I've worked around the problem by moving the tzinfo behavior into a helper object and delegating all the calls, but it's not as tidy as this original solution, so I'd still appreciate some advice:
1) What did I do wrong? Is there some fundamental design patten in python that says you have to do a certain thing when you subclass in order to expose an interface? What is that thing I didn't do? 2) Why is this code OK in development, but not in production? The code that's throwing the exception (that call to __new__ in __init__.py) doesn't even exist in the development python code. 3) What's up with this changing during "system maintenance" and not as part of an SDK update? I can't be the only one who's code unexpectedly stopped working. -Joshua On May 4, 2011, at 10:10 AM, Joshua Smith wrote: > I have some code that has been working for a really long time, that suddenly > started throwing an exception. > > In my app, I have to keep some different time zones around, so I have a Model > that carries the interesting stuff, and it acts as a tzinfo for convenience. > > Like this: > > class RegionModel(db.Model, datetime.tzinfo): > name = db.StringProperty() > gmtOffset = db.IntegerProperty() > tzName = db.StringProperty() > tzDstName = db.StringProperty() > > def utcoffset(self, dt): > return datetime.timedelta(hours=self.gmtOffset) + self.dst(dt) > > etc. > > This has been working fine, but starting at 5/3 at 15:50, I'm getting this > exception: > > 2011-05-03 15:50:27.934 > datetime.tzinfo.__new__(RegionModel) is not safe, use object.__new__() > Traceback (most recent call last): > File > "/base/python_runtime/python_lib/versions/1/google/appengine/ext/webapp/__init__.py", > line 698, in __call__ > handler.get(*groups) > File "/base/data/home/apps/towngovernment/37.349853758361595417/main.py", > line 1691, in get > default = board.anyTown().nextLikelyMeetingTime() > File "/base/data/home/apps/towngovernment/37.349853758361595417/main.py", > line 248, in nextLikelyMeetingTime > t = self.nextLegalMeetingTime() > File "/base/data/home/apps/towngovernment/37.349853758361595417/main.py", > line 242, in nextLegalMeetingTime > now = self.region.currentLocalTime() > File > "/base/python_runtime/python_lib/versions/1/google/appengine/ext/db/__init__.py", > line 3491, in __get__ > instance = get(reference_id) > File > "/base/python_runtime/python_lib/versions/1/google/appengine/ext/db/__init__.py", > line 1471, in get > return get_async(keys, **kwargs).get_result() > File > "/base/python_runtime/python_lib/versions/1/google/appengine/datastore/datastore_rpc.py", > line 644, in get_result > results = self.__extra_hook(results) > File > "/base/python_runtime/python_lib/versions/1/google/appengine/api/datastore.py", > line 488, in local_extra_hook > return extra_hook(result) > File > "/base/python_runtime/python_lib/versions/1/google/appengine/ext/db/__init__.py", > line 1441, in extra_hook > model = cls1.from_entity(entity) > File > "/base/python_runtime/python_lib/versions/1/google/appengine/ext/db/__init__.py", > line 1370, in from_entity > instance = cls(None, _from_entity=True, **entity_values) > File > "/base/python_runtime/python_lib/versions/1/google/appengine/ext/db/__init__.py", > line 767, in __new__ > return super(Model, cls).__new__(cls) > TypeError: datetime.tzinfo.__new__(RegionModel) is not safe, use > object.__new__() > > It appears that I suddenly need to start defining __init__ or __new__ or > something, but I'm out of my depth to know how to fix this. Also, everything > still works just fine in the development environment. It's only broken in > production. > > Can one of you python gurus please tell me how to override __init__ or > __new__ or whatever so that I don't break the db.Model stuff, and it allows > me to extend tzinfo with this class as I have been doing? > > This is urgent! > > Thanks. > > -Joshua > > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" group. > To post to this group, send email to google-appengine@googlegroups.com. > To unsubscribe from this group, send email to > google-appengine+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/google-appengine?hl=en. -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com. To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
