patch 9.1.1475: completion: regression when "nearest" in 'completeopt'

Problem:  completion: regression when "nearest" in 'completeopt'
Solution: fix compare function (Girish Palya)

closes: #17577

Signed-off-by: Girish Palya <girishji@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/insexpand.c

@@ -1404,7 +1404,7 @@ cp_compare_nearest(const void* a, const void* b)
 {
     int score_a = ((compl_T*)a)->cp_score;
     int score_b = ((compl_T*)b)->cp_score;
-    if (score_a < 0 || score_b < 0)
+    if (score_a == 0 || score_b == 0)
 	return 0;
     return (score_a > score_b) ? 1 : (score_a < score_b) ? -1 : 0;
 }

src/testdir/test_ins_complete.vim

@@ -4492,6 +4492,22 @@ func Test_nearest_cpt_option()
   exe "normal! of\<c-n>\<c-r>=PrintMenuWords()\<cr>"
   call assert_equal('f{''matches'': [''foo1'', ''foo3'', ''foo2''], ''selected'': -1}', getline(2))
 
+  " Multiple sources
+  func F1(findstart, base)
+    if a:findstart
+      return col('.') - 1
+    endif
+    return ['foo4', 'foo5']
+  endfunc
+  %d
+  set complete+=FF1
+  call setline(1, ["foo1", "foo2", "bar1", "foo3"])
+  exe "normal! 2jof\<c-n>\<c-r>=PrintMenuWords()\<cr>"
+  call assert_equal('f{''matches'': [''foo3'', ''foo2'', ''foo1'', ''foo4'', ''foo5''],
+        \ ''selected'': -1}', getline(4))
+  set complete-=FF1
+  delfunc F1
+
   set completeopt=menu,longest,nearest
   %d
   call setline(1, ["fo", "foo", "foobar", "foobarbaz"])

src/version.c

@@ -709,6 +709,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1475,
 /**/
     1474,
 /**/