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reflect: disallow Interface method on Value obtained via unexported name

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Had been allowing it for use by fmt, but it is too hard to lock down.
Fix other packages not to depend on it.

R=r, r
CC=golang-dev
https://golang.org/cl/5266054
This commit is contained in:
Russ Cox 2011-10-17 18:48:45 -04:00
parent e5f3dc8bc5
commit 304cf4dc9b
6 changed files with 288 additions and 167 deletions
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16
src/pkg/fmt/fmt_test.go
View File

@ -62,7 +62,7 @@ type I int
func (i I) String() string { return Sprintf("<%d>", int(i)) }
type B struct {
i I
I I
j int
}
@ -84,8 +84,8 @@ func (g G) GoString() string {
}
type S struct {
f F // a struct field that Formats
g G // a struct field that GoStrings
F F // a struct field that Formats
G G // a struct field that GoStrings
}
// A type with a String method with pointer receiver for testing %p
@ -333,8 +333,8 @@ var fmttests = []struct {
{"%+v", A{1, 2, "a", []int{1, 2}}, `{i:1 j:2 s:a x:[1 2]}`},
// +v on structs with Stringable items
{"%+v", B{1, 2}, `{i:<1> j:2}`},
{"%+v", C{1, B{2, 3}}, `{i:1 B:{i:<2> j:3}}`},
{"%+v", B{1, 2}, `{I:<1> j:2}`},
{"%+v", C{1, B{2, 3}}, `{i:1 B:{I:<2> j:3}}`},
// q on Stringable items
{"%s", I(23), `<23>`},
@ -350,7 +350,7 @@ var fmttests = []struct {
{"%#v", uint64(1<<64 - 1), "0xffffffffffffffff"},
{"%#v", 1000000000, "1000000000"},
{"%#v", map[string]int{"a": 1, "b": 2}, `map[string] int{"a":1, "b":2}`},
{"%#v", map[string]B{"a": {1, 2}, "b": {3, 4}}, `map[string] fmt_test.B{"a":fmt_test.B{i:1, j:2}, "b":fmt_test.B{i:3, j:4}}`},
{"%#v", map[string]B{"a": {1, 2}, "b": {3, 4}}, `map[string] fmt_test.B{"a":fmt_test.B{I:1, j:2}, "b":fmt_test.B{I:3, j:4}}`},
{"%#v", []string{"a", "b"}, `[]string{"a", "b"}`},
// slices with other formats
@ -385,11 +385,11 @@ var fmttests = []struct {
// Formatter
{"%x", F(1), "<x=F(1)>"},
{"%x", G(2), "2"},
{"%+v", S{F(4), G(5)}, "{f:<v=F(4)> g:5}"},
{"%+v", S{F(4), G(5)}, "{F:<v=F(4)> G:5}"},
// GoStringer
{"%#v", G(6), "GoString(6)"},
{"%#v", S{F(7), G(8)}, "fmt_test.S{f:<v=F(7)>, g:GoString(8)}"},
{"%#v", S{F(7), G(8)}, "fmt_test.S{F:<v=F(7)>, G:GoString(8)}"},
// %T
{"%T", (4 - 3i), "complex128"},

