Add some checks for the optional fields of ModifyForm

Add some checks for the optional fields of ModifyForm

[Thomas.J.Waldmann, 2013-07-23 15:18:59]

https://codereview.appspot.com/11715043/diff/1/MoinMoin/items/__init__.py
File MoinMoin/items/__init__.py (right):

https://codereview.appspot.com/11715043/diff/1/MoinMoin/items/__init__.py#new...
MoinMoin/items/__init__.py:446:
meta.update(item.meta_text_to_dict(self['extra_meta_text'].value))
what happens without that check?

what values have are present in that case for:

self['extra_meta_text'].value
self['extra_meta_text']

[spy, 2013-07-24 21:11:43]

Replied

https://codereview.appspot.com/11715043/diff/1/MoinMoin/items/__init__.py
File MoinMoin/items/__init__.py (right):

https://codereview.appspot.com/11715043/diff/1/MoinMoin/items/__init__.py#new...
MoinMoin/items/__init__.py:446:
meta.update(item.meta_text_to_dict(self['extra_meta_text'].value))
On 2013/07/23 15:18:59, Thomas.J.Waldmann wrote:
> what happens without that check?
> 
> what values have are present in that case for:
> 
> self['extra_meta_text'].value
> self['extra_meta_text']

Without that check in case when the 'extra_meta_text' field wasn't set up (for
example when the 'extra_meta_text' wasn't sent with the POST request) it raises
an exception in item.meta_text_to_dict(self['extra_meta_text'].value). The value
is None and it is used in json deserialization.

This check is useful for the +addcomment view implementation, because there is
no 'extra_meta_text' form field to be sent to this view. We can reuse the
existing _dump method if we check the 'extra_meta_text' field was set up
correctly.


Here is the code snippet from flatland's scalars.py:

class Scalar(Element):
    ...
    def __nonzero__(self):
        return True if self.u and self.value else False
    ...

If the field was not set up:
self['extra_meta_text'].value is equal to None
self['extra_meta_text'] is equal to False

[Thomas.J.Waldmann, 2013-07-26 12:02:17]

looks ok

https://codereview.appspot.com/11715043/diff/1/MoinMoin/items/__init__.py
File MoinMoin/items/__init__.py (right):

https://codereview.appspot.com/11715043/diff/1/MoinMoin/items/__init__.py#new...
MoinMoin/items/__init__.py:446:
meta.update(item.meta_text_to_dict(self['extra_meta_text'].value))
ok.