[Buildbot-devel] Support for Github Pull Requests

[Dustin J. Mitchell]

Polling wouldn't necessarily be better.

The difference between using Changes and having the scheduler interact
with github (either through hooks or polling) is that Changes model
commits, not pushes, tags, branch creation, pull requests, or any of
the other myriad events that Github handles.  We have gotten into a
lot of trouble before trying to shoe-horn one thing into another.
Having Changes in the DB (so it's much harder to just add an
isAPullRequest attribute) is actually a good thing here, since it will
force us to look for better alternatives such as a Github-specific
scheduler.

Dustin