[Buildbot-devel] Issue with master 0.8.8

[Dustin J. Mitchell]

On Mon, May 5, 2014 at 6:49 AM, Francesco Di Mizio
<francescodimizio at gmail.com> wrote:
> In the beginning I was on Twisted 11.1.0. Having had the same guess as you,
> I upgraded to 12.0 but the issue is still there.

Well, Twisted's weak point is its tracebacks, so it's pretty hard to
tell exactly what's wrong from what you've attached.  It looks like
something, somewhere, is calling defer.returnValue(xx) where xx is
itself a Deferred.  But you figured that out in the OP.  I can't see
that happening in any of the related code, though, and it's something
I would expect unit tests to uncover.  I've never seen this error
before.

Is any of the Buildbot or Twisted code modified from upstream?  Can
you verify that to be sure?

If not, please try adding a 'traceback.print_stack()' call to
defer.returnValue, conditioned on its argument being an instance of
Deferred.  That should show where the offending call is.

Dustin