decode_test.go

// 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"
	"maps"
	"math"
	"math/big"
	"net"
	"reflect"
	"slices"
	"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.TypeFor[SS]()}
}

type TAlias T

func (tt *TAlias) UnmarshalJSON(data []byte) error {
	t := T{}
	if err := Unmarshal(data, &t); err != nil {
		return err
	}
	*tt = TAlias(t)
	return nil
}

type TOuter struct {
	T TAlias
}

// 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 B struct {
	B bool `json:",string"`
}

type DoublePtr struct {
	I **int
	J **int
}

var unmarshalTests = []struct {
	CaseName
	in                    string
	ptr                   any // new(type)
	out                   any
	err                   error
	useNumber             bool
	golden                bool
	disallowUnknownFields bool
}{
	// basic types
	{CaseName: Name(""), in: `true`, ptr: new(bool), out: true},
	{CaseName: Name(""), in: `1`, ptr: new(int), out: 1},
	{CaseName: Name(""), in: `1.2`, ptr: new(float64), out: 1.2},
	{CaseName: Name(""), in: `-5`, ptr: new(int16), out: int16(-5)},
	{CaseName: Name(""), in: `2`, ptr: new(Number), out: Number("2"), useNumber: true},
	{CaseName: Name(""), in: `2`, ptr: new(Number), out: Number("2")},
	{CaseName: Name(""), in: `2`, ptr: new(any), out: float64(2.0)},
	{CaseName: Name(""), in: `2`, ptr: new(any), out: Number("2"), useNumber: true},
	{CaseName: Name(""), in: `"a\u1234"`, ptr: new(string), out: "a\u1234"},
	{CaseName: Name(""), in: `"http:\/\/"`, ptr: new(string), out: "http://"},
	{CaseName: Name(""), in: `"g-clef: \uD834\uDD1E"`, ptr: new(string), out: "g-clef: \U0001D11E"},
	{CaseName: Name(""), in: `"invalid: \uD834x\uDD1E"`, ptr: new(string), out: "invalid: \uFFFDx\uFFFD"},
	{CaseName: Name(""), in: "null", ptr: new(any), out: nil},
	{CaseName: Name(""), in: `{"X": [1,2,3], "Y": 4}`, ptr: new(T), out: T{Y: 4}, err: &UnmarshalTypeError{"array", reflect.TypeFor[string](), 7, "T", "X"}},
	{CaseName: Name(""), in: `{"X": 23}`, ptr: new(T), out: T{}, err: &UnmarshalTypeError{"number", reflect.TypeFor[string](), 8, "T", "X"}},
	{CaseName: Name(""), in: `{"x": 1}`, ptr: new(tx), out: tx{}},
	{CaseName: Name(""), in: `{"x": 1}`, ptr: new(tx), out: tx{}},
	{CaseName: Name(""), in: `{"x": 1}`, ptr: new(tx), err: fmt.Errorf("json: unknown field \"x\""), disallowUnknownFields: true},
	{CaseName: Name(""), in: `{"S": 23}`, ptr: new(W), out: W{}, err: &UnmarshalTypeError{"number", reflect.TypeFor[SS](), 0, "W", "S"}},
	{CaseName: Name(""), in: `{"T": {"X": 23}}`, ptr: new(TOuter), out: TOuter{}, err: &UnmarshalTypeError{"number", reflect.TypeFor[string](), 0, "TOuter", "T.X"}},
	{CaseName: Name(""), in: `{"F1":1,"F2":2,"F3":3}`, ptr: new(V), out: V{F1: float64(1), F2: int32(2), F3: Number("3")}},
	{CaseName: Name(""), in: `{"F1":1,"F2":2,"F3":3}`, ptr: new(V), out: V{F1: Number("1"), F2: int32(2), F3: Number("3")}, useNumber: true},
	{CaseName: Name(""), in: `{"k1":1,"k2":"s","k3":[1,2.0,3e-3],"k4":{"kk1":"s","kk2":2}}`, ptr: new(any), out: ifaceNumAsFloat64},
	{CaseName: Name(""), 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
	{CaseName: Name(""), in: "\n true ", ptr: new(bool), out: true},
	{CaseName: Name(""), in: "\t 1 ", ptr: new(int), out: 1},
	{CaseName: Name(""), in: "\r 1.2 ", ptr: new(float64), out: 1.2},
	{CaseName: Name(""), in: "\t -5 \n", ptr: new(int16), out: int16(-5)},
	{CaseName: Name(""), in: "\t \"a\\u1234\" \n", ptr: new(string), out: "a\u1234"},

