[Zope-CMF] Re: Effective Date inconsistencies

[Laurence Rowe]

Maurits van Rees wrote:
> Wichert Akkerman, on 2007-06-23:
>> Previously Maurits van Rees wrote:
>>> Wichert Akkerman, on 2007-06-23:
>>>> I misread the interface; that only specified what should happen if no
>>>> timezone is given. The interface says that the method should return a
>>>> string which corresponds to the time or None if no time is set. So the
>>>> behaviour you see is expected and can not be changed without breaking
>>>> backwards compatibility.
>>> Where are you reading that?  Products.CMFCore.interfaces.IDublinCore
>>> only has some comments:
>> Look at what interfaces/__init__.py does: it imports the interface from
>> _content.py. DublinCore.py is a bbb stub.
> 
> Ah, there. :)
> 
> But that interface says:
> 
>   Result is a string, formatted 'YYYY-MM-DD H24:MN:SS TZ', or None.
> 
> I parse that as:
> 
>   Result is (a string, formatted 'YYYY-MM-DD H24:MN:SS TZ',) or None.
> 
> and not as:
> 
>   Result is a string, formatted ('YYYY-MM-DD H24:MN:SS TZ' or 'None').
> 
> Put simpler, I parse that as:
> 
>   Result is a string or None.
> 
> which seems just what Limi wants.
> 
> In zope.dublincore that I quoted, the idea was that the result is a
> formatted string or an empty string.  In other words, there it is
> always a string, though it may be empty.  At least the boolean values
> of the empty string and None are the same: False, as opposed to
> bool('None') which is True.
> 
> I am not sure where I am going with this line of reasoning :) but it
> seems to me the zope.dublincore interface is slightly preferable,
> always returning a string and still giving a good boolean value.
> 

How about changing EffectiveDate to:

         return ed and ed.toZone(zone).ISO() or ''

from the existing (as pointed out by Charlie):

         return ed and ed.toZone(zone).ISO() or 'None'

It would seem the least risky fix. (I'm not sure it's strictly a bug but 
it struck me as completely brain dead when I was caught out by it).

Laurence