fix issues caused by empty save id

ee50171d13 broke some codes that relied on
unique save ids, that is in particular the statistic code and
scoped_recall_unit, so now these codes fallback to the side number if
the save id is empty.

(cherry-picked from commit c79e1645c8)

src/actions/create.cpp

@@ -130,7 +130,7 @@ namespace { // Helpers for get_recalls()
 	                                 std::set<std::size_t> * already_added = nullptr)
 	{
 		const team& leader_team = resources::gameboard->get_team(leader->side());
-		const std::string& save_id = leader_team.save_id();
+		const std::string& save_id = leader_team.save_id_or_number();
 
 		const unit_filter ufilt(vconfig(leader->recall_filter()));
 
@@ -245,7 +245,7 @@ namespace { // Helpers for check_recall_location()
 
 		// Make sure the recalling unit can recall this specific unit.
 		team& recall_team = (*resources::gameboard).get_team(recaller.side());
-		scoped_recall_unit this_unit("this_unit", recall_team.save_id(),
+		scoped_recall_unit this_unit("this_unit", recall_team.save_id_or_number(),
 						recall_team.recall_list().find_index(recall_unit.id()));
 
 		const unit_filter ufilt(vconfig(recaller.recall_filter()));

src/game_events/action_wml.cpp

@@ -474,7 +474,7 @@ WML_HANDLER_FUNCTION(recall,, cfg)
 
 	for(int index = 0; index < static_cast<int>(resources::gameboard->teams().size()); ++index) {
 		LOG_NG << "for side " << index + 1 << "...\n";
-		const std::string player_id = resources::gameboard->teams()[index].save_id();
+		const std::string player_id = resources::gameboard->teams()[index].save_id_or_number();
 
 		if(resources::gameboard->teams()[index].recall_list().size() < 1) {
 			DBG_NG << "recall list is empty when trying to recall!\n"

src/game_events/conditional_wml.cpp

@@ -71,7 +71,7 @@ namespace builtin_conditions {
 					if(counts == default_counts && match_count) {
 						break;
 					}
-					scoped_recall_unit auto_store("this_unit", team.save_id(), t);
+					scoped_recall_unit auto_store("this_unit", team.save_id_or_number(), t);
 					if(ufilt(*team.recall_list()[t])) {
 						++match_count;
 					}

src/gui/dialogs/statistics_dialog.cpp

@@ -45,8 +45,8 @@ REGISTER_DIALOG(statistics_dialog)
 
 statistics_dialog::statistics_dialog(const team& current_team)
 	: current_team_(current_team)
-	, campaign_(statistics::calculate_stats(current_team.save_id()))
-	, scenarios_(statistics::level_stats(current_team.save_id()))
+	, campaign_(statistics::calculate_stats(current_team.save_id_or_number()))
+	, scenarios_(statistics::level_stats(current_team.save_id_or_number()))
 	, scenario_index_(scenarios_.size() - 1)
 	, main_stat_table_()
 {

src/play_controller.cpp

@@ -1147,7 +1147,7 @@ void play_controller::play_side()
 		// This flag can be set by derived classes (in overridden functions).
 		player_type_changed_ = false;
 
-		statistics::reset_turn_stats(gamestate().board_.get_team(current_side()).save_id());
+		statistics::reset_turn_stats(gamestate().board_.get_team(current_side()).save_id_or_number());
 
 		play_side_impl();
 

src/scripting/game_lua_kernel.cpp

@@ -614,7 +614,7 @@ int game_lua_kernel::intf_match_unit(lua_State *L)
 			WRN_LUA << "but unit to match was on recall list. ";
 			WRN_LUA << "Thus the 3rd argument is ignored.\n";
 			team &t = board().get_team(side);
-			scoped_recall_unit auto_store("this_unit", t.save_id(), t.recall_list().find_index(u->id()));
+			scoped_recall_unit auto_store("this_unit", t.save_id_or_number(), t.recall_list().find_index(u->id()));
 			lua_pushboolean(L, unit_filter(filter).matches(*u, map_location()));
 			return 1;
 		}
@@ -626,7 +626,7 @@ int game_lua_kernel::intf_match_unit(lua_State *L)
 		map_location loc;
 		luaW_tolocation(L, 3, loc); // If argument 3 isn't a location, loc is unchanged
 		team &t = board().get_team(side);
-		scoped_recall_unit auto_store("this_unit", t.save_id(), t.recall_list().find_index(u->id()));
+		scoped_recall_unit auto_store("this_unit", t.save_id_or_number(), t.recall_list().find_index(u->id()));
 		lua_pushboolean(L, unit_filter(filter).matches(*u, loc));
 		return 1;
 	} else {
@@ -659,7 +659,7 @@ int game_lua_kernel::intf_get_recall_units(lua_State *L)
 		{
 			if (!filter.null()) {
 				scoped_recall_unit auto_store("this_unit",
-					t.save_id(), t.recall_list().find_index(u->id()));
+					t.save_id_or_number(), t.recall_list().find_index(u->id()));
 				if (!ufilt( *u, map_location() ))
 					continue;
 			}

src/side_filter.cpp

@@ -139,7 +139,7 @@ bool side_filter::match_internal(const team &t) const
 		}
 		if(!found && ufilt_cfg["search_recall_list"].to_bool(false)) {
 			for(const unit_const_ptr & u : t.recall_list()) {
-				scoped_recall_unit this_unit("this_unit", t.save_id(),t.recall_list().find_index(u->id()));
+				scoped_recall_unit this_unit("this_unit", t.save_id_or_number(), t.recall_list().find_index(u->id()));
 				if(ufilter_->matches(*u)) {
 					found = true;
 					break;

src/statistics.cpp

@@ -41,7 +41,7 @@ typedef std::map<std::string,stats> team_stats_t;
 std::string get_team_save_id(const unit & u)
 {
 	assert(resources::gameboard);
-	return resources::gameboard->get_team(u.side()).save_id();
+	return resources::gameboard->get_team(u.side()).save_id_or_number();
 }
 
 struct scenario_stats

src/team.hpp

@@ -228,6 +228,7 @@ public:
 	void last_recruit(const std::string & u_type) { last_recruit_ = u_type; }
 
 	const std::string& save_id() const { return info_.save_id; }
+	std::string save_id_or_number() const { return info_.save_id.empty() ? std::to_string(info_.side) : info_.save_id; }
 	void set_save_id(const std::string& save_id) { info_.save_id = save_id; }
 	const std::string& current_player() const { return info_.current_player; }
 

src/variable.cpp

@@ -534,7 +534,7 @@ void scoped_recall_unit::activate()
 
 	const std::vector<team>& teams = resources::gameboard->teams();
 
-	std::vector<team>::const_iterator team_it = std::find_if(teams.begin(), teams.end(), [&](const team& t) { return t.save_id() == player_; });
+	std::vector<team>::const_iterator team_it = std::find_if(teams.begin(), teams.end(), [&](const team& t) { return t.save_id_or_number() == player_; });
 
 	if(team_it != teams.end()) {
 		if(team_it->recall_list().size() > recall_index_) {