Model.validate raises TypeError on NULL for DateField, DateTimeField, and TimeField

[RahmCoff@…]

When you have a model with any of the date/time fields, it throws a TypeError. For example:

class TestModel(models.Model):
    test_date = models.DateField()
    test_date_time = models.DateTimeField()
    test_time = models.TimeField()

TestModel().validate()

Traceback (most recent call last):
  File "<console>", line 1, in ?
  File "django/db/models/base.py", line 230, in validate
    setattr(self, f.attname, f.to_python(getattr(self, f.attname, f.get_default())))
  File "django/db/models/fields/__init__.py", line 435, in to_python
    validators.isValidANSIDate(value, None)
  File "django/core/validators.py", line 146, in isValidANSIDate
    if not ansi_date_re.search(field_data):
TypeError: expected string or buffer

Similar errors appear with DateTime and Time.

[Russell Keith-Magee]

Behaviour is as designed. TestModel() is a new, empty instance. The fields test_date, test_date_time and test_time don't yet have values. As a result, validation fails, as the fields do not have values that are a string or a DateTime instance.

[RahmCoff@…]

I'm sorry, I guess I didn't explain myself properly. validate() does not return a dict of problems, it throws a TypeError. Changing models.DateField() to models.DateField(null=True, blank=True) doesn't help either.

[RahmCoff@…]

Diff for your viewing pleasure:

Index: django/db/models/fields/__init__.py
===================================================================
--- django/db/models/fields/__init__.py (revision 4236)
+++ django/db/models/fields/__init__.py (working copy)
@@ -428,6 +428,8 @@
         Field.__init__(self, verbose_name, name, **kwargs)
 
     def to_python(self, value):
+        if value is None:
+            return value
         if isinstance(value, datetime.datetime):
             return value.date()
         if isinstance(value, datetime.date):
@@ -488,6 +490,8 @@
 
 class DateTimeField(DateField):
     def to_python(self, value):
+        if value is None: 
+            return value
         if isinstance(value, datetime.datetime):
             return value
         if isinstance(value, datetime.date):

[jimmy@…]

I experiencing the same problem.

[Chris Beaven]

It's obviously a bug. Probably could do with a regression test

[floguy@…]

Updated patch to revision 4427 and added unit tests.

[floguy@…]

I have updated the patch which was posted here to revision 4427. Also, I have taken that test case which was given in the original post and converted it to a unit test which is also included in the patch. As long as this patch applies cleanly for others, it should be ready for production now. All regression tests pass as well.

[Jacob]

(In [4592]) Fixed #3172: Model.validate() no longer raises TypeErrors on empty Date*Fields. Thanks, floguy@….