
+	Foo2 string `json:"bar2,dummyopt"`
+
+	IntStr     int64   `json:",string"`
+	UintptrStr uintptr `json:",string"`
+
+	PBool    *bool
+	PInt     *int
+	PInt8    *int8
+	PInt16   *int16
+	PInt32   *int32
+	PInt64   *int64
+	PUint    *uint
+	PUint8   *uint8
+	PUint16  *uint16
+	PUint32  *uint32
+	PUint64  *uint64
+	PUintptr *uintptr
+	PFloat32 *float32
+	PFloat64 *float64
+
+	String  string
+	PString *string
+
+	Map   map[string]Small
+	MapP  map[string]*Small
+	PMap  *map[string]Small
+	PMapP *map[string]*Small
+
+	EmptyMap map[string]Small
+	NilMap   map[string]Small
+
+	Slice   []Small
+	SliceP  []*Small
+	PSlice  *[]Small
+	PSliceP *[]*Small
+
+	EmptySlice []Small
+	NilSlice   []Small
+
+	StringSlice []string
+	ByteSlice   []byte
+
+	Small   Small
+	PSmall  *Small
+	PPSmall **Small
+
+	Interface  any
+	PInterface *any
+
+	unexported int
+}
+
+type Small struct {
+	Tag string
+}
+
+var allValue = All{
+	Bool:       true,
+	Int:        2,
+	Int8:       3,
+	Int16:      4,
+	Int32:      5,
+	Int64:      6,
+	Uint:       7,
+	Uint8:      8,
+	Uint16:     9,
+	Uint32:     10,
+	Uint64:     11,
+	Uintptr:    12,
+	Float32:    14.1,
+	Float64:    15.1,
+	Foo:        "foo",
+	Foo2:       "foo2",
+	IntStr:     42,
+	UintptrStr: 44,
+	String:     "16",
+	Map: map[string]Small{
+		"17": {Tag: "tag17"},
+		"18": {Tag: "tag18"},
+	},
+	MapP: map[string]*Small{
+		"19": {Tag: "tag19"},
+		"20": nil,
+	},
+	EmptyMap:    map[string]Small{},
+	Slice:       []Small{{Tag: "tag20"}, {Tag: "tag21"}},
+	SliceP:      []*Small{{Tag: "tag22"}, nil, {Tag: "tag23"}},
+	EmptySlice:  []Small{},
+	StringSlice: []string{"str24", "str25", "str26"},
+	ByteSlice:   []byte{27, 28, 29},
+	Small:       Small{Tag: "tag30"},
+	PSmall:      &Small{Tag: "tag31"},
+	Interface:   5.2,
+}
+
+var pallValue = All{
+	PBool:      &allValue.Bool,
+	PInt:       &allValue.Int,
+	PInt8:      &allValue.Int8,
+	PInt16:     &allValue.Int16,
+	PInt32:     &allValue.Int32,
+	PInt64:     &allValue.Int64,
+	PUint:      &allValue.Uint,
+	PUint8:     &allValue.Uint8,
+	PUint16:    &allValue.Uint16,
+	PUint32:    &allValue.Uint32,
+	PUint64:    &allValue.Uint64,
+	PUintptr:   &allValue.Uintptr,
+	PFloat32:   &allValue.Float32,
+	PFloat64:   &allValue.Float64,
+	PString:    &allValue.String,
+	PMap:       &allValue.Map,
+	PMapP:      &allValue.MapP,
+	PSlice:     &allValue.Slice,
+	PSliceP:    &allValue.SliceP,
+	PPSmall:    &allValue.PSmall,
+	PInterface: &allValue.Interface,
+}
+
+var allValueIndent = `{
+	"Bool": true,
+	"Int": 2,
+	"Int8": 3,
+	"Int16": 4,
+	"Int32": 5,
+	"Int64": 6,
+	"Uint": 7,
+	"Uint8": 8,
+	"Uint16": 9,
+	"Uint32": 10,
+	"Uint64": 11,
+	"Uintptr": 12,
+	"Float32": 14.1,
+	"Float64": 15.1,
+	"bar": "foo",
+	"bar2": "foo2",
+	"IntStr": "42",
+	"UintptrStr": "44",
+	"PBool": null,
+	"PInt": null,
+	"PInt8": null,
+	"PInt16": null,
+	"PInt32": null,
+	"PInt64": null,
+	"PUint": null,
+	"PUint8": null,
+	"PUint16": null,
+	"PUint32": null,
+	"PUint64": null,
+	"PUintptr": null,
+	"PFloat32": null,
+	"PFloat64": null,
+	"String": "16",
+	"PString": null,
+	"Map": {
+		"17": {
+			"Tag": "tag17"
+		},
