Move open_help to the gui module (as show_help)

This also exposes it in kernels besides the game kernel.

data/lua/core/gui.lua

@@ -154,3 +154,7 @@ wesnoth.get_dialog_value = wesnoth.deprecate_api('wesnoth.get_dialog_value', val
 wesnoth.add_dialog_tree_node = wesnoth.deprecate_api('wesnoth.add_dialog_tree_node', '<widget>:add_item_of_type', 1, nil, add_dialog_tree_node)
 wesnoth.remove_dialog_item = wesnoth.deprecate_api('wesnoth.remove_dialog_item', '<widget>:remove_items_at', 1, nil, remove_dialog_item)
 wesnoth.show_dialog = wesnoth.deprecate_api('wesnoth.show_dialog', 'gui.show_dialog', 1, nil, gui.show_dialog)
+if wesnoth.kernel_type() == "Game Lua Kernel" then
+	-- The deprecated function was only available in Game Lua Kernel, so even though show_help is available in other kernels, there's no need to expose the deprecated function there.
+	wesnoth.open_help = wesnoth.deprecate_api('wesnoth.open_help', 'gui.show_help', 1, nil, gui.show_help)
+end

data/lua/wml-tags.lua

@@ -753,7 +753,7 @@ function wml_actions.label( cfg )
 end
 
 function wml_actions.open_help(cfg)
-	wesnoth.open_help(cfg.topic)
+	gui.open_help(cfg.topic)
 end
 
 function wml_actions.redraw(cfg)

src/help/help.cpp

@@ -87,16 +87,14 @@ void show_unit_description(const unit_type &t)
 		help::show_unit_help(t.id(), t.show_variations_in_help(), hide_help);
 }
 
-help_manager::help_manager(const game_config_view *cfg) //, gamemap *_map)
+static game_config_view dummy_view;
+help_manager::help_manager(const game_config_view *cfg)
+	: guard(game_cfg, cfg == nullptr ? &dummy_view : cfg)
 {
-	static game_config_view dummy_view;
-	game_cfg = cfg == nullptr ? &dummy_view : cfg;
-//	map = _map;
 }
 
 help_manager::~help_manager()
 {
-	game_cfg = nullptr;
 //	map = nullptr;
 	default_toplevel.clear();
 	hidden_sections.clear();

src/help/help.hpp

@@ -22,12 +22,15 @@ class CVideo;
 class game_config_view;
 
 #include <string>
+#include "utils/guard_value.hpp"
 
 namespace help {
 
 struct help_manager {
 	help_manager(const game_config_view *game_config);
 	~help_manager();
+private:
+	utils::guard_value<const game_config_view*> guard;
 };
 
 struct section;

src/scripting/game_lua_kernel.cpp

@@ -55,7 +55,6 @@
 #include "game_events/entity_location.hpp"
 #include "game_events/pump.hpp"         // for queued_event
 #include "preferences/game.hpp"         // for encountered_units
-#include "help/help.hpp"
 #include "log.hpp"                      // for LOG_STREAM, logger, etc
 #include "utils/make_enum.hpp"                // for operator<<
 #include "map/map.hpp"                      // for gamemap
@@ -1292,14 +1291,6 @@ int game_lua_kernel::intf_message(lua_State *L)
 	return 0;
 }
 
-int game_lua_kernel::intf_open_help(lua_State *L)
-{
-	if (game_display_) {
-		help::show_help(luaL_checkstring(L, 1));
-	}
-	return 0;
-}
-
 int game_lua_kernel::intf_zoom(lua_State* L)
 {
 	if(!game_display_) {
@@ -4005,7 +3996,6 @@ game_lua_kernel::game_lua_kernel(game_state & gs, play_controller & pc, reports
 		{ "log_replay",                &dispatch<&game_lua_kernel::intf_log_replay                 >        },
 		{ "log",                       &dispatch<&game_lua_kernel::intf_log                        >        },
 		{ "message",                   &dispatch<&game_lua_kernel::intf_message                    >        },
-		{ "open_help",                 &dispatch<&game_lua_kernel::intf_open_help                  >        },
 		{ "print",                     &dispatch<&game_lua_kernel::intf_print                      >        },
 		{ "redraw",                    &dispatch<&game_lua_kernel::intf_redraw                     >        },
 		{ "remove_event_handler",      &dispatch<&game_lua_kernel::intf_remove_event               >        },

src/scripting/lua_gui2.cpp

@@ -35,6 +35,8 @@
 #include "scripting/lua_widget_methods.hpp"
 #include "scripting/push_check.hpp"
 #include "serialization/string_utils.hpp"
+#include "help/help.hpp"
+#include "game_config_manager.hpp"
 #include "tstring.hpp"
 #include "game_data.hpp"
 #include "game_state.hpp"
@@ -249,6 +251,13 @@ int show_gamestate_inspector(const vconfig& cfg, const game_data& data, const ga
 	return 0;
 }
 
+int show_help(lua_State *L)
+{
+	help::help_manager help_manager(&game_config_manager::get()->game_config());
+	help::show_help(luaL_checkstring(L, 1));
+	return 0;
+}
+
 
 /**
  * - Arg 1: string, widget type
@@ -280,6 +289,7 @@ int luaW_open(lua_State* L)
 		{ "show_popup",         &show_popup_dialog },
 		{ "show_story",         &show_story },
 		{ "show_prompt",        &show_message_box },
+		{ "show_help",          &show_help   },
 		{ "add_widget_definition",    &intf_add_widget_definition },
 		{ "show_dialog",              &intf_show_dialog   },
 		{ nullptr, nullptr },