251
src/pkg/fmt/print.go
View File

@ -262,10 +262,8 @@ func Sprintln(a ...interface{}) string {
// the thing inside the interface, not the interface itself.
func getField(v reflect.Value, i int) reflect.Value {
val := v.Field(i)
if i := val; i.Kind() == reflect.Interface {
if inter := i.Interface(); inter != nil {
return reflect.ValueOf(inter)
}
if val.Kind() == reflect.Interface && !val.IsNil() {
val = val.Elem()
}
return val
}
@ -292,27 +290,32 @@ func (p *pp) unknownType(v interface{}) {
p.buf.WriteByte('?')
}
func (p *pp) badVerb(verb int, val interface{}) {
func (p *pp) badVerb(verb int, val interface{}, val1 reflect.Value) {
p.add('%')
p.add('!')
p.add(verb)
p.add('(')
if val == nil {
p.buf.Write(nilAngleBytes)
} else {
switch {
case val != nil:
p.buf.WriteString(reflect.TypeOf(val).String())
p.add('=')
p.printField(val, 'v', false, false, 0)
case val1.IsValid():
p.buf.WriteString(val1.Type().String())
p.add('=')
p.printValue(val1, 'v', false, false, 0)
default:
p.buf.Write(nilAngleBytes)
}
p.add(')')
}
func (p *pp) fmtBool(v bool, verb int, value interface{}) {
func (p *pp) fmtBool(v bool, verb int, value interface{}, value1 reflect.Value) {
switch verb {
case 't', 'v':
p.fmt.fmt_boolean(v)
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
@ -326,7 +329,7 @@ func (p *pp) fmtC(c int64) {
p.fmt.pad(p.runeBuf[0:w])
}
func (p *pp) fmtInt64(v int64, verb int, value interface{}) {
func (p *pp) fmtInt64(v int64, verb int, value interface{}, value1 reflect.Value) {
switch verb {
case 'b':
p.fmt.integer(v, 2, signed, ldigits)
@ -340,7 +343,7 @@ func (p *pp) fmtInt64(v int64, verb int, value interface{}) {
if 0 <= v && v <= unicode.MaxRune {
p.fmt.fmt_qc(v)
} else {
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
case 'x':
p.fmt.integer(v, 16, signed, ldigits)
@ -349,7 +352,7 @@ func (p *pp) fmtInt64(v int64, verb int, value interface{}) {
case 'X':
p.fmt.integer(v, 16, signed, udigits)
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
@ -384,7 +387,7 @@ func (p *pp) fmtUnicode(v int64) {
p.fmt.sharp = sharp
}
func (p *pp) fmtUint64(v uint64, verb int, goSyntax bool, value interface{}) {
func (p *pp) fmtUint64(v uint64, verb int, goSyntax bool, value interface{}, value1 reflect.Value) {
switch verb {
case 'b':
p.fmt.integer(int64(v), 2, unsigned, ldigits)
@ -404,7 +407,7 @@ func (p *pp) fmtUint64(v uint64, verb int, goSyntax bool, value interface{}) {
if 0 <= v && v <= unicode.MaxRune {
p.fmt.fmt_qc(int64(v))
} else {
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
case 'x':
p.fmt.integer(int64(v), 16, unsigned, ldigits)
@ -413,11 +416,11 @@ func (p *pp) fmtUint64(v uint64, verb int, goSyntax bool, value interface{}) {
case 'U':
p.fmtUnicode(int64(v))
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
func (p *pp) fmtFloat32(v float32, verb int, value interface{}) {
func (p *pp) fmtFloat32(v float32, verb int, value interface{}, value1 reflect.Value) {
switch verb {
case 'b':
p.fmt.fmt_fb32(v)
@ -432,11 +435,11 @@ func (p *pp) fmtFloat32(v float32, verb int, value interface{}) {
case 'G':
p.fmt.fmt_G32(v)
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
func (p *pp) fmtFloat64(v float64, verb int, value interface{}) {
func (p *pp) fmtFloat64(v float64, verb int, value interface{}, value1 reflect.Value) {
switch verb {
case 'b':
p.fmt.fmt_fb64(v)
@ -451,33 +454,33 @@ func (p *pp) fmtFloat64(v float64, verb int, value interface{}) {
case 'G':
p.fmt.fmt_G64(v)
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
func (p *pp) fmtComplex64(v complex64, verb int, value interface{}) {
func (p *pp) fmtComplex64(v complex64, verb int, value interface{}, value1 reflect.Value) {
switch verb {
case 'e', 'E', 'f', 'F', 'g', 'G':
p.fmt.fmt_c64(v, verb)
case 'v':
p.fmt.fmt_c64(v, 'g')
