commit https://github.com/vim/vim/commit/5f1032d2a55b9417a0a6fa225e35089c98a5a419 Author: Bram Moolenaar <Bram@vim.org> Date: Tue Jun 7 22:16:36 2016 +0200 patch 7.4.1906 Problem: Collapsing channel buffers and searching for NL does not work properly. (Xavier de Gary, Ramel Eshed) Solution: Do not assume the buffer contains a NUL or not. Change NUL bytes to NL to avoid the string is truncated.

" 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