On 04:33 pm, benjamin.r...@gs.com wrote:
>Am currently trying to upgrade to twisted-8.2.0. For some reason,
>twisted-8.2.0 thinks my deferred below was gc'd with an unhandled
>error,
>and tells me about it upon reactor exit. With
>python-2.4.2/twisted-2.1.0, no issues. With
>python-2.6.1/twisted-8.2.0,
>I see these issues. Any ideas why? Thanks.
A second Deferred is created during getProcessOutput to track the ending
of the process as distinct from the end of its output. You have to
catch that exception as well if you don't want any exceptions logged.
Arguably, this is a bug, since it changes the behavior and complicates
error handling; if you think so, feel free to file a ticket on the
tracker. I just learned about this behavior myself, in the process of
tracking down your question :).
This behavior was changed in:
http://twistedmatrix.com/trac/changeset/24810
as part of a fix for:
http://twistedmatrix.com/trac/ticket/3239
and that took place after 8.1 but before 8.2. In the meanwhile, you
could upgrade to 8.2 before going to 8.2 to avoid this issue; going from
8.1 to 8.2 should be significantly easier than going from 2.1 to 8.1 ;).
If you'd still like to upgrade all the way, here's a "correct" version
of your program (with spurious imports removed), according to the
behavior in 8.2.0:
#!/usr/bin/env python
from twisted.internet import reactor
from twisted.internet.utils import getProcessOutput
def foo():
d = getProcessOutput('/some/non/existent/program')
def cb(result):
print 'cb: %s' % (result)
def eb(failure):
failure.trap(IOError)
def endedException(ended):
print 'really, caught it!'
failure.value.processEnded.addErrback(endedException)
print 'eb caught the failure!'
d.addCallback(cb)
d.addErrback(eb)
def stopit():
print 'Stopping reactor.'
reactor.stop()
print 'Stopped.'
reactor.callWhenRunning(foo)
reactor.callLater(1.0, stopit)
reactor.run()
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