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
func (p *pp) fmtComplex128(v complex128, verb int, value interface{}) {
func (p *pp) fmtComplex128(v complex128, verb int, value interface{}, value1 reflect.Value) {
switch verb {
case 'e', 'E', 'f', 'F', 'g', 'G':
p.fmt.fmt_c128(v, verb)
case 'v':
p.fmt.fmt_c128(v, 'g')
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
func (p *pp) fmtString(v string, verb int, goSyntax bool, value interface{}) {
func (p *pp) fmtString(v string, verb int, goSyntax bool, value interface{}, value1 reflect.Value) {
switch verb {
case 'v':
if goSyntax {
@ -494,11 +497,11 @@ func (p *pp) fmtString(v string, verb int, goSyntax bool, value interface{}) {
case 'q':
p.fmt.fmt_q(v)
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
func (p *pp) fmtBytes(v []byte, verb int, goSyntax bool, depth int, value interface{}) {
func (p *pp) fmtBytes(v []byte, verb int, goSyntax bool, depth int, value interface{}, value1 reflect.Value) {
if verb == 'v' || verb == 'd' {
if goSyntax {
p.buf.Write(bytesBytes)
@ -533,7 +536,7 @@ func (p *pp) fmtBytes(v []byte, verb int, goSyntax bool, depth int, value interf
case 'q':
p.fmt.fmt_q(s)
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
@ -543,12 +546,12 @@ func (p *pp) fmtPointer(field interface{}, value reflect.Value, verb int, goSynt
case reflect.Chan, reflect.Func, reflect.Map, reflect.Ptr, reflect.Slice, reflect.UnsafePointer:
u = value.Pointer()
default:
p.badVerb(verb, field)
p.badVerb(verb, field, value)
return
}
if goSyntax {
p.add('(')
p.buf.WriteString(reflect.TypeOf(field).String())
p.buf.WriteString(value.Type().String())
p.add(')')
p.add('(')
if u == 0 {
@ -594,12 +597,51 @@ func (p *pp) catchPanic(val interface{}, verb int) {
}
}
func (p *pp) handleMethods(field interface{}, verb int, plus, goSyntax bool, depth int) (wasString, handled bool) {
// Is it a Formatter?
if formatter, ok := field.(Formatter); ok {
handled = true
wasString = false
defer p.catchPanic(field, verb)
formatter.Format(p, verb)
return
}
// Must not touch flags before Formatter looks at them.
if plus {
p.fmt.plus = false
}
// If we're doing Go syntax and the field knows how to supply it, take care of it now.
if goSyntax {
p.fmt.sharp = false
if stringer, ok := field.(GoStringer); ok {
wasString = false
handled = true
defer p.catchPanic(field, verb)
// Print the result of GoString unadorned.
p.fmtString(stringer.GoString(), 's', false, field, reflect.Value{})
return
}
} else {
// Is it a Stringer?
if stringer, ok := field.(Stringer); ok {
wasString = false
handled = true
defer p.catchPanic(field, verb)
p.printField(stringer.String(), verb, plus, false, depth)
return
}
}
handled = false
return
}
func (p *pp) printField(field interface{}, verb int, plus, goSyntax bool, depth int) (wasString bool) {
if field == nil {
if verb == 'T' || verb == 'v' {
p.buf.Write(nilAngleBytes)
} else {
p.badVerb(verb, field)
p.badVerb(verb, field, reflect.Value{})
}
return false
}
@ -614,118 +656,133 @@ func (p *pp) printField(field interface{}, verb int, plus, goSyntax bool, depth
p.fmtPointer(field, reflect.ValueOf(field), verb, goSyntax)
return false
}
// Is it a Formatter?
if formatter, ok := field.(Formatter); ok {
defer p.catchPanic(field, verb)
formatter.Format(p, verb)
return false // this value is not a string
}
// Must not touch flags before Formatter looks at them.
if plus {
p.fmt.plus = false
}
// If we're doing Go syntax and the field knows how to supply it, take care of it now.
if goSyntax {
p.fmt.sharp = false
if stringer, ok := field.(GoStringer); ok {
defer p.catchPanic(field, verb)
// Print the result of GoString unadorned.
p.fmtString(stringer.GoString(), 's', false, field)
return false // this value is not a string
}
} else {
// Is it a Stringer?
if stringer, ok := field.(Stringer); ok {
