For those not on the nosy list, here's the latest post
to http://bugs.python.org/issue6210:
-------------------------------------------------------
It looks like agreement is forming around the
raise ... from None
method. It has been mentioned more than once that having the context
saved on the exception would be a Good Thing, and for further debugging
(or logging or what-have-you) I must agree.
The patch attached now sets __cause__ to True, leaving __context__
unclobbered. The exception printing routine checks to see if __cause__
is True, and if so simply skips the display of either cause or
__context__, but __context__ can still be queried by later code.
One concern raised was that since it is possible to write (even before
this patch)
raise KeyError from NameError
outside of a try block that some would get into the habit of writing
raise KeyError from None
as a way of preemptively suppressing implicit context chaining; I am
happy to report that this is not an issue, since when that exception is
caught and a new exception raised, it is the new exception that controls
the display.
In other words:
>>> >>> try:
... raise ValueError from None
... except:
... raise NameError
...
Traceback (most recent call last):
File "<stdin>", line 2, in <module>
ValueError
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "<stdin>", line 4, in <module>
NameError
_______________________________________________
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
