From 1df1b0bd19ba2e767dcb82279babc28593ca604d Mon Sep 17 00:00:00 2001
From: Golang Lemonade <147884153+golanglemonade@users.noreply.github.com>
Date: Tue, 23 Apr 2024 16:57:58 -0600
Subject: [PATCH 1/2] add test that passed before v0.21.2 for omitempty tags

Signed-off-by: Golang Lemonade <147884153+golanglemonade@users.noreply.github.com>
---
 clientv2/client_test.go | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/clientv2/client_test.go b/clientv2/client_test.go
index da9606b..ef58324 100644
--- a/clientv2/client_test.go
+++ b/clientv2/client_test.go
@@ -578,6 +578,13 @@ func TestMarshalJSON(t *testing.T) {
 		Name   string `json:"name"`
 		Number Number `json:"number"`
 	}
+
+	// example with omitted fields
+	type Input struct {
+		ID   string   `json:"id"`
+		Tags []string `json:"tags,omitempty"`
+	}
+
 	testDate := time.Date(2021, 1, 1, 0, 0, 0, 0, time.UTC)
 	type args struct {
 		v any
@@ -642,6 +649,37 @@ func TestMarshalJSON(t *testing.T) {
 			},
 			want: []byte(`{"time":"2021-01-01T00:00:00Z"}`),
 		},
+		{
+			name: "marshal omitted fields",
+			args: args{
+				v: Request{
+					OperationName: "query",
+					Query:         `query ($input: Number!) { input }`,
+					Variables: map[string]any{
+						"input": Input{
+							ID: "1",
+						},
+					},
+				},
+			},
+			want: []byte(`{"operationName":"query", "query":"query ($input: Number!) { input }","variables":{"input":{"id":"1"}}}`),
+		},
+		{
+			name: "marshal fields",
+			args: args{
+				v: Request{
+					OperationName: "query",
+					Query:         `query ($input: Number!) { input }`,
+					Variables: map[string]any{
+						"input": Input{
+							ID:   "1",
+							Tags: []string{"tag1", "tag2"},
+						},
+					},
+				},
+			},
+			want: []byte(`{"operationName":"query", "query":"query ($input: Number!) { input }","variables":{"input":{"id":"1", "tags":["tag1","tag2"]}}}`),
+		},
 		{
 			name: "marshal time.Time",
 			args: args{

From c970a942e0e9c1b1375f5603ce4ed907f4a56d02 Mon Sep 17 00:00:00 2001
From: Golang Lemonade <147884153+golanglemonade@users.noreply.github.com>
Date: Tue, 23 Apr 2024 17:14:34 -0600
Subject: [PATCH 2/2] respect omitempty on fields

Signed-off-by: Golang Lemonade <147884153+golanglemonade@users.noreply.github.com>
---
 clientv2/client.go | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/clientv2/client.go b/clientv2/client.go
index e0aa017..1b08563 100644
--- a/clientv2/client.go
+++ b/clientv2/client.go
@@ -504,9 +504,10 @@ func encodeString(v reflect.Value) ([]byte, error) {
 }
 
 type fieldInfo struct {
-	name     string
-	jsonName string
-	typ      reflect.Type
+	name      string
+	jsonName  string
+	omitempty bool
+	typ       reflect.Type
 }
 
 func prepareFields(t reflect.Type) []fieldInfo {
@@ -521,16 +522,24 @@ func prepareFields(t reflect.Type) []fieldInfo {
 		if jsonTag == "-" {
 			continue // Skip fields explicitly marked to be ignored
 		}
+
 		jsonName := f.Name
 		if jsonTag != "" {
 			parts := strings.Split(jsonTag, ",")
 			jsonName = parts[0] // Use the name specified in the JSON tag
 		}
-		fields = append(fields, fieldInfo{
+
+		fi := fieldInfo{
 			name:     f.Name,
 			jsonName: jsonName,
 			typ:      f.Type,
-		})
+		}
+
+		if strings.Contains(jsonTag, "omitempty") {
+			fi.omitempty = true
+		}
+
+		fields = append(fields, fi)
 	}
 
 	return fields
@@ -545,6 +554,10 @@ func encodeStruct(v reflect.Value) ([]byte, error) {
 			continue // Skip invalid or nil pointers to avoid panics
 		}
 
+		if field.omitempty && fieldValue.IsZero() {
+			continue // Skip nil fields marked with omitempty
+		}
+
 		encodedValue, err := encode(fieldValue)
 		if err != nil {
 			return nil, err