[Buildbot-devel] exception after checkout in buildbot 0.3.4

[Brian Warner]

> I got the exception pasted below twice recently. Seems to happen after the
> build bot has been up for a few days. The build slave is on the same
> physical host, it's a vmware machine.

Hmm, it looks like 'current' was None. I think that means the progress record
was updated before the step actually finished. I'd bet some of the
failed-build code paths have problems: probably one of them doesn't mark the
step as having finished, but calls the buildFinished function anyway. If the
step doesn't finish, progress.stopTime isn't set, so the step has an
undefined running time. When the build finishes it tries to average None into
the previous running time, hence your exception.

I've added a test to buildbot/status/progress.py to catch this case and
ignore the time updates. It will also emit a message to the log: 

   log.msg("Expectations.update: current[%s] was None!" % name)

If you see this message, look back through the display to see what steps have
passed or failed in the current build. I suspect a step is failing in a way
that doesn't terminate the step properly. Another symptom might be if you
click on the "log" link for that step and your browser behaves like it's
waiting for more text after the log is finished downloading. The trick I use
to let you start viewing logs that aren't finished yet (such that the
contents are sent to your browser as they arrive) tends to get confused when
the step fails unexpectedly, such that the step is done but doesn't know it
is done, so it never closes the HTTP connection.

If you see either of these symptoms, could you take a look at the logs and
see if you can figure out which step failed and what messages it emitted as
it failed? I'd like to figure out which code path is not cleaning up
properly.

thanks,
 -Brian