Introduction - Marijan Smetko

In this codelab I'll introduce a new VCS called jj. This codelab is written by Marijan Smetko, a.k.a. InCogNiTo124.

This tutorial came to be because, just like Steve, I like to write little notes and tutorials for, and by, myself when learning. I'm a big proponent of project-based learning, and I just happened to have a small project aside on which I would teach myself jj VCS and write about it. When I finished my independently created tutorial, I was surprised by just how similar my and Steve's tutorials were -- while the topics would, naturally, going to be mostly same, I actually wrote some eeringly similar sentences sounding just like Steve, even some similar jokes! The sole difference was that I have a concrete project. After asking Steve privately if it was OK¹, I decided to merge my tutorial to his.

Unlike Steve, though, I have a deep dislike of git. My VCS background to my sadness consists solely of git - while I have heard about other VCSs (hg, pijul, svn etc), I've never had an opportunity to work with them extensively². I understand git's model and theory (it's just DAG's all the way down, right?), but I am fed up with git's CLI and magical incantations. Splitting individual commits, reordering the parent and children, merging multiple commits, undoing the operations... those should all be easy operations. Yet, in git's case, they really aren't.

I discovered that jj turned out to solve all of the forementioned problems I had with git. I did not have to remember exactly which command to invoke, they came to me naturally. I could easily go back in time, fix stuff and later changes would rebase automatically. If I made a mistake, jj undo was always there.

There was a second subtle effect - using jj made me care about what goes into the changes I'm making. Before, with git, I did not care much what was a part of the commit. Commit cleanliness wasn't much enforced with my previous employers, let alone during Uni days, and editing the staging area to split a chage or commit partiall was always a PITA. Now, it's brainless for me to make a new commit or clean up an old one, so much that now that that friction is gone I started caring more about what goes into every change.