What Changes the Most
jj log --no-graph -r 'ancestors(trunk()) & committer_date(after:"1 year ago")' \
-T 'self.diff().files().map(|f| f.path() ++ "\n").join("")' \
| sort | uniq -c | sort -nr | head -20
jj log --no-graph -r 'ancestors(trunk()) & ~merges()' \
-T 'self.author().name() ++ "\n"' \
| sort | uniq -c | sort -nr
jj log --no-graph -r 'ancestors(trunk()) & description(regex:"(?i)fix|bug|broken")' \
-T 'self.diff().files().map(|f| f.path() ++ "\n").join("")' \
| sort | uniq -c | sort -nr | head -20
jj log --no-graph -r 'ancestors(trunk())' \
-T 'self.committer().timestamp().format("%Y-%m") ++ "\n"' \
| sort | uniq -c
jj log --no-graph \
-r 'ancestors(trunk()) & committer_date(after:"1 year ago") & description(regex:"(?i)revert|hotfix|emergency|rollback")'
Not meaning to offend anyone: Nix is cool, but adds complexity. And as a disclaimer: I used jujutsu for a few months and went back to git. Mostly because git is wired in my fingers, and git is everywhere. Those examples of what jujutsu can do and not git sound nice, but in those few months I never remotely had a need for them, so it felt overkill for me.
The most frequent "complex" command I use is to find commits in my name that are unsigned, and then sign them (this is owing to my workflow with agents that commit on my behalf but I'm not going to give agents my private key!)
jj log -r 'mine() & ~signed()'
# or if yolo mode...
jj sign -r 'mine() & ~signed()'
All joking aside, it really is a chronic problem in the corporate world. Most codebases I encounter just have "changed stuff" or "hope this works now".
It's a small minority of developers (myself included) who consider the git commit log to be important enough to spend time writing something meaningful.
AI generated commit messages helps this a lot, if developers would actually use it (I hope they will).
git log --oneline a sprinkle of your personal sauce on .claude goes a long way :)
Random, subjective, or written in a state of mental exhaustion commit messages.
I also love the switcheroo the author made: git not logs. But hey :)
# summary: print a helpful summary of some typical metrics
summary = "!f() { \
printf \"Summary of this branch...\n\"; \
printf \"%s\n\" $(git rev-parse --abbrev-ref HEAD); \
printf \"%s first commit timestamp\n\" $(git log --date-order --format=%cI | tail -1); \
printf \"%s latest commit timestamp\n\" $(git log -1 --date-order --format=%cI); \
printf \"%d commit count\n\" $(git rev-list --count HEAD); \
printf \"%d date count\n\" $(git log --format=oneline --format=\"%ad\" --date=format:\"%Y-%m-%d\" | awk '{a[$0]=1}END{for(i in a){n++;} print n}'); \
printf \"%d tag count\n\" $(git tag | wc -l); \
printf \"%d author count\n\" $(git log --format=oneline --format=\"%aE\" | awk '{a[$0]=1}END{for(i in a){n++;} print n}'); \
printf \"%d committer count\n\" $(git log --format=oneline --format=\"%cE\" | awk '{a[$0]=1}END{for(i in a){n++;} print n}'); \
printf \"%d local branch count\n\" $(git branch | grep -v \" -> \" | wc -l); \
printf \"%d remote branch count\n\" $(git branch -r | grep -v \" -> \" | wc -l); \
printf \"\nSummary of this directory...\n\"; \
printf \"%s\n\" $(pwd); \
printf \"%d file count via git ls-files\n\" $(git ls-files | wc -l); \
printf \"%d file count via find command\n\" $(find . | wc -l); \
printf \"%d disk usage\n\" $(du -s | awk '{print $1}'); \
printf \"\nMost-active authors, with commit count and %%...\n\"; git log-of-count-and-email | head -7; \
printf \"\nMost-active dates, with commit count and %%...\n\"; git log-of-count-and-day | head -7; \
printf \"\nMost-active files, with churn count\n\"; git churn | head -7; \
}; f"
The most changed file is the one people are afraid of touching?
