mappers aren't cleared correctly, seems like leaking references

[Former user]

We're running our application in tests and repeatedly setup and tear down databases.

Currently (trunk in r4115) sqlalchemy.orm.clear_mappers() does not necessarily clear all mappers. It seems that somewhere in SQLAlchemy references to those mappers are leaking and the weak ref dictionary never gets cleared.

We're relatively sure that our application doesn't hold any references to the mappers anymore.

[Former user]

I'd like to subscribe myself as cc ([e-mail]) but can't find a way to do that. If someone could (please) put me on CC.

[Mike Bayer]

we have three pretty strong unit tests for this over at http://www.sqlalchemy.org/trac/browser/sqlalchemy/trunk/test/orm/memusage.py , as well as some other folks who complain loudly whenever this problem arises, so unless you can provide a test case illustrating clear_mappers() failing we cant really go further with this. make sure you call gc.collect().