x.json2: fix nest level check (#10584)

vlib/x/json2/decoder.v

@@ -92,13 +92,9 @@ fn (mut p Parser) decode() ?Any {
 }
 
 fn (mut p Parser) decode_value() ?Any {
-	if p.n_level == 500 {
+	if p.n_level + 1 == 500 {
 		return error(p.emit_error('reached maximum nesting level of 500'))
 	}
-	if (p.tok.kind == .lsbr && p.n_tok.kind == .lcbr)
-		|| (p.p_tok.kind == p.tok.kind && p.tok.kind == .lsbr) {
-		p.n_level++
-	}
 	match p.tok.kind {
 		.lsbr {
 			return p.decode_array()
@@ -150,6 +146,7 @@ fn (mut p Parser) decode_value() ?Any {
 fn (mut p Parser) decode_array() ?Any {
 	mut items := []Any{}
 	p.next_with_err() ?
+	p.n_level++
 	for p.tok.kind != .rsbr {
 		item := p.decode_value() ?
 		items << item
@@ -169,12 +166,14 @@ fn (mut p Parser) decode_array() ?Any {
 		}
 	}
 	p.next_with_err() ?
+	p.n_level--
 	return Any(items)
 }
 
 fn (mut p Parser) decode_object() ?Any {
 	mut fields := map[string]Any{}
 	p.next_with_err() ?
+	p.n_level++
 	for p.tok.kind != .rcbr {
 		is_key := p.tok.kind == .str_ && p.n_tok.kind == .colon
 		if !is_key {
@@ -196,5 +195,6 @@ fn (mut p Parser) decode_object() ?Any {
 		}
 	}
 	p.next_with_err() ?
+	p.n_level--
 	return Any(fields)
 }

vlib/x/json2/decoder_test.v

@@ -1,80 +1,61 @@
-import x.json2
+module json2
 
-fn test_raw_decode_string() {
-	str := json2.raw_decode('"Hello!"') or {
-		assert false
-		json2.Any(json2.null)
-	}
+fn test_raw_decode_string() ? {
+	str := raw_decode('"Hello!"') ?
 	assert str.str() == 'Hello!'
 }
 
-fn test_raw_decode_number() {
-	num := json2.raw_decode('123') or {
-		assert false
-		json2.Any(json2.null)
-	}
+fn test_raw_decode_number() ? {
+	num := raw_decode('123') ?
 	assert num.int() == 123
 }
 
-fn test_raw_decode_array() {
-	raw_arr := json2.raw_decode('["Foo", 1]') or {
-		assert false
-		json2.Any(json2.null)
-	}
+fn test_raw_decode_array() ? {
+	raw_arr := raw_decode('["Foo", 1]') ?
 	arr := raw_arr.arr()
 	assert arr[0].str() == 'Foo'
 	assert arr[1].int() == 1
 }
 
-fn test_raw_decode_bool() {
-	bol := json2.raw_decode('false') or {
-		assert false
-		json2.Any(json2.null)
-	}
+fn test_raw_decode_bool() ? {
+	bol := raw_decode('false') ?
 	assert bol.bool() == false
 }
 
-fn test_raw_decode_map() {
-	raw_mp := json2.raw_decode('{"name":"Bob","age":20}') or {
-		assert false
-		json2.Any(json2.null)
-	}
+fn test_raw_decode_map() ? {
+	raw_mp := raw_decode('{"name":"Bob","age":20}') ?
 	mp := raw_mp.as_map()
 	assert mp['name'].str() == 'Bob'
 	assert mp['age'].int() == 20
 }
 
-fn test_raw_decode_null() {
-	nul := json2.raw_decode('null') or {
-		assert false
-		json2.Any(json2.null)
-	}
-	assert nul is json2.Null
+fn test_raw_decode_null() ? {
+	nul := raw_decode('null') ?
+	assert nul is Null
 }
 
-fn test_raw_decode_invalid() {
-	json2.raw_decode('1z') or {
+fn test_raw_decode_invalid() ? {
+	raw_decode('1z') or {
 		assert err.msg == '[x.json2] invalid token `z` (0:17)'
 		return
 	}
 	assert false
 }
 
-fn test_raw_decode_string_with_dollarsign() {
-	str := json2.raw_decode(r'"Hello $world"') or {
-		assert false
-		json2.Any(json2.null)
-	}
+fn test_raw_decode_string_with_dollarsign() ? {
+	str := raw_decode(r'"Hello $world"') ?
 	assert str.str() == r'Hello $world'
 }
 
-fn test_raw_decode_map_with_whitespaces() {
-	raw_mp := json2.raw_decode(' \n\t{"name":"Bob","age":20}\n\t') or {
-		eprintln(err.msg)
-		assert false
-		json2.Any(json2.null)
-	}
+fn test_raw_decode_map_with_whitespaces() ? {
+	raw_mp := raw_decode(' \n\t{"name":"Bob","age":20}\n\t') ?
 	mp := raw_mp.as_map()
 	assert mp['name'].str() == 'Bob'
 	assert mp['age'].int() == 20
 }
+
+fn test_nested_array_object() ? {
+	mut parser := new_parser(r'[[[[[],[],[]]]],{"Test":{}},[[]]]', false)
+	decoded := parser.decode() ?
+	assert parser.n_level == 0
+}