remove ai.synced_command

fixes #1649 . ai.synced_command could easily be used to implement all types of
undeteced cheats so it was removed. As a replacement this commit adds a
[custom_command] synced command that just calls
wesnoth.game_events.on_synced_command which calls a lua handler that
must first be set.

data/_main.cfg

@@ -60,6 +60,7 @@
 {scenario-story.cfg}
 {ai/scenarios/}
 {ai/micro_ais/scenarios/}
+{ai/utils/custom_command.cfg}
 #define DONT_RELOAD_CORE
 #enddef
 

data/ai/micro_ais/cas/ca_forest_animals_move.lua

@@ -3,6 +3,7 @@ local W = H.set_wml_action_metatable {}
 local AH = wesnoth.require "ai/lua/ai_helper.lua"
 local LS = wesnoth.require "location_set"
 local M = wesnoth.map
+local T = H.set_wml_tag_metatable {}
 
 local function get_forest_animals(cfg)
     -- We want the deer/rabbits to move first, tuskers afterward
@@ -157,8 +158,7 @@ function ca_forest_animals_move:execution(cfg)
 
         -- If this is a rabbit ending on a hole -> disappears
         if (unit.type == rabbit_type) and hole_map:get(farthest_hex[1], farthest_hex[2]) then
-            local command =  "wesnoth.erase_unit(x1, y1)"
-            ai.synced_command(command, farthest_hex[1], farthest_hex[2])
+			wesnoth.invoke_synced_command("rabbit_despawn", { x = farthest_hex[1], y = farthest_hex[2]})
         end
     end
 

data/ai/micro_ais/cas/ca_forest_animals_new_rabbit.lua

@@ -1,6 +1,7 @@
 local H = wesnoth.require "helper"
 local W = H.set_wml_action_metatable {}
 local AH = wesnoth.require "ai/lua/ai_helper.lua"
+local T = H.set_wml_tag_metatable {}
 
 local ca_forest_animals_new_rabbit = {}
 
@@ -58,12 +59,7 @@ function ca_forest_animals_new_rabbit:execution(cfg)
             x, y = wesnoth.find_vacant_tile(holes[i].x, holes[i].y)
         end
 
-        local command =  "wesnoth.put_unit({ side = "
-            .. wesnoth.current.side
-            .. ", type = '"
-            ..  cfg.rabbit_type
-            .. "' }, x1, y1)"
-        ai.synced_command(command, x, y)
+		wesnoth.invoke_synced_command("rabbit_spawn", { rabbit_type = cfg.rabbit_type, x = x, y = y})
     end
 
     if wesnoth.sides[wesnoth.current.side].shroud then

data/ai/utils/custom_command.cfg

@@ -0,0 +1,18 @@
+
+#define ENABLE_AI_COMMAND_RABBIT_SPAWN
+[lua]
+code = <<
+
+function wesnoth.custom_synced_commands.rabbit_despawn(cfg)
+	--TODO: maybe we only want to allow erasing of unit of certain types/sides/locations ?
+	wesnoth.erase_unit(cfg.x, cfg.y)
+end
+
+function wesnoth.custom_synced_commands.rabbit_spawn(cfg)
+	--TODO: maybe we only want to allow creation of unit of certain types/sides/locations ?
+	wesnoth.put_unit({ side = wesnoth.current.side, type = cfg.rabbit_type}, cfg.x, cfg.y)
+end
+
+>>
+[/lua]
+#enddef

data/campaigns/Son_Of_The_Black_Eye/ai/ca_transport_S6.lua

@@ -1,6 +1,7 @@
 local H = wesnoth.require "helper"
 local LS = wesnoth.require "location_set"
 local M = wesnoth.map
+local T = H.set_wml_tag_metatable {}
 
 local ca_transport = {}
 
@@ -110,29 +111,12 @@ function ca_transport:execution()
         -- Also unload units
         table.sort(best_adj_tiles, function(a, b) return a[3] > b[3] end)
 
