You get a nicer, significantly simpler interface. You don’t need any tricks. You don’t have to google how to work yourself out of a bad state, ever. And you get near-perfect git compatibility (ie you can use jj on a shared git repo, doing all the same things, and your teammates won’t know the difference).
I’ve wondered if there is a psychological thing here: someone who spent time memorizing all the git nonsense may have some pride in that (which is earned, certainly), that introduces some mental friction in walking away???
Also, I dislike all of the alternate git frontends I tried, because they are opinionated in a way they clash with my workflow.
Moreover, I don’t think the git CLI is that bad. Once you learn some basic concepts, it makes a lot of sense and is pretty consistent.
Most problems people report stem from a refusal to learn the underlying structure and models. That is on them. And when using a different frontend, they don’t disappear either. They are just abstracted, to allow you to avoid learning them. But they are still there, and you will probably still need to know them at some point.
i went from being a "jj cli power user" to relying on jjui for all of my complex rebase needs so quickly that i now have to read the man page to recall basic commands
It's very easy to fall into the trap of believing this: git's implementation fits together neatly enough that it feels like the best you could do. Like, yes it's complex, but surely that's just intrinsic complexity of the problem? (Also, I think we all sometimes feel like someone with a different view must just not know as much as us.)
But if you have used other version control systems (I'm thinking particularly Mercurial here) you realise that actually some of that complexity is just totally made up by git.
I don't think it's just mental friction. Suppose you've learned git well enough that everything you do in it is automatic and fast, and the things which aren't fast by default you've built aliases and tooling for over the years. Yes, starting from ground zero you might want something like jj, but at the current point in your life you're not starting from ground zero. Switching to jj means learning another tool to achieve similar outcomes on your workflows.
1. I had quite a bit of trouble figuring out a workflow for branches. Since my companies unit of work is the branch, with specifically named branches, my `jj ls` was confusing as hell.
`jj st` might have helped a bit, but there were scenarios where creating an commit would abandon the branch... if i'm reading my post history correctly. My coworker who was more familiar explained my jj problems away with "definitely pre-release software", so at the time neither of us were aware of a workflow which considered branches more core.
Fwiw, I don't even remember when the jj workflow had branches come into play.. but i was not happy with the UX around branches.
2. iirc i didn't like how it auto stashed/committed things. I found random `dbg!` statements could slip in more easily and i had to be on guard about what is committed, since everything just auto pushed. My normal workflow has me purposefully stashing chunks when i'm satisfied with them, and i use that as the visual metric. That felt less solid with jj.
Please take this with a huge grain of salt, this is 10 month old memory i scavenged from slack history. Plus as my coworker was saying, jj was changing a lot.. so maybe my issues are less relevant now? Or just flat out wrong, but nonetheless i bounced off of jj despite wanting to stick with it.
1. It's very new; I haven't had time to learn it properly yet.
2. It's very new and tooling doesn't support it well, e.g. VSCode. There aren't many GUIs yet.
3. I tried it once co-locating with Git and you definitely can't use both at the same time, even if it can use a `.git` directory. It ended up in a huge mess.
I'm definitely in favour of better-than-Git alternatives but I don't think it's reasonable to expect everyone to switch to JJ right now. It isn't so much better that abandoning the de facto standard is obviously worth it yet. (In contrast to things like the iPhone, Rust, SSDs, etc.).
Also I really wish they would focus on some of the bigger pain points of Git. I can deal with rebasing and whatnot. Sometimes it's painful but it's usually not that bad.
What I can't deal with are submodules and LFS. Both are awful and fixing them properly requires fundamental changes to the VCS which aren't going to happen in Git. JJ has an opportunity to do that. Imagine if JJ could say "we have submodules but they aren't awful!" or "you can check in large files!". Those are the sort of huge advantages that would mean you can say "why not just use JJ".
I explicitly said that git IS NOT the best we can do. But it is universal and good enough. Not nearly as bad as some people make it out to be.
It's not something I can just shift away from.
jj is harder to adopt for people with a thorough mental model of git, because it's harder to accept jj commands at face value. I know it's modifying my git tree, so I feel compelled to grok exactly what it's doing, but that's distracting and time consuming.
People like me should probably trial jj exclusively for two weeks, to shed that antijjotic resistance and form a more clear-headed opinion.
