Marshalling json.RawMessage returns base64 encoded string

Question

I run the following code:

package main  import (     "encoding/json"     "fmt" )  func main() {     raw := json.RawMessage(`{"foo":"bar"}`)     j, err := json.Marshal(raw)     if err != nil {         panic(err)     }     fmt.Println(string(j))   } 

Playground: http://play.golang.org/p/qbkEIZRTPQ

Output:

"eyJmb28iOiJiYXIifQ==" 

Desired output:

{"foo":"bar"} 

Why does it base64 encode my RawMessage as if it was an ordinary []byte?

After all, RawMessage's implementation of MarshalJSON is just returning the byte slice

// MarshalJSON returns *m as the JSON encoding of m. func (m *RawMessage) MarshalJSON() ([]byte, error) {     return *m, nil  } 

Answer 1

Found the answer in a go-nuts thread

The value passed to json.Marshal must be a pointer for json.RawMessage to work properly:

package main  import (     "encoding/json"     "fmt" )  func main() {     raw := json.RawMessage(`{"foo":"bar"}`)     j, err := json.Marshal(&raw)     if err != nil {         panic(err)     }     fmt.Println(string(j))   }