-        local command = "local unit = wesnoth.get_unit(x1, y1) "
-            .. "unit.variables.landed = 'yes' "
-            .. "unit.variables.destination_x = 1 "
-            .. "unit.variables.destination_y = 30"
-        ai.synced_command(command, best_unit.x, best_unit.y)
+		local command_data = { x = best_unit.x, y = best_unit.y }
+		for i = 1, math.min(#best_adj_tiles, 3) do
+			table.insert(command_data, T.dst { x = best_adj_tiles[i][1], y = best_adj_tiles[i][2]} )
+		end
 
-        -- Unload 1 level 2 unit
-        local l2_type = H.rand('Swordsman,Javelineer,Pikeman')
-        local command = "wesnoth.put_unit({ side = " .. wesnoth.current.side
-            .. ", type = '" .. l2_type
-            .. "', moves = 2 }, "
-            .. best_adj_tiles[1][1] .. "," .. best_adj_tiles[1][2] .. ")"
-        ai.synced_command(command, best_unit.x, best_unit.y)
-
-        -- Unload up to 2 level 1 units
-        for i = 2, math.min(#best_adj_tiles, 3) do
-            local l1_type = H.rand('Fencer,Mage,Cavalryman,Bowman,Spearman')
-            local command = "wesnoth.put_unit({ side = " .. wesnoth.current.side
-                .. ", type = '" .. l1_type
-                .. "', moves = 2 }, "
-                .. best_adj_tiles[i][1] .. "," .. best_adj_tiles[i][2] .. ")"
-            ai.synced_command(command, best_unit.x, best_unit.y)
-        end
+		wesnoth.invoke_synced_command("ship_unload", command_data)
 
         return
     end

data/campaigns/Son_Of_The_Black_Eye/scenarios/06_Black_Flag.cfg

@@ -83,6 +83,7 @@
     [/side]
 
     {SOTBE_TRACK {JOURNEY_06_NEW} }
+    {ENABLE_AI_COMMAND_CA_TRANSPORT_S6}
 
     [event]
         name=prestart

data/campaigns/Son_Of_The_Black_Eye/utils/utils.cfg

@@ -199,3 +199,30 @@
         [/unstore_unit]
     [/event]
 #enddef
+
+#define ENABLE_AI_COMMAND_CA_TRANSPORT_S6
+[lua]
+code = <<
+local helper = wesnoth.require "helper"
+
+function wesnoth.custom_synced_commands.ship_unload(cfg)
+
+	local unit = wesnoth.get_unit(cfg.x, cfg.y)
+	unit.variables.landed = 'yes'
+	unit.variables.destination_x = 1
+	unit.variables.destination_y = 30
+
+	local locs = helper.child_array(cfg, "dst")
+
+	local l2_type = helper.rand('Swordsman,Javelineer,Pikeman')
+	wesnoth.put_unit({ side = wesnoth.current.side, type = l2_type, moves = 2 }, locs[1].x, locs[1].y)
+
+	for i = 2, #locs do
+		local l1_type = helper.rand('Fencer,Mage,Cavalryman,Bowman,Spearman')
+		wesnoth.put_unit({ side = wesnoth.current.side, type = l1_type, moves = 2 }, locs[i].x, locs[i].y)
+	end
+end
+
+>>
+[/lua]
+#enddef

data/core/_main.cfg

@@ -8,6 +8,7 @@
 wesnoth.dofile 'lua/backwards-compatibility.lua'
 wesnoth.dofile 'lua/wml-tags.lua'
 wesnoth.dofile 'lua/feeding.lua'
+wesnoth.dofile 'lua/custom_command.lua'
 >>
 [/lua]
 

data/lua/custom_command.lua

@@ -0,0 +1,20 @@
+local helper = wesnoth.require "helper"
+local T = helper.set_wml_tag_metatable {}
+
+wesnoth.custom_synced_commands = {}
+
+function wesnoth.game_events.on_synced_command(cfg)
+	local handler = wesnoth.custom_synced_commands[cfg.name]
+	local data = helper.get_child(cfg, "data")
+	if handler then
+		handler(data)
+	end
+end
+
+function wesnoth.register_synced_command(name, handler)
+	wesnoth.custom_synced_commands[name] = handler
+end
+
+function wesnoth.invoke_synced_command(name, data)
+	wesnoth.wml_actions.do_command { T.custom_command { name=name, T.data(data) } }
+end

src/ai/actions.cpp

@@ -968,7 +968,7 @@ void synced_command_result::do_execute()
 	}
 	s << lua_code_;
 