With `jjui` this strategy takes only a few keystrokes to do operations like adding/removing parents from merge commits.
It's so nice to have like 4 parallel PRs in flight and then rebase all of them and all the other experimental branches you have on top onto main in 1 command.
Also, I cannot even stress to you how much first-class-conflicts is a game changer. Like seriously you do NOT understand how much better it is to not have to resolve conflicts immediately when rebasing and being able to come back and resolve them whenever you want. It cannot be overstated how much better this is than git.
Also, anonymous branches are SOOOO much better than git stashes.
You can do anonymous branches in Git as well. I use both for different use cases.
Also git has no equivalent to the operation log. `jj undo` and `jj op restore` are so sweet.
What I will say is this: there is certainly an adjustment period, and I also totally hear you about how learning internals can be time consuming.
I think you can get a lot of the way there with at least the core concept with something like this, if you'll indulge me:
With git, you build up stuff on your filesystem. You then select which bits go into a diff in your index, and then when you're done, you stamp out a commit.
With jj, you instead start by creating a commit. In this case, it's empty. Then, every time you run a jj command, it does a snapshot, and this produces a new commit. However, because we want to have a stable identifier for a commit, we introduce a new one: the change id. This is basically an alias for the latest commit snapshot that was made. Your git history is just made up of each of these latest commits for each change.
... does that make any sense? Obviously there's more to all of the features than this, but that's sort of the core way that the histories map to each other.
No, it really isn’t. I have used git since shortly after it was first released and I’ve written a git implementation.
I switched to jj in one day. And the amount of git arcana I have to keep in working memory is now basically nil. My VCS now works in almost a 1:1 mapping with how my brain wants to interact with my repo rather than having to go through a translation layer.
If you understand what git commands are doing, what jj does is essentially trivial to add to your mental model.
I also get the benefit of being able to use workflows that I always want to use in git but which are an enormous pain in practice. And I get access to wildly powerful new workflows I didn’t even consider because they would be outlandish in git.
Both submodules and LFS are things that jj wants to address, but they take time.
The jj CLI is very easy to grok, even for a seasoned git user. Maybe even especially so for a seasoned git user.
Auto-commit is still a thing, but you can regain the stuff you like with a workflow change, this is called the "squash workflow" and is very popular: https://steveklabnik.github.io/jujutsu-tutorial/real-world-w...
Git is simple enough and has features and capabilities that jj does not have. Contrary to popular belief, git is not hard to use. I refuse to use any "simpler" system that is slower or less feature-rich than git. I don't even want to learn another commit graph model, because git's model is very good. About 95% of what people like yourself call "git nonsense" consists of useful features that many people would be annoyed to not have.
I believe that a large number of git or general VCS users have no idea about commit hygiene. They have not had to cherry-pick or edit commits, and have no idea what to do about conflicts. To people like that, git's features and methods will appear especially foreign.
I looked over jj specifically many moons ago and concluded it would annoy me and not function at my job. I forgot what the reasons were. One reason was most likely because I need submodules and worktrees to work. I just looked at its FAQ, and saw a bunch of nonsensical new terms as well. Nothing is more compatible with git than git itself, and I am very satisfied with how well git works for me.
worktrees are called "workspaces" in jj, but are the same.
A lot of people find jj easier to have good commit hygiene with, and find it simpler and more powerful, not less. But that said, if you're happy with git, you should continue to use it.
I don't mind other people using jj, but I simply don't feel a need to try it. There's nothing prideful about that, it's just pragmatism.
IIRC forcing some specific branch name to point to my changes with `jj` was non-obvious and what made me give up and go back to git when I tried it last year.
I agree. That's why jj uses practically the same model. That's how Git can quite easily be used as a backend.
> I just looked at its FAQ, and saw a bunch of nonsensical new terms as well.
Like what? Perhaps we can improve it.
I'm sure it is stuff that makes sense to a jj user. Since I have not read the manual, it is nonsense to me. I'm just drawing attention to the fact it's a different set of non-obvious terminology and features as compared to git. I'm sure anyone who read the manual for either tool could figure it out. The trouble with git is that people don't read the manual, and hardly try to do anything with it, then loudly complain about it being tricky. Anything as complicated as version control is going to be tricky if you don't read the manual. I don't think making another tool entirely is the right solution. Perhaps a different set of git porcelain tools could help, or some git aliases. Maybe better documentation too. But some people just can't be pleased.
