Uniformize (and document) the use of a dummy race...

...to guarantee certain pointers are never NULL.

(The pointers cannot be references because they sometimes need to
change what they point to.)

src/dialogs.cpp

@@ -906,9 +906,7 @@ const unit_preview_pane::details units_list_preview_pane::get_details() const
 
 	det.name = u.name();
 	det.type_name = u.type_name();
-	if(u.race() != NULL) {
-		det.race = u.race()->name(u.gender());
-	}
+	det.race = u.race()->name(u.gender());
 	det.level = u.level();
 	det.alignment = unit_type::alignment_description(u.alignment(), u.gender());
 	det.traits = utils::join(u.trait_names(), ", ");

src/race.cpp

@@ -26,6 +26,11 @@
 #include "random.hpp"
 #include "simple_rng.hpp"
 
+
+/// Dummy race used when a race is not yet known.
+const unit_race unit_race::null_race;
+
+
 static const config &empty_traits() {
 		static config cfg;
 		return cfg;

src/race.hpp

@@ -31,8 +31,7 @@ class unit_race
 public:
 	enum GENDER { MALE, FEMALE, NUM_GENDERS };
 
-	unit_race();
-	unit_race(const config& cfg);
+	explicit unit_race(const config& cfg);
 
 	const config& get_cfg() const { return cfg_; };
 	const std::string& id() const { return id_; };
@@ -49,7 +48,13 @@ public:
 	unsigned int num_traits() const;
 	const std::string& undead_variation() const { return undead_variation_; };
 
+	/// Dummy race used when a race is not yet known.
+	static const unit_race null_race;
+
 private:
+	/// Only used to construct null_race.
+	unit_race();
+
 	const config cfg_;
 
 	std::string id_;

src/unit.cpp

@@ -202,7 +202,7 @@ unit::unit(const config &cfg, bool use_traits, game_state* state, const vconfig*
 	loc_(cfg["x"] - 1, cfg["y"] - 1),
 	advances_to_(),
 	type_(cfg["type"]),
-	race_(NULL),
+	race_(&unit_race::null_race),
 	id_(cfg["id"]),
 	name_(cfg["name"].t_str()),
 	underlying_id_(0),
@@ -327,8 +327,7 @@ unit::unit(const config &cfg, bool use_traits, game_state* state, const vconfig*
 		if (const unit_race *r = unit_types.find_race(*v)) {
 			race_ = r;
 		} else {
-			static const unit_race dummy_race;
-			race_ = &dummy_race;
+			race_ = &unit_race::null_race;
 		}
 	}
 	level_ = cfg["level"].to_int(level_);
@@ -583,7 +582,7 @@ unit::unit(const unit_type *t, int side, bool real_unit,
 	loc_(),
 	advances_to_(),
 	type_(),
-	race_(NULL),
+	race_(&unit_race::null_race),
 	id_(),
 	name_(),
 	underlying_id_(real_unit? 0: n_unit::id_manager::instance().next_fake_id()),

src/unit.hpp

@@ -313,6 +313,7 @@ public:
 
 	std::string usage() const { return cfg_["usage"]; }
 	unit_type::ALIGNMENT alignment() const { return alignment_; }
+	/// Never returns NULL, but may point to the null race.
 	const unit_race* race() const { return race_; }
 
 	const unit_animation* choose_animation(const display& disp,
@@ -409,7 +410,7 @@ private:
 
 	std::vector<std::string> advances_to_;
 	std::string type_;
-	const unit_race* race_;
+	const unit_race* race_;	/// Never NULL, but may point to the null race.
 	std::string id_;
 	t_string name_;
 	size_t underlying_id_;

src/unit_types.cpp

@@ -599,11 +599,6 @@ int defense_modifier_internal(defense_cache &defense_mods,
 	return (std::max)(def.max_, def.min_);
 }
 
-static const unit_race& dummy_race(){
-	static unit_race ur;
-	return ur;
-}
-
 
 #ifdef _MSC_VER
 #pragma warning(push)
@@ -686,7 +681,7 @@ unit_type::unit_type(config &cfg) :
 	num_traits_(0),
 	gender_types_(),
 	variations_(),
-	race_(&dummy_race()),
+	race_(&unit_race::null_race),
 	alpha_(),
 	abilities_(),
 	adv_abilities_(),
@@ -746,7 +741,7 @@ void unit_type::build_full(const movement_type_map &mv_types,
 		alignment_ = NEUTRAL;
 	}
 
-	if (race_ != &dummy_race())
+	if ( race_ != &unit_race::null_race )
 	{
 		if (!race_->uses_global_traits()) {
 			possibleTraits_.clear();
@@ -836,7 +831,7 @@ void unit_type::build_help_index(const movement_type_map &mv_types,
 	if(race_it != races.end()) {
 		race_ = &race_it->second;
 	} else {
-		race_ = &dummy_race();
+		race_ = &unit_race::null_race;
 	}
 
 	// if num_traits is not defined, we use the num_traits from race

src/unit_types.hpp

@@ -298,6 +298,7 @@ public:
 	std::vector<std::string> variations() const;
 
 	const std::string race() const { return cfg_["race"]; } //race_->id(); }
+	/// Never returns NULL, but may point to the null race.
 	const unit_race* race_ptr() const { return race_; }
 	bool hide_help() const;
 
@@ -340,7 +341,7 @@ private:
 	typedef std::map<std::string,unit_type*> variations_map;
 	variations_map variations_;
 
-	const unit_race* race_;
+	const unit_race* race_;	/// Never returns NULL, but may point to the null race.
 
 	fixed_t alpha_;