Makes me happy to see the influx of jj posts as of late. Great tool. Roughly this workflow is how I convinced a few friends to finally loosen their death grip on git and try something new.
It's interesting to see the strange workflows that come from jujutsu users, as someone who works on git workflows.
There's some counterproductive stuff in there from my perspective but at its core you're keeping up a throwaway integration branch, which is helpful practice if you'll ever care about an integration. It's annoying with git because the interface for updating your throwaway integration branch is very clunky and easy to get wrong.
I saw Jujutsu on HN a few days ago and gave it a try. I picked a bunch of it up in just a couple hours and a couple days later I've completely switched to it for all my projects, it's not even close. Git is dead to me.
I just wish Jujutsu supported git tags rather than only supporting bookmarks as branches. And I also wish that Jujutsu supported preserving commit dates during rebases.
One of my absolute favorite things about Jujutsu is how easy it is to manipulate the commit graph remotely without having to manually checkout each commit first. I've been working on some pull requests to their built-in diff editor lately trying to improve the user experience enough that most conflicts will be fixable without having to use a text editor.
Also, the lack of a special staging area means you also never have to fucking stash your changes before you can do practically anything. Your changes always have a place, you can always go somewhere else and you can always come back.
I love this stuff as a hobbyist, but professionally I can't help but think this is all obsolete in the age of agent-driven development. I wish jj was around a decade ago.
Been trying to get into jj lately, but I rely a lot on VS Code's git gutter to review changes as I code. Doesn't look like jj has an equivalent in VS Code. Anyone got tool recommendations?
Great writeup! I've been using `jj parallelize` [1] a lot (and wrote about it here [2]) to fan out a sequence of commits to set up a megamerge, but your stack alias sounds super useful to create them on the fly, rather than at the very end of a work stream. Thanks for the tips!
I found octopus megamerge hard to collaborate - my colleagues don't use JJ so they may introduce changes that would cause conflitcts to my megamerge. When you have a conflict on a change that has more than 2 parents, the conflict resolution becomes unmanageable very quickly. No merge tool can handle more than 3-way merge, so you have to do that manually.
Eventually I settled on a tree-like megamerge that's more practical: merge 2 branches at a time and merge the merged branch with the next branch. This way I only need to handle 2-way conflicts at a time which is more manageable.
Also you have to be very careful to decide the order when you (and your colleagues) are going to land the branches, or if you expect any new features other people are working on that's going to conflict with your branches. When using megamerger workflow, most of the problems come from coordinating with other colleagues.
I do not understand the appeal of the workflow of working on separate things in parallel, then splitting it off into branches/commits. imo, isn't it better to fully focus on one thing at a time, even if it is "simple"?
I imagine if I follow this workflow, I might accidentally split it off in a way that branch A is dependent on some code changes in branch B, and/or vice versa. Or I might accidentally split it off in a way that makes it uncompilable (or introduce a subtle bug) in one commit/branch because I accidentally forgot there was a dependency on some code that was split off somewhere else. Of course, the CI/CD pipeline/reviewers/self-testing can catch this, but this all seems to introduce a lot of extra work when I could have just been working on things one at a time.
I'm open to changing my mind, I'm sure there are lots of benefits to this approach, since it is popular. What am I missing here?
>The absorb command will do a lot of this for you by identifying which downstream mutable commit each line or hunk of your current commit belong in and automatically squashing them down for you. This feels like magic every time I use it (and not the evil black box black magic kind of magic where nothing can be understood), and it’s one of the core pieces of Jujutsu’s functionality that make the megamerge workflow so seamless.
I've worked with git using the mega-merge approach, and one thing I found is that git-absorb won't merge commits into anything that precedes a merge. It works fine for absorbing changes into earlier commits on a feature branch, but not from the WIP branch back into the multiple feature branches that are the parents of the mega-merge. jj handles this with no problems.
Semi off-topic, but does anyone know of good resources for jj that don't assume git knowledge? Steve's and others are high quality, but often things are explained in terms of git equivalents or describe workflows that I struggle to fully understand the purpose of, as someone who knows only the barest basics of git necessary to work on personal projects.
If none exist, I think there's a great opportunity there, for anyone with the knowledge and motivation to make some absolute beginner guides. Already jj is infinitely more user-friendly, and as the tool matures, it isn't far fetched to think a new generation of programmers could go straight to jj without knowing their way around git first.
"Evil" merged are only evil if your tooling skips over merge commits as "unimportant" which is a common tactic to try and prune some of the crazy trees you get when hundreds of people are making merge commits into a repo which then creates its own commits for automation reasons...
Trying out jj is super low-risk--since it uses git as a backend, you can test it out and bail back to git without any drawbacks other than a detached head state.
