[Zope] Should lambda method be legal or not?

[Dieter Maurer]

Terry Hancock writes:
 > I ran across this limitation in part of a product design.
 > ...
 > class MyFolder(OFS.Folder.Folder):
 > ...
 > def manage_addMyFolder(self, id, title='', REQUEST=None):
 >   ...
 >     ob.mymethod = lambda: 2
 >   ...
 > ....
 > Until I restart.
 > 
 > Then, an attempt to view the contents of the folder containing
 > MyFolder (i.e. not MyFolder itself, but its parent), yields the
 > following traceback:
 > 
 > Failed to import class from module __main__ 
 >   File /usr/local/narya/z2.5.1/lib/python/ZODB/Connection.py, line 472,
 > in setstate
 > SystemError: (see above)
ZODB content is the serialized (pickled) state of the objects.

For security reasons, pickle refuses to serialize code. Instead,
it just stores the module and name of code/function objects.
When loaded later again, the name is imported from the remembered
module. As you can see, there are a number of (well documented ;-))
restrictions: functions/classes must be named and defined in the
global namespace of the defining module.



Dieter