vim-patch:9.1.1742: complete: preinsert does not work well with 'autocomplete' (#35692)

Problem:  complete: preinsert does not work well with preinsert
Solution: Make "preinsert" completeopt value work with autocompletion
          (Girish Palya)

This change extends Insert mode autocompletion so that 'preinsert' also
works when 'autocomplete' is enabled.

Try: `:set ac cot=preinsert`

See `:help 'cot'` for more details.

closes: vim/vim#18213

fa6fd41a94

Co-authored-by: Girish Palya <girishji@gmail.com>

test/functional/ui/cursor_spec.lua

@@ -262,7 +262,7 @@ describe('ui/cursor', function()
         m.attr = { background = Screen.colors.DarkGray }
       end
       if m.id_lm then
-        m.id_lm = 76
+        m.id_lm = 77
         m.attr_lm = {}
       end
     end

test/old/testdir/test_cmdline.vim

@@ -475,12 +475,13 @@ func Test_highlight_completion()
   call assert_equal('"hi clear', getreg(':'))
 
   " A cleared group does not show up in completions.
+  hi clear Added
   hi Anders ctermfg=green
-  call assert_equal(['Aardig', 'Added', 'Anders'], getcompletion('A', 'highlight'))
+  call assert_equal(['Aardig', 'Anders'], getcompletion('A', 'highlight'))
   hi clear Aardig
-  call assert_equal(['Added', 'Anders'], getcompletion('A', 'highlight'))
+  call assert_equal(['Anders'], getcompletion('A', 'highlight'))
   hi clear Anders
-  call assert_equal(['Added'], getcompletion('A', 'highlight'))
+  call assert_equal([], getcompletion('A', 'highlight'))
 endfunc
 
 func Test_getcompletion()

test/old/testdir/test_ins_complete.vim

@@ -5472,7 +5472,7 @@ func Test_autocomplete_timer()
   call assert_equal(-1, b:selected)
 
   " Test 7: Following 'cot' option values have no effect
-  set completeopt=menu,menuone,noselect,noinsert,longest,preinsert
+  set completeopt=menu,menuone,noselect,noinsert,longest
   set complete=.,Ffunction('TestComplete'\\,\ [0\\,\ 0\\,\ 0])
   let g:CallCount = 0
   call feedkeys("Sab\<c-n>\<F2>\<F3>\<Esc>0", 'tx!')
@@ -5691,4 +5691,109 @@ func Test_autocompletedelay()
   call StopVimInTerminal(buf)
 endfunc
 
+func Test_autocomplete_completeopt_preinsert()
+  func GetLine()
+    let g:line = getline('.')
+    let g:col = col('.')
+  endfunc
+
+  call Ntest_override("char_avail", 1)
+  new
+  inoremap <buffer><F5> <C-R>=GetLine()<CR>
+  set completeopt=preinsert autocomplete
+  call setline(1, ["foobar", "foozbar"])
+  call feedkeys("Go\<ESC>", 'tx')
+
+  func DoTest(typed, line, col)
+    call feedkeys($"S{a:typed}\<F5>\<ESC>", 'tx')
+    call assert_equal(a:line, g:line)
+    call assert_equal(a:col, g:col)
+  endfunc
+
+  call DoTest("f", 'foo', 2)
+  call DoTest("fo", 'foo', 3)
+  call DoTest("foo", 'foo', 4)
+  call DoTest("foob", 'foobar', 5)
+  call DoTest("foob\<BS>", 'foo', 4)
+  call DoTest("foob\<BS>\<BS>", 'foo', 3)
+  call DoTest("foo\<BS>", 'foo', 3)
+  call DoTest("foo\<BS>\<BS>", 'foo', 2)
+  call DoTest("foo\<BS>\<BS>\<BS>", '', 1)
+
+  call DoTest("foo \<BS>", 'foo', 4)
+  call DoTest("foo \<BS>\<BS>", 'foo', 3)
+
+  call DoTest("f\<C-N>", 'foozbar', 8)
+  call DoTest("f\<C-N>\<C-N>", 'foobar', 7)
+  call DoTest("f\<C-N>\<C-N>\<C-N>", 'foo', 2)
+  call DoTest("f\<C-N>\<C-N>\<C-N>\<C-N>", 'foozbar', 8)
+  call DoTest("f\<C-N>\<C-N>\<C-N>\<C-N>\<C-P>", 'foo', 2)
+  call DoTest("f\<C-N>\<C-N>\<C-N>\<C-N>\<C-P>\<C-P>", 'foobar', 7)
+  call DoTest("f\<C-P>", 'foobar', 7)
+  call DoTest("fo\<BS>\<C-P>", 'foobar', 7)
+
+  call DoTest("zar\<C-O>0f", 'foozar', 2)
+  call DoTest("zar\<C-O>0f\<C-Y>", 'foozar', 4)
+  call DoTest("zar\<C-O>0f\<C-Y>\<BS>", 'foozar', 3)
+
+  call DoTest("zar\<C-O>0f\<C-N>", 'foozbarzar', 8)
+  call DoTest("zar\<C-O>0f\<C-N>\<C-N>", 'foobarzar', 7)
+  call DoTest("zar\<C-O>0f\<C-N>\<C-N>\<C-N>", 'foozar', 2)
+  call DoTest("zar\<C-O>0f\<C-N>\<C-N>\<C-N>\<C-N>", 'foozbarzar', 8)
+  call DoTest("zar\<C-O>0f\<C-N>\<C-N>\<C-N>\<C-N>\<C-P>", 'foozar', 2)
+  call DoTest("zar\<C-O>0f\<C-N>\<C-N>\<C-N>\<C-N>\<C-P>\<C-P>", 'foobarzar', 7)
+  call DoTest("zar\<C-O>0f\<C-P>", 'foobarzar', 7)
+
+  " Should not work with fuzzy
+  set cot+=fuzzy
+  call DoTest("f", 'f', 2)
+
+  %delete _
+  let &l:undolevels = &l:undolevels
+  normal! ifoo
+  let &l:undolevels = &l:undolevels
+  normal! ofoobar
+  let &l:undolevels = &l:undolevels
+  normal! ofoobaz
+  let &l:undolevels = &l:undolevels
+
+  func CheckUndo()
+    let g:errmsg = ''
+    call assert_equal(['foo', 'foobar', 'foobaz'], getline(1, '$'))
+    undo
+    call assert_equal(['foo', 'foobar'], getline(1, '$'))
+    undo
+    call assert_equal(['foo'], getline(1, '$'))
+    undo
+    call assert_equal([''], getline(1, '$'))
+    later 3
+    call assert_equal(['foo', 'foobar', 'foobaz'], getline(1, '$'))
+    call assert_equal('', v:errmsg)
+  endfunc
+
+  " Check that switching buffer with "preinsert" doesn't corrupt undo.
+  new
+  setlocal bufhidden=wipe
+  inoremap <buffer> <F2> <Cmd>enew!<CR>
+  call feedkeys("if\<F2>\<Esc>", 'tx')
+  bwipe!
+  call CheckUndo()
+
+  " Check that closing window with "preinsert" doesn't corrupt undo.
+  new
+  setlocal bufhidden=wipe
+  inoremap <buffer> <F2> <Cmd>close!<CR>
+  call feedkeys("if\<F2>\<Esc>", 'tx')
+  call CheckUndo()
+
+  %delete _
+  delfunc CheckUndo
+
+  bw!
+  set cot& autocomplete&
+  delfunc GetLine
+  delfunc DoTest
+  call Ntest_override("char_avail", 0)
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab nofoldenable