patch 8.2.0507: getbufvar() may get the wrong dictionary

Problem:    Getbufvar() may get the wrong dictionary. (David le Blanc)
Solution:   Check for empty name. (closes #5878)

src/evalvars.c

@@ -2382,6 +2382,7 @@ find_var(char_u *name, hashtab_T **htp, int no_autoload)
 
 /*
  * Find variable "varname" in hashtab "ht" with name "htname".
+ * When "varname" is empty returns curwin/curtab/etc vars dictionary.
  * Returns NULL if not found.
  */
     dictitem_T *
@@ -3503,8 +3504,12 @@ f_getbufvar(typval_T *argvars, typval_T *rettv)
 	else
 	{
 	    // Look up the variable.
-	    // Let getbufvar({nr}, "") return the "b:" dictionary.
-	    v = find_var_in_ht(&buf->b_vars->dv_hashtab, 'b', varname, FALSE);
+	    if (*varname == NUL)
+		// Let getbufvar({nr}, "") return the "b:" dictionary.
+		v = &buf->b_bufvar;
+	    else
+		v = find_var_in_ht(&buf->b_vars->dv_hashtab, 'b',
+							       varname, FALSE);
 	    if (v != NULL)
 	    {
 		copy_tv(&v->di_tv, rettv);

src/testdir/test_functions.vim

@@ -841,6 +841,16 @@ func Test_getbufvar()
   call assert_equal('iso-8859-2', getbufvar(bufnr('%'), '&fenc'))
   close
 
+  " Get the b: dict.
+  let b:testvar = 'one'
+  new
+  let b:testvar = 'two'
+  let thebuf = bufnr()
+  wincmd w
+  call assert_equal('two', getbufvar(thebuf, 'testvar'))
+  call assert_equal('two', getbufvar(thebuf, '').testvar)
+  bwipe!
+
   set fileformats&
 endfunc
 

src/version.c

@@ -738,6 +738,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    507,
 /**/
     506,
 /**/