From 30c7ed39370964cf9494ccb60fee8083b15d019d Mon Sep 17 00:00:00 2001
From: Matthew Sykes <matthew.sykes@gmail.com>
Date: Tue, 22 Sep 2020 12:20:06 -0400
Subject: [PATCH] Add reflect support for json.Marshaler

Signed-off-by: Matthew Sykes <matthew.sykes@gmail.com>
---
 .travis.yml     | 9 ++++-----
 encoder.go      | 7 +++++++
 encoder_test.go | 7 +++++--
 3 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index b35da29..7ce1f7a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,12 +2,11 @@ language: go
 
 matrix:
   include:
-  - go: "1.12.x"
-    install: true
-    env: GO111MODULE=on
-  - go: "1.13.x"
-    env: GO111MODULE=off
   - go: "1.13.x"
     install: true
+  - go: "1.14.x"
+    install: true
+  - go: "1.15.x"
+    install: true
 
 script: go test -race ./...
diff --git a/encoder.go b/encoder.go
index 330554f..9e960cc 100644
--- a/encoder.go
+++ b/encoder.go
@@ -6,6 +6,7 @@ import (
 	"bytes"
 	"encoding"
 	"encoding/base64"
+	"encoding/json"
 	"fmt"
 	"math"
 	"reflect"
@@ -249,6 +250,12 @@ func (enc *logfmtEncoder) AppendReflected(value interface{}) error {
 			return err
 		}
 		enc.AppendString(string(b))
+	case json.Marshaler:
+		b, err := v.MarshalJSON()
+		if err != nil {
+			return err
+		}
+		enc.AppendString(string(b))
 	default:
 		rvalue := reflect.ValueOf(value)
 		switch rvalue.Kind() {
diff --git a/encoder_test.go b/encoder_test.go
index 95206e4..639117c 100644
--- a/encoder_test.go
+++ b/encoder_test.go
@@ -150,9 +150,11 @@ func TestEncoderSimple(t *testing.T) {
 
 type stringer string
 type textMarshaler string
+type jsonMarshaler string
 
 func (s stringer) String() string                    { return string(s) }
 func (t textMarshaler) MarshalText() ([]byte, error) { return []byte(t), nil }
+func (j jsonMarshaler) MarshalJSON() ([]byte, error) { return []byte(j), nil }
 
 func TestEncoderReflected(t *testing.T) {
 	dummyFunc := func(string) {}
@@ -168,6 +170,7 @@ func TestEncoderReflected(t *testing.T) {
 		{"bytes", "bytes", []byte("bytes")},
 		{"stringer", "my-stringer", stringer("my-stringer")},
 		{"text marshaler", "marshaled-text", textMarshaler("marshaled-text")},
+		{"json marshaler", `"{\"json\":\"data\"}"`, textMarshaler(`{"json":"data"}`)},
 		{"bool", "true", true},
 		{"int", "-1", -int(1)},
 		{"int8", "-8", int8(-8)},
@@ -322,7 +325,7 @@ func TestArrayEncoderComplex(t *testing.T) {
 			f: func(enc zapcore.ArrayEncoder) error {
 				for i := 0; i < 3; i++ {
 					enc.AppendObject(zapcore.ObjectMarshalerFunc(func(oe zapcore.ObjectEncoder) error {
-						oe.AddInt(string('a'+i), i)
+						oe.AddInt(string(rune('a'+i)), i)
 						return nil
 					}))
 				}
@@ -431,7 +434,7 @@ func TestObjectEncoderComplex(t *testing.T) {
 				for i := 0; i < 3; i++ {
 					enc.AddObject(strconv.Itoa(i), zapcore.ObjectMarshalerFunc(func(oe zapcore.ObjectEncoder) error {
 						for j := 0; j < 3; j++ {
-							oe.AddInt(string('a'+i*3+j), i*3+j+1)
+							oe.AddInt(string(rune('a'+i*3+j)), i*3+j+1)
 						}
 						return nil
 					}))