Question

My design is as follows:

• __main__ references a
• a references b
• b references a
• a is created and then disposed of from __main__

Thus a and b have circular references. However upon del a I would prefer both a and b disposed of.

I see in many places advice to use Context Managers, and specifically the with statement instead of __del__(). However all the examples I see of with start and end in local scope (e.g. of a certain method)

Can this be elegantly performed with with?
What is the alternative?

Answer 1

I recommend either:

• Using weakref – which is sometimes applicable when circular references are involved
• or … just manually disposing of stuff in the order you need – not in __del__ but in an explicit dispose method you call at the right time(s)

In general, when you know you have circular references, relying on automatic __del__ disposal is not a good idea. It’s brittle – even if you manage to make it work in some case, small changes in dependencies can break it again.