Awesome-Jj: Jujutsu Things
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pick 5340360 # First commit.
pick 12ccd8a # Second commit.
pick a2b6a59 # Fourth commit.
pick 2a648f2 # Commit #4.
pick 6bb5d98 # Commit #5.
pick af1f2fe # Commit #6.
pick 7e99e85 # Commit #7.
pick 7567b18 # Commit #8.
pick c23819d # Commit #9.
pick 50941da # Commit #10.
pick 5340360 # First commit.
pick a2b6a59 # Fourth commit.
pick 2a648f2 # Commit #4.
reword 12ccd8a # Second commit.
edit 6bb5d98 # Commit #5.
squash 7e99e85 # Commit #7.
pick af1f2fe # Commit #6.
squash 7567b18 # Commit #8.
drop c23819d # Commit #9.
pick 50941da # Commit #10.
pick 5340360 # First commit.
pick 2448f03 # Fourth commit.
pick 9cefee3 # Commit #4.
pick 1259a52 # Second "Hi" commit.
pick 2ca48d8 # Commit #5.Commit #7.
pick 4bf7bcd # Commit #6.Commit #8.
pick dbbb733 # Commit #10.
dbbb733 (HEAD -> master) HEAD@{18}: rebase (finish): returning to refs/heads/master
dbbb733 (HEAD -> master) HEAD@{19}: rebase (pick): Commit #10.
4bf7bcd HEAD@{20}: rebase (squash): Commit #6.Commit #8.
cdc47c1 HEAD@{21}: rebase (pick): Commit #6.
2ca48d8 HEAD@{22}: rebase (squash): Commit #5.Commit #7.
6a6fccc HEAD@{23}: commit (amend): Commit #5.
86ca5f8 HEAD@{24}: rebase (edit): Commit #5.
1259a52 HEAD@{25}: rebase (reword): Second "Hi" commit.
b33f89c HEAD@{26}: rebase (reword): Second commit.
9cefee3 HEAD@{27}: rebase (pick): Commit #4.
2448f03 HEAD@{28}: rebase (pick): Fourth commit.
5340360 HEAD@{29}: rebase: fast-forward
d1406ed HEAD@{30}: rebase (start): checkout d1406ed8145dc84695eb622bc6b3fc078e8098df
50941da HEAD@{31}: commit: Commit #10.
c23819d HEAD@{32}: commit: Commit #9.
7567b18 HEAD@{33}: commit: Commit #8.
7e99e85 HEAD@{34}: commit: Commit #7.
af1f2fe HEAD@{35}: commit: Commit #6.
6bb5d98 HEAD@{36}: commit: Commit #5.
2a648f2 HEAD@{37}: commit: Commit #4.
a2b6a59 HEAD@{38}: commit: Fourth commit.
12ccd8a HEAD@{39}: commit: Second commit.
5340360 HEAD@{40}: commit (initial): First commit.
Most importantly, I get in this situation less often in the first place. Because reodering and squashing commits can be done with an easy command[1], I tend to squash or rebase as I think of it instead of batching it up to do all at once.
Many times, I don't need to manually target which commit to squash into at all, because I can be editing at the tip of the branch, then use `jj absorb` to automatically squash all my changes down into the commits where they belong.[2]
And `jj undo` is just easier to use than the reflog[3]. While reading the reflog you posted, I have to mentally replay each commit step by step. But really, if I messed something up, it's most likely I want to just go back to `HEAD@{31}`. `jj rebase` is atomic, so the whole thing is undone with one invocation of `jj undo`.
[1]: https://docs.jj-vcs.dev/latest/git-experts/#automatic-and-sa...
[2]: https://docs.jj-vcs.dev/latest/git-experts/#jj-absorb-makes-...
[3]: https://docs.jj-vcs.dev/latest/git-experts/#undo-is-more-pow...
I tend to have lots of uncommitted files and changes that i want to keep around in this state while I move around branches and while having multiple change lists (jetbrains implementation) that I will commit at some point in time.
This loose, flexible way of using git seems hard to do in jj.
It's also so easy to go back to the change latter and remove the files (after they're already copied elsewhere, or just operations log to go get) that it's really not a problem to just let stuff get in your commits.
In git there's such a strong incentive to do things right, to make clean commits. Imo one of the huge strengths of JJ is abandoning the obsession, and having far far far better tools to clean up after.