	// Z has a "-" tag.
	{CaseName: Name(""), in: `{"Y": 1, "Z": 2}`, ptr: new(T), out: T{Y: 1}},
	{CaseName: Name(""), in: `{"Y": 1, "Z": 2}`, ptr: new(T), err: fmt.Errorf("json: unknown field \"Z\""), disallowUnknownFields: true},

	{CaseName: Name(""), in: `{"alpha": "abc", "alphabet": "xyz"}`, ptr: new(U), out: U{Alphabet: "abc"}},
	{CaseName: Name(""), in: `{"alpha": "abc", "alphabet": "xyz"}`, ptr: new(U), err: fmt.Errorf("json: unknown field \"alphabet\""), disallowUnknownFields: true},
	{CaseName: Name(""), in: `{"alpha": "abc"}`, ptr: new(U), out: U{Alphabet: "abc"}},
	{CaseName: Name(""), in: `{"alphabet": "xyz"}`, ptr: new(U), out: U{}},
	{CaseName: Name(""), in: `{"alphabet": "xyz"}`, ptr: new(U), err: fmt.Errorf("json: unknown field \"alphabet\""), disallowUnknownFields: true},

	// syntax errors
	{CaseName: Name(""), in: `{"X": "foo", "Y"}`, err: &SyntaxError{"invalid character '}' after object key", 17}},
	{CaseName: Name(""), in: `[1, 2, 3+]`, err: &SyntaxError{"invalid character '+' after array element", 9}},
	{CaseName: Name(""), in: `{"X":12x}`, err: &SyntaxError{"invalid character 'x' after object key:value pair", 8}, useNumber: true},
	{CaseName: Name(""), in: `[2, 3`, err: &SyntaxError{msg: "unexpected end of JSON input", Offset: 5}},
	{CaseName: Name(""), in: `{"F3": -}`, ptr: new(V), out: V{F3: Number("-")}, err: &SyntaxError{msg: "invalid character '}' in numeric literal", Offset: 9}},

	// raw value errors
	{CaseName: Name(""), in: "\x01 42", err: &SyntaxError{"invalid character '\\x01' looking for beginning of value", 1}},
	{CaseName: Name(""), in: " 42 \x01", err: &SyntaxError{"invalid character '\\x01' after top-level value", 5}},
	{CaseName: Name(""), in: "\x01 true", err: &SyntaxError{"invalid character '\\x01' looking for beginning of value", 1}},
	{CaseName: Name(""), in: " false \x01", err: &SyntaxError{"invalid character '\\x01' after top-level value", 8}},
	{CaseName: Name(""), in: "\x01 1.2", err: &SyntaxError{"invalid character '\\x01' looking for beginning of value", 1}},
	{CaseName: Name(""), in: " 3.4 \x01", err: &SyntaxError{"invalid character '\\x01' after top-level value", 6}},
	{CaseName: Name(""), in: "\x01 \"string\"", err: &SyntaxError{"invalid character '\\x01' looking for beginning of value", 1}},
	{CaseName: Name(""), in: " \"string\" \x01", err: &SyntaxError{"invalid character '\\x01' after top-level value", 11}},

	// array tests
	{CaseName: Name(""), in: `[1, 2, 3]`, ptr: new([3]int), out: [3]int{1, 2, 3}},
	{CaseName: Name(""), in: `[1, 2, 3]`, ptr: new([1]int), out: [1]int{1}},
	{CaseName: Name(""), in: `[1, 2, 3]`, ptr: new([5]int), out: [5]int{1, 2, 3, 0, 0}},
	{CaseName: Name(""), in: `[1, 2, 3]`, ptr: new(MustNotUnmarshalJSON), err: errors.New("MustNotUnmarshalJSON was used")},

