Re: [Python-Dev] __exit__ API?
I have a patch for this now -- python.org/sf/1445739. Please review. --Guido On 3/3/06, Guido van Rossum [EMAIL PROTECTED] wrote: A few days ago there were rumbling noises that requiring __exit__ to re-raise the exception (as I amended PEP 343 at the time) could lead to easily-missed bugs in __exit__ handlers. After thinking it over I think I agree and I think I'd like to change the API so that the exception is only ignored if __exit__ returns a true value. The easiest implementation is probably to just let the WITH_CLEANUP opcode do everything. This becomes a rather heavy opcode then but the alternative is to generate very hairy code (like the original patch did, full of ROT 4 choruses). Any objections? I probably won't get to this until Monday. -- --Guido van Rossum (home page: http://www.python.org/~guido/) -- --Guido van Rossum (home page: http://www.python.org/~guido/) ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] __exit__ API?
Guido van Rossum wrote: A few days ago there were rumbling noises that requiring __exit__ to re-raise the exception (as I amended PEP 343 at the time) could lead to easily-missed bugs in __exit__ handlers. After thinking it over I think I agree and I think I'd like to change the API so that the exception is only ignored if __exit__ returns a true value. The easiest implementation is probably to just let the WITH_CLEANUP opcode do everything. This becomes a rather heavy opcode then but the alternative is to generate very hairy code (like the original patch did, full of ROT 4 choruses). Any objections? I probably won't get to this until Monday. Sounds good to me - I believe the majority of explicit __exit__ handlers will be of a try/finally nature rather than try/except, and that situations where the exception is going to be suppressed are better handled using @contextmanager. The solution you propose means that __exit__ methods *can* suppress exceptions if they want to, but their default behaviour will still do the right thing. Cheers, Nick. -- Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia --- http://www.boredomandlaziness.org ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
[Python-Dev] __exit__ API?
A few days ago there were rumbling noises that requiring __exit__ to re-raise the exception (as I amended PEP 343 at the time) could lead to easily-missed bugs in __exit__ handlers. After thinking it over I think I agree and I think I'd like to change the API so that the exception is only ignored if __exit__ returns a true value. The easiest implementation is probably to just let the WITH_CLEANUP opcode do everything. This becomes a rather heavy opcode then but the alternative is to generate very hairy code (like the original patch did, full of ROT 4 choruses). Any objections? I probably won't get to this until Monday. -- --Guido van Rossum (home page: http://www.python.org/~guido/) ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
