ModelChoiceField validation throws OverflowError

[bstpierre]

I have a form that uses ModelChoiceField.

My unit tests throw strings and very large integers at the ModelChoiceField field. I expect the clean() method to trap any bad input so that I don't have to. Sending strings ("abcd") or very large integers (01234567890123456789012345678901234567890123456789) causes exceptions.

To reproduce, I'm attaching a minimal django project as a tarball.

I'm also attaching a patch that fixes these two cases. Not sure if there's a better fix that would be preferred.

Using svn 9692.

Test case:

1. tar zxvf overflow.tgz
2. ./manage.py syncdb --noinput [db is sqlite3 in /tmp/deleteme.sqlite3]
3. ./manage.py runserver
4. browse to ​http://127.0.0.1:8000/overflow/?blog=1234567890123456789012345678901234567890123456789, expect to see "invalid" but instead get Django error page (OverflowError)
5. browse to ​http://127.0.0.1:8000/overflow/?blog=foo, expect to see "invalid" but instead get Django error page (ValueError)

[bstpierre]

minimal project to reproduce error

[bstpierre]

Index: django/forms/models.py
===================================================================
--- django/forms/models.py (revision 9692)
+++ django/forms/models.py (working copy)
@@ -705,6 +705,12 @@

value = self.queryset.get({key: value})

except self.queryset.model.DoesNotExist:

raise ValidationError(self.error_messagesinvalid_choice)

+ except ValueError:
+ # Raised when string is passed.
+ raise ValidationError(self.error_messagesinvalid_choice)
+ except OverflowError:
+ # Raised when ridiculously large integer is passed.
+ raise ValidationError(self.error_messagesinvalid_choice)

return value

class ModelMultipleChoiceField(ModelChoiceField):

[bstpierre]

Sorry about that, let me attach it as a file...

[bstpierre]

proposed patch

[Karen Tracey]

This is really the same problem as is noted in #9209. The last patch attached there proposes using a bare except since it's quite hard (if not impossible) to figure out all the different exceptions that may be caused by incorrect user input in this case. That patch also fixes up ModelMultipleChoiceFields, which have the same issue with bad user input.