FloatRangeField/IntegerRangeField with None as a range boundary doesn't round trip in serialization

[Алексей]

1. FloatRangeField db data == None
2. ./manage dumpdata
3. ./manage loaddata

Conversion problem. accept string u'None' to float type

Traceback:

  File "/local/lib/python2.7/site-packages/django/db/models/fields/__init__.py", line 1803, in to_python
    params={'value': value},

Decision:

    def to_python(self, value):
        if value == u'None':
            return None
        elif value is None:
            return value
        try:
            return float(value)
        except (TypeError, ValueError):
            raise exceptions.ValidationError(
                self.error_messages['invalid'],
                code='invalid',
                params={'value': value},
            )

And IntegerField too

Source data dump example:

<field name="rate" type="FloatRangeField">{"upper": "None", "lower": "1.45", "bounds": "[)"}</field>

[Tim Graham]

I tried to reproduce with the attached test but it works fine. Could you provide a failing test?

[Алексей]

Replying to timgraham:

I tried to reproduce with the attached test but it works fine. Could you provide a failing test?

Sorry.
I do not write the test so far.

I did everything manually via console.
You test field DateRange and DateTimeTZRange

But i used FloatRangeField and IntegerRangeField and xml format.
Please try these

[Tim Graham]

I've understood the problem now and attached a test. Not sure if the proposed fix is correct.