Let me answer here to Nick's argument on the tracker (made last year, before the patch was committed):
> As with many context managers, a key benefit here is in the priming > effect for readers. In this code: > > try: > # Whatever > except (A, B, C): > pass > > the reader doesn't know that (A, B, C) exceptions will be ignored > until the end. The with statement form makes it clear before you > start reading the code that certain exceptions won't propagate: > > with ignored(A, B, C): > # Whatever The problem with this argument is that it assumes a very specific idiom: i.e. writing long "try" blocks in the purpose of silencing exceptions. I'd like to make the following points: - when catching an exception, the common (and recommended) behaviour is to do something else - not merely silencing it. Silencing is not very common in my experience, except in badly written code - when catching an exception, it is recommended for the "try" block to be as slim as possible - so that you don't catch other unintended exceptions by mistake. This is a point I already made in PEP 3151. Many exception classes (OSError, KeyError, RuntimeError...) are polysemic. The bottom line is that there shouldn't be any long "try" blocks followed by a single "except FooException: pass" clause in well-written code. The presence of such an idiom is a strong code smell. Therefore contextlib.ignore() seems aimed at making it easier to write bad code, not good code. I don't think it should exist in the stdlib. Regards Antoine. _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
