[Libreoffice-qa] Bibisect Roundup

[Robinson Tryon]

Yee Haw, Folks!

I just wanted to give everyone a quick update on what we've been up to
in Bibisect-land.

I've been working with Norbert and Bjoern on getting our GNU/Linux
combined bibisect repo up on dev-downloads.libreoffice.org.

Once we get some permissions issues fixed (hopefully in the next
couple of days), we'll have a combined repo ready for GNU/Linux x86_64
covering 3.5-master through 2013-11-25. If you aren't running a 64-bit
version of Linux, this is a good excuse to update :-) This repo will
be
* Downloadable as a tarball
* Updatable via git

We've also included a script (out of tree) to run LibreOffice using a
profile dir in /tmp.

The next steps for this combined repo include:
* Adding builds between 2013-11-25 and now
* Setting up our buildbot to feed into this repo

We will eventually want to provide similar resources for OSX and
Windows, but my current plan is to get the GNU/Linux system up and
running end-to-end first, and make sure that the general workflow is
running smoothly.

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Other bibisect news:

As mentioned previously, Norbert has 2 bibisect repos ready for OSX:
* Bibisect covering all released builds
* Bibisect for 4.2-master era

Florian R is working on a Windows bibisect GUI:
* http://flosmind.wordpress.com/2013/12/12/bibi-gui/

Cloph is working on buildbots and bibisect repos and gluing them together

Any other bibisect news I'm forgetting?

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The Future of Bibisect?

Shoving many builds into a single git repository is a clever hack, but
there are limits to how big we can grow our repos. Over time,
including thousands of builds into a single repo will create problems
both on the backend (including 'git gc') and on the front-end
(including downloading and running git operations on 20G+ at a time).

One possible compromise would be to chunk our bibisect efforts into
multiple repositories, with one repository per release branch. Each
repository would remain a reasonable size (probably under 10G), and
anyone could download one or more of these repositories.

To make bibisecting over the entire history of the project possible,
we'd need one additional repository that can tell us during which
release branch (or during which X.x-master branch era) a particular
regression was introduced. In nearly all cases, a small bibisect repo
containing only our released builds should be able to provide that
information.

But we want to simplify things for our users, so what we'd do ideally
would be to have a script that would provide some abstraction and
transparently move between different bibisect repos. This could have a
GUI front-end eventually, but would be easiest to mock-up as a
command-line tool first.

And yes, before you ask, it's on my todo list. I just need to get this
other repo ready for y'all first :-)

Cheers,
--R