+		"18": {
+			"Tag": "tag18"
+		}
+	},
+	"MapP": {
+		"19": {
+			"Tag": "tag19"
+		},
+		"20": null
+	},
+	"PMap": null,
+	"PMapP": null,
+	"EmptyMap": {},
+	"NilMap": null,
+	"Slice": [
+		{
+			"Tag": "tag20"
+		},
+		{
+			"Tag": "tag21"
+		}
+	],
+	"SliceP": [
+		{
+			"Tag": "tag22"
+		},
+		null,
+		{
+			"Tag": "tag23"
+		}
+	],
+	"PSlice": null,
+	"PSliceP": null,
+	"EmptySlice": [],
+	"NilSlice": null,
+	"StringSlice": [
+		"str24",
+		"str25",
+		"str26"
+	],
+	"ByteSlice": "Gxwd",
+	"Small": {
+		"Tag": "tag30"
+	},
+	"PSmall": {
+		"Tag": "tag31"
+	},
+	"PPSmall": null,
+	"Interface": 5.2,
+	"PInterface": null
+}`
+
+var allValueCompact = strings.Map(noSpace, allValueIndent)
+
+var pallValueIndent = `{
+	"Bool": false,
+	"Int": 0,
+	"Int8": 0,
+	"Int16": 0,
+	"Int32": 0,
+	"Int64": 0,
+	"Uint": 0,
+	"Uint8": 0,
+	"Uint16": 0,
+	"Uint32": 0,
+	"Uint64": 0,
+	"Uintptr": 0,
+	"Float32": 0,
+	"Float64": 0,
+	"bar": "",
+	"bar2": "",
+        "IntStr": "0",
+	"UintptrStr": "0",
+	"PBool": true,
+	"PInt": 2,
+	"PInt8": 3,
+	"PInt16": 4,
+	"PInt32": 5,
+	"PInt64": 6,
+	"PUint": 7,
+	"PUint8": 8,
+	"PUint16": 9,
+	"PUint32": 10,
+	"PUint64": 11,
+	"PUintptr": 12,
+	"PFloat32": 14.1,
+	"PFloat64": 15.1,
+	"String": "",
+	"PString": "16",
+	"Map": null,
+	"MapP": null,
+	"PMap": {
+		"17": {
+			"Tag": "tag17"
+		},
+		"18": {
+			"Tag": "tag18"
+		}
+	},
+	"PMapP": {
+		"19": {
+			"Tag": "tag19"
+		},
+		"20": null
+	},
+	"EmptyMap": null,
+	"NilMap": null,
+	"Slice": null,
+	"SliceP": null,
+	"PSlice": [
+		{
+			"Tag": "tag20"
+		},
+		{
+			"Tag": "tag21"
+		}
+	],
+	"PSliceP": [
+		{
+			"Tag": "tag22"
+		},
+		null,
+		{
+			"Tag": "tag23"
+		}
+	],
+	"EmptySlice": null,
+	"NilSlice": null,
+	"StringSlice": null,
+	"ByteSlice": null,
+	"Small": {
+		"Tag": ""
+	},
+	"PSmall": null,
+	"PPSmall": {
+		"Tag": "tag31"
+	},
+	"Interface": null,
+	"PInterface": 5.2
+}`
+
+var pallValueCompact = strings.Map(noSpace, pallValueIndent)
+
+func TestRefUnmarshal(t *testing.T) {
+	type S struct {
+		// Ref is defined in encode_test.go.
+		R0 Ref
+		R1 *Ref
+		R2 RefText
+		R3 *RefText
+	}
+	want := S{
+		R0: 12,
+		R1: new(Ref),
+		R2: 13,
+		R3: new(RefText),
+	}
+	*want.R1 = 12
+	*want.R3 = 13
+
+	var got S
+	if err := Unmarshal([]byte(`{"R0":"ref","R1":"ref","R2":"ref","R3":"ref"}`), &got); err != nil {
+		t.Fatalf("Unmarshal: %v", err)
+	}
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("got %+v, want %+v", got, want)
+	}
+}
+
+// Test that the empty string doesn't panic decoding when ,string is specified
+// Issue 3450
+func TestEmptyString(t *testing.T) {
+	type T2 struct {
+		Number1 int `json:",string"`
+		Number2 int `json:",string"`
+	}
+	data := `{"Number1":"1", "Number2":""}`
+	dec := NewDecoder(strings.NewReader(data))
+	var t2 T2
+	err := dec.Decode(&t2)
+	if err == nil {
+		t.Fatal("Decode: did not return error")
+	}
+	if t2.Number1 != 1 {
+		t.Fatal("Decode: did not set Number1")
+	}
+}
+
+// Test that a null for ,string is not replaced with the previous quoted string (issue 7046).
+// It should also not be an error (issue 2540, issue 8587).
