How to access unexported struct fields in Golang?

Question

Is there a way to use Reflect to access unexported fields in go 1.8? This no longer seems to work: https://stackoverflow.com/a/17982725/555493

Note that reflec

Answer 1

Based on cpcallen's work:

import (
    "reflect"
    "unsafe"
)

func GetUnexportedField(field reflect.Value) interface{} {
    return reflect.NewAt(field.Type(), unsafe.Pointer(field.UnsafeAddr())).Elem().Interface()
}

func SetUnexportedField(field reflect.Value, value interface{}) {
    reflect.NewAt(field.Type(), unsafe.Pointer(field.UnsafeAddr())).
        Elem().
        Set(reflect.ValueOf(value))
}

---

reflect.NewAt might be confusing to read at first. It returns a reflect.Value representing a pointer to a value of the specified field.Type(), using unsafe.Pointer(field.UnsafeAddr()) as that pointer. In this context reflect.NewAt is different than reflect.New, which would return a pointer to a freshly initialized value.

Example:

type Foo struct {
    unexportedField string
}

GetUnexportedField(reflect.ValueOf(&Foo{}).Elem().FieldByName("unexportedField"))

https://play.golang.org/p/IgjlQPYdKFR