Hello! I am running into a very perplexing issue that is very rare, but creeps up and is crashing my app.
The root cause of the issue comes down to the following check returning true: isinstance([], collections.Mapping) Obviously you can get this behavior if you register `list` as a subclass of the Mapping ABC, but I'm not doing that. Because the issue is so rare (but still common enough that I need to address it), it's hard to reproduce in a bench test. What I am going to try is to essentially monkey-patch collections.Mapping.register with a method that dumps a stack trace whenever it's called at the time of initial import so I can get an idea of where this method could *possibly* be getting called with a list as its argument. The annoying thing here is that wherever the bug is happening, the crash happens *way* far away (in a third-party library). I've also determined it as the root cause of two crashes that seem completely unrelated (except that the crash is caused by a list not behaving like a dict shortly after isinstance(obj, collections.Mapping) returns True). These are the libraries I'm using: amqp billiard celery dj-database-url Django django-redis-cache enum34 gunicorn kombu newrelic psycopg2 pyasn1 pytz redis requests rsa six vine voluptuous It's a web application, as you can probably tell. The main reason I ask here is because I'm wondering if anybody has encountered this before and managed to hunt down which of these libraries is doing something naughty? Thanks! Jason -- Jason M. Swails -- https://mail.python.org/mailman/listinfo/python-list
