[Zope3-dev] bug setting value to None via edit form

[Steve Alexander]

>>I agree that None may, in some cases, be a legitimate value that does
>>not imply "missing". However, it is convenient in the common case.
>>Therefore to me it makes sense to improve field such that the missing
>>value can be overridden in cases where None is not the missing value.
> 
> 
> Yep...this is the way it's implemented currently (recent change). Fields
> can override missing_value, which is None by default.

It seems that widgets don't use this missing_value, though.

For a start, I think _convert and _unconvert of BrowserWidget should be 
changed to use self.context.missing_value rather than None.

There are other places that should be updated to use field.missing_value 
too.

--
Steve Alexander