+func TestNullString(t *testing.T) {
+	type T struct {
+		A int  `json:",string"`
+		B int  `json:",string"`
+		C *int `json:",string"`
+	}
+	data := []byte(`{"A": "1", "B": null, "C": null}`)
+	var s T
+	s.B = 1
+	s.C = new(int)
+	*s.C = 2
+	err := Unmarshal(data, &s)
+	if err != nil {
+		t.Fatalf("Unmarshal: %v", err)
+	}
+	if s.B != 1 || s.C != nil {
+		t.Fatalf("after Unmarshal, s.B=%d, s.C=%p, want 1, nil", s.B, s.C)
+	}
+}
+
+func intp(x int) *int {
+	p := new(int)
+	*p = x
+	return p
+}
+
+func intpp(x *int) **int {
+	pp := new(*int)
+	*pp = x
+	return pp
+}
+
+var interfaceSetTests = []struct {
+	pre  any
+	json string
+	post any
+}{
+	{"foo", `"bar"`, "bar"},
+	{"foo", `2`, 2.0},
+	{"foo", `true`, true},
+	{"foo", `null`, nil},
+
+	{nil, `null`, nil},
+	{new(int), `null`, nil},
+	{(*int)(nil), `null`, nil},
+	{new(*int), `null`, new(*int)},
+	{(**int)(nil), `null`, nil},
+	{intp(1), `null`, nil},
+	{intpp(nil), `null`, intpp(nil)},
+	{intpp(intp(1)), `null`, intpp(nil)},
+}
+
+func TestInterfaceSet(t *testing.T) {
+	for _, tt := range interfaceSetTests {
+		b := struct{ X any }{tt.pre}
+		blob := `{"X":` + tt.json + `}`
+		if err := Unmarshal([]byte(blob), &b); err != nil {
+			t.Errorf("Unmarshal %#q: %v", blob, err)
+			continue
+		}
+		if !reflect.DeepEqual(b.X, tt.post) {
+			t.Errorf("Unmarshal %#q into %#v: X=%#v, want %#v", blob, tt.pre, b.X, tt.post)
+		}
+	}
+}
+
+type NullTest struct {
+	Bool      bool
+	Int       int
+	Int8      int8
+	Int16     int16
+	Int32     int32
+	Int64     int64
+	Uint      uint
+	Uint8     uint8
+	Uint16    uint16
+	Uint32    uint32
+	Uint64    uint64
+	Float32   float32
+	Float64   float64
+	String    string
+	PBool     *bool
+	Map       map[string]string
+	Slice     []string
+	Interface any
+
+	PRaw    *RawMessage
+	PTime   *time.Time
+	PBigInt *big.Int
+	PText   *MustNotUnmarshalText
+	PBuffer *bytes.Buffer // has methods, just not relevant ones
+	PStruct *struct{}
+
+	Raw    RawMessage
+	Time   time.Time
+	BigInt big.Int
+	Text   MustNotUnmarshalText
+	Buffer bytes.Buffer
+	Struct struct{}
+}
+
+// JSON null values should be ignored for primitives and string values instead of resulting in an error.
+// Issue 2540
+func TestUnmarshalNulls(t *testing.T) {
+	// Unmarshal docs:
+	// The JSON null value unmarshals into an interface, map, pointer, or slice
+	// by setting that Go value to nil. Because null is often used in JSON to mean
+	// ``not present,'' unmarshaling a JSON null into any other Go type has no effect
+	// on the value and produces no error.
+
+	jsonData := []byte(`{
+				"Bool"    : null,
+				"Int"     : null,
+				"Int8"    : null,
+				"Int16"   : null,
+				"Int32"   : null,
+				"Int64"   : null,
+				"Uint"    : null,
+				"Uint8"   : null,
+				"Uint16"  : null,
+				"Uint32"  : null,
+				"Uint64"  : null,
+				"Float32" : null,
+				"Float64" : null,
+				"String"  : null,
+				"PBool": null,
+				"Map": null,
+				"Slice": null,
+				"Interface": null,
+				"PRaw": null,
+				"PTime": null,
+				"PBigInt": null,
+				"PText": null,
+				"PBuffer": null,
+				"PStruct": null,
+				"Raw": null,
+				"Time": null,
+				"BigInt": null,
+				"Text": null,
+				"Buffer": null,
+				"Struct": null
+			}`)
+	nulls := NullTest{
+		Bool:      true,
+		Int:       2,
+		Int8:      3,
+		Int16:     4,
+		Int32:     5,
+		Int64:     6,
+		Uint:      7,
+		Uint8:     8,
+		Uint16:    9,
+		Uint32:    10,
+		Uint64:    11,
+		Float32:   12.1,
+		Float64:   13.1,
+		String:    "14",
+		PBool:     new(bool),
+		Map:       map[string]string{},
+		Slice:     []string{},
+		Interface: new(MustNotUnmarshalJSON),
+		PRaw:      new(RawMessage),
+		PTime:     new(time.Time),
+		PBigInt:   new(big.Int),