-	synced_context::run_in_synced_context_if_not_already("lua_ai", replay_helper::get_lua_ai(s.str()));
+	//synced_context::run_in_synced_context_if_not_already("lua_ai", replay_helper::get_lua_ai(s.str()));
 
 	try {
 		set_gamestate_changed();

src/ai/lua/core.cpp

@@ -273,6 +273,12 @@ static int cfun_ai_check_stopunit(lua_State *L)
 
 static int ai_synced_command(lua_State *L, bool exec)
 {
+#if 1
+	(void)L;
+	(void)exec;
+	ERR_LUA << "synced_command was removed, use wesnoth.wml_actions.do_command with [custom_command] instead\n";
+	return 0;
+#else
 	const char *lua_code = luaL_checkstring(L, 1);
 	int side = get_readonly_context(L).get_side();
 	map_location location;
@@ -283,6 +289,7 @@ static int ai_synced_command(lua_State *L, bool exec)
 
 	ai::synced_command_result_ptr synced_command_result = ai::actions::execute_synced_command_action(side,exec,std::string(lua_code),location);
 	return transform_ai_action(L,synced_command_result);
+#endif
 }
 
 static int cfun_ai_execute_synced_command(lua_State *L)

src/game_events/action_wml.cpp

@@ -281,7 +281,7 @@ WML_HANDLER_FUNCTION(do_command,, cfg)
 		return;
 	}
 
-	static const std::set<std::string> allowed_tags {"attack", "move", "recruit", "recall", "disband", "fire_event", "lua_ai"};
+	static const std::set<std::string> allowed_tags {"attack", "move", "recruit", "recall", "disband", "fire_event", "custom_command"};
 
 	const bool is_too_early = resources::gamedata->phase() != game_data::START && resources::gamedata->phase() != game_data::PLAY;
 	const bool is_unsynced_too_early = resources::gamedata->phase() != game_data::PLAY;

src/scripting/game_lua_kernel.cpp

@@ -4395,6 +4395,17 @@ bool game_lua_kernel::run_event(const game_events::queued_event& ev)
 	return true;
 }
 
+void game_lua_kernel::custom_command(const config& cfg)
+{
+	lua_State *L = mState;
+
+	if (!luaW_getglobal(L, "wesnoth", "game_events", "on_synced_command")) {
+		return;
+	}
+	luaW_pushconfig(L, cfg);
+	luaW_pcall(L, 1, 0, false);
+}
+
 /**
  * Applies its upvalue as an effect
  * Arg 1: The unit to apply to

src/scripting/game_lua_kernel.hpp

@@ -200,6 +200,7 @@ public:
 	void save_game(config & level);
 	void load_game(const config& level);
 	bool run_event(const game_events::queued_event&);
+	void custom_command(const config&);
 	void push_builtin_effect();
 	void set_wml_action(const std::string&, game_events::wml_action::handler);
 	void set_wml_condition(const std::string&, bool(*)(const vconfig&));

src/synced_commands.cpp

@@ -344,11 +344,10 @@ SYNCED_COMMAND_HANDLER_FUNCTION(fire_event, child,  use_undo, /*show*/, /*error_
 	return true;
 }
 
-SYNCED_COMMAND_HANDLER_FUNCTION(lua_ai, child,  /*use_undo*/, /*show*/, /*error_handler*/)
+SYNCED_COMMAND_HANDLER_FUNCTION(custom_command, child,  /*use_undo*/, /*show*/, /*error_handler*/)
 {
-	const std::string &lua_code = child["code"];
 	assert(resources::lua_kernel);
-	resources::lua_kernel->run(lua_code.c_str());
+	resources::lua_kernel->custom_command(child);
 	return true;
 }