Had a mistake where I wasn't tracking the live->dead transition it the new code.

src/combat/combat.cpp

@@ -12,7 +12,6 @@ namespace components {
       target.take_damage(my_dmg);
     }
 
-    INVARIANT();
     return my_dmg;
   }
 
@@ -26,20 +25,19 @@ namespace components {
     // don't go below 0
     hp = std::max(0, hp - my_dmg);
 
-    has_died = hp <= 0;
-    INVARIANT();
+    // don't mark it dead here, the System will do it
+    // so that it can notify of live->dead transition
   }
 
   bool Combat::less_than(int level) {
-    INVARIANT();
     // originally this checked main body parts like
     // head, stomach, and chest
     return hp <= level;
   }
 
   bool Combat::is_dead() {
-    INVARIANT();
-    return has_died;
+    dbc::check(hp >= 0, "invalid HP, went below zero");
+    return hp == 0;
   }
 
   bool Combat::almost_dead() {
@@ -47,17 +45,10 @@ namespace components {
   }
 
   bool Combat::can_heal() {
-    INVARIANT();
     return hp < max_hp;
   }
 
   void Combat::apply_healing(Curative& cure) {
-    INVARIANT();
     hp += std::min(hp + cure.hp, max_hp);
   }
-
-  void Combat::INVARIANT() {
-    dbc::check(!(hp <= 0 && has_died == false), "entity hp <= 0 && has_died==false, they should be dead");
-    dbc::check(!(hp > 0 && has_died == true), "entity has hp > 0 but is marked dead, should be alive");
-  }
 }

src/game/components.hpp

@@ -133,7 +133,6 @@ namespace components {
     bool almost_dead();
     bool can_heal();
     void apply_healing(Curative& cure);
-    void INVARIANT();
   };
 
   struct LightSource {

src/game/systems.cpp

@@ -191,15 +191,18 @@ void System::death() {
   std::vector<Entity> dead_things;
 
   world.query<Combat>([&](auto ent, auto &combat) {
-    // bring out yer dead
-    if(combat.is_dead()) {
+    // bring out yer dead, have to do it here to notify on the transition from
+    // live -> dead
+    if(!combat.has_died && combat.is_dead()) {
+      combat.has_died = true;
+
       if(ent != player.entity) {
         // we won't change out the player's components later
         dead_things.push_back(ent);
       }
       // we need to send this event for everything that dies
       world.send<game::Event>(game::Event::DEATH, ent, {});
-    } else if(float(combat.hp) / float(combat.max_hp) < 0.5f) {
+    } else if(combat.almost_dead()) {
       // if enemies are below 50% health they are marked with bad health
       if(world.has<ai::EntityAI>(ent)) {
         auto& enemy_ai = world.get<ai::EntityAI>(ent);