+		PText:     new(MustNotUnmarshalText),
+		PStruct:   new(struct{}),
+		PBuffer:   new(bytes.Buffer),
+		Raw:       RawMessage("123"),
+		Time:      time.Unix(123456789, 0),
+		BigInt:    *big.NewInt(123),
+	}
+
+	before := nulls.Time.String()
+
+	err := Unmarshal(jsonData, &nulls)
+	if err != nil {
+		t.Errorf("Unmarshal of null values failed: %v", err)
+	}
+	if !nulls.Bool || nulls.Int != 2 || nulls.Int8 != 3 || nulls.Int16 != 4 || nulls.Int32 != 5 || nulls.Int64 != 6 ||
+		nulls.Uint != 7 || nulls.Uint8 != 8 || nulls.Uint16 != 9 || nulls.Uint32 != 10 || nulls.Uint64 != 11 ||
+		nulls.Float32 != 12.1 || nulls.Float64 != 13.1 || nulls.String != "14" {
+		t.Errorf("Unmarshal of null values affected primitives")
+	}
+
+	if nulls.PBool != nil {
+		t.Errorf("Unmarshal of null did not clear nulls.PBool")
+	}
+	if nulls.Map != nil {
+		t.Errorf("Unmarshal of null did not clear nulls.Map")
+	}
+	if nulls.Slice != nil {
+		t.Errorf("Unmarshal of null did not clear nulls.Slice")
+	}
+	if nulls.Interface != nil {
+		t.Errorf("Unmarshal of null did not clear nulls.Interface")
+	}
+	if nulls.PRaw != nil {
+		t.Errorf("Unmarshal of null did not clear nulls.PRaw")
+	}
+	if nulls.PTime != nil {
+		t.Errorf("Unmarshal of null did not clear nulls.PTime")
+	}
+	if nulls.PBigInt != nil {
+		t.Errorf("Unmarshal of null did not clear nulls.PBigInt")
+	}
+	if nulls.PText != nil {
+		t.Errorf("Unmarshal of null did not clear nulls.PText")
+	}
+	if nulls.PBuffer != nil {
+		t.Errorf("Unmarshal of null did not clear nulls.PBuffer")
+	}
+	if nulls.PStruct != nil {
+		t.Errorf("Unmarshal of null did not clear nulls.PStruct")
+	}
+
+	if string(nulls.Raw) != "null" {
+		t.Errorf("Unmarshal of RawMessage null did not record null: %v", string(nulls.Raw))
+	}
+	if nulls.Time.String() != before {
+		t.Errorf("Unmarshal of time.Time null set time to %v", nulls.Time.String())
+	}
+	if nulls.BigInt.String() != "123" {
+		t.Errorf("Unmarshal of big.Int null set int to %v", nulls.BigInt.String())
+	}
+}
+
+type MustNotUnmarshalJSON struct{}
+
+func (x MustNotUnmarshalJSON) UnmarshalJSON(data []byte) error {
+	return errors.New("MustNotUnmarshalJSON was used")
+}
+
+type MustNotUnmarshalText struct{}
+
+func (x MustNotUnmarshalText) UnmarshalText(text []byte) error {
+	return errors.New("MustNotUnmarshalText was used")
+}
+
+func TestStringKind(t *testing.T) {
+	type stringKind string
+
+	var m1, m2 map[stringKind]int
+	m1 = map[stringKind]int{
+		"foo": 42,
+	}
+
+	data, err := Marshal(m1)
+	if err != nil {
+		t.Errorf("Unexpected error marshaling: %v", err)
+	}
+
+	err = Unmarshal(data, &m2)
+	if err != nil {
+		t.Errorf("Unexpected error unmarshaling: %v", err)
+	}
+
+	if !reflect.DeepEqual(m1, m2) {
+		t.Error("Items should be equal after encoding and then decoding")
+	}
+}
+
+// Custom types with []byte as underlying type could not be marshaled
+// and then unmarshaled.
+// Issue 8962.
+func TestByteKind(t *testing.T) {
+	type byteKind []byte
+
+	a := byteKind("hello")
+
+	data, err := Marshal(a)
+	if err != nil {
+		t.Error(err)
+	}
+	var b byteKind
+	err = Unmarshal(data, &b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(a, b) {
+		t.Errorf("expected %v == %v", a, b)
+	}
+}
+
+// The fix for issue 8962 introduced a regression.
+// Issue 12921.
+func TestSliceOfCustomByte(t *testing.T) {
+	type Uint8 uint8
+
+	a := []Uint8("hello")
+
+	data, err := Marshal(a)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var b []Uint8
+	err = Unmarshal(data, &b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(a, b) {
+		t.Fatalf("expected %v == %v", a, b)
+	}
+}
+
+var decodeTypeErrorTests = []struct {
+	dest any
+	src  string
+}{
+	{new(string), `{"user": "name"}`}, // issue 4628.
