From 9970ecb8359e59127afad499fa3d3b955a4d38af Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Fri, 24 Apr 2026 01:42:12 +0300
Subject: [PATCH] json: fix json.decode does not parse time into Struct (fixes
 #15610)

---
 vlib/json/README.md           |  3 +++
 vlib/json/json_primitives.c.v | 18 ++++++++++++++++++
 vlib/json/tests/json_test.v   |  5 +++++
 vlib/v/gen/c/json.v           | 17 +++++++++++------
 4 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/vlib/json/README.md b/vlib/json/README.md
index 5e46e97dc..daf62a8b4 100644
--- a/vlib/json/README.md
+++ b/vlib/json/README.md
@@ -7,6 +7,9 @@ For more details, see also the
 Large `i64` and `u64` values are encoded as exact decimal JSON numbers, and
 `json.decode` preserves those integer values when reading decimal integer input.
 
+Struct fields of type `time.Time` can be decoded from either a JSON number or
+from a JSON string in ISO 8601, RFC 3339, or Unix-timestamp form.
+
 ## Examples
 
 Here is an example of encoding and decoding a V struct with several fields.
diff --git a/vlib/json/json_primitives.c.v b/vlib/json/json_primitives.c.v
index 5f7eb57b4..a4b2f553d 100644
--- a/vlib/json/json_primitives.c.v
+++ b/vlib/json/json_primitives.c.v
@@ -5,6 +5,7 @@ module json
 
 import math
 import strconv
+import time
 
 #flag -I @VEXEROOT/thirdparty/cJSON
 #flag @VEXEROOT/thirdparty/cJSON/cJSON.o
@@ -205,6 +206,23 @@ fn decode_bool(root &C.cJSON) bool {
 	return C.cJSON_IsTrue(root)
 }
 
+@[markused]
+fn decode_time(root &C.cJSON) !time.Time {
+	if isnil(root) || C.cJSON_IsNull(root) {
+		return time.Time{}
+	}
+	mut decoded_time := time.Time{}
+	if C.cJSON_IsString(root) {
+		decoded_time.from_json_string(decode_string(root))!
+		return decoded_time
+	}
+	if C.cJSON_IsNumber(root) {
+		decoded_time.from_json_number(json_print(root))!
+		return decoded_time
+	}
+	return error('expected time.Time to decode from a JSON string or number, got: ${json_print(root)}')
+}
+
 // ///////////////////
 
 @[markused]
diff --git a/vlib/json/tests/json_test.v b/vlib/json/tests/json_test.v
index ccf5a58fa..b571435d9 100644
--- a/vlib/json/tests/json_test.v
+++ b/vlib/json/tests/json_test.v
@@ -167,6 +167,11 @@ fn test_encode_decode_time() {
 	// println(user2.reg_date)
 }
 
+fn test_decode_time_string_into_struct_field() {
+	user := json.decode(User2, '{"age": 25, "reg_date": "2001-01-01"}')!
+	assert user.reg_date.str() == '2001-01-01 00:00:00'
+}
+
 fn (mut u User) foo() string {
 	return json.encode(u)
 }
diff --git a/vlib/v/gen/c/json.v b/vlib/v/gen/c/json.v
index 74f1b3c2a..155e2a6c2 100644
--- a/vlib/v/gen/c/json.v
+++ b/vlib/v/gen/c/json.v
@@ -863,19 +863,24 @@ fn (mut g Gen) gen_struct_enc_dec(utyp ast.Type, type_info ast.TypeInfo, styp st
 				dec.writeln('\t}')
 			} else if field_sym.name == 'time.Time' {
 				// time struct requires special treatment
-				// it has to be decoded from a unix timestamp number
+				// it can be decoded from either a JSON string or number
 				tmp := g.new_tmp_var()
 				gen_js_get(styp, tmp, name, mut dec, is_required)
 				dec.writeln('\tif (jsonroot_${tmp}) {')
+				tmp_time_res := g.new_tmp_var()
+				dec.writeln('\t\t${result_name}_time__Time ${tmp_time_res} = json__decode_time(jsonroot_${tmp});')
+				dec.writeln('\t\tif (${tmp_time_res}.is_error) {')
+				dec.writeln('\t\t\treturn (${result_name}_${styp}){ .is_error = true, .err = ${tmp_time_res}.err, .data = {0} };')
+				dec.writeln('\t\t}')
 				if field.typ.has_flag(.option) {
-					dec.writeln('\t\tif (!(cJSON_IsNull(jsonroot_${tmp}))) {\n')
-					dec.writeln('\t\t\t${prefix}${op}${c_name(field.name)}.state = 0;\n')
+					dec.writeln('\t\tif (!(cJSON_IsNull(jsonroot_${tmp}))) {')
+					dec.writeln('\t\t\t${prefix}${op}${c_name(field.name)}.state = 0;')
 					tmp_time_var := g.new_tmp_var()
-					dec.writeln('\t\t\t${g.base_type(field.typ)} ${tmp_time_var} = time__unix(json__decode_u64(jsonroot_${tmp}));\n')
+					dec.writeln('\t\t\t${g.base_type(field.typ)} ${tmp_time_var} = *(time__Time*)${tmp_time_res}.data;')
 					dec.writeln('\t\t\tbuiltin__vmemcpy(&${prefix}${op}${c_name(field.name)}.data, &${tmp_time_var}, sizeof(${g.base_type(field.typ)}));')
-					dec.writeln('\t\t}\n')
+					dec.writeln('\t\t}')
 				} else {
-					dec.writeln('\t\t${prefix}${op}${c_name(field.name)} = time__unix(json__decode_u64(jsonroot_${tmp}));')
+					dec.writeln('\t\t${prefix}${op}${c_name(field.name)} = *(time__Time*)${tmp_time_res}.data;')
 					if field.has_default_expr {
 						dec.writeln('\t} else {')
 						dec.writeln('\t\t${prefix}${op}${c_name(field.name)} = ${g.expr_string_opt(field.typ,
-- 
2.39.5