Bazaar

The Vancouver Planetarium. Photo by Qole Pejorian.

chx and I gathered last week in Vancouver’s West End for a two-person performance sprint during the final code slush days, allowing us to finish several key improvements to Drupal’s database layer. Right afterward, many more people joined us for another sprint to port key modules to Drupal 7. People worked in-person, voluntarily over IRC, and involuntarily over IRC (lost passport).

I can say — without reservation — that our work was successful. We kicked off the weekend with Drupal 6 versions of Coder and Views. (Though there had been a touch of prior work on the Views port to Drupal 7’s new database layer.)

Fresh packages, 64-bit only. There are release notes for the curious.

• Bazaar x86_64
• Bazaar SRPM
• BzrTools x86_64
• BzrTools SRPM

Fresh packages, 64-bit only (again). I can make 32-bit ones if anyone would like some. I’d say that this is the most exciting release yet.

• Bazaar x86_64
• Bazaar SRPM
• BzrTools x86_64
• BzrTools SRPM

A discussion recently arose on the Bazaar mailing list asking, “Why isn’t rebase support in core?” Rebase support is currently packaged as a plugin. This plugin is widely distributed, even in the standard Mac OS X installation bundle.

There are boring reasons that rebase support isn’t in core, like the lack of strong test coverage. More interesting are questions about the necessity of rebasing in typical workflows.

What is rebasing, and why should I care?

In large projects, there’s a mainline branch representing the current, global, coordinated development. In Drupal’s case, this is CVS HEAD. This mainline might not always be in perfect condition, but there’s a general sense that the mainline is not a sandbox for untested changes. Many changes are small enough that the developers simply work on and test a patch, but this workflow is inadequate for larger development projects like Fields in Core. Such large features require their own branch for development, a feature branch.

Fresh packages, 64-bit only this time. I can make 32-bit ones if anyone would like some.

• Bazaar x86_64
• Bazaar SRPM
• BzrTools x86_64
• BzrTools SRPM

For me, my projects are code-based and, hence, mostly a collection of version-controlled branches. So, my “Projects” directory (located at ~/Projects) contains a smattering of branches organized into multi-level directory structures.

In my last post, I noted that shared branch storage is the key to fast branching, good offline access, and efficient disk usage. I even covered a quick way to get it rolling for Drupal branches. But it’s one thing to know how and another to know “best practices,” so I’ll share how I do things.

I originally created a Bazaar branch of Drupal HEAD with hourly snapshots of upstream updates (commits to CVS HEAD) to streamline work on patches to Drupal HEAD.

This snapshot method had a few advantages over using Launchpad’s Drupal branch:

• Because of the shallow history, branching from the Four Kitchens server was relatively fast compared to branching from Launchpad.
• The Four Kitchens server has more reserve bandwidth and capacity, making initial branching and updates faster.
• Launchpad goes down more often than the Four Kitchens server.

The snapshot-based branch also had a big disadvantage: it didn’t keep a true commit-by-commit history that mapped to CVS HEAD commits, making it hard to understand ongoing changes. After some discussions with chx, I’ve decided to combine the best of both worlds: a mirror of Launchpad’s Drupal HEAD branch on the Four Kitchens server with instructions (provided below) to avoid the trouble of pulling thousands of revisions every time you branch.

With CVS, one of the only repository-wide atomic operations is tagging a local checkout. And not all that long ago, Subversion introduced mainstream users of free, open-source version control systems to full-scale atomicity. Or, at least the ability to be atomic.

These RPMs are now obsolete. Please check this blog for the latest ones.

The EPEL RPMs for Bazaar and BzrTools are quite out of date, so I rolled some experimental packages based on the Fedora 10 spec files.

One of the key features of distributed version control systems (DVCS) is support for divergent development (branching) and then merging. Most DVCS tools, including git and Bazaar, include rather elegant support for such workflows by embedding metadata about common ancestry into branches. In this post, I’ll be focusing on Bazaar.