[Buildbot-devel] Interlocked forever

[Brian Warner]

> Upon further investigation, it looks like another cause of this is the
> feature where you can have the builder(s) not run if they are not
> interested in a change.  Since they don't run, their change number
> isn't incremented and the watcher of the interlock stays interlocked
> waiting for the feeder to update to that build number - which never
> will happen.

Yeah, this is a problem.. I think Thomas ran into this a few months ago. The
long-term fix is in the new Scheduler's dependencies code (which I haven't
written yet). I think the approach I'll take is for the "downstream" build
(the one which waits) to ask the "upstream" build for the disposition of any
given Change (rather than the current behavior which basically asks about all
Changes up-to-and-including the given one).

This question can be answered in one of five ways: SUCCESS, FAILURE, IGNORED,
(Deferred which fires with) SUCCESS, (Deferred which fires with) FAILURE. The
downstream scheduler will treat IGNORED and SUCCESS the same way.

I *think* this will fix the problem, but I'm currently trying to think up
some unit tests to verify that it does.

cheers,
 -Brian