vim-patch:8.2.0123: complete_info() does not work when CompleteDone is triggered

Problem:    complete_info() does not work when CompleteDone is triggered.
Solution:   Trigger CompleteDone before clearing the info.
17e04781f2

runtime/doc/autocmd.txt

@@ -596,6 +596,8 @@ CompleteChanged 					*CompleteChanged*
 CompleteDone			After Insert mode completion is done.  Either
 				when something was completed or abandoning
 				completion. |ins-completion|
+				|complete_info()| can be used, the info is
+				cleared after triggering CompleteDone.
 				The |v:completed_item| variable contains the
 				completed item.
 

src/nvim/edit.c

@@ -3385,6 +3385,7 @@ static bool ins_compl_prep(int c)
 {
   char_u *ptr;
   bool retval = false;
+  const int prev_mode = ctrl_x_mode;
 
   /* Forget any previous 'special' messages if this is actually
    * a ^X mode key - bar ^R, in which case we wait to see what it gives us.
@@ -3593,6 +3594,18 @@ static bool ins_compl_prep(int c)
 
       auto_format(FALSE, TRUE);
 
+      {
+        const int new_mode = ctrl_x_mode;
+
+        // Trigger the CompleteDone event to give scripts a chance to
+        // act upon the completion.  Do this before clearing the info,
+        // and restore ctrl_x_mode, so that complete_info() can be
+        // used.
+        ctrl_x_mode = prev_mode;
+        ins_apply_autocmds(EVENT_COMPLETEDONE);
+        ctrl_x_mode = new_mode;
+      }
+
       ins_compl_free();
       compl_started = false;
       compl_matches = 0;
@@ -3617,9 +3630,6 @@ static bool ins_compl_prep(int c)
        */
       if (want_cindent && in_cinkeys(KEY_COMPLETE, ' ', inindent(0)))
         do_c_expr_indent();
-      /* Trigger the CompleteDone event to give scripts a chance to act
-       * upon the completion. */
-      ins_apply_autocmds(EVENT_COMPLETEDONE);
     }
   } else if (ctrl_x_mode == CTRL_X_LOCAL_MSG)
     /* Trigger the CompleteDone event to give scripts a chance to act

src/nvim/testdir/test_ins_complete.vim

@@ -138,6 +138,8 @@ function! s:CompleteDone_CheckCompletedItemDict()
   call assert_equal( 'W',              v:completed_item[ 'kind' ] )
   call assert_equal( 'test',           v:completed_item[ 'user_data' ] )
 
+  call assert_equal('function', complete_info().mode)
+
   let s:called_completedone = 1
 endfunction