1 files changed, 23 insertions, 1 deletions
diff --git a/src/encoding/json/decode.go b/src/encoding/json/decode.go
index f08b0a1c58..dca328062f 100644
--- a/src/encoding/json/decode.go
+++ b/src/encoding/json/decode.go
@@ -448,10 +448,25 @@ func (d *decodeState) valueQuoted() interface{} {
 // if it encounters an Unmarshaler, indirect stops and returns that.
 // if decodingNull is true, indirect stops at the last pointer so it can be set to nil.
 func (d *decodeState) indirect(v reflect.Value, decodingNull bool) (Unmarshaler, encoding.TextUnmarshaler, reflect.Value) {
+	// Issue #24153 indicates that it is generally not a guaranteed property
+	// that you may round-trip a reflect.Value by calling Value.Addr().Elem()
+	// and expect the value to still be settable for values derived from
+	// unexported embedded struct fields.
+	//
+	// The logic below effectively does this when it first addresses the value
+	// (to satisfy possible pointer methods) and continues to dereference
+	// subsequent pointers as necessary.
+	//
+	// After the first round-trip, we set v back to the original value to
+	// preserve the original RW flags contained in reflect.Value.
+	v0 := v
+	haveAddr := false
+
 	// If v is a named type and is addressable,
 	// start with its address, so that if the type has pointer methods,
 	// we find them.
 	if v.Kind() != reflect.Ptr && v.Type().Name() != "" && v.CanAddr() {
+		haveAddr = true
 		v = v.Addr()
 	}
 	for {
@@ -460,6 +475,7 @@ func (d *decodeState) indirect(v reflect.Value, decodingNull bool) (Unmarshaler,
 		if v.Kind() == reflect.Interface && !v.IsNil() {
 			e := v.Elem()
 			if e.Kind() == reflect.Ptr && !e.IsNil() && (!decodingNull || e.Elem().Kind() == reflect.Ptr) {
+				haveAddr = false
 				v = e
 				continue
 			}
@@ -485,7 +501,13 @@ func (d *decodeState) indirect(v reflect.Value, decodingNull bool) (Unmarshaler,
 				}
 			}
 		}
-		v = v.Elem()
+
+		if haveAddr {
+			v = v0 // restore original value after round-trip Value.Addr().Elem()
+			haveAddr = false
+		} else {
+			v = v.Elem()
+		}
 	}
 	return nil, nil, v
 }