Show HN: Deff – Side-by-side Git diff review in your terminal

113 points by flamestro a day ago on hackernews | 63 comments

I have been using https://github.com/jeffkaufman/icdiff for the longest time to get side by side diffs.

I also use icdiff, but it is good to have the file-awareness for git diff esp. the ability to quickly skip files that I know aren't important.

Amorymeltzer | a day ago

For that in particular, I use delta (<https://github.com/dandavison/delta>) with `side-by-side = true` enabled. I find I use both icdiff and delta side-by-side on a regular basis.

: behnamoh | a day ago
Delta is so much faster than icdiff too.

[OP] flamestro | a day ago

This looks great as well! I personally prefer a bit more context. Thats why I added a bit more of it to deff. It also allows to mark files as reviewed by pressing `r` which is quite handy for my flow.

rileymichael | a day ago

getting users to adopt a new tool with its own incantations is a tough sell. git supports specifying an external pager so folks can plug in alternatives (such as https://github.com/dandavison/delta) while still using the familiar git frontend

yottamus | a day ago

    git difftool --tool=vimdiff

metalliqaz | a day ago

but is it blazingly fast?

: syngrog66 | a day ago
if its not in Rust or browser-based or a "cloud" service or the result of multi-GWH of LLM "training" or a VSCode plugin or ideally all of the prior then the HN kids wont be interested :-)

[OP] flamestro | a day ago

I personally find vimdiff a bit harder to navigate for my usecase. The reason is that I am context unaware of the file often in larger projects and wanted something that allows me to check all lines in a touched file. However, I have to admit vimdiff comes quite close to what I need and is a great tool!

PhilipRoman | a day ago

zr?

vim folds are fully programmable. For me a bigger issue was git calling vimdiff for each file, which I fixed with my own difftool: https://gist.github.com/PhilipRoman/60066716b5fa09fcabfa6c95...

: anitil | 22 hours ago
I ran in to a couple problems when trying that script (details below), but I'm really happy that you shared it, because I had not seen ':windo diffthis' before, and that method of scripting diffs. I'll definitely be customising it!
(I found that my mac machine doesn't support the '-printf' option, and also I was attempting to run 'git bvd main' on a branch but it seems it does a recursive directory diff, so I'll use 'git diff --name-only' as the input to the awk command).
Edit: worked nicely! I haven't used tabs much in vim so is a slightly new workflow but otherwise very handy
: devnonymous | 12 hours ago
> For me a bigger issue was git calling vimdiff for each file,
If you configure vimdiff as the difftool in your git config, just doing a `git diff` would show you the diff for each file sequentially.

jbaber | 10 hours ago

I wrote a script that takes two git commits and opens all changed files in vimdiff tabs side by side. I find lots of things too hard to see in github gui. It depends one [tpope's vim-fugitive].

[tpope's vim-fugitive]: https://github.com/tpope/vim-fugitive

I'll paste it next time I'm on that machine.

llbbdd | a day ago

I was looking for a good TUI tool for diffs recently, but I'm not sure yet if what I want exists already (and I don't think this tool does it (yet?)). I've been moving my workflow out of VSCode as I'm using TUI-driven coding agents more often lately but one thing I miss from my VSCode/GitHub workflow is the ability to provide a comment on lines or ranges in a diff to provide targeted feedback to the agent. Most diff tools seem to be (rightfully) focused on cleanly visualizing changes and not necessarily iterating on the change.

I admit I haven't looked super hard yet, I settled on configuring git to use delta [0] for now and I'm happy with it, but I'm curious if anyone has a workflow for reviewing/iterating on diffs in the terminal that they'd be willing to share. Also open to being told that I'm lightyears behind and that there's a better mental model for this.

[0] https://github.com/dandavison/delta/

kodomomo | a day ago

Octo [0] for nvim lets you submit reviews, add comments on ranges, reply to threads, etc.

This in conjunction with gh-dash [1] to launch a review can get you a pretty nice TUI review workflow.

[0] https://github.com/pwntester/octo.nvim

[1] https://github.com/dlvhdr/gh-dash

*Edit: I see you meant providing feedback to an agent, not a PR. Well that's what I get for reading too fast.

llbbdd | a day ago

No problem, I appreciate another reason to look at Neovim; I do sometimes have a need to interact with GH's actual PR flow and once I've moved the rest of my workflow out of VSCode, Neovim looks like the best option for the last mile of actually writing and editing code. I just have to commit the time to set it up with everything I probably take for granted in VSCode's editor.

