Thomas HERVE therve at free.fr wrote:

...

def iterfail(err, i): print " %i failed" % i

The problem is here. You add an errback to your defer, but you stop the error propagation by not returning err. Either do 'return err' or not 'addErrback(iterfail)'.

Thomas, thanks for the response. I thought that might be it, but no avail. If I 'return err' in iterfail, I get: in testdlist deferred will fail in 2s deferred will succeed in 2s 0 failed failed: testdlist Unhandled error in Deferred: Traceback (most recent call last): Failure: : True 1 succeeded If I instead comment out 'addErrback(iterfail,i)', I get: in testdlist deferred will fail in 2s deferred will succeed in 2s failed: testdlist Unhandled error in Deferred: Traceback (most recent call last): Failure: : True 1 succeeded I don't know why the error is unhandled in either case -- the DeferredList has an errback set. (If I raise a new error in iterfail, the same result occurs, naturally). It also doesn't seem to matter whether I add 'fireOnOneErrBack' to the DeferredList constructor or not. Any ideas? Does this code behave differently on your machine? Thanks, Lenny __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com