patch 8.2.1489: Vim9: error when setting an option with setbufvar()

Problem:    Vim9: error when setting an option with setbufvar().
Solution:   Do not get a number from a string value. (closes #6740)

src/evalvars.c

@@ -3292,6 +3292,24 @@ getwinvar(
     --emsg_off;
 }
 
+/*
+ * Set option "varname" to the value of "varp" for the current buffer/window.
+ */
+    static void
+set_option_from_tv(char_u *varname, typval_T *varp)
+{
+    long	numval = 0;
+    char_u	*strval;
+    char_u	nbuf[NUMBUFLEN];
+    int		error = FALSE;
+
+    if (!in_vim9script() || varp->v_type != VAR_STRING)
+	numval = (long)tv_get_number_chk(varp, &error);
+    strval = tv_get_string_buf_chk(varp, nbuf);
+    if (!error && strval != NULL)
+	set_option_value(varname, numval, strval, OPT_LOCAL);
+}
+
 /*
  * "setwinvar()" and "settabwinvar()" functions
  */
@@ -3304,7 +3322,6 @@ setwinvar(typval_T *argvars, int off)
     int		need_switch_win;
     char_u	*varname, *winvarname;
     typval_T	*varp;
-    char_u	nbuf[NUMBUFLEN];
     tabpage_T	*tp = NULL;
 
     if (check_secure())
@@ -3325,17 +3342,7 @@ setwinvar(typval_T *argvars, int off)
 	       || switch_win(&save_curwin, &save_curtab, win, tp, TRUE) == OK)
 	{
 	    if (*varname == '&')
-	    {
+		set_option_from_tv(varname + 1, varp);
-		long	numval;
-		char_u	*strval;
-		int		error = FALSE;
-
-		++varname;
-		numval = (long)tv_get_number_chk(varp, &error);
-		strval = tv_get_string_buf_chk(varp, nbuf);
-		if (!error && strval != NULL)
-		    set_option_value(varname, numval, strval, OPT_LOCAL);
-	    }
 	    else
 	    {
 		winvarname = alloc(STRLEN(varname) + 3);
@@ -3759,7 +3766,6 @@ f_setbufvar(typval_T *argvars, typval_T *rettv UNUSED)
     buf_T	*buf;
     char_u	*varname, *bufvarname;
     typval_T	*varp;
-    char_u	nbuf[NUMBUFLEN];
 
     if (check_secure())
 	return;
@@ -3772,19 +3778,12 @@ f_setbufvar(typval_T *argvars, typval_T *rettv UNUSED)
     {
 	if (*varname == '&')
 	{
-	    long	numval;
-	    char_u	*strval;
-	    int		error = FALSE;
 	    aco_save_T	aco;
 
 	    // set curbuf to be our buf, temporarily
 	    aucmd_prepbuf(&aco, buf);
 
-	    ++varname;
+	    set_option_from_tv(varname + 1, varp);
-	    numval = (long)tv_get_number_chk(varp, &error);
-	    strval = tv_get_string_buf_chk(varp, nbuf);
-	    if (!error && strval != NULL)
-		set_option_value(varname, numval, strval, OPT_LOCAL);
 
 	    // reset notion of buffer
 	    aucmd_restbuf(&aco);

src/testdir/test_vim9_func.vim

@@ -1391,6 +1391,18 @@ def Test_readdir()
    eval expand('.')->readdirex({e -> e.name[0] !=# '.'})
 enddef
 
+def Test_setbufvar()
+   setbufvar(bufnr('%'), '&syntax', 'vim')
+   assert_equal('vim', &syntax)
+   setbufvar(bufnr('%'), '&ts', 16)
+   assert_equal(16, &ts)
+   settabwinvar(1, 1, '&syntax', 'vam')
+   assert_equal('vam', &syntax)
+   settabwinvar(1, 1, '&ts', 15)
+   assert_equal(15, &ts)
+   setlocal ts=8
+enddef
+
 def Fibonacci(n: number): number
   if n < 2
     return n

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1489,
 /**/
     1488,
 /**/