patch 8.0.0486: crash and endless loop when closing windows in autocmd commit https://github.com/vim/vim/commit/8c752bd6c4af54c0b7bac35a39acc2bf16015f85 Author: Bram Moolenaar <Bram@vim.org> Date: Sun Mar 19 17:09:56 2017 +0100 patch 8.0.0486: crash and endless loop when closing windows in autocmd Problem: Crash and endless loop when closing windows in a SessionLoadPost autocommand. Solution: Check for valid tabpage. (partly neovim #6308)

" Tests for the Tcl interface.

if !has('tcl')
  finish
end

function Test_tcldo()
  " Check deleting lines does not trigger ml_get error.
  new
  call setline(1, ['one', 'two', 'three'])
  tcldo ::vim::command %d_
  bwipe!

  " Check switching to another buffer does not trigger ml_get error.
  new
  let wincount = winnr('$')
  call setline(1, ['one', 'two', 'three'])
  tcldo ::vim::command new
  call assert_equal(wincount + 1, winnr('$'))
  bwipe!
  bwipe!
endfunc