patch 8.2.2136: Vim9: Using uninitialized variable

Problem:    Vim9: Using uninitialized variable.
Solution:   Initialize "len" to zero.  Clean up fnamemodify().

Author: brammool

src/filepath.c

@@ -1019,7 +1019,7 @@ f_fnamemodify(typval_T *argvars, typval_T *rettv)
     char_u	*fname;
     char_u	*mods;
     int		usedlen = 0;
-    int		len;
+    int		len = 0;
     char_u	*fbuf = NULL;
     char_u	buf[NUMBUFLEN];
 
@@ -1028,12 +1028,13 @@ f_fnamemodify(typval_T *argvars, typval_T *rettv)
 	return;
     fname = tv_get_string_chk(&argvars[0]);
     mods = tv_get_string_buf_chk(&argvars[1], buf);
-    if (fname == NULL)
+    if (mods == NULL || fname == NULL)
 	fname = NULL;
-    else if (mods != NULL && *mods != NUL)
+    else
     {
 	len = (int)STRLEN(fname);
-	(void)modify_fname(mods, FALSE, &usedlen, &fname, &fbuf, &len);
+	if (mods != NULL && *mods != NUL)
+	    (void)modify_fname(mods, FALSE, &usedlen, &fname, &fbuf, &len);
     }
 
     rettv->v_type = VAR_STRING;

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2136,
 /**/
     2135,
 /**/