+	{new(error), `{}`},                // issue 4222
+	{new(error), `[]`},
+	{new(error), `""`},
+	{new(error), `123`},
+	{new(error), `true`},
+}
+
+func TestUnmarshalTypeError(t *testing.T) {
+	for _, item := range decodeTypeErrorTests {
+		err := Unmarshal([]byte(item.src), item.dest)
+		if _, ok := err.(*UnmarshalTypeError); !ok {
+			t.Errorf("expected type error for Unmarshal(%q, type %T): got %T",
+				item.src, item.dest, err)
+		}
+	}
+}
+
+var unmarshalSyntaxTests = []string{
+	"tru",
+	"fals",
+	"nul",
+	"123e",
+	`"hello`,
+	`[1,2,3`,
+	`{"key":1`,
+	`{"key":1,`,
+}
+
+func TestUnmarshalSyntax(t *testing.T) {
+	var x any
+	for _, src := range unmarshalSyntaxTests {
+		err := Unmarshal([]byte(src), &x)
+		if _, ok := err.(*SyntaxError); !ok {
+			t.Errorf("expected syntax error for Unmarshal(%q): got %T", src, err)
+		}
+	}
+}
+
+// Test handling of unexported fields that should be ignored.
+// Issue 4660
+type unexportedFields struct {
+	Name string
+	m    map[string]any `json:"-"`
+	m2   map[string]any `json:"abcd"`
+
+	s []int `json:"-"`
+}
+
+func TestUnmarshalUnexported(t *testing.T) {
+	input := `{"Name": "Bob", "m": {"x": 123}, "m2": {"y": 456}, "abcd": {"z": 789}, "s": [2, 3]}`
+	want := &unexportedFields{Name: "Bob"}
+
+	out := &unexportedFields{}
+	err := Unmarshal([]byte(input), out)
+	if err != nil {
+		t.Errorf("got error %v, expected nil", err)
+	}
+	if !reflect.DeepEqual(out, want) {
+		t.Errorf("got %q, want %q", out, want)
+	}
+}
+
+// Time3339 is a time.Time which encodes to and from JSON
+// as an RFC 3339 time in UTC.
+type Time3339 time.Time
+
+func (t *Time3339) UnmarshalJSON(b []byte) error {
+	if len(b) < 2 || b[0] != '"' || b[len(b)-1] != '"' {
+		return fmt.Errorf("types: failed to unmarshal non-string value %q as an RFC 3339 time", b)
+	}
+	tm, err := time.Parse(time.RFC3339, string(b[1:len(b)-1]))
+	if err != nil {
+		return err
+	}
+	*t = Time3339(tm)
+	return nil
+}
+
+func TestUnmarshalJSONLiteralError(t *testing.T) {
+	var t3 Time3339
+	err := Unmarshal([]byte(`"0000-00-00T00:00:00Z"`), &t3)
+	if err == nil {
+		t.Fatalf("expected error; got time %v", time.Time(t3))
+	}
+	if !strings.Contains(err.Error(), "range") {
+		t.Errorf("got err = %v; want out of range error", err)
+	}
+}
+
+// Test that extra object elements in an array do not result in a
+// "data changing underfoot" error.
+// Issue 3717
+func TestSkipArrayObjects(t *testing.T) {
+	json := `[{}]`
+	var dest [0]any
+
+	err := Unmarshal([]byte(json), &dest)
+	if err != nil {
+		t.Errorf("got error %q, want nil", err)
+	}
+}
+
+// Test semantics of pre-filled data, such as struct fields, map elements,
+// slices, and arrays.
+// Issues 4900 and 8837, among others.
+func TestPrefilled(t *testing.T) {
+	// Values here change, cannot reuse table across runs.
+	var prefillTests = []struct {
+		in  string
+		ptr any
+		out any
+	}{
+		{
+			in:  `{"X": 1, "Y": 2}`,
+			ptr: &XYZ{X: float32(3), Y: int16(4), Z: 1.5},
+			out: &XYZ{X: float64(1), Y: float64(2), Z: 1.5},
+		},
+		{
+			in:  `{"X": 1, "Y": 2}`,
+			ptr: &map[string]any{"X": float32(3), "Y": int16(4), "Z": 1.5},
+			out: &map[string]any{"X": float64(1), "Y": float64(2), "Z": 1.5},
+		},
+		{
+			in:  `[2]`,
+			ptr: &[]int{1},
+			out: &[]int{2},
+		},
+		{
+			in:  `[2, 3]`,
+			ptr: &[]int{1},
+			out: &[]int{2, 3},
+		},
+		{
+			in:  `[2, 3]`,
+			ptr: &[...]int{1},
+			out: &[...]int{2},
+		},
+		{
+			in:  `[3]`,
+			ptr: &[...]int{1, 2},
+			out: &[...]int{3, 0},
+		},
+	}
+
+	for _, tt := range prefillTests {
+		ptrstr := fmt.Sprintf("%v", tt.ptr)
+		err := Unmarshal([]byte(tt.in), tt.ptr) // tt.ptr edited here
+		if err != nil {
+			t.Errorf("Unmarshal: %v", err)
+		}
+		if !reflect.DeepEqual(tt.ptr, tt.out) {
+			t.Errorf("Unmarshal(%#q, %s): have %v, want %v", tt.in, ptrstr, tt.ptr, tt.out)
