[Python-Dev] breaking an exception chain (original) (raw)

Benjamin Peterson benjamin at python.org
Tue Aug 3 19:22:30 CEST 2010

2010/8/3 R. David Murray <rdmurray at bitdance.com>:

Working with Catherine on an argparse bug, we ran into a test that was apparently failing by raising a SystemExit, when the test harness was supposed to be catching that error.  It took us a bit to realize that there wasn't really a SystemExit error, but that what we were seeing was the SystemExit chained to the exception the test harness was purposfully raising after catching the SystemExit.  In Python2, only the second, intentionally raised exception would be printed by unittest.  In Python3, the "main error" printed by unittest is the SystemExit, and the error raised by the test harness appears after the "while processing the above error" sentence.  Needless to say, this is a bit confusing.

So I thought I'd break the exception chain before raising the error the test harness really wants to raise.  However, I can't figure out any way to do that.  Am I missing something, or this a missing feature?

Missing feature; there's a bug report somewhere.

-- Regards, Benjamin

More information about the Python-Dev mailing list