I ran this on the repo I have open and after I filtered out the non code files it really can only tell me which features we worked on in the last year. It says more about how we decided to split up the features into increments than anything to do with bugs and “churn”.
Nobody is afraid of changing it.
In my experience, when the team doesn't squash, this will reflect the messiest members of the team.
The top committer on the repository I maintain has 8x more commits than the second one. They were fired before I joined and nobody even remembers what they did. Git itself says: not much, just changing the same few files over and over.
Of course if nobody is making a mess in their own commits, this is not an issue. But if they are, squash can be quite more truthful.
The takeaway from my experiment is that you can really tell a lot by how / when / what people commit, but conclusions are very hard to generalize.
For example, I've also stumbled upon the "merge vs squash" issue, where squashes compress and mostly hide big chunks of history, so drawing conclusions from a squashed commit is basically just wild guessing.
(The author of course has also flagged this. But I just wanted to add my voice: yeah, careful to generalize.)
¹ Nothing is ever finished.
git log -i -E --grep="\b(fix|fixed|fixes|bug|broken)\b" --name-only --format='' | sort | uniq -c | sort -nr | head -20
I have a project with a large package named "debugger". The presence of "bug" within "debugger" causes the original command to go crazy.
For the "bus factor", there's one guy and then there's me, but I stopped being a primary contributor to this project nearly two years ago, lol.
Most good projects end up solving a problem permanently and if there is no salary to protect with bogus new features it is then to be considered final?
https://gist.github.com/aeimer/8edc0b25f3197c0986d3f2618f036...
Squash-merge workflows are stupid (you lose information without gaining anything in return as it was easily filterable at retrieval anyway) and only useful as a workaround for people not knowing how to use git, but git stores the author and committer names separately, so it doesn't matter who merged, but rather whether the squashed patchset consisted of commits with multiple authors (and even then you could store it with Co-authored-by trailers, but that's harder to use in such oneliners).
With a squash merge one PR is one commit, simple, clean and easy to roll back or cherry-pick to another branch.
1. Open PR page in whatever tool you're using
2. Read title + description to see what's up
3. Swap to diff and start reading through the changes
4. Comment and/or approve
I've never heard anyone bothering to read the previous commit messages for a second, why would they care?
this forces the reviewer to view the entire diff at once, which can greatly increase the cognitive load vs. being able to view diffs of logical units of work
for tiny PRs it may not matter, but for substantial PRs it can matter a lot
Having atomic commits lets you actually benefit from having them. Suddenly you don't have to perform weird dances with interconnected PRs with dependencies as "PR too big" is not such a problem anymore as long as commits are digestible; you can have things property bisectable; you can preserve shared authorship; you can range-diff and have a better view on what and how changed between review passes, and so on...
The unit of change is commit, and PRs group commits you want someone to pull. If you don't want or need any of that, you're just sending a patch file in a needlessly elaborate way.
This is in fact what hg does with amending changesets and yes it works far better. Keep PRs small and atomic and you never need to worry about what happens intra-pr. If you need bigger units of work that's what stacking is for.
I meant "shared place" as an open review request or a shared branch rather than shared underlying infrastructure. Shared by people's minds.
It just feels wrong to force push, destroying stuff that used to be there.
And I don't have the time or energy to bisect through my shitty PR commits and combine them into something clean looking - I can just squash instead.
Things that aren't referenced by anything anymore will eventually get garbage collected and actually destroyed, but you can just keep a reference somewhere to prevent that from happening if you need. Or even disable garbage collection completely.
Looks like people's fears about git come just from not knowing what it does.
it's hard to say fully, but unless a changeset is quite small or otherwise is basically 0% or 100%, there are usually smaller steps.
like kind of contrived but say you have one function that uses a helper. if there's a bug in the function, and it turns out to fix that it makes a lot more sense to change the return type of the helper, you would make commit 1 to change the return type, then commit 2 fix the bug. would these be separate PRs? probably not to me but I guess it depends on your project workflow. keeping them in separate commits even if they're small lets you bisect more easily later on in case there was some unforseen or untested problem that was introduced, leading you to smaller chunks of code to check for the cause.