There is no such. There are a lot of tools to manipulate commits and WIP, such as the stash, rebase, cherry pick, extracting and applying patch. You only need clean commits for review and the main branch because that helps the whole team. Your local copy can be as messy as you want to.
Where-as jj makes rework operations, IMO, basically easy enough (after a couple weeks of use to) that I worry much less about making the right commit the first time.
Eg with stacked git (stg) this is just: goto, spill, and then refresh/create the stuff I want.
[0] https://docs.jj-vcs.dev/latest/faq/#i-accidentally-changed-f...
`git reset` by itself doesn't split a commit AFAIK. You need to then `git add -p` and `git commit` (and recover the commit message from the old commit). And what happens if you had other changes in the working copy first? Or if you want to split a commit that's not at HEAD?
If you want to generate two commits with the exact same message, then do:
git checkout combined-commit
git reset --soft previous-version
git commit -C @
Do something with them. Put them in a commit, put them into a commit in the global stack of todo commits or tell git to do that automatically.
> Or if you want to split a commit that's not at HEAD?
Check it out or do a rebase.
Git reset splits a single commit, into two "things", another commit with the first part and a second part that is put into a version prepared for a commit (--soft), prepared for further editing (--mixed) or thrown away (--hard). To me that counts as commit splitting, but it may not match with JJ terms. Also splitting into two commits with the same commit message doesn't sound quite useful to me, so the default of Git two require a second commit message is sensible to me.
> Those were rhetorical questions.
Ok, but then what was your point?
Correct me I'm I'm wrong but I think were talking about using `git reset HEAD^` for splitting a commit. That will move the current branch backwards one step. With `--mixed`, it will also move the index back one step, so the index is empty (relative to HEAD) and the working copy has the combination of changes that were in the previous HEAD commit and the working copy (relative to the previous HEAD). I think that's more like squashing than splitting because we have fewer "things" after: we have one commit fewer (the previous HEAD commit may of course still be reachable from another branch, in which case we still have the same number of "things" afterwards). It's similar with `--soft` and `--hard`, except that the old changes end up in a different "thing".
At a less technical level, the point of splitting a commit is to end up with some of the changes from one commit in a new commit and the rest of the changes in another commit. That's what meant when I said "`git reset` by itself doesn't split a commit", because you need to do something like this:
git reset HEAD^
git add -p
git commit -C HEAD@{1}
Just that additional steps are needed.
For example, if you wanted to split the HEAD commit but you had already started working on a new commit so have some changes in the working copy, then you might instead have to do something like this:
git commit -m tmp
git rebase -i HEAD^^ # Use the "edit" action for the first commit
git add -p
git commit -m first
git rebase --continue
git reset HEAD^
(Take my Git commands with a grain of salt because I haven't used Git in 10 years.)
I wasn't. I wanted to do the same as in the FAQ entry we are talking about, so I wanted to reset it to an older commit representing the same change (i.e. before an amend that we are now reverting). This is likely in a rebase, but we can always rebase later and only do the splitting now.
> With `--mixed`, it will also move the index back one step, so the index is empty (relative to HEAD)
Yes and this is the default (without any flag).
> That's what meant when I said "`git reset` by itself doesn't split a commit", because you need to do something like this:
That's what the `--soft` is for, then `git reset` does not touch the index.
> Just that additional steps are needed.
The only "additional" step required is specifying a commit message, which, as I said earlier, to me is a sensible default.
What I suggested applied on this case would be:
git commit -m tmp
git checkout @~
git reset --soft previous-version # which you get from the reflog
git commit -C @
git rebase @~ branch-you-were-on --onto=@ # not of much use, when you only have a single commit you are throwing away in the next step, but when you are editing something earlier, this is likely what you want.
git reset @~
git commit -m tmp
git rebase @~2 # break after first commit
git reset --soft previous-version
git commit -C @
git rebase --continue
git reset @~
git rebase -i @~ --autostash # break after first commit
git reset --soft previous-version
git commit -C @
git rebase --continue
Actually what you can also do, but this doesn't use reset, is this:
git rebase -i @~ --autostash
# add as the first line:
pick previous-version
git rebase --continue
Honestly, what I do most of the time to split commits (when there isn't an older version I want to split it to) is to just amend and then unselect the changes I don't want with the cursor.
It's still a young tool, it's not surprising that tutorials are a bit lacking (honestly there are surprisingly many for its age). Maybe be the change you want to see in the world and make one? (Which would be an... interesting... way to learn the tool for sure).
Keep up the great work