Comment by lmm 9 hours ago
Why do you care? Small commits are great for git bisect, and having to come up with a fancy message can break your flow. Code reviewers generally review a whole PR diff, not the individual commits. Fussing about commit messages smacks of prioritising aesthetics over functionality.
> git-bisect works best when every commit works, contains a single idea, and stacks in a linear history. That works best in a publicly visible branch, and is why it is helpful to squash an entire pull-request into a single, atomic commit — one which clearly defines the change from before- to after-this-feature.
Disagree; git-bisect works best when every commit is small and most commits work (in particular, as long as any broken commit is likely to have a neighbour that works - isolated bad commits aren't a problem (that's what skip is for, and it's easy enough to include that in your script - you do automate your bisects, right?), long chains of bad commits are). Squashing means your bisect will land on a squashed commit, when it's only really done half the job. (In particular, the very worst case, where every single one of your intermediate commits was broken, is the same as the case you get when you squash)
> When it’s ready for the attention of your peers then you absolutely ought to dress it up as smartly as possible. It’s at that point that you write a cover letter for your change: what was the situation before, why that was bad, what this patch does instead, and how you proved in practice that it made things better (tests!)
And that's what the PR description is for! You don't have to destroy all your history to make one.
Thanks for responding. Everything you say I agree with. I think our differences lie in the scope of how much of my private activity do I want to share in public.
You’re right that GitHub, GitLab et al let you use their tooling to write the final commit message (for the merge commit or squash commit). My preference has always been to do that in git itself.
In both cases you end up with a single atomic commit that represents the approved change and its description. For me, the commit is created the moment a review is requested, instead of from the moment it is approved and landed. One reason this is particularly useful is that you can now treat the commit as if it had already landed on the main branch. (It is easier to share, cherry-pick, rebase, etc. — easier than doing so with a branch of many commits, in my experience.)
Prospective changes do not change type (from branch to squashed commit or merge commit) either, when they are approved, which simplifies these workflows.
You can also use just plain git and make sure the merge-commit has a useful message, while leaving the work-branch unsquashed and available to explore and bisect when necessary. The main branch looks as neat as when using squashes, and using something like git log --merges --first-parent all the small commits on the work-branches are hidden anyway. It looks just like when using atomic commits, but the extra details are still there when someone needs them.
I've followed your same approach but switched to having just "most of the commits work" after I found out about git bisect --skip.
Not sure it really has huge benefits, but I guess something like this should work:
``` #!/bin/sh N=20 msg_len=$(git log -1 --pretty=%B | wc -c) if [ "$msg_len" -lt "$N" ]; then exit 125 fi # Here you would run your actual test and report 0 (good), 1 (bad) as needed exit 0 ```
> When it’s ready for the attention of your peers then you absolutely ought to dress it up as smartly as possible. It’s at that point that you write a cover letter for your change: what was the situation before, why that was bad, what this patch does instead, and how you proved in practice that it made things better (tests!)
This is an extremely opinionated and time consuming way of working. Maybe in this context it makes sense (nvidia driver kernel somethings), but I don't think it's universally the best way to write code together.
Small commits where each commit represents nothing of value and doesn't compile are terrible for git bisect. And for code review.
A code reviewer doesn't care that you spent 10 days across 100 commits tweaking some small piece of code, the code reviewer cares about what you ended up with.
The bisecter probably wants to compile the code at every commit to try and see if they can reproduce a bug. Commits which don't compile force the bisecter to step through commits one by one until they find one which compiles, linearizing a process which should be logarithmic.
> having to come up with a fancy message
Message doesn’t need to be fancy, but it should describe what you did. Being unable to articulate your actions is a thought smell. It’s often seen when the developer is trying stuff until it sticks and needs a commit because the only way to test the fix is in a testing environment, two bad practices.
It makes it bitch to know why given change was made.
If you change 2 lines 8 times to check something just squash the commit, saves everyone the hassle
The only sane thing a maintainer can do with something like this is squash it into one commit. So if you care about `git bisect` then you don't want this.
Why do I care? Interesting question. I'm generally a person who cares, I guess. In this specific case it seems analogous to a mechanic having a tidy workshop. Would you leave your bicycle with someone head to toe in grease and tools strewn all over the place? I wouldn't.
When I was a kid and my family first moved to the US my dad used to take me for walks. He didn't know anything about the country (couldn't speak English yet) so the only thing he could comment on was what he imagined the prices of all the houses were. Some people just feel the need to comment on something even when they don't understand anything.
You have the right idea but, I believe, the wrong reasoning with your first two arguments.
git-bisect works best when every commit works, contains a single idea, and stacks in a linear history. These features are of most use in a publicly visible branch, and is why it is helpful to squash an entire pull-request into a single, atomic commit — one which clearly defines the change from before- to after-this-feature.
You’re welcome to do whatever you like in your private branch of course, but once you are presenting work for someone else to review then it’s consistent with “I believe this is now complete, correct, working, and ready for review” to squash everything into a single commit. (The fact that code review tools show the sum of all the minor commits is a workaround for people that don’t do this, not a feature to support them!)
In terms of ‘git commit -m wip’: no one is saying you should wear a suit and tie around the house, but when you show up for your senate hearing, presenting yourself formally is as necessary as it is to leave the slides, sweat pants, and tee shirt at home.
Yes, commit early and often while in the flow of putting together a new idea or piece of work. When it’s ready for the attention of your peers then you absolutely ought to dress it up as smartly as possible. It’s at that point that you write a cover letter for your change: what was the situation before, why that was bad, what this patch does instead, and how you proved in practice that it made things better (tests!)
Or to use a different analogy: they don’t want every draft of your master’s thesis from start to finish and they’ll be annoyed if they have to fix basic typos for you that should’ve been caught before the final draft. They don’t care about the typos you already found either, nor how you fixed them. They just want the final draft and to discuss the ideas of the final draft!
Conversely if your master’s thesis or git branch contains multiple semantically meaningful changes — invent calculus then invent gravity / add foo-interface to lib_bar then add foo-login to homepage — then it probably ought to be two code reviews.