I've never considered how an engineer approaches a problem. As long as I can understand the fundamental change and it passes preflights/CI I don't care if it was scryed from a crystal ball.
This does mean it is on the onus of the engineer to explain their change in natural language. In their own words of course.
Not often, but given that it costs me nothing to have it all in my tree, I'd rather have it than not.
Then I must be a bad reviewer. In a past job, I had a colleague who meticulously crafted his commits - his PRs were a joy to review because I could go commit by commit in logical chunks, rather than wading through a single 3k line diff. I tried to do the same for him and hope I succeeded.
And here's a slightly smaller one which isn't about "miscellaneous fixes": https://lore.kernel.org/netdev/20260408122027.80303-1-xuanzh...
Some of these commits even get reviewed by different maintainers before being merged, which is common when a patchset touches several subsystems at once.
For other cases, you lose the information about why things are this way. It's too verbose to //comment on every like with how it came to be this way but on (non-rare in total, but rare per line) occasion it's useful to see what the change was that made the line be like this, or even just who to potentially ask for help (when >1 person worked on a feature branch, which I'd say is common)
I use it like that too and yet the reviewers don't get to see these commits. Git has very powerful tools for manipulating the commit graph that many people just don't bother to learn. Imagine if I sent a patchset to the Linux Kernel Mailing List containing such "fix typo", "please work now", "wtf" patches - my shamelessness has its limits!
Can you explain to me what an avid squash-merger puts into the commit message of the squashed commit composed of commits "argh, let's see if this works", "crap, the CI is failing again, small fix to see if it works", and "pushing before leaving for vacation" ?
Usually pretty close to what the PR title + description are actually, just without the videos and screenshots.
Example:
feat(ui): Add support for tagging users
* Users can be tagged via the user page * User tags visible in search results (configurable)
etc..
I don't need to spend extra time cleaning up my git commits and force-pushing on the PR branch, losing context for code reviews etc. Nor does anyone have to see my shitty angry commits when I tried to figure out why Playwright tests ran on my machine and failed in the CI for 10 commits.
If you update a PR with review feedback, you shouldn’t change existing commits because GitHub’s tools for showing you what has changed since your last review assume you are pushing new commits.
But then you don’t want those multiple commits addressing PR feedback to merge as they’re noise.
So sure, there’s workflows with Git that doesn’t need squashing. But they’re incompatible with GitHub, which is at least where I keep my code today.
Is it perfect? No. But neither is git, and I live in the world I am given.
And to counter some specific points:
* In a github PR, you write the main commit msg and description once per PR, then you tack on as many commits as you want, and everyone knows they're all just pieces of work towards the main goal of the eventually squashed commit
* Forcing a clean up every time you make a new commit is not only annoying extra work, but it also overwrites history that might be important for the review of that PR (but not important for what ends up in main branch).
* When follow up is requested, you can just tack on new commits, and reviewers can easily see what new code was added since their last review. If you had to force overwrite your whole commit chain for the PR, this becomes very annoying and not useful to reviewers.
* In the end, squash merge means you clean up things once, instead of potentially many times
Yeah, I can imagine it being annoying that sqashing in that case wipes the author attribution, when not everybody is doing PRs against the main branch.
However, calling all squash-merge workflows "stupid" without any nuance.. well that's "stupid" :)
Also I can understand not squashing if the contribution comes from outside the organization. But in that case, I would expect a cleaned up history. But if every contribution is from members of the team, who can merge their own PR, squash merge is an easy way to get a clean history. Especially when most PR should be a single commit.
For really large PRs, I’m more inclined to agree with you, but those should probably have their own small-PR-and-squash-merge flow that naturally cleans up their git history, anyway.
