Properly port [heal_unit] to Lua

changelog

@@ -24,6 +24,8 @@ Version 1.13.5+dev:
    * New [remove_object] tag which removes applied [object]s from matched units;
      it can filter on the entire [object] WML. The most efficient use is to
      remove all objects with a specific duration value.
+   * New key ability_type in standard unit filters, which matches if the unit has
+     any ability of the specified type (tag name).
  * Lua API:
    * Added new functions wesnoth.fire_event_by_id and fire_event_by_name. The old
      function wesnoth.fire_event is now an alias for wesnoth.fire_event_by_name

data/lua/wml-tags.lua

@@ -631,7 +631,67 @@ function wml_actions.unpetrify(cfg)
 end
 
 function wml_actions.heal_unit(cfg)
-	wesnoth.heal_unit(cfg)
+	local healers = helper.get_child("filter_second")
+	if healers then
+		healers = wesnoth.get_units{
+			ability_type = "heals",
+			T["and"](healers)
+		}
+	else
+		healers = {}
+	end
+
+	local who = helper.get_child("filter")
+	if who then
+		who = wesnoth.get_units(who)
+	else
+		who = wesnoth.get_units{
+			x = wesnoth.current.event_context.x1,
+			y = wesnoth.current.event_context.y1
+		}
+	end
+
+	local heal_full = cfg.amount == "full"
+	local moves_full = cfg.moves == "full"
+	local heal_amount_set = false
+	for i,u in ipairs(who) do
+		local heal_amount = u.max_hitpoints - u.hitpoints
+		if heal_full then
+			u.hitpoints = u.max_hitpoints
+		else
+			heal_amount = math.min(math.max(1, cfg.amount), heal_amount)
+			u.hitpoints = u.hitpoints + heal_amount
+		end
+
+		if moves_full then
+			u.moves = u.max_moves
+		else
+			u.moves = math.min(u.max_moves, u.moves + (cfg.moves or 0))
+		end
+
+		if cfg.restore_attacks then
+			u.attacks_left = u.max_attacks
+		end
+
+		if cfg.restore_statuses then
+			u.status.poisoned = false
+			u.status.petrified = false
+			u.status.slowed = false
+			u.status.unhealable = false
+		end
+
+		if ~heal_amount_set then
+			heal_amount_set = true
+			wesnoth.set_variable("heal_amount", heal_amount)
+		end
+
+		if cfg.animate then
+			wesnoth.animate_unit{
+				T.filter(healers),
+				flag = "healing"
+			}
+		end
+	end
 end
 
 function wml_actions.transform_unit(cfg)

src/scripting/game_lua_kernel.cpp

@@ -2366,6 +2366,7 @@ int game_lua_kernel::intf_find_cost_map(lua_State *L)
 int game_lua_kernel::intf_heal_unit(lua_State *L)
 {
 	vconfig cfg(luaW_checkvconfig(L, 1));
+	WRN_LUA << "wesnoth.heal_unit is deprecated\n";
 
 	const game_events::queued_event &event_info = get_event_info();
 

src/units/filter.cpp

@@ -359,6 +359,19 @@ bool basic_unit_filter_impl::internal_matches_filter(const unit & u, const map_l
 		if (!match) return false;
 	}
 
+	if (!vcfg["ability_type"].empty())
+	{
+		bool match = false;
+
+		for (const std::string& ability : utils::split(vcfg["ability_type"])) {
+			if (u.has_ability_type(ability)) {
+				match = true;
+				break;
+			}
+		}
+		if (!match) return false;
+	}
+
 	if (!vcfg["race"].empty()) {
 		std::vector<std::string> races = utils::split(vcfg["race"]);
 		if (std::find(races.begin(), races.end(), u.race()->id()) == races.end()) {