reflect: adjust access to unexported embedded structs

This CL changes reflect to allow access to exported fields and
methods in unexported embedded structs for gccgo and after gc
has been adjusted to disallow access to embedded unexported structs.

Adresses #12367, #7363, #11007, and #7247.

Change-Id: If80536eab35abcd25300d8ddc2d27d5c42d7e78e
Reviewed-on: https://go-review.googlesource.com/14010
Reviewed-by: Russ Cox <rsc@golang.org>

diff --git a/src/reflect/export_test.go b/src/reflect/export_test.go
index 0b9d0fde9e2af5d3bed86036124bf9f82f5f2f71..26a648e193f1ad5bfd60d8daf7602460baff1e73 100644 (file)
--- a/src/reflect/export_test.go
+++ b/src/reflect/export_test.go
@@ -8,13 +8,13 @@ import "unsafe"
 
 // MakeRO returns a copy of v with the read-only flag set.
 func MakeRO(v Value) Value {
-       v.flag |= flagRO
+       v.flag |= flagStickyRO
        return v
 }
 
 // IsRO reports whether v's read-only flag is set.
 func IsRO(v Value) bool {
-       return v.flag&flagRO != 0
+       return v.flag&flagStickyRO != 0
 }
 
 var CallGC = &callGC

diff --git a/src/reflect/type.go b/src/reflect/type.go
index e98c960a03bb8e091eb3feb5a46c4f8ce3c677ec..aa56fcbe9554e5e6cd048cc88a5c21aa6b6b7046 100644 (file)
--- a/src/reflect/type.go
+++ b/src/reflect/type.go
@@ -496,7 +496,7 @@ func (t *uncommonType) Method(i int) (m Method) {
        fl := flag(Func)
        if p.pkgPath != nil {
                m.PkgPath = *p.pkgPath
-               fl |= flagRO
+               fl |= flagStickyRO
        }
        mt := p.typ
        m.Type = mt

diff --git a/src/reflect/value.go b/src/reflect/value.go
index 001d0274ecc87ddaaa4be04728a861953c46e182..2317a7bec3cc800b9fae8a6c5eb1201fe174bdc3 100644 (file)
--- a/src/reflect/value.go
+++ b/src/reflect/value.go
@@ -44,7 +44,8 @@ type Value struct {
 
        // flag holds metadata about the value.
        // The lowest bits are flag bits:
-       //      - flagRO: obtained via unexported field, so read-only
+       //      - flagStickyRO: obtained via unexported not embedded field, so read-only
+       //      - flagEmbedRO: obtained via unexported embedded field, so read-only
        //      - flagIndir: val holds a pointer to the data
        //      - flagAddr: v.CanAddr is true (implies flagIndir)
        //      - flagMethod: v is a method value.
@@ -67,11 +68,13 @@ type flag uintptr
 const (
        flagKindWidth        = 5 // there are 27 kinds
        flagKindMask    flag = 1<<flagKindWidth - 1
-       flagRO          flag = 1 << 5
-       flagIndir       flag = 1 << 6
-       flagAddr        flag = 1 << 7
-       flagMethod      flag = 1 << 8
-       flagMethodShift      = 9
+       flagStickyRO    flag = 1 << 5
+       flagEmbedRO     flag = 1 << 6
+       flagIndir       flag = 1 << 7
+       flagAddr        flag = 1 << 8
+       flagMethod      flag = 1 << 9
+       flagMethodShift      = 10
+       flagRO          flag = flagStickyRO | flagEmbedRO
 )
 
 func (f flag) kind() Kind {
@@ -745,11 +748,15 @@ func (v Value) Field(i int) Value {
        field := &tt.fields[i]
        typ := field.typ
 
-       // Inherit permission bits from v.
-       fl := v.flag&(flagRO|flagIndir|flagAddr) | flag(typ.Kind())
+       // Inherit permission bits from v, but clear flagEmbedRO.
+       fl := v.flag&(flagStickyRO|flagIndir|flagAddr) | flag(typ.Kind())
        // Using an unexported field forces flagRO.
        if field.pkgPath != nil {
-               fl |= flagRO
+               if field.name == nil {
+                       fl |= flagEmbedRO
+               } else {
+                       fl |= flagStickyRO
+               }
        }
        // Either flagIndir is set and v.ptr points at struct,
        // or flagIndir is not set and v.ptr is the actual struct data.
@@ -1104,7 +1111,7 @@ func (v Value) Method(i int) Value {
        if v.typ.Kind() == Interface && v.IsNil() {
                panic("reflect: Method on nil interface value")
        }
-       fl := v.flag & (flagRO | flagIndir)
+       fl := v.flag & (flagStickyRO | flagIndir) // Clear flagEmbedRO
        fl |= flag(Func)
        fl |= flag(i)<<flagMethodShift | flagMethod
        return Value{v.typ, v.ptr, fl}