And I hope you do. It is so much better than git in every way. It enables working with stacks and the aforementioned megamerges so easily, allowing me to continue working forward while smaller units of work are reviewed/merged.
When I first tried to use jj, I wasn't entirely committed and switched between jj and git. Finally I hit a breaking point being fed up with stacks/merges and tried jj _for real_.
I recommend to give it a serious try for a few solid days and use it exclusively to really understand it. You won't go back.
The jj Discord is a very helpful place. Thanks to everyone there. Great article Isaac!
I don't get JJ. Every time it's posted people gush about how JJ enables some super complicated workflow that I can't wrap my head around. I have a simple feature branch/rebase workflow in git that has served me well for decades so I guess I don't understand why I would want to complicate things with (in this case) an "octopus merge/megamerge". Wouldn't that make it more difficult to reason about the repository/history?
I was skeptical at first but when I dragged and dropped a bookmark in `gg` then a light went on in my head. Also the fact that jujutsu does everything in "detached mode" locally means that you can't mess up your remote git repo (unless you force push all yolo from git itself, but you're never expected to do that).
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[ 3.8 ms ] story [ 57.8 ms ] threadI'm still not as smooth at figuring out conflicts on mega-rebase.
If anyone is JJ-curious, I also can't recommend the Discord[1] enough. The community is very helpful and welcoming.
[1]: https://discord.com/invite/dkmfj3aGQN
Though, I'd be remiss not to mention that this (and any other) jj workflow would be much easier with jjui. It's the best TUI around, not just for jj
I proposed incorporating some of this article into it. https://github.com/idursun/jjui/discussions/644
There's some counterproductive stuff in there from my perspective but at its core you're keeping up a throwaway integration branch, which is helpful practice if you'll ever care about an integration. It's annoying with git because the interface for updating your throwaway integration branch is very clunky and easy to get wrong.
I just wish Jujutsu supported git tags rather than only supporting bookmarks as branches. And I also wish that Jujutsu supported preserving commit dates during rebases.
One of my absolute favorite things about Jujutsu is how easy it is to manipulate the commit graph remotely without having to manually checkout each commit first. I've been working on some pull requests to their built-in diff editor lately trying to improve the user experience enough that most conflicts will be fixable without having to use a text editor.
Also, the lack of a special staging area means you also never have to fucking stash your changes before you can do practically anything. Your changes always have a place, you can always go somewhere else and you can always come back.
[1] https://docs.jj-vcs.dev/latest/cli-reference/#jj-parallelize [2] https://blog.chay.dev/parallelized-commits
Eventually I settled on a tree-like megamerge that's more practical: merge 2 branches at a time and merge the merged branch with the next branch. This way I only need to handle 2-way conflicts at a time which is more manageable.
Also you have to be very careful to decide the order when you (and your colleagues) are going to land the branches, or if you expect any new features other people are working on that's going to conflict with your branches. When using megamerger workflow, most of the problems come from coordinating with other colleagues.
I imagine if I follow this workflow, I might accidentally split it off in a way that branch A is dependent on some code changes in branch B, and/or vice versa. Or I might accidentally split it off in a way that makes it uncompilable (or introduce a subtle bug) in one commit/branch because I accidentally forgot there was a dependency on some code that was split off somewhere else. Of course, the CI/CD pipeline/reviewers/self-testing can catch this, but this all seems to introduce a lot of extra work when I could have just been working on things one at a time.
I'm open to changing my mind, I'm sure there are lots of benefits to this approach, since it is popular. What am I missing here?
IUUC This is already implemented for git as an extension. https://github.com/tummychow/git-absorb
I think this is such a basic thing that should be part of any DVCS implementation.
From this comment on the git-absorb issue tracker I wouldn't expect it to be fixed soon either: https://github.com/tummychow/git-absorb/issues/134#issuecomm...
If none exist, I think there's a great opportunity there, for anyone with the knowledge and motivation to make some absolute beginner guides. Already jj is infinitely more user-friendly, and as the tool matures, it isn't far fetched to think a new generation of programmers could go straight to jj without knowing their way around git first.
And I hope you do. It is so much better than git in every way. It enables working with stacks and the aforementioned megamerges so easily, allowing me to continue working forward while smaller units of work are reviewed/merged.
When I first tried to use jj, I wasn't entirely committed and switched between jj and git. Finally I hit a breaking point being fed up with stacks/merges and tried jj _for real_.
I recommend to give it a serious try for a few solid days and use it exclusively to really understand it. You won't go back.
The jj Discord is a very helpful place. Thanks to everyone there. Great article Isaac!
https://github.com/anthrofract/majjit