I categorically disagree that squash-merge is “stupid” but agree there are many ways to skin this cat.
This list is also one of many arguments for maintaining good Git discipline.
What a weird check and assumption.
I mean, surely most of the "20 most-changed files" will be README and docs, plus language-specific lock-files etc. ?
So if you're not accounting for those in your git/jj syntax you're going to end up with an awful lot of false-positive noise.
You're right about package.json, pnpm-lock etc though, but those are easy to filter out if the project in question uses them.
You're right, perhaps I should have said CHANGELOG etc.
Although some projects e.g. bump version numbers in README or add extra one-liner examples ....
Another one I do, is:
$alias gss='git for-each-ref --sort=-committerdate'
$gss
ce652ca83817e83f6041f7e5cd177f2d023a5489 commit refs/heads/project-feature-development
ce652ca83817e83f6041f7e5cd177f2d023a5489 commit refs/remotes/origin/project-feature-development
1ef272ea1d3552b59c3d22478afa9819d90dfb39 commit refs/remotes/origin/feature/feature-removal-from-good-state
c30b4c67298a5fa944d0b387119c1e5ddaf551f1 commit refs/remotes/origin/feature/feature-removal
eda340eb2c9e75eeb650b5a8850b1879b6b1f704 commit refs/remotes/origin/HEAD
eda340eb2c9e75eeb650b5a8850b1879b6b1f704 commit refs/remotes/origin/main
3f874b24fd49c1011e6866c8ec0f259991a24c94 commit refs/heads/project-bugfix-emergency
...
*Mainline linux*
Most changed files: pretty much what I expected for 1 and 2... the "cutting edge" of Linux development over other OSes -- bpf and containers. The bpf verifier and AMD GPU driver might get a boost in this list due to sheer LoCs in those files (26K and 14K respectively). An intel equivalent of amdgpu_dm is #21 in the list (drivers/gpu/drm/i915/display/intel_display.c) and nvidia is nowhere to be seen (presumably due to out-of-tree modules/blobs?).
186 kernel/bpf/verifier.c
174 fs/namespace.c
162 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
161 kernel/sched/ext.c
159 fs/f2fs/f2fs.h
10399 Christoph Hellwig -> I only know his name because of drama last year regarding rust bindings to DMA subsystem
8481 Mauro Carvalho Chehab -> I also know his name from the classic "Mauro, shut the fuck up!" Linus rant
8413 Takashi Iwai -> Listed as maintainer for sound subsystem, I think he manages ALSA
8072 Al Viro -> His name is all over bunch of filesystem code
1477 drivers/gpu/drm/i915/intel_display.c
1406 MAINTAINERS
1390 sound/pci/hda/patch_realtek.c
1102 drivers/gpu/drm/i915/i915_drv.h
943 arch/x86/kvm/x86.c
928 mm/page_alloc.c
871 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
862 drivers/gpu/drm/i915/i915_reg.h
840 fs/btrfs/inode.c
Most changed files: IR autovectorization code, riscv heuristics tables, and C++ template handling (pt.c is "paramaterized types").
152 gcc/tree-vect-stmts.cc
145 gcc/config/riscv/riscv.cc
131 gcc/tree-vect-loop.cc
116 gcc/cp/pt.cc
1017 gcc/dwarf2out.c
885 gcc/config/i386/i386.c
796 gcc/cp/cp-tree.h
740 gcc/config/rs6000/rs6000.c
720 gcc/cp/pt.c
This has not told me much other than where most of the functionality of this project lies.
Bus factor: Pretty huge. Not really an issue in this case due to lack of development I guess.
3298 Olivier Fourdan
530 Anonymous
319 Xfce Bot
121 Jasper Huijsmans
I think these massive open projects (excl xfwm) are generally pretty consistent code quality across the heavily trodden areas because of the amount of manpower available to refactor the pain points. I've yet to see an example of "god help you if you have to change that file" in e.g. linux, but I have of course seen that situation many times in large proprietary codebases.