patch 9.1.1814: Patch v9.1.1812 causes crashes

Problem:  Patch v9.1.1812 causes crashes
Solution: Revert v9.1.1812

Revert "patch 9.1.1812: completion: flicker with slow LSPs"
This reverts commit 71b97f2905.

fixes: #18450

Signed-off-by: Christian Brabandt <cb@256bit.org>

src/globals.h

@@ -1133,9 +1133,6 @@ EXTERN int	secure INIT(= FALSE);
 				// allowed, e.g. when sourcing .exrc or .vimrc
 				// in current directory
 
-EXTERN int	no_flush INIT(= 0);
-				// non-zero to prevent flushing output buffer
-
 EXTERN int	textlock INIT(= 0);
 				// non-zero when changing text and jumping to
 				// another window or editing another buffer is

src/insexpand.c

@@ -3601,18 +3601,8 @@ expand_by_function(int type, char_u *base, callback_T *cb)
     // Insert mode in another buffer.
     ++textlock;
 
-    // Suppress flushing of the output buffer. Without this, text removed
-    // temporarily by ins_compl_delete() is flushed to the terminal and shown
-    // as deleted, only to be redrawn later. This causes visible flicker (typed
-    // chars disappear and reappear) when a user func (e.g. an LSP server)
-    // responds slowly. Such funcs may call sleep(), which indirectly triggers
-    // out_flush(). We want deleted text to remain visible.
-    ++no_flush;
-
     retval = call_callback(cb, 0, &rettv, 2, args);
 
-    --no_flush;
-
     // Call a function, which returns a list or dict.
     if (retval == OK)
     {
@@ -6103,6 +6093,7 @@ find_next_completion_match(
     int		compl_fuzzy_match = (cur_cot_flags & COT_FUZZY) != 0;
     string_T	*leader;
 
+
     while (--todo >= 0)
     {
 	if (compl_shows_dir_forward() && compl_shown_match->cp_next != NULL)
@@ -6212,7 +6203,7 @@ find_next_completion_match(
  *
  * Note that this function may be called recursively once only.  First with
  * "allow_get_expansion" TRUE, which calls ins_compl_get_exp(), which in turn
- * calls this with "allow_get_expansion" FALSE (via ins_compl_check_keys()).
+ * calls this function with "allow_get_expansion" FALSE.
  */
     static int
 ins_compl_next(

src/term.c

@@ -2772,7 +2772,7 @@ out_flush(void)
 {
     int	    len;
 
-    if (no_flush > 0 || out_pos == 0)
+    if (out_pos == 0)
 	return;
 
     // set out_pos to 0 before ui_write, to avoid recursiveness

src/testdir/test_ins_complete.vim

@@ -420,7 +420,7 @@ func Test_CompleteDoneDict()
   au CompleteDone * :call <SID>CompleteDone_CheckCompletedItemDict(0)
 
   set complete=.,F<SID>CompleteDone_CompleteFuncDict
-  execute "normal dda\<C-N>\<C-Y>"
+  execute "normal a\<C-N>\<C-Y>"
   set complete&
 
   call assert_equal(['one', 'two'], v:completed_item[ 'user_data' ])
@@ -473,7 +473,7 @@ func Test_CompleteDoneDictNoUserData()
   let s:called_completedone = 0
 
   set complete=.,F<SID>CompleteDone_CompleteFuncDictNoUserData
-  execute "normal dda\<C-N>\<C-Y>"
+  execute "normal a\<C-N>\<C-Y>"
   set complete&
 
   call assert_equal('', v:completed_item[ 'user_data' ])

src/version.c

@@ -729,6 +729,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1814,
 /**/
     1813,
 /**/