I am beginning to think that there are serious problems with attaching the traceback to the exception; I really don't like the answer that pre-creating an exception is unpythonic in Py3k.
On 2/28/07, Jean-Paul Calderone <[EMAIL PROTECTED]> wrote: > On Wed, 28 Feb 2007 18:29:11 -0700, Adam Olsen <[EMAIL PROTECTED]> wrote: > >On 2/28/07, Greg Ewing <[EMAIL PROTECTED]> wrote: > >> Adam Olsen wrote: > >> > >> > It sounds like we should always copy the exception given to raise, > >> > >> I don't like that either, for all the reasons that > >> make it infeasible to copy an arbitrary object in a > >> general way. > > > >Exceptions aren't arbitrary objects though. The requirement that they > >inherit from BaseException is specifically to create a common > >interface. Copying would be an extension of that interface. > > > >I believe calling copy.copy() would be sufficient. > > > > Does copying every exception given to `raise' solve the problem being > discussed here? > > Consider the current Python behavior: no copying is performed, most code > instantiates a new exception instance for each raise statement, some code > creates a single exception and re-raises it repeatedly. > > And the new behavior? Every raise statement copies an exception instance, > some code will create a new exception instance for each raise statement, > some code will create a single exception and re-raise it repeatedly. > > That doesn't sound like an improvement to me. Normal code will be more > wasteful. Code which the author has gone out of his way to tune will be > as wasteful as /average/ code currently is, and more wasteful than tuned > code now is. > > Plus you now have the added mental burden of keeping track of which objects > are copies of what (and if you throw in the refcount=1 optimization, then > this burden is increased - was something accidentally relying on copying or > non-copying? Did a debugger grab a reference to the exception object, thus > changing the programs behavior? Did a third-party hang on to an exception > for longer than the raising code expected? etc). > > Jean-Paul > _______________________________________________ > 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/guido%40python.org > -- --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
