vim-patch:8.0.1223: crash when using autocomplete and tab pages

Problem:    Crash when using autocomplete and tab pages.
Solution:   Check if the current tab changed. (Christian Brabandt, closes
            vim/vim#2239)

9ad89c6c4f

src/nvim/misc1.c

@@ -1469,7 +1469,7 @@ void ins_char_bytes(char_u *buf, size_t charlen)
     }
   }
 
-  char_u *newp = (char_u *) xmalloc((size_t)(linelen + newlen - oldlen));
+  char_u *newp = xmalloc((size_t)(linelen + newlen - oldlen));
 
   // Copy bytes before the cursor.
   if (col > 0) {
@@ -1478,7 +1478,10 @@ void ins_char_bytes(char_u *buf, size_t charlen)
 
   // Copy bytes after the changed character(s).
   char_u *p = newp + col;
-  memmove(p + newlen, oldp + col + oldlen, (size_t)(linelen - col - oldlen));
+  if (linelen > col + oldlen) {
+    memmove(p + newlen, oldp + col + oldlen,
+            (size_t)(linelen - col - oldlen));
+  }
 
   // Insert or overwrite the new character.
   memmove(p, buf, charlen);

src/nvim/popupmnu.c

@@ -567,6 +567,7 @@ static int pum_set_selected(int n, int repeat)
         && (repeat <= 1)
         && (vim_strchr(p_cot, 'p') != NULL)) {
       win_T *curwin_save = curwin;
+      tabpage_T *curtab_save = curtab;
       int res = OK;
 
       // Open a preview window.  3 lines by default.  Prefer
@@ -647,7 +648,12 @@ static int pum_set_selected(int n, int repeat)
           curwin->w_cursor.lnum = 1;
           curwin->w_cursor.col = 0;
 
-          if ((curwin != curwin_save) && win_valid(curwin_save)) {
+          if ((curwin != curwin_save && win_valid(curwin_save))
+              || (curtab != curtab_save && valid_tabpage(curtab_save))) {
+            if (curtab != curtab_save && valid_tabpage(curtab_save)) {
+              goto_tabpage_tp(curtab_save, false, false);
+            }
+
             // When the first completion is done and the preview
             // window is not resized, skip the preview window's
             // status line redrawing.

src/nvim/testdir/test_popup.vim

@@ -570,4 +570,41 @@ func Test_completion_clear_candidate_list()
 endfunc
 
 
+func Test_popup_and_preview_autocommand()
+  " This used to crash Vim
+  if !has('python')
+    return
+  endif
+  let h = winheight(0)
+  if h < 15
+    return
+  endif
+  new
+  augroup MyBufAdd
+    au!
+    au BufAdd * nested tab sball
+  augroup END
+  set omnifunc=pythoncomplete#Complete
+  call setline(1, 'import os')
+  " make the line long
+  call setline(2, '                                 os.')
+  $
+  call feedkeys("A\<C-X>\<C-O>\<C-N>\<C-N>\<C-N>\<enter>\<esc>", 'tx')
+  call assert_equal(["import os", "                                 os.EX_IOERR", ''], getline(1,'$'))
+  call assert_equal(1, winnr('$'))
+  " previewwindow option is not set
+  call assert_equal(0, &previewwindow)
+  norm! gt
+  call assert_equal(0, &previewwindow)
+  norm! gT
+  call assert_equal(12, tabpagenr('$'))
+  tabonly
+  pclose
+  augroup MyBufAdd
+    au!
+  augroup END
+  augroup! MyBufAdd
+  bw!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab