[Python-Dev] Possible language summit topic: buildbots

Zooko O'Whielacronx zookog at gmail.com
Tue Oct 27 16:41:42 CET 2009

Right, how do developers benefit from a buildbot?

>From my experience (five large buildbots with many developers plus two
with only a couple of developers), a buildbot does little good unless
the tests are reliable and not too noisy.  "Reliable" is best achieved
by having tests be deterministic and reproducible.  "Not too noisy"
means that the builders are all green all the time (at least for a
"supported" subset of the buildslaves).

Beyond that, then I think there has to be a culture change where the
development team decides that it is really, really not okay to leave a
builder red after you turned it red, and that instead you need to
revert the patch that made it go from green to red before you do
anything else.  It has taken me a long time to acculturate to that and
I wouldn't expect most people to do it quickly or easily.

(It is interesting to think of what would happen if that policy were
automated -- any patch which caused any "supported" builder to go from
green to red would be automatically be reverted.)

Also, of course, this is mostly meaningless unless the code that is
being changed by the patches is well-covered by tests.



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