Recently I needed another copy of the git repository I was working on but it seemed like an awful lot of work cloning it another folder and then switching back and forth and fetching/pushing to keep it all up-to-date.
This is where git worktree can be a very useful feature.
Git “worktrees” gives you a full working copy of your repository that you can treat like any other clone? So why are “worktrees” better than simply cloning repositories?
A few reasons:
- “worktrees” are hard linked, so they are really light-weight and unlike clones they don’t pull the entire repository locally.
- You can access locally committed changes across different “worktrees”. With cloned repositories you’d need to push the changes upstream and then fetch in a different clone where those changes are required.
- You can switch between “worktrees” without affecting changes in your current repo. So all the goodness of clones but without the additional overhead.
How to
To create a “worktree” simply run:
# git worktree add -b <new-branch> <directory> <upstream>/<branch>
Documentation on git branch can be found here.
Use Cases
Following are some use-cases from my personal experiences to give you an idea when and how can “worktrees” be useful.
Running tests
Before I had access to CI testing services on my testable repositories, I would create a “worktree” for branch that was ready to be merged, cd into the worktree directory and run the tests. In the meantime I would cd back to my working directory and carry on working while the tests ran in the background.
Once tests finished and I was happy with the outcome, I would merge the branch and simply delete the worktree directory. This is especially useful if you are low on inodes or storage or if that is a concern (as it was in my case).
I still sometimes do that when I want to run the tests in the background so I can continue working on code.
Building “Github Pages”
Those who use Github Pages would know that it is possible to publish your site from the gh-pages branches. Normally, to deploy changes to your Github Pages you would switch the gh-pages branch, build the site and then push up.
With worktrees, I create a “worktree” for the gh-pages branch in the dist folder. Then I can compile/build my site directly into the dist folder, cd into it and then push it up which will always update the gh-pages.