If you have others in mind then go ahead lol. I was just trying to make it easy.
> I don't think making another tool entirely is the right solution.
I considered making the changes to Git but the changes I wanted to make would make the UX so different that it would basically mean introducing a whole parallel command set to Git. I figured it would take ages to get Git to that state, if I could sell the ideas to the Git community at all. By the way, the video above talks about an proposed `git history` series of commands inspired by Jujutsu (also see https://lore.kernel.org/git/20250819-b4-pks-history-builtin-...).
Yes, it's only meant for local branches. When I used Git, I had a script for rebasing dependent branches. I remember that a coworker had written a similar script.
I think jj is generally more useful for people like me who often have lots of independent and dependent work in progress. If you mostly just have a one review at a time, there's much less benefit. Perhaps I would say that `jj undo` might be the most useful feature for users with simpler development (yes, I know about the reflog, but see the video I linked to in the other message).
The most common reason is that the git user has no idea it exists. I am in this bucket alongside 99% of git users.
There are an assortment of other potential reasons:
- It is a new tool that hasn't been battle tested as much as git has, which can decrease confidence.
- Git has inertia. People have learned it, it takes less effort to add a new git skill to your repertoire than learn a new tool from scratch, even if the new tool is easy to pick up.
- Due to its novelty, the auxiliary tooling ecosystem for jj is smaller (does it have plugins for all the popular editors? Lots of people like those, git's are high quality)
- Git is good enough. It's not perfect, but its popularity means that its shortcomings have readily available fixes or tweaks from users. It simply isn't bad enough and there are bountiful resources on how to use it effectively.
This makes it unusable for me.
jj is sort of a bag of git tricks for me that I use when needed. It's no different than some things being easier with the git CLI vs others being easier in Sublime. I'll be at a stage where my committing/branching/rearranging wants are something that jj nails perfectly, and I do those there. As far at the other tools are concerned, I just did a bunch of sophisticated git operations.
The "colocated with git" capability of jj is probably it's most amazing feature tbh, and is key to any sort of adoption.
I think I saw Scott Chacon talk about his git config file and advanced git features. Whoever it was, it mentioned GitButler. That was a good talk. I would certainly expect someone like that to have a lot of interest and expertise in git. But it seem to me that there is also a potential commercial angle to making a new/alternative VCS.
I looked at the mailing list entry you linked to about `git history` commands and thought to myself, it sounds all wrong and redundant. `git history` sounds like too broad of a name for one thing. I'd want to have it be `git <verb>` instead. All the operations listed can be done with rebase:
- `git history drop`: Instead, rebase interactively and drop one or more commits.
- `git history reorder`: Interactively rebasing makes this work already.
- `git history split`: Insert a pause in the interactive rebase. Do a soft reset or something to the previous commit, and use `git restore` to unstage the changes (there might be a more efficient way to do this in one step, but idk). Then, do `git add -p` to add what you want, commit, as many times as you want to split the patch. Then continue the rebase.
- `git history reword`: There is a reword option in interactive rebase mode, and also a fixup-like option to do it as well if you want to postpone the rebase.
- `git history squash`: Rebase can do this now in multiple ways.
Rebasing is not that hard. It is the Swiss Army knife of VCS tools. Once you realize that you can just break in the middle of a rebase and do nearly anything (except start another rebase), the world is your oyster. We don't need to spam people with many more single-purpose tools. We need people to understand why the way things are is actually pretty damn good already, if only they read the manual.
> Also git has no equivalent to the operation log.
For easy cases it's just git reset @{1}, but sure the oplog is a cool thing. I think it will be just added to git eventually, it can't be that hard.
I agree that Git could gain an operation log. I haven't thought much about it but it feels like it could be done in a backwards-compatible way. It sounds like a ton of work, though, especially if it's going to be a transition from having the current ref storage be the source of truth to making the operation log the source of truth.
I also tend to have the builtin GUI log equivalent (gitk) open. This has the behaviour, that no commit vanishes on refresh, even when it isn't on a branch anymore. To stop showing a commit you need to do a hard reload. This automatically puts the commit currently selected into the clipboard selection, so all you need to do is press Insert in the terminal.
