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.