:DiffOrig but smarter

diff.md

:DiffOrig but smarter

This is an enhanced version of the snippet provided under :help diff-original-file.

Where the original :DiffOrig only shows differences between the buffer in memory and the file on disk, :Diff can be used in two ways:

• against the file on disk, like the original, with:

  :Diff
  

• against an arbitrary Git revision of the current file, with:

  :Diff HEAD
  

---

My Vim-related gists.

diff.vim

function! Diff(spec)
    vertical new
    setlocal bufhidden=wipe buftype=nofile nobuflisted noswapfile
        let cmd = "++edit #"
    if len(a:spec)
        let cmd = "!git -C " . shellescape(fnamemodify(finddir('.git', '.;'), ':p:h:h')) . " show " . a:spec . ":#"
    endif
    execute "read " . cmd
    silent 0d_
    diffthis
    wincmd p
    diffthis
endfunction
command! -nargs=? Diff call Diff(<q-args>)

This is quite an old gist but I guess some people may still use it. So it's probably worth noting that finddir() trick is not needed. Instead, we can force git to figure path itself:

let cmd = '!git -C #:p:h:S show '..a:spec..':./#:t:S'

-C option makes git to change its working directory first; then it's okay to use "single dot" as relative path inside any commit too.