[Zope3-dev] Re: [Checkins] SVN: zope.app.form/trunk/src/zope/app/form/browser/te FileWidget tries to be smarter about not deleting the currently stored content when the user did not upload a new file.

[Gary Poster]

On Jun 23, 2007, at 6:38 AM, Christian Zagrodnick wrote:

> Log message for revision 76975:
>   FileWidget tries to be smarter about not deleting the currently  
> stored content when the user did not upload a new file.

...

> Modified: zope.app.form/trunk/src/zope/app/form/browser/textwidgets.py
> ===================================================================
> --- zope.app.form/trunk/src/zope/app/form/browser/textwidgets.py	 
> 2007-06-23 10:25:23 UTC (rev 76974)
> +++ zope.app.form/trunk/src/zope/app/form/browser/textwidgets.py	 
> 2007-06-23 10:38:37 UTC (rev 76975)
> @@ -475,6 +475,11 @@
>
>      def _toFieldValue(self, input):
>          if input is None or input == '':
> +            # There was no input. With File-Upload this usually  
> means that the
> +            # value should *not* change. Let's try to get the old  
> value.
> +            content = self.context.context
> +            if self.context.interface.providedBy(content):
> +                return self.context.get(content)
>              return self.context.missing_value
>          try:
>              seek = input.seek

Hey.  This has a couple of bugs, IMO.  It might also be a misfeature,  
but I'm less sure about that.

First, "return self.context.get(content)" assumes that this widget  
will be used on an edit form (not true for us).

Second, "if self.context.interface.providedBy(content):" assumes that  
the schema field is part of an interface (not true for us).

Neither of these are valid assumptions generally for a form field, IMO.

I'm also not sure about the semantics.  Shouldn't this be handled  
more at the form level?  I can see why you want to do this here, but  
it seems pretty gray, and I'm not sure how to solve the bugs in a  
sane and reliable way.

I agree that this is a tricky problem, and it would be nice to solve  
it, but your solution is not correct for a generic form widget.  The  
only suggestion I have ATM is to revert this, unfortunately, but I  
welcome other approaches that solve the issues I raised.

(I'm reverting to zope.app.form 3.4.0b1 for now)

Gary