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by epolanski 610 days ago
I'm not doing it wrong, I'm questioning whether it's worth the effort.

I have spent hours rebasing on very active branches when a merge would've taken minutes (as many colleagues do) just because "it's a best practice" but I've never got to fully appreciate the benefits.

3 comments

You don't have to keep rebasing your entire history on long-running branches. That will generate a ton of conflicts. But before you wrap it up it would be preferable for you to reduce your changes into one or a handful of stand-alone commits. If you're going to rebase often onto very active branches then you need to reduce the commits as much as possible to minimize the work involved. Ideally you could get other people to coordinate their work too.

The main reason people want to rebase instead of merging is to keep the commit history from looking like a bowl of spaghetti. A commit history like that is hard to navigate, and more likely to contain a lot of frivolous edits.

You should do the squashing/fixing regularly too, not once right at the end. Again, rebasing gives you the chance to fix these things as soon as it happens, rather than deal with one massive merge conflict at the end of a long running feature branch.
Also if you use rerere you don't really spend much time doing repetitive rebases after the first rebase
merge feature branches when reintegrating main, squash merge onto the main branch when you’re finished - best of both worlds imo

I never need to rebase, or unfuck a botched rebase or go reflog diving - and the commit history is linear where it matters.

Makes the history less useful for bisection - you'll always land on a squash merge rather than the specific commit that caused the problem.
In practice that's never been a problem for me. Work is delivered in functional units and segmented "sections" of code are basically useless on their own for the purpose of debugging.
So here's the thing: if you are putting more work into rebasing but not getting anything more out of it, you are doing it wrong.

You should always do the easiest thing that gets you what you want, otherwise you're just doing pointless work. If you and your colleagues are happy merging and you find that easier, that's what you should be doing.

Rebasing supports a totally different workflow. With a rebase I can submit a well-formed set of changes for review that are conflict free. You can't do that with merging. With merging you submit a bunch of crap "history" that nobody will ever look at and the project maintainer has to deal with the conflicts.

Merge commits look like this (newest to oldest):

    * Final tweaks
    * Merge master branch
    * Implement bar
    * Fix foo
    * Merge master branch
    * Shit I did on Wednesday before lunch
    * Implement foo
    * End of day
Totally impenetrable mess that nobody will ever look at.

Rebased commits look like this:

    * Add customise option to UI
    * Add use case baz
    * Extend model to support bar
    * Refactor model foo
These can be reviewed in insolation and when approved they merge without conflict.

If you want to do this but none of your colleagues are on board and you don't have the swing to make them, then I'm sorry. But you are wasting your time rebasing in that case. :(

Doesn't the rebased commits example take longer to put together than the merge commits example (where you'd likely want to just squash the merge commits)?

The merge version looks like the way code is actually written in practice to me, so doesn't the rebased version take extra time to create after you're done adding code? E.g. the "Add use case baz" rebase commit isn't likely to be a simple squashing of commits from the merge version, but cherrypicking specific lines from multiple commits.

I fully agree the rebased version is nicer, but I'm not seeing anyone talk about how much extra time it takes. Or you're doing it in a way that doesn't take much time somehow?

Yeah, it takes longer, but with the right tools and practice it doesn't take much longer. The main thing is rebasing often, reordering commits, using commit --amend, fixup commits, git autofixup and rebase --autosquash. That and being determined to deliver rebased commits from the start.

I'm not saying that every single feature must be split into multiple commits. If it's one change then just keep amending that one change as you go. But quite often you'll identify standalone changes as you go, like refactors, little unrelated bugfixes you find as you go etc. When this happens I'll commit that unrelated change separately and rebase to reorder it so it comes first, then continue amending my feature commit.

The paradigm shift for a lot of people is not to think of git as tracking history. Nobody cares about that. It's useless to you and doubly useless for everyone else. Think instead about tracking changes. I don't need to know every key press, every dead end explored or what you did on Tuesday afternoon. I want to know what changes are being applied to the project.

> Yeah, it takes longer, but with the right tools and practice it doesn't take much longer.

Maybe it depends on the kind of feature as well? I do the rebase with clean separate commits approach when it's easy, where reordering and squashing commits doesn't create tricky conflicts.

But for more exploratory stuff like UI/UX changes where I'm moving blocks of the UI around, and making changes in multiple files to add plumbing to get data where it needs to go, and changing it after demoing and getting feedback, it can get really messy with lots of dead-ends you backtrack out of later.

For that kind of work, it's probably easier to start again in a new branch, figure out some logical way to group the changes, then copy in code snippets from the other branch rather than rebasing? I can't see how this would be worth the effort in most cases though. The more granular commits helps figuring out where a bug got introduced, but then I don't think this happens often and when it does it's usually pretty obvious which lines of code caused the bug even in a large commit e.g. if dates are now being formatted weirdly, look for changes to code that does stuff with dates.