Ipython deep_reload Exception when importing from sqlalchemy

Question

I am working on several modules of my python library, doing most of the testing through IPython.

Anytime I attempt to reload (deep_reload) a module that uses sqlalchemy, the reload throws an Exception and fails to reload the module (I must start a new kernel and re-import). More specifically, any module that imports my sqlalchemy declarative models.

The traceback is quite long, so I will summarize for now, and provide more if requested.

Before the Exception, StdOUT reads (this is only the bottom portion):

Reloading pysqlite2
Reloading sqlalchemy.dialects.sqlite.sqlite3
Reloading sqlite3
Reloading sqlite3.dbapi2
Reloading sqlite3.datetime
Reloading sqlite3.time
Reloading sqlite3._sqlite3
Reloading _sqlite3

Then the exception is thrown, and here is the most recent entry of the traceback:

\pydir\lib\site-packages\sqlalchemy-0.7.9-py2.7.egg\sqlalchemy\util\_collections.pyc in __setitem__(self, object, value)
    697         if oid not in self._weakrefs:
    698             self._weakrefs[oid] = self._ref(object)
--> 699         weakref.WeakKeyDictionary.__setitem__(self, object, value)
    700 
    701     def __delitem__(self, object):

TypeError: unbound method __setitem__() must be called with WeakKeyDictionary instance as first argument (got WeakIdentityMapping instance instead)

Edit: Problem Update

When calling reload, I started adding exclusions based on the module on the top of the traceback stack ('_sqlite3' in the example above).

What I found was that I kept getting the same Error, only it would come from a new module ('pysqlite2', 'sqlite3'). And in each case, there was always SqlAlchemy higher up on the traceback, more specifically, 'sqlalchemy.orm.mapper'.

When defining my model orm classes, I was defining my orm classes and adding them to the session directly from the module on import. The solution was to wrap these few lines in a function that should not be executed on import. Seems to fix.

I think this was just a case of some lazy coding finally catching up with me.

minrk · Accepted Answer · 2013-06-08 00:30:47Z

1

You might add sqlite3 (or pysqlite2) to deep reload's exclusions:

dreload(mymod, exclude=['sys', 'os.path', '__builtin__', '__main__', 'sqlite3'])

etc.

answered Jun 8, 2013 at 0:30

minrk

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2 Comments

minrk Over a year ago

Why would you need sqlite3 to be reloaded?

user2097818 Over a year ago

I mistook the exact intent of your suggestion, and trying your suggestion led me to a solution (but not an answer).

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