[Python-Dev] Exceptions *must*? be old-style classes?

["Martin v. Löwis"]

Simon Percivall wrote:
> What would happen if Exception were made a new-style class, enforce
> inheritance from Exception for all new-style exceptions, and allow all
> old-style exceptions as before.

string exceptions would break.

In addition, code may break which assumes that exceptions are classic
instances, e.g. that they are picklable, have an __dict__, and so on.

 > Am I wrong in assuming that only the
> most esoteric exceptions inheriting from Exception would break by
> Exception becoming new-style?

Yes, I think so.

Regards,
Martin