> It sounds like a ton of work, though, especially if it's going to be a transition from having the current ref storage be the source of truth to making the operation log the source of truth.
I don't think that needs to be implemented like this. The only thing you need to do is recording the list of commands and program a resolver that outputs the inverse command of any given command.
If you don't have anything to update then that would be somewhat pointless to me. You can also just rebase them, when you start working on the branch again or want to merge them.
--
For me branches also represent features, that should have clear boundaries, so when I work on one feature and that means, I need to rebase another one on top instead of being able to just merge them later, this indicates a spaghetti codebase where the interfaces between features are not properly defined and things depend on internals of other things.
When I’m exploring a problem I end up with complex tree of many anonymous branches as I try different solutions to a problem and they all show up in my jj log and it’s so easy to refer to them by stable change ids. Often I’ll like part of a solution but not another part so I split a change into 2 commits and branch off the part I like and try something else for the other part. This way of working is not nearly as frictionless with git. A lot of times I do not even bother with editor undo unless it’s just a small amount of undoing because I have this workflow.
Git is to jj like asm is to C: you can do it all with git that you can do with jj but it’s all a lot easier in jj.
What we should do instead is provide a bunch of primitives, that as high-level are as possible so to not end up with duplicate commands, which is what git does currently. `git history` as a name is somewhat pointless, since the whole point of git is to produce and modify the history. In that sense `git history` already exists, it is called `git`.
I think the issue newbies have is not that git commands are hard per se, but that they don't think in terms of modifying the graph yet, or that they don't know which primitives are available.
``` A---B---C main \ D---E---F feature1 \ \---G---H feature2 \ \---I---J feature3 ```
(sorry about the formatting here. I guess you'll have to copy & paste it to read it)
What I'm saying is that if I want to fix something in D, I do `jj new D` to create a new commit on top of D. Then I make the fix, run tests, etc., and then I run `jj squash` to amend the changes into D. The descendant commits (E through J) then get automatically rebased and the feature bookmarks/branches get updated.
I didn't follow what you about it other changes needed for updating the ancestor. Can you explain in the context of this example?
--
The other thing I am saying is that I don't really let features depend on each other, I let them specify the API between them first and then develop them independently. Otherwise it is easy to violate boundaries. So the ideal is that any of G,H and I,J works with D,E,F and vice versa. Of course that is tangential and it doesn't always work that way.
Keeping these things in a private commit is one option.
Configuring auto-tracking to be off is another option.
But for me, it's not so much features that git doesn't have, it's that the core is factored in a way that's more focused and orthogonal. The stuff that I used to like to do with git is even easier and more straightforward with jj. This is more of the result of a bunch of different design decisions and how they fit together rather than just some specific feature that's great.
I try to do this too but I often end up in situations where I have multiple incomplete (in testing, not merged) features with outstanding patches. Instead of one branch per topic, I end up with one branch for a bunch of related stuff. I then rebase and pause at the feature boundaries to do more testing. Sometimes, if I find myself doing this a lot, I will use the `exec` feature of `git rebase` to automate my testing.
I think rewriting all related branches can cause problems. It would be really weird to do interactively for one thing. The other problem is that you may have unrelated topic branches broken by such a change. If you have a broken patch X that reveals problem Y on branch Z1, but you are working on fixing that on Z2, you may lose your ability to reproduce the Z1 issue if X is fixed on every branch. What if you get conflicts on all those branches? What does this do to the reflog? Yikes! It seems more dangerous than git itself.
These complaints are very niche of course, but the problem of rewriting many branches at once is also very niche. It can cause more problems than it solves.
My advice is to try it. You should like it, if you're in the majority of folks to give it a sincere shot. If you don't like it, cool. But then my advice changes. jj is probably the future. Adapt or become one of those old-timers who froze their learning in time.
I recognize that some folks are stuck with it, and yeah, in your case jj probably just doesn't make sense. Stay tuned though.
> You rebase feature-1 onto main:
feature2 moves as well. Basically, the behavior here is just the default.
Within a day of switching I was fully up to speed with jj and I never see myself going back. I use colocated repos so I can still use git tools in my editor for blaming and viewing file history.
Sure even rebasing a complex tree in git can be done by creating an octopus merge of all leaf nodes and rebasing with preserve merges but like that’s such a pain.