The YOLO Approach To Upgrading Your Bullet Train Application

Pulling Updates from the Starter Repository

There are times when you'll want to pull updates from the starter repository into your local application. Thankfully, git merge provides us with the perfect tool for just that. You can simply merge the upstream Bullet Train repository into your local repository. If you haven’t tinkered with the starter repository defaults at all, then this should happen with no meaningful conflicts at all. Simply run your automated tests (including the comprehensive integration tests Bullet Train ships with) to make sure everything is still working as it was before.

If you have modified some starter repository defaults and we also happened to update that same logic upstream, then pulling the most recent version of the starter repository should cause a merge conflict in Git. This is actually great, because Git will then give you the opportunity to compare our upstream changes with your local customizations and allow you to resolve them in a way that makes sense for your application.

1. Make sure you're working with a clean local copy.

git status

If you've got uncommitted or untracked files, you can clean them up with the following.

# ⚠️ This will destroy any uncommitted or untracked changes and files you have locally.
git checkout .
git clean -d -f

2. Fetch the latest and greatest from the Bullet Train repository.

git fetch bullet-train

3. Create a new "upgrade" branch off of your main branch.

git checkout main
git checkout -b updating-bullet-train

4. Merge in the newest stuff from Bullet Train and resolve any merge conflicts.

git merge bullet-train/main

It's quite possible you'll get some merge conflicts at this point. No big deal! Just go through and resolve them like you would if you were integrating code from another developer on your team. We tend to comment our code heavily, but if you have any questions about the code you're trying to understand, let us know on Discord!

One of the files that's likely to have conflicts, and which can be the most frustrating to resolve is Gemfile.lock. You can try to sort it out by hand, or you can checkout a clean copy and then let bundler generate a new one that matches what you need:

git checkout HEAD -- Gemfile.lock
bundle install

If you choose to sort out Gemfile.lock by hand it's a good idea to run bundle install just to make sure that your Gemfile.lock agrees with the new state of Gemfile.

Once you've resolved all the conflicts go ahead and commit the changes.

git diff
git add -A
git commit -m "Upgrading Bullet Train."

5. Run Tests.

rails test
rails test:system

6. Merge into main and delete the branch.

git checkout main
git merge updating-bullet-train
git push origin main
git branch -d updating-bullet-train

Alternatively, if you're using GitHub, you can push the updating-bullet-train branch up and create a PR from it and let your CI integration do it's thing and then merge in the PR and delete the branch there. (That's what we typically do.)