defer p.catchPanic(field, verb)
p.printField(stringer.String(), verb, plus, false, depth)
return false // this value is not a string
}
if wasString, handled := p.handleMethods(field, verb, plus, goSyntax, depth); handled {
return wasString
}
// Some types can be done without reflection.
switch f := field.(type) {
case bool:
p.fmtBool(f, verb, field)
p.fmtBool(f, verb, field, reflect.Value{})
return false
case float32:
p.fmtFloat32(f, verb, field)
p.fmtFloat32(f, verb, field, reflect.Value{})
return false
case float64:
p.fmtFloat64(f, verb, field)
p.fmtFloat64(f, verb, field, reflect.Value{})
return false
case complex64:
p.fmtComplex64(complex64(f), verb, field)
p.fmtComplex64(complex64(f), verb, field, reflect.Value{})
return false
case complex128:
p.fmtComplex128(f, verb, field)
p.fmtComplex128(f, verb, field, reflect.Value{})
return false
case int:
p.fmtInt64(int64(f), verb, field)
p.fmtInt64(int64(f), verb, field, reflect.Value{})
return false
case int8:
p.fmtInt64(int64(f), verb, field)
p.fmtInt64(int64(f), verb, field, reflect.Value{})
return false
case int16:
p.fmtInt64(int64(f), verb, field)
p.fmtInt64(int64(f), verb, field, reflect.Value{})
return false
case int32:
p.fmtInt64(int64(f), verb, field)
p.fmtInt64(int64(f), verb, field, reflect.Value{})
return false
case int64:
p.fmtInt64(f, verb, field)
p.fmtInt64(f, verb, field, reflect.Value{})
return false
case uint:
p.fmtUint64(uint64(f), verb, goSyntax, field)
p.fmtUint64(uint64(f), verb, goSyntax, field, reflect.Value{})
return false
case uint8:
p.fmtUint64(uint64(f), verb, goSyntax, field)
p.fmtUint64(uint64(f), verb, goSyntax, field, reflect.Value{})
return false
case uint16:
p.fmtUint64(uint64(f), verb, goSyntax, field)
p.fmtUint64(uint64(f), verb, goSyntax, field, reflect.Value{})
return false
case uint32:
p.fmtUint64(uint64(f), verb, goSyntax, field)
p.fmtUint64(uint64(f), verb, goSyntax, field, reflect.Value{})
return false
case uint64:
p.fmtUint64(f, verb, goSyntax, field)
p.fmtUint64(f, verb, goSyntax, field, reflect.Value{})
return false
case uintptr:
p.fmtUint64(uint64(f), verb, goSyntax, field)
p.fmtUint64(uint64(f), verb, goSyntax, field, reflect.Value{})
return false
case string:
p.fmtString(f, verb, goSyntax, field)
p.fmtString(f, verb, goSyntax, field, reflect.Value{})
return verb == 's' || verb == 'v'
case []byte:
p.fmtBytes(f, verb, goSyntax, depth, field)
p.fmtBytes(f, verb, goSyntax, depth, field, reflect.Value{})
return verb == 's'
}
// Need to use reflection
value := reflect.ValueOf(field)
return p.printReflectValue(reflect.ValueOf(field), verb, plus, goSyntax, depth)
}
// printValue is like printField but starts with a reflect value, not an interface{} value.
func (p *pp) printValue(value reflect.Value, verb int, plus, goSyntax bool, depth int) (wasString bool) {
if !value.IsValid() {
if verb == 'T' || verb == 'v' {
p.buf.Write(nilAngleBytes)
} else {
p.badVerb(verb, nil, value)
}
return false
}
// Special processing considerations.
// %T (the value's type) and %p (its address) are special; we always do them first.
switch verb {
case 'T':
p.printField(value.Type().String(), 's', false, false, 0)
return false
case 'p':
p.fmtPointer(nil, value, verb, goSyntax)
return false
}
// Handle values with special methods.
// Call always, even when field == nil, because handleMethods clears p.fmt.plus for us.
var field interface{}
if value.CanInterface() {
field = value.Interface()
}
if wasString, handled := p.handleMethods(field, verb, plus, goSyntax, depth); handled {
return wasString
}
return p.printReflectValue(value, verb, plus, goSyntax, depth)
}
// printReflectValue is the fallback for both printField and printValue.
// It uses reflect to print the value.
func (p *pp) printReflectValue(value reflect.Value, verb int, plus, goSyntax bool, depth int) (wasString bool) {