: Imustaskforhelp | 13 hours ago
Micro editor is a great choice as well imo but I don't think that micro has the thriving plugin ecosystem as compared to neovim but it is possible to make plugins for micro editor as well
https://github.com/micro-editor/plugin-channel
Link to Micro editor: https://micro-editor.github.io/

mckn1ght | a day ago

I use delta for quick diffs in a shell (along with the -U0 option on git-diff), but in my claude workflow, i have a 3 pane setup in tmux: :| where the right side is a claude session, the top left is emacs opened to magit, and the bottom left is a shell. Magit makes navigating around a diff pretty easy (as well as all the other git operations), and I can dive into anything and hand edit as well.

jfyne | a day ago

Not TUI based but I made something called meatcheck. The idea being that the LLM requests a review from the human, you can leave inline comments like a PR review.

Once you submit it outputs to stdout and the agent reads your comments and actions them.

https://github.com/jfyne/meatcheck

: llbbdd | a day ago
Thank you! At a glance this is very close to what I had in mind, especially with the straightforward output format, I'll give this a try.

coryrc | a day ago

magit

[OP] flamestro | a day ago

I was also searching for some time, but most of them did not have enough context for my workflow tbh. So thats why I decided to make deff. Another good one I liked is vimdiff

thamer | a day ago

I had tried `delta` a few years ago but eventually went with `diff-so-fancy`[1]

The two are kind of similar if I remember correctly, and both offer a lot of config options to change the style and more. I mostly use it for diffs involving long lines since it highlights changes within a line, which makes it easier to spot such edits.

I have an alias set in `~/.gitconfig` to pipe the output of `git diff` (with options) to `diff-so-fancy` with `git diffs`:

    diffs = "!f() { git diff $@ | diff-so-fancy; }; f"

[1] https://github.com/so-fancy/diff-so-fancy

: petepete | 23 hours ago
You can do this with diff-highlight, which comes packaged with git. No extra packages needed.

agavra | 22 hours ago

Checkout https://github.com/agavra/tuicr - it's built exactly for this purpose (reviewing code in your terminal and then adding comments and exporting it to an agent to fix).

jamiecode | a day ago

The specific gap side-by-side covers for me is reviewing changes on a remote box without firing up an IDE. Delta is great but keeps the unified format. icdiff does the split view but is pretty barebones. So there's definitely space here.

What nobody's mentioned yet is difftastic. Takes a completely different approach - parses syntax trees instead of lines, so indentation changes and bracket shuffles don't show up as noise. Worth a look if you're comparing options.

Main question I'd have: how does it hold up on large files? 5k+ line diffs are where most of these tools either choke or produce unreadable output. That'd be the test I'd run first.

: rileymichael | a day ago
delta supports split view: https://dandavison.github.io/delta/side-by-side-view.html
: [OP] flamestro | a day ago
So I tested this on huge files (checking cargo lock for instance) and it is super fast in the navigation of those. Until now I did not encounter any issue with bigger files (around 4k-6k changes but also only 4k-6k lines).

ZoomZoomZoom | a day ago

Why shouldn't this be a simple wrapper to tie Delta to some kind of file browser or a thing like television[1]?

[1]: https://alexpasmantier.github.io/television/

: syngrog66 | a day ago
television??

teddyh | a day ago

  emacs --eval='(ediff-files "file1" "file2")'

(The “|” key toggles side-by-side view.)

: [OP] flamestro | a day ago
Yes, but emacs < vim

k_bx | a day ago

What I would love to see is "tig" replacement that is:

- even faster, especially if you have couple thousand files and just want to press "u" for some time and see them very quickly all get staged

- has this split-view diff opened for a file

Otherwise tig is one of my favorite tools to quickly commit stuff without too many key presses but with review abilities, i have its "tig status" aliased to "t"

raphinou | a day ago

Looks interesting. I'm currently using https://tuicr.dev/ , of which I like that the first screen it shows is the choice of commit range you want to review. Might be something to consider for deff?

hatradiowigwam | a day ago

vimdiff is pretty fast, and is likely installed on your linux system without you realizing it.

: [OP] flamestro | a day ago
Its a great tool, but misses some of the context I needed.

insane_dreamer | a day ago

we need something like this in lazygit -- which is excellent all around but lacking in visual diffing/merging.

What is most useful though is a 3-panel setup, like JetBrains -- still the best git client I have worked with.

[OP] flamestro | a day ago

What would the third panel contain in this case? Do you mean the setup that IntelliJ has in merge conflicts?