	// empty array to interface test
	{CaseName: Name(""), in: `[]`, ptr: new([]any), out: []any{}},
	{CaseName: Name(""), in: `null`, ptr: new([]any), out: []any(nil)},
	{CaseName: Name(""), in: `{"T":[]}`, ptr: new(map[string]any), out: map[string]any{"T": []any{}}},
	{CaseName: Name(""), in: `{"T":null}`, ptr: new(map[string]any), out: map[string]any{"T": any(nil)}},

	// composite tests
	{CaseName: Name(""), in: allValueIndent, ptr: new(All), out: allValue},
	{CaseName: Name(""), in: allValueCompact, ptr: new(All), out: allValue},
	{CaseName: Name(""), in: allValueIndent, ptr: new(*All), out: &allValue},
	{CaseName: Name(""), in: allValueCompact, ptr: new(*All), out: &allValue},
	{CaseName: Name(""), in: pallValueIndent, ptr: new(All), out: pallValue},
	{CaseName: Name(""), in: pallValueCompact, ptr: new(All), out: pallValue},
	{CaseName: Name(""), in: pallValueIndent, ptr: new(*All), out: &pallValue},
	{CaseName: Name(""), in: pallValueCompact, ptr: new(*All), out: &pallValue},

	// unmarshal interface test
	{CaseName: Name(""), in: `{"T":false}`, ptr: new(unmarshaler), out: umtrue}, // use "false" so test will fail if custom unmarshaler is not called
	{CaseName: Name(""), in: `{"T":false}`, ptr: new(*unmarshaler), out: &umtrue},
	{CaseName: Name(""), in: `[{"T":false}]`, ptr: new([]unmarshaler), out: umslice},
	{CaseName: Name(""), in: `[{"T":false}]`, ptr: new(*[]unmarshaler), out: &umslice},
	{CaseName: Name(""), in: `{"M":{"T":"x:y"}}`, ptr: new(ustruct), out: umstruct},

	// UnmarshalText interface test
	{CaseName: Name(""), in: `"x:y"`, ptr: new(unmarshalerText), out: umtrueXY},
	{CaseName: Name(""), in: `"x:y"`, ptr: new(*unmarshalerText), out: &umtrueXY},
	{CaseName: Name(""), in: `["x:y"]`, ptr: new([]unmarshalerText), out: umsliceXY},
	{CaseName: Name(""), in: `["x:y"]`, ptr: new(*[]unmarshalerText), out: &umsliceXY},
	{CaseName: Name(""), in: `{"M":"x:y"}`, ptr: new(ustructText), out: umstructXY},

	// integer-keyed map test
	{
		CaseName: Name(""),
		in:       `{"-1":"a","0":"b","1":"c"}`,
		ptr:      new(map[int]string),
		out:      map[int]string{-1: "a", 0: "b", 1: "c"},
	},
	{
		CaseName: Name(""),
		in:       `{"0":"a","10":"c","9":"b"}`,
		ptr:      new(map[u8]string),
		out:      map[u8]string{0: "a", 9: "b", 10: "c"},
	},
	{
		CaseName: Name(""),
		in:       `{"-9223372036854775808":"min","9223372036854775807":"max"}`,
		ptr:      new(map[int64]string),
		out:      map[int64]string{math.MinInt64: "min", math.MaxInt64: "max"},
	},
	{
		CaseName: Name(""),
		in:       `{"18446744073709551615":"max"}`,
		ptr:      new(map[uint64]string),
		out:      map[uint64]string{math.MaxUint64: "max"},
	},
	{
		CaseName: Name(""),
		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.
	{
		CaseName: Name(""),
		in:       `{"u2":4}`,
		ptr:      new(map[u8marshal]int),
		out:      map[u8marshal]int{2: 4},
	},
	{
		CaseName: Name(""),
		in:       `{"2":4}`,
		ptr:      new(map[u8marshal]int),
		err:      errMissingU8Prefix,
	},

