[Twisted-Python] chainDeferred does not pass result

Christopher Armstrong radix at twistedmatrix.com
Thu May 29 10:29:27 EDT 2008

On Thu, May 29, 2008 at 10:06 AM, "Lutz Pälike" <lutz_p at gmx.net> wrote:
> I was trying to chain two Deferreds together but there is a problem with chainDeferred().
> If i add  Deferred object b in the middle of the call chain of  object a, the result is correctly passed on to the branched call chain of b but the call chain of a is broken because b.callback() does not return a result.
> Am i missing something or is this a bug ?
> The example below illustrates the problem. If you uncomment the line
> deferred_a.chainDeferred(deferred_b)
> you should see
> result:  None

It's not a bug, it's how chainDeferred is meant to work.

Christopher Armstrong
International Man of Twistery

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