@awead

Technical notes and explications of code

Git

This is my usual workflow when submitting patches, or even working on my own applications. There’s been a lot of focus on Git branching models as of late. This is a good one, for example. Mine isn’t always that complicated, but no matter how many topic branches, my workflow is pretty much the same.

Start with a topic branch, and make sure you’re current:

git checkout master
git pull
git checkout -b fixing-a-bug

Start working. Take a break… oh, it’s the weekend? Okay, I’ll try again next week. Make a few stabs at it over the weekend and finally get it fixed next week. Now your git log probably looks like:

cdf5389ff978e4ba87150ca599fe6c4dcb6674b3 yay, done!
445cbfcf9ae8b18667474675213612c24a75190d ugh, no.
4e79c46f3e2410a09ddf609d442741e2cf1e8266 got it fixed!
f4f18f3117498f9e0735095fc7f44d63dc3557fe uh oh, this broke something
2a6ed6e963248a138996381f482ef500dea29bcf stashing changes
480ec8c17cb4ba535a97782167d73ba14528730e first stab

If you’re anything like me, some fixes are a journey and you sometimes end up going places you didn’t intend. Your git log may reflect this. Let’s clean this up:

git rebase -i HEAD~6

Now we can squash all those commits down to one, well-written and polished commit that makes it look like we knew exactly what we were doing all along. Of course, you don’t have to, it’s just easier. Sometimes I do squash to more than one commit if there are two different issues at hand and I want the comments in the commit log to reflect that; otherwise, it’s just one big one.

If we’ve been pushing up to Github along the way, we’ll need to force update origin since our commits have now diverged:

git push origin +fixing-a-bug

If you’re the only person working on this repo, you’re probably fine unless you’re Tyler Durden. Otherwise, check on any commits from origin or upstream if you’re using a forked repo. Then, get this into master and rebase against your topic branch:

git checkout master
git pull
git checkout fixing-a-bug
git rebase master

Since you’ve squashed down to one commit, you only have to go through the rebase once, as opposed to multiple times for each commit. Push any changes back up to Github and let Travis run the tests (if you’re using continuous integration):

git push origin fixing-a-bug

Once everything is green, merge your changes to master:

git checkout master
git merge fixing-a-bug

Since you’re merging one commit from the branch, this will be fast-forwarded, and the commit you’ve pulled in will appear with all the other commits in master as if there was never any branch. For small projects, this is probably fine. Alternatively, you can leave your branch in Github and submit a pull request. I’ve even done this on repos where I’m the only one working. It feels odd submitting a PR to yourself, but it helps document the branch and merge process.

If you want to preserve the branch/merge process and you don’t want to submit PRs, when you merge into master:

git checkout master
git merge fixing-a-bug --no-ff

The --no-ff is short for “no fast-forward”. This essentially preserves the merge as a separate commit in the log. Yes, it makes the log a bit longer, but it’s good for clarity because you’ll see the history of the branch and merge process.

Finally, clean up!

git push origin :fixing-a-bug
get remote prune origin

This deletes the branch in Github and cleans up your local clone.