Creating dangling branches in Git
Say, you want to keep some auxiliary info inside your git repository: tickets, post-commit/post-receive hooks, wiki pages etc. Storing them inside a folder might not be a good idea: you’d probably want to have same content across all the branches. It is natural to keep such data in a separate branch.
Given that, you can create your “tickets” branch simply by checking out new branch, removing all the code, adding initial files and committing it. This works great until you get bored with the irrelevant history in the tail of the git-log. It is rather easy to disconnect your branch from the old history: just take the latest tree id, create an orphan commit (that is: without parent commits) and reset branch to this commit.
# emit tree id for the latest commit
$ git log -1 --pretty=format:%T
# emit new commit id
$ echo "initial commit" | git commit-tree <tree-id>
# reset current branch to this commit id
$ git reset --hard <commit-id>
Put it in a single bash command:
$ git reset --hard `echo "initial commit" | git commit-tree \`git log -1 --pretty=format:%T\``
Dangling branches are great for keeping meta-data of any sort: .git/config files, tickets, hooks, documentation, tickets.
PS. Since you can store hooks inside repository itself, you can have a self-contained deployment system like Capistrano without any additional tools installed on a server. Hooks can even update themselves on each post-receive hook before actual deployment recipes are run. This allows you to specify all the dependencies in the source repository and even setup them with a single “git push” command. All manual setup you have to do initially is to clone local repository inside .git/hooks folder (yes, inside itself) and check out hooks branch appropriate for your environment. Ain’t that sweet?