x.json2: fix decode_number for u8 (fix #26027) (#26033)

Author: kbkpbot

vlib/x/json2/decode.v

@@ -930,95 +930,19 @@ fn (mut decoder Decoder) decode_number[T](val &T) ! {
 	$if T.unaliased_typ is $float {
 		*val = T(strconv.atof_quick(decoder.json[number_info.position..number_info.position +
 			number_info.length]))
-	} $else { // this part is a minefield
-		mut is_negative := false
-		mut index := 0
-
-		if decoder.json[number_info.position] == `-` {
-			$if T.unaliased_typ is u8 || T.unaliased_typ is u16 || T.unaliased_typ is u32
-				|| T.unaliased_typ is u64 || T.unaliased_typ is $enum {
-				decoder.decode_error('expected positive integer for ${typeof(val).name} but got ${decoder.json[number_info.position..
-					number_info.position + number_info.length]}')!
-			}
-
-			is_negative = true
-			index++
-		}
-
-		// doing it like this means the minimum of signed numbers does not overflow before being inverted
-		*val = 0 // initialize to zero before accumulating digits
-		if !is_negative {
-			digit_amount := get_number_digits(*val)
-
-			if number_info.length > digit_amount {
-				decoder.decode_error('overflows ${typeof(val).name}')!
-			}
-
-			for index < int_min(number_info.length, digit_amount - 1) {
-				digit := T(decoder.json[number_info.position + index] - `0`)
-
-				if digit > 9 { // comma, e and E are all smaller 0 in ASCII so they underflow
-					decoder.decode_error('expected integer but got real number')!
-				}
-
-				*val = *val * 10 + digit
-
-				index++
-			}
-
-			if index == digit_amount - 1 {
-				digit := T(decoder.json[number_info.position + index] - `0`)
-
-				if digit > 9 { // comma, e and E are all smaller 0 in ASCII so they underflow
-					decoder.decode_error('expected integer but got real number')!
-				}
-
-				type_max := get_number_max(*val)
-				max_digits := type_max / 10
-				last_digit := type_max % 10
-
-				if *val > max_digits || (*val == max_digits && digit > last_digit) {
-					decoder.decode_error('overflows ${typeof(val).name}s')!
-				}
-
-				*val = *val * 10 + digit
-			}
-		} else {
-			digit_amount := get_number_digits(*val) + 1
-
-			if number_info.length > digit_amount {
-				decoder.decode_error('underflows ${typeof(val).name}')!
-			}
-
-			for index < int_min(number_info.length, digit_amount - 1) {
-				digit := T(decoder.json[number_info.position + index] - `0`)
-
-				if digit > 9 { // comma, e and E are all smaller 0 in ASCII so they underflow
-					decoder.decode_error('expected integer but got real number')!
-				}
-
-				*val = *val * 10 - digit
-
-				index++
-			}
-
-			if index == digit_amount - 1 {
-				digit := T(decoder.json[number_info.position + index] - `0`)
-
-				if digit > 9 { // comma, e and E are all smaller 0 in ASCII so they underflow
-					decoder.decode_error('expected integer but got real number')!
-				}
-
-				type_min := get_number_min(*val)
-				min_digits := type_min / 10
-				last_digit := type_min % 10
-
-				if *val < min_digits || (*val == min_digits && -digit < last_digit) {
-					decoder.decode_error('underflows ${typeof(val).name}')!
-				}
-
-				*val = *val * 10 - digit
-			}
+	} $else {
+		str := decoder.json[number_info.position..number_info.position + number_info.length]
+		$match T.unaliased_typ {
+			i8 { *val = strconv.atoi8(str)! }
+			i16 { *val = strconv.atoi16(str)! }
+			i32 { *val = strconv.atoi32(str)! }
+			i64 { *val = strconv.atoi64(str)! }
+			u8 { *val = strconv.atou8(str)! }
+			u16 { *val = strconv.atou16(str)! }
+			u32 { *val = strconv.atou32(str)! }
+			u64 { *val = strconv.atou64(str)! }
+			int { *val = strconv.atoi(str)! }
+			$else { return error('`decode_number` can not decode ${T.name} type') }
 		}
 	}
 }

vlib/x/json2/tests/decode_struct_test.v

@@ -73,3 +73,20 @@ fn test_option_types() {
 		assert false, 'Should not return none'
 	}
 }
+
+struct JsonU8 {
+	val1 u8
+	val2 u8
+}
+
+fn test_u8_vals() {
+	x := JsonU8{
+		val1: 58
+		val2: 58
+	}
+
+	str := json.encode(x)
+
+	y := json.decode[JsonU8](str) or { panic(err) }
+	assert x == y
+}