vim-patch:8.2.3459: Vim9: need more tests for empty string arguments

Problem:    Vim9: need more tests for empty string arguments.
Solution:   Add more tests.  Also use empty argument with menu_info() to get
            the top-level menu names. (Yegappan Lakshmanan, closes vim/vim#8925)
51491adfa8

runtime/doc/builtin.txt

@@ -5259,7 +5259,8 @@ menu_get({path} [, {modes}])				*menu_get()*
 menu_info({name} [, {mode}])				*menu_info()*
 		Return information about the specified menu {name} in
 		mode {mode}. The menu name should be specified without the
-		shortcut character ('&').
+		shortcut character ('&'). If {name} is "", then the top-level
+		menu names are returned.
 
 		{mode} can be one of these strings:
 			"n"	Normal
@@ -5310,6 +5311,20 @@ menu_info({name} [, {mode}])				*menu_info()*
 		Examples: >
 			:echo menu_info('Edit.Cut')
 			:echo menu_info('File.Save', 'n')
+
+			" Display the entire menu hierarchy in a buffer
+			func ShowMenu(name, pfx)
+			  let m = menu_info(a:name)
+			  call append(line('$'), a:pfx .. m.display)
+			  for child in m->get('submenus', [])
+			    call ShowMenu(a:name .. '.' .. escape(child, '.'),
+							\ a:pfx .. '    ')
+			  endfor
+			endfunc
+			new
+			for topmenu in menu_info('').submenus
+			  call ShowMenu(topmenu, '')
+			endfor
 <
 		Can also be used as a |method|: >
 			GetMenuName()->menu_info('v')

src/nvim/menu.c

@@ -1892,9 +1892,22 @@ static char *menu_translate_tab_and_shift(char *arg_start)
 }
 
 /// Get the information about a menu item in mode 'which'
-static void menuitem_getinfo(const vimmenu_T *menu, int modes, dict_T *dict)
+static void menuitem_getinfo(const char *menu_name, const vimmenu_T *menu, int modes, dict_T *dict)
   FUNC_ATTR_NONNULL_ALL
 {
+  if (*menu_name == NUL) {
+    // Return all the top-level menus
+    list_T *const l = tv_list_alloc(kListLenMayKnow);
+    tv_dict_add_list(dict, S_LEN("submenus"), l);
+    // get all the children.  Skip PopUp[nvoci].
+    for (const vimmenu_T *topmenu = menu; topmenu != NULL; topmenu = topmenu->next) {
+      if (!menu_is_hidden(topmenu->dname)) {
+        tv_list_append_string(l, topmenu->dname, -1);
+      }
+    }
+    return;
+  }
+
   tv_dict_add_str(dict, S_LEN("name"), menu->name);
   tv_dict_add_str(dict, S_LEN("display"), menu->dname);
   if (menu->actext != NULL) {
@@ -1990,6 +2003,6 @@ void f_menu_info(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   }
 
   if (menu->modes & modes) {
-    menuitem_getinfo(menu, modes, retdict);
+    menuitem_getinfo(menu_name, menu, modes, retdict);
   }
 }

src/nvim/testdir/test_menu.vim

@@ -362,6 +362,9 @@ func Test_menu_info()
         \ shortcut: '', modes: ' ', submenus: ['menu']},
         \ menu_info(']Test'))
   unmenu ]Test
+
+  " Test for getting all the top-level menu names
+  call assert_notequal(menu_info('').submenus, [])
 endfunc
 
 " Test for <special> keyword in a menu with 'cpo' containing '<'