patch 9.1.1381: completion: cannot return to original text

Problem:  Cannot return to the original text after selecting the next
          item when the currently selected item is the last one.
Solution: When continuing to move down past the last item, locate the
          original completion at the head/tail nodes of the completed
          linked list (glepnir).

closes: #17300

Signed-off-by: glepnir <glephunter@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/insexpand.c

@@ -5236,9 +5236,8 @@ find_comp_when_fuzzy(void)
 
     if ((is_forward && compl_selected_item == compl_match_arraysize - 1)
 	    || (is_backward && compl_selected_item == 0))
-	return compl_first_match != compl_shown_match ?
+	return match_at_original_text(compl_first_match)
-	    (is_forward ? compl_shown_match->cp_next : compl_first_match) :
+			    ? compl_first_match : compl_first_match->cp_prev;
-	    (compl_first_match->cp_prev ? compl_first_match->cp_prev : NULL);
 
     if (is_forward)
 	target_idx = compl_selected_item + 1;

src/testdir/test_ins_complete.vim

@@ -3387,11 +3387,15 @@ func Test_complete_opt_fuzzy()
     autocmd CompleteChanged * :call OnPumChange()
   augroup END
 
+  let g:change = 0
   func Omni_test(findstart, base)
     if a:findstart
       return col(".")
     endif
-    return [#{word: "foo"}, #{word: "foobar"}, #{word: "fooBaz"}, #{word: "foobala"}, #{word: "你好吗"}, #{word: "我好"}]
+    if g:change == 0
+      return [#{word: "foo"}, #{word: "foobar"}, #{word: "fooBaz"}, #{word: "foobala"}, #{word: "你好吗"}, #{word: "我好"}]
+    endif
+    return [#{word: "for i = .."}, #{word: "bar"}, #{word: "foo"}, #{word: "for .. ipairs"}, #{word: "for .. pairs"}]
   endfunc
 
   new
@@ -3488,6 +3492,15 @@ func Test_complete_opt_fuzzy()
   call feedkeys("Salpha bravio charlie\<CR>alpha\<C-X>\<C-N>\<C-X>\<C-N>\<C-X>\<C-N>\<ESC>", 'tx')
   call assert_equal('alpha bravio charlie', getline('.'))
 
+  set cot=fuzzy,menu,noinsert
+  call feedkeys(":let g:change=1\<CR>")
+  call feedkeys("S\<C-X>\<C-O>for\<C-N>\<C-N>\<C-N>", 'tx')
+  call assert_equal('for', getline('.'))
+  call feedkeys("S\<C-X>\<C-O>for\<C-P>", 'tx')
+  call assert_equal('for', getline('.'))
+  call feedkeys("S\<C-X>\<C-O>for\<C-P>\<C-P>", 'tx')
+  call assert_equal('for .. ipairs', getline('.'))
+
   " clean up
   set omnifunc=
   bw!

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1381,
 /**/
     1380,
 /**/