Fixed #20440 -- Ensured CharField's max_length/min_length are integers

AUTHORS

@@ -164,6 +164,7 @@ answer newbie questions, and generally made Django that much better:
     Leah Culver <leah.culver@gmail.com>
     Raúl Cumplido <raulcumplido@gmail.com>
     flavio.curella@gmail.com
+    Tome Cvitan <tome@cvitan.com>
     John D'Agostino <john.dagostino@gmail.com>
     dackze+django@gmail.com
     Jim Dalton <jim.dalton@gmail.com>

django/forms/fields.py

@@ -198,14 +198,15 @@ class Field(object):
         result.validators = self.validators[:]
         return result
 
+
 class CharField(Field):
     def __init__(self, max_length=None, min_length=None, *args, **kwargs):
         self.max_length, self.min_length = max_length, min_length
         super(CharField, self).__init__(*args, **kwargs)
         if min_length is not None:
-            self.validators.append(validators.MinLengthValidator(min_length))
+            self.validators.append(validators.MinLengthValidator(int(min_length)))
         if max_length is not None:
-            self.validators.append(validators.MaxLengthValidator(max_length))
+            self.validators.append(validators.MaxLengthValidator(int(max_length)))
 
     def to_python(self, value):
         "Returns a Unicode object."
@@ -220,6 +221,7 @@ class CharField(Field):
             attrs.update({'maxlength': str(self.max_length)})
         return attrs
 
+
 class IntegerField(Field):
     default_error_messages = {
         'invalid': _('Enter a whole number.'),
@@ -444,6 +446,7 @@ class TimeField(BaseTemporalField):
     def strptime(self, value, format):
         return datetime.datetime.strptime(force_str(value), format).time()
 
+
 class DateTimeField(BaseTemporalField):
     widget = DateTimeInput
     input_formats = formats.get_format_lazy('DATETIME_INPUT_FORMATS')
@@ -482,6 +485,7 @@ class DateTimeField(BaseTemporalField):
     def strptime(self, value, format):
         return datetime.datetime.strptime(force_str(value), format)
 
+
 class RegexField(CharField):
     def __init__(self, regex, max_length=None, min_length=None, error_message=None, *args, **kwargs):
         """
@@ -511,6 +515,7 @@ class RegexField(CharField):
 
     regex = property(_get_regex, _set_regex)
 
+
 class EmailField(CharField):
     widget = EmailInput
     default_validators = [validators.validate_email]
@@ -519,6 +524,7 @@ class EmailField(CharField):
         value = self.to_python(value).strip()
         return super(EmailField, self).clean(value)
 
+
 class FileField(Field):
     widget = ClearableFileInput
     default_error_messages = {
@@ -626,6 +632,7 @@ class ImageField(FileField):
             f.seek(0)
         return f
 
+
 class URLField(CharField):
     widget = URLInput
     default_error_messages = {
@@ -792,6 +799,7 @@ class ChoiceField(Field):
                     return True
         return False
 
+
 class TypedChoiceField(ChoiceField):
     def __init__(self, *args, **kwargs):
         self.coerce = kwargs.pop('coerce', lambda val: val)
@@ -903,6 +911,7 @@ class ComboField(Field):
             value = field.clean(value)
         return value
 
+
 class MultiValueField(Field):
     """
     A Field that aggregates the logic of multiple Fields.
@@ -1047,6 +1056,7 @@ class FilePathField(ChoiceField):
 
         self.widget.choices = self.choices
 
+
 class SplitDateTimeField(MultiValueField):
     widget = SplitDateTimeWidget
     hidden_widget = SplitHiddenDateTimeWidget

tests/forms_tests/tests/test_fields.py

@@ -125,6 +125,15 @@ class FieldsTests(SimpleTestCase):
         self.assertEqual(f.max_length, None)
         self.assertEqual(f.min_length, 10)
 
+    def test_charfield_length_not_int(self):
+        """
+        Ensure that setting min_length or max_length to something that is not a
+        number returns an exception.
+        """
+        self.assertRaises(ValueError, CharField, min_length='a')
+        self.assertRaises(ValueError, CharField, max_length='a')
+        self.assertRaises(ValueError, CharField, 'a')
+
     def test_charfield_widget_attrs(self):
         """
         Ensure that CharField.widget_attrs() always returns a dictionary.