Function to toggle terminal creates extra empty buffer

Question

I have modified a function from CKolkey's dotfiles - ToggleTerminalDrawer (line 230) so that it works for Vim8.2 (instead of neovim). Here is my modified function now in my vimrc:

nnoremap <silent><leader>/           :call ToggleTerminalDrawer()<CR>
tnoremap <silent><leader>/ <C-\><C-n>:call ToggleTerminalDrawer()<CR>

let g:terminal_drawer = { 'win_id': v:null, 'buffer_id': v:null }
function! ToggleTerminalDrawer() abort
  if win_gotoid(g:terminal_drawer.win_id)
    hide
    set laststatus=2 showmode ruler
  else
    botright new
    if !g:terminal_drawer.buffer_id
      call term_start($SHELL)
      let g:terminal_drawer.buffer_id = bufnr("")
    else
      exec "buffer" g:terminal_drawer.buffer_id
      call RemoveEmptyBuffers()
    endif

    exec "resize" float2nr(&lines * 0.25)
    setlocal laststatus=0 noshowmode noruler
    setlocal nobuflisted
    startinsert!
    let g:terminal_drawer.win_id = win_getid()

  endif
endfunction

function! RemoveEmptyBuffers()
  let buffers = filter(range(1, bufnr('$')), 'buflisted(v:val) && empty(bufname(v:val)) && bufwinnr(v:val)<0 && !getbufvar(v:val, "&mod")')
  if !empty(buffers)
      silent exe 'bw ' . join(buffers, ' ')
  endif
endfunction

This works great most of the time. It toggles a terminal pane at the bottom of the editor, and always uses the same terminal buffer.

However, when the toggle is run and a Terminal buffer doesn't yet exist, it creates one terminal buffer (good, intended) and an extra blank buffer editor which I can write in - this is unintended. When this happens I always have to do :q to get rid of it. How do I modify this function to not cause that side effect?

Answer 1

Fixed by removing botright new and then calling botright call term_start($SHELL) (to start a Terminal buffer if one doesn't exist) or execute 'botright sbuffer' . g:terminal_drawer.buffer_id (to show the buffer) fixed it. Here is the full function now:

let g:terminal_drawer = { 'win_id': v:null, 'buffer_id': v:null }
function! ToggleTerminalDrawer() abort
  if win_gotoid(g:terminal_drawer.win_id)
    hide
    set laststatus=2 showmode ruler
  else
    if !g:terminal_drawer.buffer_id
      botright call term_start($SHELL)
      let g:terminal_drawer.buffer_id = bufnr("$")
    else
      execute 'botright sbuffer' . g:terminal_drawer.buffer_id
      exec 'normal! i'
    endif

    exec "resize" float2nr(&lines * 0.25)
    setlocal laststatus=0 noshowmode noruler
    setlocal nobuflisted
    let g:terminal_drawer.win_id = win_getid()

  endif
endfunction