It's missing the case when the whole part is greater than max_digits-decimal_places, which leads to ProgrammingError? raised when you add such a number
Corrected version:
class IsValidFloat:
def __init__(self, max_digits, decimal_places):
self.max_digits, self.decimal_places = max_digits, decimal_places
def __call__(self, field_data, all_data):
data = str(field_data)
try:
float(data)
except ValueError:
raise ValidationError, _("Please enter a valid decimal number.")
if len(data) > (self.max_digits + 1):
raise ValidationError, ngettext( "Please enter a valid decimal number with at most %s total digit.",
"Please enter a valid decimal number with at most %s total digits.", self.max_digits) % self.max_digits
if (not '.' in data and len(data) > (self.max_digits - self.decimal_places)) or ('.' in data and len(data.split('.')[1]) == 0 and len(data) > (self.max_digits - self.decimal_places + 1)):
raise ValidationError, ngettext( "Please enter a valid decimal number with a whole part of at most %s digit.",
"Please enter a valid decimal number with a whole part of at most %s digits.", str(int(self.max_digits)-int(self.decimal_places))) % str(int(self.max_digits)-int(self.decimal_places))
if '.' in data and len(data.split('.')[1]) > self.decimal_places:
raise ValidationError, ngettext("Please enter a valid decimal number with at most %s decimal place.",
"Please enter a valid decimal number with at most %s decimal places.", self.decimal_places) % self.decimal_places
