Difftastic is a diff tool that uses treesitter parsing to compare code AST nodes instead of comparing lines. After following the instructions for use with git I’m seeing some very nice diffs when I run git diff or run git show --ext-diff. I thought it would be nice to get the same output for hunk diffs in the fugitive status window, and in fugitive buffers in general (which use the git filetype). But I haven’t seen any easy way to do it. Has anyone got a setup like this?

I can run a command in neovim like :Git show --ext-diff to get difftastic output in a buffer. I’m thinking maybe I can set up fugitive to use the --ext-diff flag by default, or set up some aliases. But there is no syntax highlighting for the difftastic outputs since the ANSI color codes that difftastic uses in interactive terminal output don’t work in neovim, and the syntax highlighting for the git filetype assumes standard diff output which is not compatible with difftastic output. For me losing colors is not a worthwhile trade for the otherwise more readable diff output.

My best idea right now is to set up a new filetype called difftastic, and write a new treesitter grammar or syntax plugin for it. Then set up some kind of neovim configuration to feed output from difftastic into buffers with the new filetype.

There is an open neovim issue discussing adding syntax-aware diffs directly to neovim, but that doesn’t seem to have gone anywhere.