BigSwitch:
switch f := value; f.Kind() {
case reflect.Bool:
p.fmtBool(f.Bool(), verb, field)
p.fmtBool(f.Bool(), verb, nil, value)
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
p.fmtInt64(f.Int(), verb, field)
p.fmtInt64(f.Int(), verb, nil, value)
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
p.fmtUint64(uint64(f.Uint()), verb, goSyntax, field)
p.fmtUint64(uint64(f.Uint()), verb, goSyntax, nil, value)
case reflect.Float32, reflect.Float64:
if f.Type().Size() == 4 {
p.fmtFloat32(float32(f.Float()), verb, field)
p.fmtFloat32(float32(f.Float()), verb, nil, value)
} else {
p.fmtFloat64(float64(f.Float()), verb, field)
p.fmtFloat64(float64(f.Float()), verb, nil, value)
}
case reflect.Complex64, reflect.Complex128:
if f.Type().Size() == 8 {
p.fmtComplex64(complex64(f.Complex()), verb, field)
p.fmtComplex64(complex64(f.Complex()), verb, nil, value)
} else {
p.fmtComplex128(complex128(f.Complex()), verb, field)
p.fmtComplex128(complex128(f.Complex()), verb, nil, value)
}
case reflect.String:
p.fmtString(f.String(), verb, goSyntax, field)
p.fmtString(f.String(), verb, goSyntax, nil, value)
case reflect.Map:
if goSyntax {
p.buf.WriteString(f.Type().String())
@ -742,9 +799,9 @@ BigSwitch:
p.buf.WriteByte(' ')
}
}
p.printField(key.Interface(), verb, plus, goSyntax, depth+1)
p.printValue(key, verb, plus, goSyntax, depth+1)
p.buf.WriteByte(':')
p.printField(f.MapIndex(key).Interface(), verb, plus, goSyntax, depth+1)
p.printValue(f.MapIndex(key), verb, plus, goSyntax, depth+1)
}
if goSyntax {
p.buf.WriteByte('}')
@ -753,7 +810,7 @@ BigSwitch:
}
case reflect.Struct:
if goSyntax {
p.buf.WriteString(reflect.TypeOf(field).String())
p.buf.WriteString(value.Type().String())
}
p.add('{')
v := f
@ -772,20 +829,20 @@ BigSwitch:
p.buf.WriteByte(':')
}
}
p.printField(getField(v, i).Interface(), verb, plus, goSyntax, depth+1)
p.printValue(getField(v, i), verb, plus, goSyntax, depth+1)
}
p.buf.WriteByte('}')
case reflect.Interface:
value := f.Elem()
if !value.IsValid() {
if goSyntax {
p.buf.WriteString(reflect.TypeOf(field).String())
p.buf.WriteString(value.Type().String())
p.buf.Write(nilParenBytes)
} else {
p.buf.Write(nilAngleBytes)
}
} else {
return p.printField(value.Interface(), verb, plus, goSyntax, depth+1)
return p.printValue(value, verb, plus, goSyntax, depth+1)
}
case reflect.Array, reflect.Slice:
// Byte slices are special.
@ -801,11 +858,11 @@ BigSwitch:
for i := range bytes {
bytes[i] = byte(f.Index(i).Uint())
}
p.fmtBytes(bytes, verb, goSyntax, depth, field)
p.fmtBytes(bytes, verb, goSyntax, depth, nil, value)
return verb == 's'
}
if goSyntax {
p.buf.WriteString(reflect.TypeOf(field).String())
p.buf.WriteString(value.Type().String())
p.buf.WriteByte('{')
} else {
p.buf.WriteByte('[')
@ -818,7 +875,7 @@ BigSwitch:
p.buf.WriteByte(' ')
}
}
p.printField(f.Index(i).Interface(), verb, plus, goSyntax, depth+1)
p.printValue(f.Index(i), verb, plus, goSyntax, depth+1)
}
if goSyntax {
p.buf.WriteByte('}')
@ -833,17 +890,17 @@ BigSwitch:
switch a := f.Elem(); a.Kind() {
case reflect.Array, reflect.Slice:
p.buf.WriteByte('&')
p.printField(a.Interface(), verb, plus, goSyntax, depth+1)
p.printValue(a, verb, plus, goSyntax, depth+1)
break BigSwitch
case reflect.Struct:
p.buf.WriteByte('&')
p.printField(a.Interface(), verb, plus, goSyntax, depth+1)
p.printValue(a, verb, plus, goSyntax, depth+1)
break BigSwitch
}
}
if goSyntax {
p.buf.WriteByte('(')
p.buf.WriteString(reflect.TypeOf(field).String())
p.buf.WriteString(value.Type().String())
p.buf.WriteByte(')')
p.buf.WriteByte('(')
if v == 0 {
@ -860,7 +917,7 @@ BigSwitch:
}
p.fmt0x64(uint64(v), true)
case reflect.Chan, reflect.Func, reflect.UnsafePointer:
p.fmtPointer(field, value, verb, goSyntax)
p.fmtPointer(nil, value, verb, goSyntax)
default:
p.unknownType(f)
}

