attempt to fix crashes when units with invalid sides appear,

by rejecting such invalide sides in the unit's constructor

src/game.cpp

@@ -635,6 +635,11 @@ int play_game(int argc, char** argv)
 				gui::show_dialog(disp,NULL,"",
 				           string_table["bad_save_message"],gui::OK_ONLY);
 				continue;
+			} catch(gamestatus::game_error& e) {
+				std::cerr << "caught game_error\n";
+				gui::show_dialog(disp,NULL,"",
+				           string_table["bad_save_message"],gui::OK_ONLY);
+				continue;
 			} catch(config::error& e) {
 				std::cerr << "caught config::error\n";
 				gui::show_dialog(disp,NULL,"",
@@ -690,10 +695,12 @@ int play_game(int argc, char** argv)
 					play_level(units_data,game_config,&starting_pos,video,state,story);
 					recorder.clear();
 				} catch(gamestatus::load_game_failed& e) {
+					gui::show_dialog(disp,NULL,"","error loading the game: " + e.message,gui::OK_ONLY);
 					std::cerr << "error loading the game: " << e.message
 					          << "\n";
 					return 0;
 				} catch(gamestatus::game_error& e) {
+					gui::show_dialog(disp,NULL,"","error while playing the game: " + e.message,gui::OK_ONLY);
 					std::cerr << "error while playing the game: "
 					          << e.message << "\n";
 					return 0;

src/pathfind.cpp

@@ -177,6 +177,10 @@ void find_routes(const gamemap& map, const gamestatus& status,
 				 std::vector<team>& teams,
 				 bool ignore_zocs, bool allow_teleport, int turns_left, bool starting_pos)
 {
+	if(size_t(u.side()-1) >= teams.size()) {
+		return;
+	}
+
 	team& current_team = teams[u.side()-1];
 
 	//find adjacent tiles

src/playlevel.cpp

@@ -162,6 +162,8 @@ LEVEL_RESULT play_level(game_data& gameinfo, const config& game_config,
 
 	std::vector<team> teams;
 
+	const teams_manager team_manager(teams);
+
 	int first_human_team = -1;
 
 	const config::child_list& unit_cfg = level->get_children("side");
@@ -193,6 +195,8 @@ LEVEL_RESULT play_level(game_data& gameinfo, const config& game_config,
 
 		std::cerr << "set gold to '" << ngold << "'\n";
 
+		teams.push_back(team(**ui,ngold));
+
 		//if this side tag describes the leader of the side
 		if((**ui)["no_leader"] != "yes") {
 			unit new_unit(gameinfo, **ui);
@@ -234,8 +238,6 @@ LEVEL_RESULT play_level(game_data& gameinfo, const config& game_config,
 			}
 		}
 
-		teams.push_back(team(**ui,ngold));
-
 		//if the game state specifies units that can be recruited for the player
 		//then add them
 		if(teams.size() == 1 && state_of_game.can_recruit.empty() == false) {
@@ -265,8 +267,6 @@ LEVEL_RESULT play_level(game_data& gameinfo, const config& game_config,
 		}
 	}
 
-	const teams_manager team_manager(teams);
-
 	const config* theme_cfg = NULL;
 	if((*level)["theme"] != "") {
 		theme_cfg = game_config.find_child("theme","name",(*level)["theme"]);

src/team.cpp

@@ -368,10 +368,14 @@ const std::string& team::name() const
 
 bool team::is_enemy(int n) const
 {
+	const size_t index = size_t(n-1);
+	if(teams == NULL || index >= teams->size()) {
+		return false;
+	}
+
 	//if we have a team name, we are friends with anyone who has the same team name
 	if(info_.team_name.empty() == false) {
-		return teams != NULL && size_t(n-1) < teams->size() &&
-	           (*teams)[n-1].info_.team_name != info_.team_name;
+		return (*teams)[index].info_.team_name != info_.team_name;
 	}
 
 	//if enemies aren't listed, then everyone is an enemy
@@ -589,3 +593,15 @@ bool is_observer()
 
 	return true;
 }
+
+void validate_side(int side)
+{
+	if(teams == NULL) {
+		return;
+	}
+
+	if(side < 1 || side > int(teams->size())) {
+		std::cerr << "invalid side " << side << " throwing game_error\n";
+		throw gamestatus::game_error("invalid side found in unit definition");
+	}
+}

src/team.hpp

@@ -146,4 +146,8 @@ struct teams_manager {
 
 bool is_observer();
 
+//function which will validate a side. Throws gamestatus::game_error
+//if the side is invalid
+void validate_side(int side); //throw gamestatus::game_error
+
 #endif

src/unit.cpp

@@ -71,6 +71,9 @@ unit::unit(const unit_type* t, int side, bool use_traits) :
 			   backupAttacks_(t->attacks()),
                guardian_(false), upkeep_(UPKEEP_FULL_PRICE)
 {
+
+	validate_side(side_);
+
 	if(use_traits) {
 		//units that don't have traits generated are just generic
 		//units, so they shouldn't get a description either.
@@ -100,6 +103,8 @@ unit::unit(const unit_type* t, const unit& u) :
 			   traitsDescription_(u.traitsDescription_),
                guardian_(false), upkeep_(u.upkeep_)
 {
+	validate_side(side_);
+
 	//apply modifications etc, refresh the unit
 	apply_modifications();
 	heal_all();
@@ -541,6 +546,8 @@ void unit::read(game_data& data, const config& cfg)
 	if(side_ <= 0)
 		side_ = 1;
 
+	validate_side(side_);
+
 	description_ = cfg["user_description"];
 	underlying_description_ = cfg["description"];
 	if(description_ == "") {