[Python-Dev] Deprecating string exceptions

[Martin v. Loewis]

Guido van Rossum <guido@python.org> writes:

> > http://python.org/sf/518846 reports that new-style classes cannot be
> > used as exceptions. I think it is desirable that this is fixed, but I
> > also believe that it conflicts with string exceptions.
> 
> Can you explain this conflict?  Couldn't this be worked around by
> making an exception for strings?

Currently, if you write

try:
  raise "Hallo"
except str:
  pass

the exception will pass through. If "new-style classes" (aka types)
are allowed, then the string /should/ be caught.

> I think string exceptions are used enough that we should deprecate
> them on a slower schedule.

If you follow Paul's rationale (exceptions should inherit from
Exception), then the bug report could be closed, and no action would
be needed until Exception becomes a type.

Regards,
Martin