DecimalField does not correctly set default value

[Moof]

DecimalField's default argument appears to set the field to a unicode rather than a Decimal instance, this then makes calculations involving Decimals not work.

I've attached a small models.py file that can be used to check the behaviour, including expected results and the actual ones.

There's a smallish bug that Decimal("0.00") doesn't retain its precision on loading, but this may be a python bug.

[Moof]

Attached: A patch to fix the strings_only behaviour of django.utils.encoding.force_unicode() which seems to be the cause of the problem, as it checks for certain types and misses out Decimal.

This fixes the default being returned as a unicode rather than a Decimal.

However, I can't seem to find an obvious place in the test suite to add these tests.

[Moof]

Fixes force_unicode to take Decimal values into account

[Moof]

Failing tests for Decimal

[Moof]

Removed the precision tests. That should be in another ticket, and needs a fuller discussion.
This ticket and patch is merely for the default value problem.

[Ramiro Morales]

Duplicate of #5903 that included a similar patch and adds a regression test.