On 2/28/07, James Y Knight <[EMAIL PROTECTED]> wrote: > It seems to me that a stack trace should always be attached to an > exception object at creation time of the exception, and never at any > other time. Then, if someone pre-creates an exception object, they > get consistent and easily explainable behavior (the traceback to the > creation point). The traceback won't necessarily be *useful*, but > presumably someone pre-creating an exception object did so to save > run-time, and creating the traceback is generally very expensive, so > doing that only once, too, seems like a win to me.
The only example I found in about 2 dozen packages where the exception was precreated was in pyparsing. I don't know the reason why it was done that way, but I'm certain it wasn't for performance. The exception is created as part of the format definition. In that case if the traceback is important then it's important to know which code was attempting the parse. The format definition was probably certainly done at module import time. In any case, reraising the same exception instance is a rare construct in current Python code. PJE had never seen it before. It's hard to get a good intuition from zero data points. :) _______________________________________________ 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
