commit https://github.com/vim/vim/commit/41e0f2f48f541eb2c8eb5620d3f1d270eb979154 Author: Bram Moolenaar <Bram@vim.org> Date: Tue Mar 8 14:44:42 2016 +0100 patch 7.4.1513 Problem: "J" fails if there are not enough lines. (Christian Neukirchen) Solution: Reduce the count, only fail on the last line.

" Test for joining lines.

func Test_join_with_count()
  new
  call setline(1, ['one', 'two', 'three', 'four'])
  normal J
  call assert_equal('one two', getline(1))
  %del
  call setline(1, ['one', 'two', 'three', 'four'])
  normal 10J
  call assert_equal('one two three four', getline(1))
  quit!
endfunc