3 ms·

Git rebases don't work if there are conflicts, jj doesn't have this problem. Also idk if you can rebase onto multiple parents with git but jj can do it.

aidos 6mo ago
Can you explain how conflicts are not conflicts? If I change a line of code several times and rebase on to a branch that changed the same lines of code, how are you sure what the right one is?
- sunnyps 6mo ago
  JJ can save conflict related state with the change so that you don't need to resolve a conflict in the middle of a stack of changes for rebasing to continue for the remaining changes. Concretely, it uses a "conflict algebra" where it can track the impact of a conflict as it propagates through the stack of rebased changes: https://docs.jj-vcs.dev/latest/technical/conflicts/ https://docs.jj-vcs.dev/latest/technical/conflicts/
  - waisbrot 6mo ago
    That sounds like https://git-scm.com/book/en/v2/Git-Tools-Rerere https://git-scm.com/book/en/v2/Git-Tools-Rerere ?
    - martinvonz 6mo ago
      Not really very similar at all for the scenario discussed here. Rerere remembers how you have resolved a conflict before. It doesn't let you rebase a stack of commits that result in different conflicts. You will have to stop and resolve each conflict and then `git rebase --continue`. However, the conflict algebra does remove many common uses of rerere. See https://github.com/jj-vcs/jj/issues/175#issuecomment-1079831788 https://github.com/jj-vcs/jj/issues/175#issuecomment-1079831... for a longer discussion.
      - account42 6mo ago
        Avoiding manual conflict resolution isn't really a good thing though - conflicts are an indication that multiple different changes affect some code and you really should think hard about what the combination of them should be. Even what git does automatically already can be dangerous.
        martinvonz 6mo ago
        I agree, but that doesn't seem relevant. I did not say the jj automatically resolves conflicts.
  - palata 6mo ago
    But what does that bring? Your code won't compile as long as you don't fix the conflicts, so anyway you have to fix them when you rebase, right?
    - compiler-guy 6mo ago
      You have to fix them at some point, but not in the middle of doing other things. Right now. With no possible way to make progress elsewhere while deferring this decision.

aidos 6mo ago

Can you explain how conflicts are not conflicts? If I change a line of code several times and rebase on to a branch that changed the same lines of code, how are you sure what the right one is?

sunnyps 6mo ago
JJ can save conflict related state with the change so that you don't need to resolve a conflict in the middle of a stack of changes for rebasing to continue for the remaining changes. Concretely, it uses a "conflict algebra" where it can track the impact of a conflict as it propagates through the stack of rebased changes: https://docs.jj-vcs.dev/latest/technical/conflicts/ https://docs.jj-vcs.dev/latest/technical/conflicts/
- waisbrot 6mo ago
  That sounds like https://git-scm.com/book/en/v2/Git-Tools-Rerere https://git-scm.com/book/en/v2/Git-Tools-Rerere ?
  - martinvonz 6mo ago
    Not really very similar at all for the scenario discussed here. Rerere remembers how you have resolved a conflict before. It doesn't let you rebase a stack of commits that result in different conflicts. You will have to stop and resolve each conflict and then `git rebase --continue`. However, the conflict algebra does remove many common uses of rerere. See https://github.com/jj-vcs/jj/issues/175#issuecomment-1079831788 https://github.com/jj-vcs/jj/issues/175#issuecomment-1079831... for a longer discussion.
    - account42 6mo ago
      Avoiding manual conflict resolution isn't really a good thing though - conflicts are an indication that multiple different changes affect some code and you really should think hard about what the combination of them should be. Even what git does automatically already can be dangerous.
      - martinvonz 6mo ago
        I agree, but that doesn't seem relevant. I did not say the jj automatically resolves conflicts.
- palata 6mo ago
  But what does that bring? Your code won't compile as long as you don't fix the conflicts, so anyway you have to fix them when you rebase, right?
  - compiler-guy 6mo ago
    You have to fix them at some point, but not in the middle of doing other things. Right now. With no possible way to make progress elsewhere while deferring this decision.