+		}
+	}
+}
+
+var invalidUnmarshalTests = []struct {
+	v    any
+	want string
+}{
+	{nil, "json: Unmarshal(nil)"},
+	{struct{}{}, "json: Unmarshal(non-pointer struct {})"},
+	{(*int)(nil), "json: Unmarshal(nil *int)"},
+}
+
+func TestInvalidUnmarshal(t *testing.T) {
+	buf := []byte(`{"a":"1"}`)
+	for _, tt := range invalidUnmarshalTests {
+		err := Unmarshal(buf, tt.v)
+		if err == nil {
+			t.Errorf("Unmarshal expecting error, got nil")
+			continue
+		}
+		if got := err.Error(); got != tt.want {
+			t.Errorf("Unmarshal = %q; want %q", got, tt.want)
+		}
+	}
+}
+
+var invalidUnmarshalTextTests = []struct {
+	v    any
+	want string
+}{
+	{nil, "json: Unmarshal(nil)"},
+	{struct{}{}, "json: Unmarshal(non-pointer struct {})"},
+	{(*int)(nil), "json: Unmarshal(nil *int)"},
+	{new(net.IP), "json: cannot unmarshal number into Go value of type *net.IP"},
+}
+
+func TestInvalidUnmarshalText(t *testing.T) {
+	buf := []byte(`123`)
+	for _, tt := range invalidUnmarshalTextTests {
+		err := Unmarshal(buf, tt.v)
+		if err == nil {
+			t.Errorf("Unmarshal expecting error, got nil")
+			continue
+		}
+		if got := err.Error(); got != tt.want {
+			t.Errorf("Unmarshal = %q; want %q", got, tt.want)
+		}
+	}
+}
+
+// Test that string option is ignored for invalid types.
+// Issue 9812.
+func TestInvalidStringOption(t *testing.T) {
+	num := 0
+	item := struct {
+		T time.Time         `json:",string"`
+		M map[string]string `json:",string"`
+		S []string          `json:",string"`
+		A [1]string         `json:",string"`
+		I any               `json:",string"`
+		P *int              `json:",string"`
+	}{M: make(map[string]string), S: make([]string, 0), I: num, P: &num}
+
+	data, err := Marshal(item)
+	if err != nil {
+		t.Fatalf("Marshal: %v", err)
+	}
+
+	err = Unmarshal(data, &item)
+	if err != nil {
+		t.Fatalf("Unmarshal: %v", err)
+	}
+}
+
+// Test unmarshal behavior with regards to embedded unexported structs.
+//
+// (Issue 21357) If the embedded struct is a pointer and is unallocated,
+// this returns an error because unmarshal cannot set the field.
+//
+// (Issue 24152) If the embedded struct is given an explicit name,
+// ensure that the normal unmarshal logic does not panic in reflect.
+//
+// (Issue 28145) If the embedded struct is given an explicit name and has
+// exported methods, don't cause a panic trying to get its value.
+func TestUnmarshalEmbeddedUnexported(t *testing.T) {
+	type (
+		embed1 struct{ Q int }
+		embed2 struct{ Q int }
+		embed3 struct {
+			Q int64 `json:",string"`
+		}
+		S1 struct {
+			*embed1
+			R int
+		}
+		S2 struct {
+			*embed1
+			Q int
+		}
+		S3 struct {
+			embed1
+			R int
+		}
+		S4 struct {
+			*embed1
+			embed2
+		}
+		S5 struct {
+			*embed3
+			R int
+		}
+		S6 struct {
+			embed1 `json:"embed1"`
+		}
+		S7 struct {
+			embed1 `json:"embed1"`
+			embed2
+		}
+		S8 struct {
+			embed1 `json:"embed1"`
+			embed2 `json:"embed2"`
+			Q      int
+		}
+		S9 struct {
+			unexportedWithMethods `json:"embed"`
+		}
+	)
+
+	tests := []struct {
+		in  string
+		ptr any
+		out any
+		err error
+	}{{
+		// Error since we cannot set S1.embed1, but still able to set S1.R.
+		in:  `{"R":2,"Q":1}`,
+		ptr: new(S1),
+		out: &S1{R: 2},
+		err: fmt.Errorf("json: cannot set embedded pointer to unexported struct: json.embed1"),
+	}, {
+		// The top level Q field takes precedence.
+		in:  `{"Q":1}`,
+		ptr: new(S2),
+		out: &S2{Q: 1},
+	}, {
+		// No issue with non-pointer variant.
+		in:  `{"R":2,"Q":1}`,
+		ptr: new(S3),
+		out: &S3{embed1: embed1{Q: 1}, R: 2},
+	}, {
+		// No error since both embedded structs have field R, which annihilate each other.
+		// Thus, no attempt is made at setting S4.embed1.
+		in:  `{"R":2}`,
+		ptr: new(S4),
+		out: new(S4),
+	}, {
+		// Error since we cannot set S5.embed1, but still able to set S5.R.
