Re: buildbot setup

[Stefan Monnier]

> We don't currently have any users with requirements like Alan
> Mackenzie's, but if we did I'd simply keep track of potentially
> destabilizing commits, and tag the last version before one of those.
> That might not work so well with Emacs, though.  XEmacs has a very few
> large committers whose stuff comes in batches, while others don't tend
> to commit patches to areas that might break the build.  I gather Emacs
> has several committers working in areas with some risk of breaking the
> build, so it might not be so easy to choose an apparently stable
> version.

There's indeed some difficulty figuring out when a bootstrap is needed,
as well as how to make sure "make bootstrap" works reliably.

I think the need for bootstrap increases if you update less often
(i.e. if you update everyday, you may never need to bootstrap, whereas
if you update every month you may have to bootstrap every time).

So maybe the buildbot could do a "checkout last bootstrap-tag",
then update and try "make"; if that succeeds, move the tag; else try
again with "make bootstrap" if that succeeds, then add some flag
somewhere indicating that this revision needs a bootstrap and move both
the tested-tag and the bootstrap-tag.

> If you could automatically tag based on green buildbots, that might be
> a worthwhile alternative, though.

I don't know what are green buildbots.


        Stefan