[Python-Dev] SF #1462485 - StopIteration raised in body of 'with' statement suppressed

Delaney, Timothy (Tim) tdelaney at avaya.com
Sun Apr 2 23:47:22 CEST 2006

Discovered this while playing around with the 2.5 released end of last


def gen():
    print '__enter__'
    print '__exit__'

with gen():
    raise StopIteration('body')

I would expect to get the StopIteration exception raised. Instead it's
suppressed by the @contextmanager decorator.

I think we should only suppress the exception if it's *not* the
exception passed into gen.throw() i.e. it's raised by the generator.
Does this sound like the correct behaviour? I've attached tests and a
fix implementing this to the bug report.

I can't confirm right now (at work, need to install 2.5) but I'm also
wondering what will happen if KeyboardInterrupt or SystemExit is raised
from inside the generator when it's being closed via __exit__. I suspect
a RuntimeError will be raised, whereas I think these should pass

Tim Delaney

More information about the Python-Dev mailing list