feat: pretty highlight for unified diff

[justinmk]

Problem

Nvim's default unified diff is very sparse.

Expected behavior

unified diff should look nicer, similar to github:

Proposal

• use colorized result from git diff --color-words="[^[:space:]]|[[:alnum:]]+"
• or upstream something to Nvim
• or use code from one of these:
  • https://github.com/YouSame2/inlinediff-nvim
  • https://github.com/barrettruth/diffs.nvim
  • https://github.com/esmuellert/vscode-diff.nvim
  • https://github.com/tanvirtin/vgit.nvim
  • https://github.com/chrisgrieser/nvim-tinygit
  • https://github.com/axkirillov/unified.nvim
  • https://github.com/nvim-mini/mini.diff
    • "word diff" which is basically a hack that slices two lines into "one character per line" and applies vim.diff to that.

[justinmk]

Related...

• feat(diff): add language injection for changes nvim-treesitter/nvim-treesitter#8239

[lewis6991]

You may also want to look at gitsigns inline_preview.

It works by creating space using virtual lines, and then placing a floating window on top of those lines with the buffer set to the buffer being compared against. This is the only way I think currently works if you want full syntax highlighting. Otherwise you need to implement your own highlighter if you just want to use virtual lines.

Currently, it only works for a single hunk, but I want to support it for all hunks in a buffer, however doing so would require lots of management of floating windows.

[lewis6991]

word diff" which is basically a hack that slices two lines into "one character per line" and applies vim.diff to that.

Gitsigns does the exact same thing. I don't consider this a hack. Do you have other ideas on how this could be implemented leveraging existing diff libraries? One of the reasons I didn't like the chardiff pr in core, was because it implemented its own diff algorithm rather than leverage proper ones.

[justinmk]

I don't consider this a hack. Do you have other ideas on how this could be implemented leveraging existing diff libraries?

Those were @echasnovski's words! 😂 He was probably being humble :)

Thanks for your notes/hints.

[echasnovski]

word diff" which is basically a hack that slices two lines into "one character per line" and applies vim.diff to that.

Gitsigns does the exact same thing.

For the record, when answering the question in private I did mention that 'mini.diff' probably (wasn't sure and didn't have time to check) adapted this approach from 'gitsigns.nvim' with adjustments.

Those were @echasnovski's words! 😂 He was probably being humble :)

To me it does feel like a hack because it a) requires non-trivial amount of work to function properly; and b) utilizes features (vim.text.diff()) in a context that they were not quite meant to be used.