	// integer-keyed map errors
	{
		CaseName: Name(""),
		in:       `{"abc":"abc"}`,
		ptr:      new(map[int]string),
		err:      &UnmarshalTypeError{Value: "number abc", Type: reflect.TypeFor[int](), Offset: 2},
	},
	{
		CaseName: Name(""),
		in:       `{"256":"abc"}`,
		ptr:      new(map[uint8]string),
		err:      &UnmarshalTypeError{Value: "number 256", Type: reflect.TypeFor[uint8](), Offset: 2},
	},
	{
		CaseName: Name(""),
		in:       `{"128":"abc"}`,
		ptr:      new(map[int8]string),
		err:      &UnmarshalTypeError{Value: "number 128", Type: reflect.TypeFor[int8](), Offset: 2},
	},
	{
		CaseName: Name(""),
		in:       `{"-1":"abc"}`,
		ptr:      new(map[uint8]string),
		err:      &UnmarshalTypeError{Value: "number -1", Type: reflect.TypeFor[uint8](), Offset: 2},
	},
	{
		CaseName: Name(""),
		in:       `{"F":{"a":2,"3":4}}`,
		ptr:      new(map[string]map[int]int),
		err:      &UnmarshalTypeError{Value: "number a", Type: reflect.TypeFor[int](), Offset: 7},
	},
	{
		CaseName: Name(""),
		in:       `{"F":{"a":2,"3":4}}`,
		ptr:      new(map[string]map[uint]int),
		err:      &UnmarshalTypeError{Value: "number a", Type: reflect.TypeFor[uint](), Offset: 7},
	},

	// Map keys can be encoding.TextUnmarshalers.
	{CaseName: Name(""), 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.
	{CaseName: Name(""), in: `{"x:y":false,"x:y":true}`, ptr: new(map[unmarshalerText]bool), out: ummapXY},

	{
		CaseName: Name(""),
		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,
			},
		},
	},
	{
		CaseName: Name(""),
		in:       `{"hello": 1}`,
		ptr:      new(Ambig),
		out:      Ambig{First: 1},
	},

