[RFC] vim-patch:7.4.434

```
Problem:    gettabvar() is not consistent with getwinvar() and getbufvar().
Solution:   Return a dict with all variables when the varname is empty.
	    (Yasuhiro Matsumoto)

https://code.google.com/p/vim/source/detail?r=v7-4-434
```

Original patch:

```diff
diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -3575,6 +3575,8 @@ gettabvar({tabnr}, {varname} [, {def}])	
 		Get the value of a tab-local variable {varname} in tab page
 		{tabnr}. |t:var|
 		Tabs are numbered starting with one.
+		When {varname} is empty a dictionary with all tab-local
+		variables is returned.
 		Note that the name without "t:" must be used.
 		When the tab or variable doesn't exist {def} or an empty
 		string is returned, there is no error message.
diff --git a/src/eval.c b/src/eval.c
--- a/src/eval.c
+++ b/src/eval.c
@@ -12071,7 +12071,8 @@ f_gettabvar(argvars, rettv)
     typval_T	*argvars;
     typval_T	*rettv;
 {
-    tabpage_T	*tp;
+    win_T	*win, *oldcurwin;
+    tabpage_T	*tp, *oldtabpage;
     dictitem_T	*v;
     char_u	*varname;
     int		done = FALSE;
@@ -12083,13 +12084,21 @@ f_gettabvar(argvars, rettv)
     tp = find_tabpage((int)get_tv_number_chk(&argvars[0], NULL));
     if (tp != NULL && varname != NULL)
     {
+	/* Set curwin to be our win, temporarily.  Also set the tabpage,
+	 * otherwise the window is not valid. */
+	switch_win(&oldcurwin, &oldtabpage, win, tp, TRUE);
+
 	/* look up the variable */
-	v = find_var_in_ht(&tp->tp_vars->dv_hashtab, 0, varname, FALSE);
+	/* Let gettabvar({nr}, "") return the "t:" dictionary. */
+	v = find_var_in_ht(&tp->tp_vars->dv_hashtab, 't', varname, FALSE);
 	if (v != NULL)
 	{
 	    copy_tv(&v->di_tv, rettv);
 	    done = TRUE;
 	}
+
+	/* restore previous notion of curwin */
+	restore_win(oldcurwin, oldtabpage, TRUE);
     }
 
     if (!done && argvars[2].v_type != VAR_UNKNOWN)
diff --git a/src/testdir/test91.in b/src/testdir/test91.in
--- a/src/testdir/test91.in
+++ b/src/testdir/test91.in
@@ -55,6 +55,7 @@ STARTTEST
 :tabnew
 :tabnew
 :let t:var_list = [1, 2, 3]
+:let t:other = 777
 :let def_list = [4, 5, 6, 7]
 :tabrewind
 :$put =string(gettabvar(3, 'var_list'))
diff --git a/src/testdir/test91.ok b/src/testdir/test91.ok
--- a/src/testdir/test91.ok
+++ b/src/testdir/test91.ok
@@ -26,8 +26,8 @@ 0
 0
 [1, 2, 3]
 [1, 2, 3]
-''
-[4, 5, 6, 7]
+{'var_list': [1, 2, 3], 'other': 777}
+{'var_list': [1, 2, 3], 'other': 777}
 [4, 5, 6, 7]
 ''
 [4, 5, 6, 7]
diff --git a/src/version.c b/src/version.c
--- a/src/version.c
+++ b/src/version.c
@@ -742,6 +742,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    434,
+/**/
     433,
 /**/
     432,
```