: insane_dreamer | 18 hours ago
yes, it shows the final merge (what was accepted from the left and right panels); very handy

lolive | 11 hours ago

unfortunately for terminal lovers, the best .gitconfig snippet is still this:

  [diff]
    tool = intellij
  [difftool "intellij"]
    cmd = idea diff \"$LOCAL\" \"$REMOTE\"
  [merge]
    tool = intellij
  [mergetool "intellij"]
    cmd = idea merge \"$LOCAL\" \"$REMOTE\" \"$BASE\" \"$MERGED\"
    trustExitCode = true

dec0dedab0de | a day ago

looks pretty good at a glance, though I would like to see three views for handling conflicts. Target on the left, source on the right, and the combined result in the middle.

...I really just like the way the Jetbrains IDEs do it, and I wish there were a TUI version that I could launch automatically from the git cli.

greatgib | a day ago

It blows my mind that nowadays, some random tools on internet tells you to do "curl -fsSL https://.... | bash" to install some "binary" things and a lot of people will do it without hesitation.

It probably explains why there is so many data leaks recently but it is like we did a 20 years jump back in time in terms of security in just a few years.

[OP] flamestro | a day ago

I get the hesitation :D But the code is open and the install.sh is as minimal as it gets tbh. Still, as said, I get the hesitation. What a time to be alive.

It does not install binaries, it builds the binary by checking out the project basically. You can also do the process manually and use the tool.

: warkdarrior | a day ago
> But the code is open and the install.sh is as minimal as it gets tbh.
I bet 99.9999% of users do not review the code nor the install script.

holoduke | a day ago

Cowboys rule the internet.

pwdisswordfishy | 23 hours ago

One day folks who live inside commandlines and TUIs all day will realize that there's nothing particular about webapps or the sandboxes that they execute in that requires we build exclusively graphical runtimes around them, instead of taking advantage of the same security and distribution model for programs accessible and usable from within terminal emulator.

jaden | 23 hours ago

Is it that different from downloading and running a binary?

: greatgib | 20 hours ago
No, but who said that downloading and running a random binary found on internet is a good idea?
As I said, it's like being back 20 years back in the past.

duskdozer | 10 hours ago

How else are you going to get your openclaw to run blazingly fast??

But seriously, I think there's a bit of overzealousness/misalignment in security lately with a disregard for usability and privacy, making people less tolerant of dealing with inconveniences.

zem | a day ago

will this play well with jj?

suralind | 23 hours ago

What you want is difftastic. No need to thank me.

spartanatreyu | 22 hours ago

You definitely need a gif or apng file showing it's use in the github readme.

And a link to an asciicinema would help a lot too.

---

Also, I'm not sure how useful the side-by-side view is.

The second example (https://github.com/flamestro/deff/blob/main/docs/example_02....) is confusing.

The left side has lines 1365-1371 having the same code as lines 1374-1380 on the right side, yet they're not aligned with each other.

Most diff views would put padding between lines 1364-1365 on the left side so lines 1365-1371 are aligned with 1374-1380 on the right side.

agavra | 22 hours ago

I just built a version of this a month ago that also allows you to add review comments so you can export them back to an Agent to fix: https://github.com/agavra/tuicr

Great work on deff, would love to brainstorm here :)

ivanjermakov | 21 hours ago

8 terminal lines are taken by the tool's UI. Could have been 2.

tty456 | 21 hours ago

So, basically 'vim -d' in rust? cool

sourcegrift | 19 hours ago

Does it show moved codeblocks like reviewboard. Is that the second screenshot

esafak | 16 hours ago

Any chance of binstall support? https://github.com/cargo-bins/cargo-binstall

riteshyadav02 | 14 hours ago

Very cool. How are you handling large diffs performance-wise? Are you rendering the whole buffer or virtualizing the viewport?

Also curious why you chose Rust TUI instead of building on top of something like delta.

toastal | 13 hours ago

kitty terminal has diff like this builtin https://sw.kovidgoyal.net/kitty/kittens/diff/

I use it with

    darcs diff --diff-command="kitten diff %1 %2"

: tmarice | 13 hours ago
Nice, I did not know about this!
I feel Kitty doesn't get enough love, it's all ghostty this, ghostty that, but Kitty has been my top performing terminal emulator for 10 years now.

xmorse | 12 hours ago

Check out Critique too if you are looking for a side by side diffs TUI

It uses opentui, the same framework uses by opencode.

It can also render diffs to images, pdf and html. Very useful for agents to share diffs in remote environments like Openclaw or Kimaki

https://github.com/remorses/critique

def13 | 8 hours ago

I’m not really sure what would pull me away for a vim based solution for viewing diffs (current using codediff.nvim). For a git client in general, I use a cli/tui based solution (lazygit or plain git depending on what I need to do) but when it comes to directly manipulating text why would I throw away all the muscle memory and custom configuration of my editor for a comparatively bare bones standalone tui?