Method decodeFromStringToInt

json/decode.go:327–400

(b []byte, p unsafe.Pointer, t reflect.Type, decode decodeFunc)

}

func (d decoder) decodeFromStringToInt(b []byte, p unsafe.Pointer, t reflect.Type, decode decodeFunc) ([]byte, error) {
	if hasNullPrefix(b) {
		return decode(d, b, p)
	}

	if len(b) > 0 && b[0] != '"' {
		v, r, k, err := d.parseNumber(b)
		if err == nil {
			// The encoding/json package will return a *json.UnmarshalTypeError if
			// the input was a floating point number representation, even tho a
			// string is expected here.
			if k == Float {
				_, err := strconv.ParseFloat(*(*string)(unsafe.Pointer(&v)), 64)
				if err != nil {
					return r, unmarshalTypeError(v, t)
				}
			}
		}
		return r, fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal unquoted value into int")
	}

	if len(b) > 1 && b[0] == '"' && b[1] == '"' {
		return b, fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal \"\" into int")
	}

	v, b, _, err := d.parseStringUnquote(b, nil)
	if err != nil {
		return d.inputError(v, t)
	}

	if hasLeadingZeroes(v) {
		// In this context the encoding/json package accepts leading zeroes because
		// it is not constrained by the JSON syntax, remove them so the parsing
		// functions don't return syntax errors.
		u := make([]byte, 0, len(v))
		i := 0

		if i < len(v) && v[i] == '-' || v[i] == '+' {
			u = append(u, v[i])
			i++
		}

		for (i+1) < len(v) && v[i] == '0' && '0' <= v[i+1] && v[i+1] <= '9' {
			i++
		}

		v = append(u, v[i:]...)
	}

	if r, err := decode(d, v, p); err != nil {
		if _, isSyntaxError := err.(*SyntaxError); isSyntaxError {
			if hasPrefix(v, "-") {
				// The standard library interprets sequences of '-' characters
				// as numbers but still returns type errors in this case...
				return b, unmarshalTypeError(v, t)
			}
			return b, fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into int", prefix(v))
		}