I think an asdict() method is not necessary. Instanciating a dict from os.environ is enough: 

>>> import os
>>> os.environ
environ({'SHELL': '/bin/bash', ...})
>>> dict(os.environ)
{'SHELL': '/bin/bash', ...})

With 'dict()', it's obvious there is no side effect.


I think os._Environ should not be pickable too because there is an ambiguity too when it will be unpicked: should we set the unpickled data to a basic dict (or another _Environ instance) or to the environment variables?

It seems there are more maintainers in favour of the removal. Removing the copy is a breaking change so it should be done on several releases.

Are you interested by a PR which adds DeprecationWarning when copy.copy(os.environ) or os.environ.copy() are called? It seems to be the first step to implement.