[Andrew MacIntyre commenting on Raymond H's changes from "if x" to "if x is not None"]
You have in fact changed the semantics of this test with your change.
In the case where file = '', the original would fall through to the elif, whereas with your change it won't.
The question is whether that's an important change or not. Raymond has changed the semantics in every case where he made this particular change. Usually that's fine. Occasionally it's not.
It concerns me that your extensive changes have introduced some unexpected traps which won't be sprung until 2.3 is released.
Me too. I think 99% of the changes were "right", but without looking at actual use cases much more we won't know where the 1% mistakes are.
I think it's okay to do this (because of the 99%) but we should be aware that we may be breaking some code and willing to revert the decision in some cases. I'm not sure how we can test this enough before 2.3 is released -- surely the alphas won't shake out enough.
--Guido van Rossum (home page: http://www.python.org/%7Eguido/)