Add error handling if queue has content not know by the client

Old situation:
* unknown scenario - defaults to aethermaw
* unknown era - crash
* unknown modification - ignored and game continues without it

New situation: all three possibilities now kick the player back to the MP lobby with an error message stating what wasn't found.

Author: Pentarctagon

src/game_initialization/create_engine.cpp

@@ -371,9 +371,9 @@ void create_engine::prepare_for_new_level()
 	state_.expand_random_scenario();
 }
 
-void create_engine::prepare_for_era_and_mods()
+void create_engine::prepare_for_era_and_mods(const std::string era_id)
 {
-	get_parameters();
+	get_parameters(era_id);
 	state_.classification().era_define = game_config_.find_mandatory_child("era", "id", state_.classification().era_id)["define"].str();
 	for(const std::string& mod_id : state_.classification().active_mods) {
 		state_.classification().mod_defines.push_back(game_config_.find_mandatory_child("modification", "id", mod_id)["define"].str());
@@ -648,11 +648,16 @@ const config& create_engine::curent_era_cfg() const
 	return *eras_[era_index]->cfg;
 }
 
-const mp_game_settings& create_engine::get_parameters()
+const mp_game_settings& create_engine::get_parameters(const std::string era_id)
 {
 	DBG_MP << "getting parameter values";
 
 	int era_index = current_level().allow_era_choice() ? current_era_index_ : 0;
+	// in case of joining a server queue with an unknown era
+	// the depcheck's get_era_index() returns -1 when not found
+	if(era_index == -1) {
+		throw config::error(_("Era not found: ")+era_id);
+	}
 	state_.classification().era_id = eras_[era_index]->id;
 	state_.mp_settings().mp_era_name = eras_[era_index]->name;
 

src/game_initialization/create_engine.hpp

@@ -289,7 +289,7 @@ class create_engine
 	void init_generated_level_data();
 
 	void prepare_for_new_level();
-	void prepare_for_era_and_mods();
+	void prepare_for_era_and_mods(const std::string era_id = "");
 	void prepare_for_scenario();
 	void prepare_for_campaign(const std::string& difficulty = "");
 	void prepare_for_saved_game();
@@ -387,7 +387,7 @@ class create_engine
 	std::vector<std::string>& active_mods();
 	std::vector<extras_metadata_ptr> active_mods_data();
 
-	const mp_game_settings& get_parameters();
+	const mp_game_settings& get_parameters(const std::string era_id = "");
 
 	saved_game& get_state();
 

src/game_initialization/multiplayer.cpp

@@ -584,6 +584,10 @@ bool mp_manager::enter_lobby_mode()
 				gui2::show_error_message(error.message);
 			}
 
+			if(dlg_retval == gui2::dialogs::mp_lobby::CREATE_PRESET) {
+				connection->send_data(config{"queue_game_create_failure", config{"reason", error.message, "queue_id", queue_id}});
+			}
+
 			// Update lobby content
 			connection->send_data(config{"refresh_lobby"});
 		}

src/gui/dialogs/multiplayer/mp_create_game.cpp

@@ -156,16 +156,21 @@ void mp_create_game::quick_mp_setup(saved_game& state, const config presets)
 	// from pre_show
 	create.set_current_level_type(level_type::type::scenario);
 	const auto& levels = create.get_levels_by_type(level_type::type::scenario);
+	bool found_scenario = false;
 	for(std::size_t i = 0; i < levels.size(); i++) {
 		if(levels[i]->id() == presets["scenario"].str()) {
 			create.set_current_level(i);
+			found_scenario = true;
 		}
 	}
+	if(!found_scenario) {
+		throw config::error(_("Scenario not found: ")+presets["scenario"].str());
+	}
 
 	create.set_current_era_id(presets["era"]);
 
 	// from post_show
-	create.prepare_for_era_and_mods();
+	create.prepare_for_era_and_mods(presets["era"]);
 	create.prepare_for_scenario();
 	create.get_parameters();
 	create.prepare_for_new_level();
@@ -224,6 +229,13 @@ void mp_create_game::quick_mp_setup(saved_game& state, const config presets)
 	params.name = settings::game_name_default();
 
 	for(const std::string& mod : utils::split(presets["modifications"].str())) {
+		std::vector<std::string> missing_mods;
+		if(!game_config_manager::get()->game_config().find_child("modification", "id", mod)) {
+			missing_mods.emplace_back(mod);
+		}
+		if(!missing_mods.empty()) {
+			throw config::error(_("Modification(s) not found: ")+utils::join(missing_mods));
+		}
 		create.active_mods().push_back(mod);
 	}
 

src/server/wesnothd/server.cpp

@@ -30,6 +30,7 @@
 #include "serialization/string_utils.hpp"
 #include "serialization/unicode.hpp"
 #include "utils/charconv.hpp"
+#include "utils/general.hpp"
 #include "utils/iterable_pair.hpp"
 #include "game_version.hpp"
 
@@ -1251,6 +1252,11 @@ void server::handle_player_in_lobby(player_iterator player, simple_wml::document
 		return;
 	}
 
+	if(simple_wml::node* join_server_queue = data.child("queue_game_create_failure")) {
+		handle_server_queue_create_failure(player, *join_server_queue);
+		return;
+	}
+
 	if(simple_wml::node* leave_server_queue = data.child("leave_server_queue")) {
 		handle_leave_server_queue(player, *leave_server_queue);
 		return;
@@ -1759,6 +1765,29 @@ void server::handle_join_server_queue(player_iterator p, simple_wml::node& data)
 	}
 }
 
+void server::handle_server_queue_create_failure(player_iterator p, simple_wml::node& data)
+{
+	int queue_id = data.attr("queue_id").to_int();
+
+	if(queue_info_.count(queue_id) == 0) {
+		ERR_SERVER << "attempted to remove " << p->info().name() << " from non-existing server-side queue " << data.attr("queue_id");
+		return;
+	}
+
+	queue_info& queue = queue_info_.at(queue_id);
+	if(!utils::contains(queue.players_in_queue, p->info().name())) {
+		DBG_SERVER << "player " << p->info().name() << " already not in server-side queue " << data.attr("queue_id");
+		return;
+	}
+
+	// if they're in the queue, remove them
+	utils::erase(queue.players_in_queue, p->info().name());
+	p->info().remove_from_queue(queue.id);
+	LOG_SERVER << p->client_ip() << "\t" << p->name() << "\tremoving from " << queue.settings["scenario"] << " due to reason " << data.attr("reason");
+
+	send_queue_update(queue);
+}
+
 void server::handle_leave_server_queue(player_iterator p, simple_wml::node& data)
 {
 	int queue_id = data.attr("queue_id").to_int();

src/server/wesnothd/server.hpp

@@ -69,6 +69,7 @@ class server : public server_base
 	void cleanup_game(game*); // deleter for shared_ptr
 	void handle_join_game(player_iterator player, simple_wml::node& join);
 	void handle_join_server_queue(player_iterator p, simple_wml::node& data);
+	void handle_server_queue_create_failure(player_iterator p, simple_wml::node& data);
 	void handle_leave_server_queue(player_iterator p, simple_wml::node& data);
 	void disconnect_player(player_iterator player);
 	void remove_player(player_iterator player);