From 286350aa9ba3ce8950f92366f96921c7c1d36577 Mon Sep 17 00:00:00 2001
From: yuyi <yuyi98@163.com>
Date: Mon, 9 Jan 2023 21:33:08 +0800
Subject: [PATCH] cgen: fix `json` encoding of structs with option fields (skip
 the fields with a value of `none`) (#16916)

---
 .../json_encode_struct_with_option_field_test.v | 17 +++++++++++++----
 vlib/v/gen/c/json.v                             |  2 +-
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/vlib/json/json_encode_struct_with_option_field_test.v b/vlib/json/json_encode_struct_with_option_field_test.v
index 4edeb15e3..e4567c60d 100644
--- a/vlib/json/json_encode_struct_with_option_field_test.v
+++ b/vlib/json/json_encode_struct_with_option_field_test.v
@@ -1,4 +1,5 @@
 import json
+import x.json2
 
 struct Foo {
 	name string
@@ -11,10 +12,18 @@ fn test_json_encode_struct_with_option_field() {
 	}
 	ret1 := json.encode(f1)
 	println(ret1)
-	assert ret1 == '{"name":"hello","num":null}'
+	assert ret1 == '{"name":"hello"}'
 
-	f2 := Foo{'hello', 22}
-	ret2 := json.encode(f2)
+	ret2 := json2.encode(f1)
 	println(ret2)
-	assert ret2 == '{"name":"hello","num":22}'
+	assert ret2 == '{"name":"hello"}'
+
+	f2 := Foo{'hello', 22}
+	ret3 := json.encode(f2)
+	println(ret3)
+	assert ret3 == '{"name":"hello","num":22}'
+
+	ret4 := json2.encode(f2)
+	println(ret4)
+	assert ret4 == '{"name":"hello","num":22}'
 }
diff --git a/vlib/v/gen/c/json.v b/vlib/v/gen/c/json.v
index dcbd0d345..5a97874d2 100644
--- a/vlib/v/gen/c/json.v
+++ b/vlib/v/gen/c/json.v
@@ -170,7 +170,7 @@ ${enc_fn_dec} {
 
 fn (mut g Gen) gen_option_enc_dec(typ ast.Type, mut enc strings.Builder, mut dec strings.Builder) {
 	enc.writeln('\tif (val.state == 2) {')
-	enc.writeln('\t\treturn cJSON_CreateNull();')
+	enc.writeln('\t\treturn NULL;')
 	enc.writeln('\t}')
 	type_str := g.typ(typ.clear_flag(.option))
 	encode_name := js_enc_name(type_str)
-- 
2.30.2