collect commit hash from vim plugins using vimscript

commit-hash.vim

let s:packpath = expand('~/.local/share/nvim/site/pack/minpac')
let s:hash_dir = expand('~/.local/share/nvim/site/pack/minpac/hashes')
let s:pattern = '/{opt,start}'

function! s:save_hashes() abort
  let plugin_dirs = glob(s:packpath .. s:pattern, 1, 1)

  if empty(plugin_dirs)
    return
  endif

  let hashes = []

  for dir in plugin_dirs
    for plug in split(glob(dir . '*'), '\n')
      let githash = system('cd ' . shellescape(plug) . ' && git rev-parse HEAD')
      call add(hashes, fnamemodify(plug, ':t') . ': ' . githash)
    endfor
  endfor

  if empty(glob(s:hash_dir))
    call mkdir(s:hash_dir, 'p')
  end

  call writefile(hashes, s:hash_dir . '/commits_' . strftime('%Y-%m-%d@%H:%M:%S') . '.txt')
endfunction

command! PackSave call s:save_hashes()