Support Gerrit's ref-update and patchset-created hooks. Gerrit (http://gerrit.googlecode.com/) is a web-based code review system which incorporates a Git server implemented with JGit (http://www.eclipse.org/jgit/), which is a pure Java implementation of Git. Up to version 2.2.0 JGit still doesn't support Git standard hooks. However, Gerrit implements its own special hooks (http://gerrit-documentation.googlecode.com/svn/Documentation/2.6/ config-hooks.html), which are rather different from Git's.
New option: githooks.disable. This option can be used to disable plugins otherwise enabled by the githooks.plugin option. It's useful if you want to enable a plugin globally and only disable it for some repositories.
Fixes
CheckRewrite: Detect and allow fast-forward "git rebase upstream base". If upstream is a decendant of base, the base-commit is empty. In this situation the rebase will turn out to be a simple fast-forward merge from base on upstream and there is nothing to lose.
Fix plugin disabling detection. Plugins enabled in the configuration using their full module name could not be disabled via the environment variable trick, because the variable must have the full plugin name, but ':' characters are not accepted in environment variable names.