+		in:  `{"R":2,"Q":1}`,
+		ptr: new(S5),
+		out: &S5{R: 2},
+		err: fmt.Errorf("json: cannot set embedded pointer to unexported struct: json.embed3"),
+	}, {
+		// Issue 24152, ensure decodeState.indirect does not panic.
+		in:  `{"embed1": {"Q": 1}}`,
+		ptr: new(S6),
+		out: &S6{embed1{1}},
+	}, {
+		// Issue 24153, check that we can still set forwarded fields even in
+		// the presence of a name conflict.
+		//
+		// This relies on obscure behavior of reflect where it is possible
+		// to set a forwarded exported field on an unexported embedded struct
+		// even though there is a name conflict, even when it would have been
+		// impossible to do so according to Go visibility rules.
+		// Go forbids this because it is ambiguous whether S7.Q refers to
+		// S7.embed1.Q or S7.embed2.Q. Since embed1 and embed2 are unexported,
+		// it should be impossible for an external package to set either Q.
+		//
+		// It is probably okay for a future reflect change to break this.
+		in:  `{"embed1": {"Q": 1}, "Q": 2}`,
+		ptr: new(S7),
+		out: &S7{embed1{1}, embed2{2}},
+	}, {
+		// Issue 24153, similar to the S7 case.
+		in:  `{"embed1": {"Q": 1}, "embed2": {"Q": 2}, "Q": 3}`,
+		ptr: new(S8),
+		out: &S8{embed1{1}, embed2{2}, 3},
+	}, {
+		// Issue 228145, similar to the cases above.
+		in:  `{"embed": {}}`,
+		ptr: new(S9),
+		out: &S9{},
+	}}
+
+	for i, tt := range tests {
+		err := Unmarshal([]byte(tt.in), tt.ptr)
+		if !equalError(err, tt.err) {
+			t.Errorf("#%d: %v, want %v", i, err, tt.err)
+		}
+		if !reflect.DeepEqual(tt.ptr, tt.out) {
+			t.Errorf("#%d: mismatch\ngot:  %#+v\nwant: %#+v", i, tt.ptr, tt.out)
+		}
+	}
+}
+
+func TestUnmarshalErrorAfterMultipleJSON(t *testing.T) {
+	tests := []struct {
+		in  string
+		err error
+	}{{
+		in:  `1 false null :`,
+		err: &SyntaxError{"invalid character ':' looking for beginning of value", 14},
+	}, {
+		in:  `1 [] [,]`,
+		err: &SyntaxError{"invalid character ',' looking for beginning of value", 7},
+	}, {
+		in:  `1 [] [true:]`,
+		err: &SyntaxError{"invalid character ':' after array element", 11},
+	}, {
+		in:  `1  {}    {"x"=}`,
+		err: &SyntaxError{"invalid character '=' after object key", 14},
+	}, {
+		in:  `falsetruenul#`,
+		err: &SyntaxError{"invalid character '#' in literal null (expecting 'l')", 13},
+	}}
+	for i, tt := range tests {
+		dec := NewDecoder(strings.NewReader(tt.in))
+		var err error
+		for {
+			var v any
+			if err = dec.Decode(&v); err != nil {
+				break
+			}
+		}
+		if !reflect.DeepEqual(err, tt.err) {
+			t.Errorf("#%d: got %#v, want %#v", i, err, tt.err)
+		}
+	}
+}
+
+type unmarshalPanic struct{}
+
+func (unmarshalPanic) UnmarshalJSON([]byte) error { panic(0xdead) }
+
+func TestUnmarshalPanic(t *testing.T) {
+	defer func() {
+		if got := recover(); !reflect.DeepEqual(got, 0xdead) {
+			t.Errorf("panic() = (%T)(%v), want 0xdead", got, got)
+		}
+	}()
+	Unmarshal([]byte("{}"), &unmarshalPanic{})
+	t.Fatalf("Unmarshal should have panicked")
+}
+
+// The decoder used to hang if decoding into an interface pointing to its own address.
+// See golang.org/issues/31740.
+func TestUnmarshalRecursivePointer(t *testing.T) {
+	var v any
+	v = &v
+	data := []byte(`{"a": "b"}`)
+
+	if err := Unmarshal(data, v); err != nil {
+		t.Fatal(err)
+	}
+}
+
+type textUnmarshalerString string
+
+func (m *textUnmarshalerString) UnmarshalText(text []byte) error {
+	*m = textUnmarshalerString(strings.ToLower(string(text)))
+	return nil
+}
+
+// Test unmarshal to a map, where the map key is a user defined type.
+// See golang.org/issues/34437.
+func TestUnmarshalMapWithTextUnmarshalerStringKey(t *testing.T) {
+	var p map[textUnmarshalerString]string
+	if err := Unmarshal([]byte(`{"FOO": "1"}`), &p); err != nil {
+		t.Fatalf("Unmarshal unexpected error: %v", err)
+	}
+
+	if _, ok := p["foo"]; !ok {
+		t.Errorf(`Key "foo" does not exist in map: %v`, p)
+	}
+}
+
+func TestUnmarshalRescanLiteralMangledUnquote(t *testing.T) {
+	// See golang.org/issues/38105.
