I am Python 2.5. I've pasted a working code example (can be run in the interactive console).
Also raised S/O question: http://stackoverflow.com/questions/15765659/assigning-empty-list-to-stringlistproperty-with-default-value-results-in-entity?noredirect=1#comment22409783_15765659
Is this expected? If so:
1) please show where this is explained in the GAE documentation (or update docs to reflect).
2) please show a pattern for a db.Model that defaults to a populated list for some property at the moment of creation, but still allows us to assign the empty list (or None) at a later moment.
Otherwise, it's a bug :-) For me it's critical because I use list properties to manage user email subscriptions.. so users are unsubscribing from everything and finding that the they are actually getting subscribed to EVERYTHING.
from google.appengine.ext import db
my_string_list = db.StringListProperty(default=['foo', 'bar'])
instance = TestClass()
instance.my_string_list = 
instance2 = db.get(instance.key())
#expected , got ['foo', 'bar'] ???