There's no urgency at all but a bug report isn't the right place for the discussin, nor is our group's private email. I didn't think that raising the question in the appropriate forum constituted emergency action :-).
One of your messages sounded like you were impatiently waiting to commit your change, and I wondered why that was.
GvR> I don't think the patch is ready yet, see my comment on SF. If GvR> we decide that anything needs to be done in this area I want to GvR> look at it first, so please don't check anything in yet.
Did I miss the consensus on inheriting from Exception? I tried to review the earlier thread, but the early stuff didn't have much on Exception and the later stuff seemed to be about documentation. So it must be buried in the middle if it's there :-).
At any rate, I don't understand why it is helpful for classes to inherit from exception.
There are different views on this, but fact is that we've documented this as a recommendation since class exceptions were first introduced, and I've certainly considered starting to warn about exceptions raised or tested for that are *not* subclasses of Exception. There was some discussion that concluded that it was a useful feature (e.g. because the Exception class defines a standard signature and some standard attributes), and it was even suggested that in the future the traceback could be stored on the exception instance rather than in a separate variable. This would pave the way to deprecating sys.exc_info(). I kind of like that idea, so I am all for striving to enforce this in the future.
I am also curious -- this is off-topic for exceptions -- what the right way to check for a new-style class is? And what other things define Py_TPFLAGS_HEAPTYPE?
There is no way to distinguish a new-style class, because all type objects can be considered new-style classes. The only thing you could do is checking for "not classic-class". The HEAPTYPE flag is set only for new-style classes that are created dynamically; but eventually I expect that the built-in exceptions will be statically declared new-style classes. --Guido van Rossum (home page: http://www.python.org/~guido/)