[devel at bb.net] Problem with GerritChangeSource & Gerrit remote refs

[Mikhail Sobolev]

Hi Kevin,

On Wed, Jul 13, 2016 at 06:48:55PM +0200, Kevin Funk wrote:
> Problem: master/35230 is totally wrong, Buildbot should look for something 
> like refs/changes/30/35230/1 instead.
I wonder whether you use Git or Gerrit source step.

In our setup we have only one Buildbot master, but a number of workers.
While I can't really estimate how heavily it's loaded (I need to check
our logs when I am back from vacation), I did not see the behaviour you
describe.

I do remember though that when I took the responsibility over our
installation, the previous administrator used Git step + some hacks to
get the right remote reference: once I switched to the stock Gerrit
step, no hacks were needed any more.

Just a few numbers to throw in:

* for each new patch set, we trigger up to 18 builds
* these are run on about dozen workers (I need to check the exact
  number here)
* unfortunately, some of the build requests have to wait up to one hour
  before they get processed

[snip]

> I see that the following file is responsible for deciding which branch to 
> fetch:
>   master/buildbot/steps/source/gerrit.py
Yes, that's the code.

> # Questions
> 
> Educated guess: It looks like Buildbot "forgets" about the 
> 'event.patchSet.ref' build property somewhere in-between?!

If it somehow were to forget, you should not see 'event.patchSet.ref' on
the corresponding build page, do you see it there for the problematic
builds?

-- 
Misha

PS  Sorry for a slow reply: my vacation started just great -- the
    home notebook just does not want to start :)

PPS I'll try to get online on our IRC channel, so maybe we could try to
    find the problem interactively.