Comment 2 for bug 1313793

The approach I was taking was making the relationships not nil maps, but instead empty maps. This approach is complicated when a charm is fetched from the database, which seems to occur in multiple places in the code.

There seems two options to fix this bug.

1 Make maps not nil, but instead empty. Already have code that takes care of reading metadata file in.
  This would likely require one of these
  1. Create a standard way to get the charm back from the database that doesn't directly call the mgo bindings. This would allow the initialization of the maps.
  2. Change the data that's saved in the mongo database. I suspect this may have backward compatibility implications.

2. Change juju to not care if the map is nil. This would probably be the simplest, but it seems less consistent to me.

Could I get an outside opinion on the best route to take this?