encoding/json: addrMarshalerEncoder does not respect SetEscapeHTML

[nkovacs]

What version of Go are you using (go version)?

1.12.5 (playground)

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

play.golang.org

What did you do?

https://play.golang.org/p/lt-Mky4vAtq

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
)

type T1 int
type T2 int

func (t T1) MarshalJSON() ([]byte, error) {
	return []byte(`"<script>T1</script>"`), nil
}

func (t *T2) MarshalJSON() ([]byte, error) {
	return []byte(`"<script>T2</script>"`), nil
}

func main() {
	var t struct {
		T1 T1
		T2 T2
	}

	var out bytes.Buffer
	encoder := json.NewEncoder(&out)
	encoder.SetEscapeHTML(false)

	err := encoder.Encode(&t)
	if err != nil {
		panic(err)
	}

	fmt.Println(out.String())
}

What did you expect to see?

{"T1":"<script>T1</script>","T2":"<script>T2</script>"}

What did you see instead?

{"T1":"<script>T1</script>","T2":"\u003cscript\u003eT2\u003c/script\u003e"}

I noticed this inconsistency while studying the code of encoding/json, and I believe this is an edge case that was missed in #14749.

[bcmills]

CC @cespare @dsnet @mvdan

[gopherbot]

Change https://golang.org/cl/184757 mentions this issue: encoding/json: obey SetEscapeHTML in all MarshalJSON cases

[mvdan]

Thanks - this seems like a simple fix, so I've sent a CL with a test.