2009/6/14 Raymond Hettinger <python@rcn.com>:
FWIW, I think resurrecting contextlib.nested() is a bad idea. Part of the justification for the new with-statement syntax was that nested() doesn't have a way to finalize the constructors if one of them fails. It is a pitfall for the unwary. And now that we have the new with-statement syntax, it mostly just represents a second-way-to-do-it (a second way that has has the stated pitfall).
I don't consider changing a DeprecationWarning to a PendingDeprecationWarning "resurrecting" its target. Fully deprecating a feature in the same version that we add its replacement will just make more difficulties for cross-version libraries. ....
I suggest a PEP for 2.7 and 3.2 for building-out the with-statement to support tuples of context managers (perhaps modeled after the syntax for except-statements which allows either individual exceptions or tuples of exceptions).
I think the question of extending the syntax later is orthogonal to the issue of the DeprecationWarning. -- Regards, Benjamin