+	var p map[textUnmarshalerString]string
+	if err := Unmarshal([]byte(`{"开源":"12345开源"}`), &p); err != nil {
+		t.Fatalf("Unmarshal unexpected error: %v", err)
+	}
+	if _, ok := p["开源"]; !ok {
+		t.Errorf(`Key "开源" does not exist in map: %v`, p)
+	}
+
+	// See golang.org/issues/38126.
+	type T struct {
+		F1 string `json:"F1,string"`
+	}
+	t1 := T{"aaa\tbbb"}
+
+	b, err := Marshal(t1)
+	if err != nil {
+		t.Fatalf("Marshal unexpected error: %v", err)
+	}
+	var t2 T
+	if err := Unmarshal(b, &t2); err != nil {
+		t.Fatalf("Unmarshal unexpected error: %v", err)
+	}
+	if t1 != t2 {
+		t.Errorf("Marshal and Unmarshal roundtrip mismatch: want %q got %q", t1, t2)
+	}
+
+	// See golang.org/issues/39555.
+	input := map[textUnmarshalerString]string{"FOO": "", `"`: ""}
+
+	encoded, err := Marshal(input)
+	if err != nil {
+		t.Fatalf("Marshal unexpected error: %v", err)
+	}
+	var got map[textUnmarshalerString]string
+	if err := Unmarshal(encoded, &got); err != nil {
+		t.Fatalf("Unmarshal unexpected error: %v", err)
+	}
+	want := map[textUnmarshalerString]string{"foo": "", `"`: ""}
+	if !reflect.DeepEqual(want, got) {
+		t.Fatalf("Unexpected roundtrip result:\nwant: %q\ngot:  %q", want, got)
+	}
+}
+
+func TestUnmarshalMaxDepth(t *testing.T) {
+	testcases := []struct {
+		name        string
+		data        string
+		errMaxDepth bool
+	}{
+		{
+			name:        "ArrayUnderMaxNestingDepth",
+			data:        `{"a":` + strings.Repeat(`[`, 10000-1) + strings.Repeat(`]`, 10000-1) + `}`,
+			errMaxDepth: false,
+		},
+		{
+			name:        "ArrayOverMaxNestingDepth",
+			data:        `{"a":` + strings.Repeat(`[`, 10000) + strings.Repeat(`]`, 10000) + `}`,
+			errMaxDepth: true,
+		},
+		{
+			name:        "ArrayOverStackDepth",
+			data:        `{"a":` + strings.Repeat(`[`, 3000000) + strings.Repeat(`]`, 3000000) + `}`,
+			errMaxDepth: true,
+		},
+		{
+			name:        "ObjectUnderMaxNestingDepth",
+			data:        `{"a":` + strings.Repeat(`{"a":`, 10000-1) + `0` + strings.Repeat(`}`, 10000-1) + `}`,
+			errMaxDepth: false,
+		},
+		{
+			name:        "ObjectOverMaxNestingDepth",
+			data:        `{"a":` + strings.Repeat(`{"a":`, 10000) + `0` + strings.Repeat(`}`, 10000) + `}`,
+			errMaxDepth: true,
+		},
+		{
+			name:        "ObjectOverStackDepth",
+			data:        `{"a":` + strings.Repeat(`{"a":`, 3000000) + `0` + strings.Repeat(`}`, 3000000) + `}`,
+			errMaxDepth: true,
+		},
+	}
+
+	targets := []struct {
+		name     string
+		newValue func() any
+	}{
+		{
+			name: "unstructured",
+			newValue: func() any {
+				var v any
+				return &v
+			},
+		},
+		{
+			name: "typed named field",
+			newValue: func() any {
+				v := struct {
+					A any `json:"a"`
+				}{}
+				return &v
+			},
+		},
+		{
+			name: "typed missing field",
+			newValue: func() any {
+				v := struct {
+					B any `json:"b"`
+				}{}
+				return &v
+			},
+		},
+		{
+			name: "custom unmarshaler",
+			newValue: func() any {
+				v := unmarshaler{}
+				return &v
+			},
+		},
+	}
+
+	for _, tc := range testcases {
+		for _, target := range targets {
+			t.Run(target.name+"-"+tc.name, func(t *testing.T) {
+				err := Unmarshal([]byte(tc.data), target.newValue())
+				if !tc.errMaxDepth {
+					if err != nil {
+						t.Errorf("unexpected error: %v", err)
+					}
+				} else {
+					if err == nil {
+						t.Errorf("expected error containing 'exceeded max depth', got none")
+					} else if !strings.Contains(err.Error(), "exceeded max depth") {
+						t.Errorf("expected error containing 'exceeded max depth', got: %v", err)
+					}
+				}
+			})
+		}
+	}
+}