json2: add compatibility of @[skip] in json2

vlib/x/json2/decoder.v

@@ -165,6 +165,9 @@ fn decode_struct[T](_ T, res map[string]Any) !T {
 			mut json_name := field.name
 
 			for attr in field.attrs {
+				if attr.contains('skip') {
+					skip_field = true
+				}
 				if attr.contains('json: ') {
 					json_name = attr.replace('json: ', '')
 					if json_name == '-' {

vlib/x/json2/encoder.v

@@ -200,6 +200,9 @@ fn (e &Encoder) encode_struct[U](val U, level int, mut buf []u8) ! {
 	$for field in U.fields {
 		mut @continue := false
 		for attr in field.attrs {
+			if attr.contains('skip') {
+				@continue = true
+			}
 			if attr.contains('json: ') {
 				if attr.replace('json: ', '') == '-' {
 					@continue = true
@@ -227,6 +230,9 @@ fn (e &Encoder) encode_struct[U](val U, level int, mut buf []u8) ! {
 		mut json_name := ''
 
 		for attr in field.attrs {
+			if attr.contains('skip') {
+				ignore_field = true
+			}
 			if attr.contains('json: ') {
 				json_name = attr.replace('json: ', '')
 				if json_name == '-' {

vlib/x/json2/tests/decode_struct_test.v

@@ -73,6 +73,22 @@ mut:
 	val map[string]string @[json: '-']
 }
 
+struct StructTypeSkippedFields5[T] {
+mut:
+	val  T @[skip]
+	val1 T @[skip]
+	val2 T @[skip]
+	val3 T @[skip]
+}
+
+struct StructTypeSkippedFields6[T] {
+mut:
+	val  T
+	val1 T @[skip]
+	val2 T
+	val3 T @[skip]
+}
+
 fn test_types() {
 	assert json.decode[StructType[string]]('{"val": ""}')!.val == ''
 	assert json.decode[StructType[string]]('{"val": "0"}')!.val == '0'
@@ -188,4 +204,22 @@ fn test_skipped_fields() {
 	} else {
 		assert false
 	}
+
+	if x := json.decode[StructTypeSkippedFields5[int]]('{"val":10,"val1":10,"val2":10,"val3":10}') {
+		assert x.val == 0
+		assert x.val1 == 0
+		assert x.val2 == 0
+		assert x.val3 == 0
+	} else {
+		assert false
+	}
+
+	if x := json.decode[StructTypeSkippedFields6[int]]('{"val":10,"val1":10,"val2":10,"val3":10}') {
+		assert x.val == 10
+		assert x.val1 == 0
+		assert x.val2 == 10
+		assert x.val3 == 0
+	} else {
+		assert false
+	}
 }

vlib/x/json2/tests/encode_struct_skippable_fields_test.v

@@ -73,6 +73,14 @@ mut:
 	val3 time.Time @[json: '-']
 }
 
+struct StructTypeSkippedFields9 {
+mut:
+	val  string
+	val1 i64 @[skip]
+	val2 f64
+	val3 time.Time @[skip]
+}
+
 fn test_encode_struct_skipped_fields() {
 	assert json.encode(StructTypeSkippedFields[string]{
 		val:  'string_val'
@@ -131,4 +139,10 @@ fn test_encode_struct_skipped_fields() {
 		val1: 1
 		val2: 1.0
 	}) == '{"val":"string_val","val2":1.0}'
+
+	assert json.encode(StructTypeSkippedFields9{
+		val:  'string_val'
+		val1: 1
+		val2: 1.0
+	}) == '{"val":"string_val","val2":1.0}'
 }