3 ms·

How to build a `Git diff` driver

132 points by zdw 6mo ago

deleted 6mo ago
[deleted]
gritzko 6mo ago
I recently implemented a diff driver as part of git-dogs. The integration part Claude one-shotted. Mine is token based: https://replicated.wiki/blog/img/difflet.png https://replicated.wiki/blog/img/difflet.png The set of git tools itself, very much in development: https://github.com/gritzko/git-dogs https://github.com/gritzko/git-dogs
yboris 6mo ago
Related: my favorite viewer is diff2html-cli which lets you see the diff in your browser: https://diff2html.xyz/ https://diff2html.xyz/
- JavierFlores09 6mo ago
  my favorite online diff viewer so far is https://diffs.dev/ https://diffs.dev/, very straightforward. Diff2html looks cool too given it can work in terminal
- forrestthewoods 6mo ago
  Why not just use Araxis Merge or Beyond Compare?
  - WalterGR 6mo ago
    Some alternatives to paid solutions: WinMerge is excellent, open source, and while Windows-only, it runs well in Wine without needing any tweaks. Kdiff is open source, cross-platform, and while I personally don’t love it, it supports 4-pane merge, which is quite ergonomic and rare.
- danvk 6mo ago
  You might also like webdiff, which does something similar https://github.com/danvk/webdiff https://github.com/danvk/webdiff (I built this years ago and still use it every day.)
- Joker_vD 6mo ago
  I've personally settled on running diff's output into diff-highlight (supplied with Git!) and into ansi2html (one of them; there are many versions of it, and you can write one yourself in about 20 minutes, you only really need very few escape sequences handled, and then wrangle with CSS for additional 2 hours), and calling xdg-open on the temporary file. A neat pipeline, all in all.
semanticintent 6mo ago
The point about textconv being sufficient in many cases is worth emphasizing — the cases where you actually need a full diff driver are when the file has semantics that text diff destroys. OpenAPI specs are a good example: a field rename looks like a deletion + addition in text diff but is a single semantic change. I ran into the same thing building a semantic diff for a DSL compiler — text diff would report noise on every whitespace or reorder change, but the meaningful question is "which fields changed type, which statements were added or removed." Once you're operating on the AST the signal-to-noise ratio is completely different.
tarun_anand 6mo ago
Is there an OSS git diff for images and multimedia?
- alkh 6mo ago
  I bet there might be something but you can probably create your own by using ImageMagick[1] and some manipulations. For ex. for images, I would create a temp file or use a process substitition + open on OSX or xdg-open on Linux. Here is a first post about Or you can make it even easier(cause the output is only a text) and simply print out the difference in metadata directly. You might need some other tools like ImageMagick but at least no shenanigans with viewing binary data as part of your diff. [1]https://stackoverflow.com/questions/5132749/diff-an-image-using-imagemagick https://stackoverflow.com/questions/5132749/diff-an-image-us...
- da_rob 6mo ago
  Yes, there is imgap: https://github.com/roblillack/imgap https://github.com/roblillack/imgap You can use it to create delta images for git diff but also to interactively compare changes via git difftool.
faangguyindia 6mo ago
Nothing beats sublime merge for this.
pabs3 6mo ago
https://diffoscope.org/ https://diffoscope.org/ is my favorite diff tool.
davvid 6mo ago
git-difftool is quite helpful, especially if you want an easy way to integrate existing file-based diff tools.

132 points by zdw 6mo ago

deleted 6mo ago

[deleted]

I recently implemented a diff driver as part of git-dogs. The integration part Claude one-shotted. Mine is token based: https://replicated.wiki/blog/img/difflet.png https://replicated.wiki/blog/img/difflet.png The set of git tools itself, very much in development: https://github.com/gritzko/git-dogs https://github.com/gritzko/git-dogs

yboris 6mo ago

Related: my favorite viewer is diff2html-cli which lets you see the diff in your browser: https://diff2html.xyz/ https://diff2html.xyz/

JavierFlores09 6mo ago
my favorite online diff viewer so far is https://diffs.dev/ https://diffs.dev/, very straightforward. Diff2html looks cool too given it can work in terminal
forrestthewoods 6mo ago
Why not just use Araxis Merge or Beyond Compare?
- WalterGR 6mo ago
  Some alternatives to paid solutions: WinMerge is excellent, open source, and while Windows-only, it runs well in Wine without needing any tweaks. Kdiff is open source, cross-platform, and while I personally don’t love it, it supports 4-pane merge, which is quite ergonomic and rare.
danvk 6mo ago
You might also like webdiff, which does something similar https://github.com/danvk/webdiff https://github.com/danvk/webdiff (I built this years ago and still use it every day.)
Joker_vD 6mo ago
I've personally settled on running diff's output into diff-highlight (supplied with Git!) and into ansi2html (one of them; there are many versions of it, and you can write one yourself in about 20 minutes, you only really need very few escape sequences handled, and then wrangle with CSS for additional 2 hours), and calling xdg-open on the temporary file. A neat pipeline, all in all.

semanticintent 6mo ago

The point about textconv being sufficient in many cases is worth emphasizing — the cases where you actually need a full diff driver are when the file has semantics that text diff destroys. OpenAPI specs are a good example: a field rename looks like a deletion + addition in text diff but is a single semantic change. I ran into the same thing building a semantic diff for a DSL compiler — text diff would report noise on every whitespace or reorder change, but the meaningful question is "which fields changed type, which statements were added or removed." Once you're operating on the AST the signal-to-noise ratio is completely different.

tarun_anand 6mo ago

Is there an OSS git diff for images and multimedia?

alkh 6mo ago
I bet there might be something but you can probably create your own by using ImageMagick[1] and some manipulations. For ex. for images, I would create a temp file or use a process substitition + open on OSX or xdg-open on Linux. Here is a first post about Or you can make it even easier(cause the output is only a text) and simply print out the difference in metadata directly. You might need some other tools like ImageMagick but at least no shenanigans with viewing binary data as part of your diff. [1]https://stackoverflow.com/questions/5132749/diff-an-image-using-imagemagick https://stackoverflow.com/questions/5132749/diff-an-image-us...
da_rob 6mo ago
Yes, there is imgap: https://github.com/roblillack/imgap https://github.com/roblillack/imgap You can use it to create delta images for git diff but also to interactively compare changes via git difftool.

faangguyindia 6mo ago

Nothing beats sublime merge for this.

pabs3 6mo ago

https://diffoscope.org/ https://diffoscope.org/ is my favorite diff tool.

davvid 6mo ago

git-difftool is quite helpful, especially if you want an easy way to integrate existing file-based diff tools.