115
src/pkg/reflect/all_test.go
View File

@ -853,13 +853,13 @@ func TestIsNil(t *testing.T) {
func TestInterfaceExtraction(t *testing.T) {
var s struct {
w io.Writer
W io.Writer
}
s.w = os.Stdout
s.W = os.Stdout
v := Indirect(ValueOf(&s)).Field(0).Interface()
if v != s.w.(interface{}) {
t.Error("Interface() on interface: ", v, s.w)
if v != s.W.(interface{}) {
t.Error("Interface() on interface: ", v, s.W)
}
}
@ -1190,18 +1190,18 @@ type D2 struct {
}
type S0 struct {
a, b, c int
A, B, C int
D1
D2
}
type S1 struct {
b int
B int
S0
}
type S2 struct {
a int
A int
*S1
}
@ -1216,36 +1216,36 @@ type S1y struct {
type S3 struct {
S1x
S2
d, e int
D, E int
*S1y
}
type S4 struct {
*S4
a int
A int
}
var fieldTests = []FTest{
{struct{}{}, "", nil, 0},
{struct{}{}, "foo", nil, 0},
{S0{a: 'a'}, "a", []int{0}, 'a'},
{S0{}, "d", nil, 0},
{S1{S0: S0{a: 'a'}}, "a", []int{1, 0}, 'a'},
{S1{b: 'b'}, "b", []int{0}, 'b'},
{struct{}{}, "Foo", nil, 0},
{S0{A: 'a'}, "A", []int{0}, 'a'},
{S0{}, "D", nil, 0},
{S1{S0: S0{A: 'a'}}, "A", []int{1, 0}, 'a'},
{S1{B: 'b'}, "B", []int{0}, 'b'},
{S1{}, "S0", []int{1}, 0},
{S1{S0: S0{c: 'c'}}, "c", []int{1, 2}, 'c'},
{S2{a: 'a'}, "a", []int{0}, 'a'},
{S1{S0: S0{C: 'c'}}, "C", []int{1, 2}, 'c'},
{S2{A: 'a'}, "A", []int{0}, 'a'},
{S2{}, "S1", []int{1}, 0},
{S2{S1: &S1{b: 'b'}}, "b", []int{1, 0}, 'b'},
{S2{S1: &S1{S0: S0{c: 'c'}}}, "c", []int{1, 1, 2}, 'c'},
{S2{}, "d", nil, 0},
{S2{S1: &S1{B: 'b'}}, "B", []int{1, 0}, 'b'},
{S2{S1: &S1{S0: S0{C: 'c'}}}, "C", []int{1, 1, 2}, 'c'},
{S2{}, "D", nil, 0},
{S3{}, "S1", nil, 0},
{S3{S2: S2{a: 'a'}}, "a", []int{1, 0}, 'a'},
{S3{}, "b", nil, 0},
{S3{d: 'd'}, "d", []int{2}, 0},
{S3{e: 'e'}, "e", []int{3}, 'e'},
{S4{a: 'a'}, "a", []int{1}, 'a'},
{S4{}, "b", nil, 0},
{S3{S2: S2{A: 'a'}}, "A", []int{1, 0}, 'a'},
{S3{}, "B", nil, 0},
{S3{D: 'd'}, "D", []int{2}, 0},
{S3{E: 'e'}, "E", []int{3}, 'e'},
{S4{A: 'a'}, "A", []int{1}, 'a'},
{S4{}, "B", nil, 0},
}
func TestFieldByIndex(t *testing.T) {
@ -1587,3 +1587,68 @@ func TestSetBytes(t *testing.T) {
t.Errorf("ValueOf(%p).Bytes() = %p", &x[0], &y[0])
}
}
type Private struct {
x int
y **int
}
func (p *Private) m() {
}
type Public struct {
X int
Y **int
}
func (p *Public) M() {
}
func TestUnexported(t *testing.T) {
var pub Public
v := ValueOf(&pub)
isValid(v.Elem().Field(0))
isValid(v.Elem().Field(1))
isValid(v.Elem().FieldByName("X"))
isValid(v.Elem().FieldByName("Y"))
isValid(v.Type().Method(0).Func)
isNonNil(v.Elem().Field(0).Interface())
isNonNil(v.Elem().Field(1).Interface())
isNonNil(v.Elem().FieldByName("X").Interface())
isNonNil(v.Elem().FieldByName("Y").Interface())
isNonNil(v.Type().Method(0).Func.Interface())
var priv Private
v = ValueOf(&priv)
isValid(v.Elem().Field(0))
isValid(v.Elem().Field(1))
isValid(v.Elem().FieldByName("x"))
isValid(v.Elem().FieldByName("y"))
isValid(v.Type().Method(0).Func)
shouldPanic(func() { v.Elem().Field(0).Interface() })
shouldPanic(func() { v.Elem().Field(1).Interface() })
shouldPanic(func() { v.Elem().FieldByName("x").Interface() })
shouldPanic(func() { v.Elem().FieldByName("y").Interface() })
shouldPanic(func() { v.Type().Method(0).Func.Interface() })
}
func shouldPanic(f func()) {
defer func() {
if recover() == nil {
panic("did not panic")
}
}()
f()
}
func isNonNil(x interface{}) {
if x == nil {
panic("nil interface")
}
}
func isValid(v Value) {
if !v.IsValid() {
panic("zero Value")
}
}

