src/pkg/encoding/json/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"
	"fmt"
	"reflect"
	"strings"
	"testing"
)

type T struct {
	X string
	Y int
	Z int `json:"-"`
}

type U struct {
	Alphabet string `json:"alpha"`
}

type tx struct {
	x int
}

var txType = reflect.TypeOf((*tx)(nil)).Elem()

// 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
}

var (
	um0, um1 unmarshaler // target2 of unmarshaling
	ump      = &um1
	umtrue   = unmarshaler{true}
	umslice  = []unmarshaler{{true}}
	umslicep = new([]unmarshaler)
	umstruct = ustruct{unmarshaler{true}}
)

type unmarshalTest struct {
	in  string
	ptr interface{}
	out interface{}
	err error
}

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: `"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(interface{}), out: nil},
	{in: `{"X": [1,2,3], "Y": 4}`, ptr: new(T), out: T{Y: 4}, err: &UnmarshalTypeError{"array", reflect.TypeOf("")}},
	{in: `{"x": 1}`, ptr: new(tx), out: tx{}, err: &UnmarshalFieldError{"x", txType, txType.Field(0)}},

	// Z has a "-" tag.
	{in: `{"Y": 1, "Z": 2}`, ptr: new(T), out: T{Y: 1}},

	{in: `{"alpha": "abc", "alphabet": "xyz"}`, ptr: new(U), out: U{Alphabet: "abc"}},
	{in: `{"alpha": "abc"}`, ptr: new(U), out: U{Alphabet: "abc"}},
	{in: `{"alphabet": "xyz"}`, ptr: new(U), out: U{}},

	// 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}},

	// 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}},

	// 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: &um0, out: umtrue}, // use "false" so test will fail if custom unmarshaler is not called
	{in: `{"T":false}`, ptr: &ump, out: &umtrue},
	{in: `[{"T":false}]`, ptr: &umslice, out: umslice},
	{in: `[{"T":false}]`, ptr: &umslicep, out: &umslice},
	{in: `{"M":{"T":false}}`, ptr: &umstruct, out: umstruct},
}

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
	}
}

func TestMarshalBadUTF8(t *testing.T) {
	s := "hello\xffworld"
	b, err := Marshal(s)
	if err == nil {
		t.Fatal("Marshal bad UTF8: no error")
	}
	if len(b) != 0 {
		t.Fatal("Marshal returned data")
	}
	if _, ok := err.(*InvalidUTF8Error); !ok {
		t.Fatalf("Marshal did not return InvalidUTF8Error: %T %v", err, err)
	}
}

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 !reflect.DeepEqual(err, tt.err) {
				t.Errorf("#%d: checkValid: %#v", i, err)
				continue
			}
		}
		if tt.ptr == nil {
			continue
		}
		// v = new(right-type)
		v := reflect.New(reflect.TypeOf(tt.ptr).Elem())
		if err := Unmarshal([]byte(in), v.Interface()); !reflect.DeepEqual(err, tt.err) {
			t.Errorf("#%d: %v want %v", i, err, tt.err)
			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.
		if tt.err == nil {
			enc, err := Marshal(v.Interface())
			if err != nil {
				t.Errorf("#%d: error re-marshaling: %v", i, err)
				continue
			}
			vv := reflect.New(reflect.TypeOf(tt.ptr).Elem())
			if err := Unmarshal(enc, vv.Interface()); err != nil {
				t.Errorf("#%d: error re-unmarshaling: %v", i, 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())
				continue
			}
		}
	}
}

func TestUnmarshalMarshal(t *testing.T) {
	initBig()
	var v interface{}
	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.Compare(jsonBig, b) != 0 {
		t.Errorf("Marshal jsonBig")
		diff(t, b, jsonBig)
		return
	}
}

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.Compare(s0, s1) != 0 {
		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 interface{} = &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>`
	const expected = `"\"foobar\"\u003chtml\u003e"`
	b, err := Marshal(input)
	if err != nil {
		t.Fatalf("Marshal error: %v", err)
	}
	if s := string(b); s != expected {
		t.Errorf("Encoding of [%s] was [%s], want [%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`},
}

// 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(c) {
		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"`

	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  interface{}
	PInterface *interface{}

	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,
	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",
	"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",
	"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
	}
	want := S{
		R0: 12,
		R1: new(Ref),
	}
	*want.R1 = 12

	var got S
	if err := Unmarshal([]byte(`{"R0":"ref","R1":"ref"}`), &got); err != nil {
		t.Fatalf("Unmarshal: %v", err)
	}
	if !reflect.DeepEqual(got, want) {
		t.Errorf("got %+v, want %+v", got, want)
	}
}

// Test that anonymous fields are ignored.
// We may assign meaning to them later.
func TestAnonymous(t *testing.T) {
	type S struct {
		T
		N int
	}

	data, err := Marshal(new(S))
	if err != nil {
		t.Fatalf("Marshal: %v", err)
	}
	want := `{"N":0}`
	if string(data) != want {
		t.Fatalf("Marshal = %#q, want %#q", string(data), want)
	}

	var s S
	if err := Unmarshal([]byte(`{"T": 1, "T": {"Y": 1}, "N": 2}`), &s); err != nil {
		t.Fatalf("Unmarshal: %v", err)
	}
	if s.N != 2 {
		t.Fatal("Unmarshal: did not set N")
	}
	if s.T.Y != 0 {
		t.Fatal("Unmarshal: did set T.Y")
	}
}

// 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")
	}
}

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  interface{}
	json string
	post interface{}
}{
	{"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 interface{} }{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)
		}
	}
}