From e4d56e7ad9a99b9bc457b2f0ecadfc89cde134cf Mon Sep 17 00:00:00 2001
From: John Guo <john@johng.cn>
Date: Wed, 23 Feb 2022 16:54:15 +0800
Subject: [PATCH] improve package gjson

---
 encoding/gjson/gjson.go                       |  3 ++
 encoding/gjson/gjson_api_new_load.go          | 40 ++++++++-----------
 .../gjson/gjson_z_unit_feature_set_test.go    |  8 ++++
 3 files changed, 27 insertions(+), 24 deletions(-)

diff --git a/encoding/gjson/gjson.go b/encoding/gjson/gjson.go
index e35a7b026..c7938ad3f 100644
--- a/encoding/gjson/gjson.go
+++ b/encoding/gjson/gjson.go
@@ -90,6 +90,9 @@ func (j *Json) setValue(pattern string, value interface{}, removed bool) error {
 					// Delete item from map.
 					delete((*pointer).(map[string]interface{}), array[i])
 				} else {
+					if (*pointer).(map[string]interface{}) == nil {
+						*pointer = map[string]interface{}{}
+					}
 					(*pointer).(map[string]interface{})[array[i]] = value
 				}
 			} else {
diff --git a/encoding/gjson/gjson_api_new_load.go b/encoding/gjson/gjson_api_new_load.go
index 367657fa5..75f8e7bef 100644
--- a/encoding/gjson/gjson_api_new_load.go
+++ b/encoding/gjson/gjson_api_new_load.go
@@ -67,38 +67,30 @@ func NewWithOptions(data interface{}, options Options) *Json {
 			}
 		}
 	default:
-		var reflectInfo = utils.OriginValueAndKind(data)
+		var (
+			pointedData interface{}
+			reflectInfo = utils.OriginValueAndKind(data)
+		)
 		switch reflectInfo.OriginKind {
 		case reflect.Slice, reflect.Array:
-			var i interface{} = gconv.Interfaces(data)
-			j = &Json{
-				p:  &i,
-				c:  byte(defaultSplitChar),
-				vc: false,
-			}
+			pointedData = gconv.Interfaces(data)
+
 		case reflect.Map:
-			var i interface{} = gconv.MapDeep(data, options.Tags)
-			j = &Json{
-				p:  &i,
-				c:  byte(defaultSplitChar),
-				vc: false,
-			}
+			pointedData = gconv.MapDeep(data, options.Tags)
+
 		case reflect.Struct:
 			if v, ok := data.(iVal); ok {
 				return NewWithOptions(v.Val(), options)
 			}
-			var i interface{} = gconv.MapDeep(data, options.Tags)
-			j = &Json{
-				p:  &i,
-				c:  byte(defaultSplitChar),
-				vc: false,
-			}
+			pointedData = gconv.MapDeep(data, options.Tags)
+
 		default:
-			j = &Json{
-				p:  &data,
-				c:  byte(defaultSplitChar),
-				vc: false,
-			}
+			pointedData = data
+		}
+		j = &Json{
+			p:  &pointedData,
+			c:  byte(defaultSplitChar),
+			vc: false,
 		}
 	}
 	j.mu = rwmutex.New(options.Safe)
diff --git a/encoding/gjson/gjson_z_unit_feature_set_test.go b/encoding/gjson/gjson_z_unit_feature_set_test.go
index 003682a5d..a389d0f79 100644
--- a/encoding/gjson/gjson_z_unit_feature_set_test.go
+++ b/encoding/gjson/gjson_z_unit_feature_set_test.go
@@ -339,3 +339,11 @@ func Test_Set_GArray(t *testing.T) {
 		t.Assert(j.Get("arr").Array(), g.Slice{"test"})
 	})
 }
+
+func Test_Set_WithEmptyStruct(t *testing.T) {
+	gtest.C(t, func(t *gtest.T) {
+		j := gjson.New(&struct{}{})
+		t.AssertNil(j.Set("aa", "123"))
+		t.Assert(j.MustToJsonString(), `{"aa":"123"}`)
+	})
+}