2
src/pkg/reflect/deepequal.go
View File

@ -104,7 +104,7 @@ func deepValueEqual(v1, v2 Value, visited map[uintptr]*visit, depth int) (b bool
return true
default:
// Normal equality suffices
return v1.Interface() == v2.Interface()
return valueInterface(v1, false) == valueInterface(v2, false)
}
panic("Not reached")

31
src/pkg/reflect/value.go
View File

@ -876,14 +876,7 @@ func (v Value) CanInterface() bool {
if iv.kind == Invalid {
panic(&ValueError{"reflect.Value.CanInterface", iv.kind})
}
// TODO(rsc): Check flagRO too. Decide what to do about asking for
// interface for a value obtained via an unexported field.
// If the field were of a known type, say chan int or *sync.Mutex,
// the caller could interfere with the data after getting the
// interface. But fmt.Print depends on being able to look.
// Now that reflect is more efficient the special cases in fmt
// might be less important.
return v.InternalMethod == 0
return v.InternalMethod == 0 && iv.flag&flagRO == 0
}
// Interface returns v's value as an interface{}.
@ -891,22 +884,28 @@ func (v Value) CanInterface() bool {
// (as opposed to Type.Method), Interface cannot return an
// interface value, so it panics.
func (v Value) Interface() interface{} {
return v.internal().Interface()
return valueInterface(v, true)
}
func (iv internalValue) Interface() interface{} {
func valueInterface(v Value, safe bool) interface{} {
iv := v.internal()
return iv.valueInterface(safe)
}
func (iv internalValue) valueInterface(safe bool) interface{} {
if iv.kind == 0 {
panic(&ValueError{"reflect.Value.Interface", iv.kind})
}
if iv.method {
panic("reflect.Value.Interface: cannot create interface value for method with bound receiver")
}
/*
if v.flag()&noExport != 0 {
panic("reflect.Value.Interface: cannot return value obtained from unexported struct field")
}
*/
if safe && iv.flag&flagRO != 0 {
// Do not allow access to unexported values via Interface,
// because they might be pointers that should not be
// writable or methods or function that should not be callable.
panic("reflect.Value.Interface: cannot return value obtained from unexported field or method")
}
if iv.kind == Interface {
// Special case: return the element inside the interface.
// Won't recurse further because an interface cannot contain an interface.
@ -1758,7 +1757,7 @@ func convertForAssignment(what string, addr unsafe.Pointer, dst Type, iv interna
if addr == nil {
addr = unsafe.Pointer(new(interface{}))
}
x := iv.Interface()
x := iv.valueInterface(false)
if dst.NumMethod() == 0 {
*(*interface{})(addr) = x
} else {

40
test/interface/fake.go
View File

@ -12,20 +12,20 @@ package main
import "reflect"
type T struct {
f float32
g float32
F float32
G float32
s string
t string
S string
T string
u uint32
v uint32
U uint32
V uint32
w uint32
x uint32
W uint32
X uint32
y uint32
z uint32
Y uint32
Z uint32
}
func add(s, t string) string {
@ -40,16 +40,16 @@ func assert(b bool) {
func main() {
var x T
x.f = 1.0
x.g = x.f
x.s = add("abc", "def")
x.t = add("abc", "def")
x.u = 1
x.v = 2
x.w = 1 << 28
x.x = 2 << 28
x.y = 0x12345678
x.z = x.y
x.F = 1.0
x.G = x.F
x.S = add("abc", "def")
x.T = add("abc", "def")
x.U = 1
x.V = 2
x.W = 1 << 28
x.X = 2 << 28
x.Y = 0x12345678
x.Z = x.Y
// check mem and string
v := reflect.ValueOf(x)