	{
		CaseName: Name(""),
		in:       `{"X": 1,"Y":2}`,
		ptr:      new(S5),
		out:      S5{S8: S8{S9: S9{Y: 2}}},
	},
	{
		CaseName:              Name(""),
		in:                    `{"X": 1,"Y":2}`,
		ptr:                   new(S5),
		err:                   fmt.Errorf("json: unknown field \"X\""),
		disallowUnknownFields: true,
	},
	{
		CaseName: Name(""),
		in:       `{"X": 1,"Y":2}`,
		ptr:      new(S10),
		out:      S10{S13: S13{S8: S8{S9: S9{Y: 2}}}},
	},
	{
		CaseName:              Name(""),
		in:                    `{"X": 1,"Y":2}`,
		ptr:                   new(S10),
		err:                   fmt.Errorf("json: unknown field \"X\""),
		disallowUnknownFields: true,
	},
	{
		CaseName: Name(""),
		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.
	{
		CaseName: Name(""),
		in:       "\"hello\xffworld\"",
		ptr:      new(string),
		out:      "hello\ufffdworld",
	},
	{
		CaseName: Name(""),
		in:       "\"hello\xc2\xc2world\"",
		ptr:      new(string),
		out:      "hello\ufffd\ufffdworld",
	},
	{
		CaseName: Name(""),
		in:       "\"hello\xc2\xffworld\"",
		ptr:      new(string),
		out:      "hello\ufffd\ufffdworld",
	},
	{
		CaseName: Name(""),
		in:       "\"hello\\ud800world\"",
		ptr:      new(string),
		out:      "hello\ufffdworld",
	},
	{
		CaseName: Name(""),
		in:       "\"hello\\ud800\\ud800world\"",
		ptr:      new(string),
		out:      "hello\ufffd\ufffdworld",
	},
	{
		CaseName: Name(""),
		in:       "\"hello\\ud800\\ud800world\"",
		ptr:      new(string),
		out:      "hello\ufffd\ufffdworld",
	},
	{
		CaseName: Name(""),
		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.
	{
		CaseName: Name(""),
		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
	{
		CaseName: Name(""),
		in:       `{"2009-11-10T23:00:00Z": "hello world"}`,
		ptr:      new(map[Point]string),
		err:      &UnmarshalTypeError{Value: "object", Type: reflect.TypeFor[map[Point]string](), Offset: 1},
	},
	{
		CaseName: Name(""),
		in:       `{"asdf": "hello world"}`,
		ptr:      new(map[unmarshaler]string),
		err:      &UnmarshalTypeError{Value: "object", Type: reflect.TypeFor[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.
	{
		CaseName: Name(""),
		in:       `"AQID"`,
		ptr:      new([]byteWithMarshalJSON),
		out:      []byteWithMarshalJSON{1, 2, 3},
	},
	{
		CaseName: Name(""),
		in:       `["Z01","Z02","Z03"]`,
		ptr:      new([]byteWithMarshalJSON),
		out:      []byteWithMarshalJSON{1, 2, 3},
		golden:   true,
	},
	{
		CaseName: Name(""),
		in:       `"AQID"`,
		ptr:      new([]byteWithMarshalText),
		out:      []byteWithMarshalText{1, 2, 3},
	},
	{
		CaseName: Name(""),
		in:       `["Z01","Z02","Z03"]`,
		ptr:      new([]byteWithMarshalText),
		out:      []byteWithMarshalText{1, 2, 3},
		golden:   true,
	},
	{
		CaseName: Name(""),
		in:       `"AQID"`,
		ptr:      new([]byteWithPtrMarshalJSON),
		out:      []byteWithPtrMarshalJSON{1, 2, 3},
	},
	{
		CaseName: Name(""),
		in:       `["Z01","Z02","Z03"]`,
		ptr:      new([]byteWithPtrMarshalJSON),
		out:      []byteWithPtrMarshalJSON{1, 2, 3},
		golden:   true,
	},
	{
		CaseName: Name(""),
		in:       `"AQID"`,
		ptr:      new([]byteWithPtrMarshalText),
		out:      []byteWithPtrMarshalText{1, 2, 3},
	},
	{
		CaseName: Name(""),
		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
	{
		CaseName: Name(""),
		in:       `["Z01","Z02","Z03"]`,
		ptr:      new([]intWithMarshalJSON),
		out:      []intWithMarshalJSON{1, 2, 3},
		golden:   true,
	},
	{
		CaseName: Name(""),
		in:       `["Z01","Z02","Z03"]`,
		ptr:      new([]intWithMarshalText),
		out:      []intWithMarshalText{1, 2, 3},
		golden:   true,
	},
	{
		CaseName: Name(""),
		in:       `["Z01","Z02","Z03"]`,
		ptr:      new([]intWithPtrMarshalJSON),
		out:      []intWithPtrMarshalJSON{1, 2, 3},
		golden:   true,
	},
	{
		CaseName: Name(""),
		in:       `["Z01","Z02","Z03"]`,
		ptr:      new([]intWithPtrMarshalText),
		out:      []intWithPtrMarshalText{1, 2, 3},
		golden:   true,
	},

	{CaseName: Name(""), in: `0.000001`, ptr: new(float64), out: 0.000001, golden: true},
	{CaseName: Name(""), in: `1e-7`, ptr: new(float64), out: 1e-7, golden: true},
	{CaseName: Name(""), in: `100000000000000000000`, ptr: new(float64), out: 100000000000000000000.0, golden: true},
	{CaseName: Name(""), in: `1e+21`, ptr: new(float64), out: 1e21, golden: true},
	{CaseName: Name(""), in: `-0.000001`, ptr: new(float64), out: -0.000001, golden: true},
	{CaseName: Name(""), in: `-1e-7`, ptr: new(float64), out: -1e-7, golden: true},
	{CaseName: Name(""), in: `-100000000000000000000`, ptr: new(float64), out: -100000000000000000000.0, golden: true},
	{CaseName: Name(""), in: `-1e+21`, ptr: new(float64), out: -1e21, golden: true},
	{CaseName: Name(""), in: `999999999999999900000`, ptr: new(float64), out: 999999999999999900000.0, golden: true},
	{CaseName: Name(""), in: `9007199254740992`, ptr: new(float64), out: 9007199254740992.0, golden: true},
	{CaseName: Name(""), in: `9007199254740993`, ptr: new(float64), out: 9007199254740992.0, golden: false},

