Re: [Twisted-Python] The case of the missing Traceback
"Dan" == Dan <tw.1@pyxos.com> writes: Dan> I was playing around with Twisted today and ran into a problem where Dan> Tracebacks aren't emitted on stderr after a deferred callback from a Dan> process called launched by reactor.spawnProcess. The simplified test Dan> case is below. I put "x = y" in the callback function to generate an Dan> exception, y doesn't exist. Uncomment "x = z" right before the Dan> callback and it produces the traceback on stderr just fine.
Hi Dan The callback function raises an exception, which Twisted converts to failure and stores in the deferred. But seeing as there are no errback functions in the deferred *and you leave the reactor running*, the failure just sits there (just as it should). If you do a 'from twisted.python import log' and Change the addCallback line in test() to look like this d.addCallback(response).addErrback(log.err) You'll see the expected NameError just fine. Terry
Awesome! Thanks for helping out a noob Terry! :) At 02:11 PM 11/3/2009, you wrote:
"Dan" == Dan <tw.1@pyxos.com> writes: Dan> I was playing around with Twisted today and ran into a problem where Dan> Tracebacks aren't emitted on stderr after a deferred callback from a Dan> process called launched by reactor.spawnProcess. The simplified test Dan> case is below. I put "x = y" in the callback function to generate an Dan> exception, y doesn't exist. Uncomment "x = z" right before the Dan> callback and it produces the traceback on stderr just fine.
Hi Dan
The callback function raises an exception, which Twisted converts to failure and stores in the deferred. But seeing as there are no errback functions in the deferred *and you leave the reactor running*, the failure just sits there (just as it should). If you do a 'from twisted.python import log' and Change the addCallback line in test() to look like this
d.addCallback(response).addErrback(log.err)
You'll see the expected NameError just fine.
Terry
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Terry Jones