[Checkins] Re: SVN: Zope3/trunk/src/zope/app/module/ Use normal strings for ModuleManager names

[Philipp von Weitershausen]

Ross Patterson wrote:
> Log message for revision 72386:
>   Use normal strings for ModuleManager names
>   
>   When unicode strings are used for manager names, interfaces break.  As
>   such, convert unicode values to ascii values on manager registration
>   to solve this problem.

...

>  def setNameOnActivation(manager, event):
>      """Set the module name upon registration activation."""
> -    manager.name = event.object.name
> +    # Convert the name to a normal string to avoid problems with
> +    # unicode module names
> +    manager.name = str(event.object.name)

Using str(some_unicode) isn't exactly a safe conversion to ASCII. In 
fact, str(some_unicode) is one of the most magical things in Python 
because it's installation dependent (because of the most evil 
sys.setdefaultencoding thing). I don't understand the context of this 
code completely, but if event.object.name can be any kind of unicode and 
manager.name can only be ASCII, the only way to be completely safe is to 
do one of the following:

* explicitly mention the 'ascii' output encoding. If you do that, you 
will want to replace or ignore non-ASCII characters in the unicode 
string, like

   >>> event.object.name.encode('ascii', errors='ignore').

This transformation is obviously lossy.

* use an ASCII-only encoding such as UTF-7 or Quoted Printable. This 
isn't lossy but pretty wordy and sometimes ugly.


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