patch 9.1.1389: completion: still some issue when 'isexpand' contains a space

Problem:  Cannot get completion startcol when space is not the first
          trigger character (after v9.1.1383)
Solution: Detect the next comma followed by a space in the option string
          and use in next compare loop (glepnir)

closes: #17311

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

src/insexpand.c

@@ -3661,19 +3661,27 @@ f_complete_match(typval_T *argvars, typval_T *rettv)
     else
     {
 	char_u	    *p = ise;
+	char_u	    *p_space = NULL;
+
 	cur_end = before_cursor + (int)STRLEN(before_cursor);
 
 	while (*p != NUL)
 	{
 	    int	    len = 0;
-	    if (*p == ',' && *(p+1) == ' ' && (*(p+2) == ',' || *(p+2) == NUL))
+	    if (p_space)
 	    {
-		part[0] = ' ';
+		len = p - p_space - 1;
-		len = 1;
+		memcpy(part, p_space + 1, len);
-		p++;
+		p_space = NULL;
 	    }
 	    else
+	    {
+		char_u *next_comma = vim_strchr((*p == ',') ? p + 1 : p, ',');
+		if (next_comma && *(next_comma + 1) == ' ')
+		    p_space = next_comma;
+
 		len = copy_option_part(&p, part, MAXPATHL, ",");
+	    }
 
 	    if (len > 0 && len <= col)
 	    {

src/testdir/test_ins_complete.vim

@@ -4507,6 +4507,13 @@ func Test_complete_match()
   set ise=\ ,=
   call feedkeys("Sif true  \<ESC>:let g:result=complete_match()\<CR>", 'tx')
   call assert_equal([[8, ' ']], g:result)
+  call feedkeys("Slet a = \<ESC>:let g:result=complete_match()\<CR>", 'tx')
+  call assert_equal([[7, '=']], g:result)
+  set ise={,\ ,=
+  call feedkeys("Sif true  \<ESC>:let g:result=complete_match()\<CR>", 'tx')
+  call assert_equal([[8, ' ']], g:result)
+  call feedkeys("S{ \<ESC>:let g:result=complete_match()\<CR>", 'tx')
+  call assert_equal([[1, '{']], g:result)
 
   bw!
   unlet g:result

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1389,
 /**/
     1388,
 /**/