	{
		CaseName: Name(""),
		in:       `{"V": {"F2": "hello"}}`,
		ptr:      new(VOuter),
		err: &UnmarshalTypeError{
			Value:  "string",
			Struct: "V",
			Field:  "V.F2",
			Type:   reflect.TypeFor[int32](),
			Offset: 20,
		},
	},
	{
		CaseName: Name(""),
		in:       `{"V": {"F4": {}, "F2": "hello"}}`,
		ptr:      new(VOuter),
		err: &UnmarshalTypeError{
			Value:  "string",
			Struct: "V",
			Field:  "V.F2",
			Type:   reflect.TypeFor[int32](),
			Offset: 30,
		},
	},

	// issue 15146.
	// invalid inputs in wrongStringTests below.
	{CaseName: Name(""), in: `{"B":"true"}`, ptr: new(B), out: B{true}, golden: true},
	{CaseName: Name(""), in: `{"B":"false"}`, ptr: new(B), out: B{false}, golden: true},
	{CaseName: Name(""), in: `{"B": "maybe"}`, ptr: new(B), err: errors.New(`json: invalid use of ,string struct tag, trying to unmarshal "maybe" into bool`)},
	{CaseName: Name(""), in: `{"B": "tru"}`, ptr: new(B), err: errors.New(`json: invalid use of ,string struct tag, trying to unmarshal "tru" into bool`)},
	{CaseName: Name(""), in: `{"B": "False"}`, ptr: new(B), err: errors.New(`json: invalid use of ,string struct tag, trying to unmarshal "False" into bool`)},
	{CaseName: Name(""), in: `{"B": "null"}`, ptr: new(B), out: B{false}},
	{CaseName: Name(""), in: `{"B": "nul"}`, ptr: new(B), err: errors.New(`json: invalid use of ,string struct tag, trying to unmarshal "nul" into bool`)},
	{CaseName: Name(""), 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
	{
		CaseName: Name(""),
		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,
	},
	{
		CaseName: Name(""),
		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
	{
		CaseName: Name(""),
		in:       `{"data":{"test1": "bob", "test2": 123}}`,
		ptr:      new(mapStringToStringData),
		err:      &UnmarshalTypeError{Value: "number", Type: reflect.TypeFor[string](), Offset: 37, Struct: "mapStringToStringData", Field: "data"},
	},
	{
		CaseName: Name(""),
		in:       `{"data":{"test1": 123, "test2": "bob"}}`,
		ptr:      new(mapStringToStringData),
		err:      &UnmarshalTypeError{Value: "number", Type: reflect.TypeFor[string](), Offset: 21, Struct: "mapStringToStringData", Field: "data"},
	},

	// trying to decode JSON arrays or objects via TextUnmarshaler
	{
		CaseName: Name(""),
		in:       `[1, 2, 3]`,
		ptr:      new(MustNotUnmarshalText),
		err:      &UnmarshalTypeError{Value: "array", Type: reflect.TypeFor[*MustNotUnmarshalText](), Offset: 1},
	},
	{
		CaseName: Name(""),
		in:       `{"foo": "bar"}`,
		ptr:      new(MustNotUnmarshalText),
		err:      &UnmarshalTypeError{Value: "object", Type: reflect.TypeFor[*MustNotUnmarshalText](), Offset: 1},
	},
	// #22369
	{
		CaseName: Name(""),
		in:       `{"PP": {"T": {"Y": "bad-type"}}}`,