Add node field to PlayerHPChangeReason table (#8368)

doc/lua_api.txt

@@ -3738,15 +3738,16 @@ Call these functions only at load time!
                         giving a type - use this for custom damage types.
             * `punch`: Was punched. `reason.object` will hold the puncher, or nil if none.
             * `fall`
-            * `node_damage`: damage_per_second from a neighbouring node.
+            * `node_damage`: `damage_per_second` from a neighbouring node.
+                             `reason.node` will hold the node name or nil.
             * `drown`
             * `respawn`
         * Any of the above types may have additional fields from mods.
         * `reason.from` will be `mod` or `engine`.
     * `modifier`: when true, the function should return the actual `hp_change`.
-       Note: modifiers only get a temporary hp_change that can be modified by later modifiers.
-       modifiers can return true as a second argument to stop the execution of further functions.
-       Non-modifiers receive the final hp change calculated by the modifiers.
+       Note: modifiers only get a temporary `hp_change` that can be modified by later modifiers.
+       Modifiers can return true as a second argument to stop the execution of further functions.
+       Non-modifiers receive the final HP change calculated by the modifiers.
 * `minetest.register_on_dieplayer(function(ObjectRef, reason))`
     * Called when a player dies
     * `reason`: a PlayerHPChangeReason table, see register_on_player_hpchange

src/content_sao.cpp

@@ -1022,6 +1022,7 @@ void PlayerSAO::step(float dtime, bool send_recommended)
 
 	if (m_node_hurt_interval.step(dtime, 1.0f)) {
 		u32 damage_per_second = 0;
+		std::string nodename;
 		// Lowest and highest damage points are 0.1 within collisionbox
 		float dam_top = m_prop.collisionbox.MaxEdge.Y - 0.1f;
 
@@ -1031,20 +1032,26 @@ void PlayerSAO::step(float dtime, bool send_recommended)
 			v3s16 p = floatToInt(m_base_position +
 				v3f(0.0f, dam_height * BS, 0.0f), BS);
 			MapNode n = m_env->getMap().getNodeNoEx(p);
-			damage_per_second = std::max(damage_per_second,
-				m_env->getGameDef()->ndef()->get(n).damage_per_second);
+			const ContentFeatures &c = m_env->getGameDef()->ndef()->get(n);
+			if (c.damage_per_second > damage_per_second) {
+				damage_per_second = c.damage_per_second;
+				nodename = c.name;
+			}
 		}
 
 		// Top damage point
 		v3s16 ptop = floatToInt(m_base_position +
 			v3f(0.0f, dam_top * BS, 0.0f), BS);
 		MapNode ntop = m_env->getMap().getNodeNoEx(ptop);
-		damage_per_second = std::max(damage_per_second,
-			m_env->getGameDef()->ndef()->get(ntop).damage_per_second);
+		const ContentFeatures &c = m_env->getGameDef()->ndef()->get(ntop);
+		if (c.damage_per_second > damage_per_second) {
+			damage_per_second = c.damage_per_second;
+			nodename = c.name;
+		}
 
 		if (damage_per_second != 0 && m_hp > 0) {
 			s32 newhp = (s32)m_hp - (s32)damage_per_second;
-			PlayerHPChangeReason reason(PlayerHPChangeReason::NODE_DAMAGE);
+			PlayerHPChangeReason reason(PlayerHPChangeReason::NODE_DAMAGE, nodename);
 			setHP(newhp, reason);
 			m_env->getGameDef()->SendPlayerHPOrDie(this, reason);
 		}

src/content_sao.h

@@ -401,10 +401,14 @@ struct PlayerHPChangeReason {
 	};
 
 	Type type = SET_HP;
-	ServerActiveObject *object;
 	bool from_mod = false;
 	int lua_reference = -1;
 
+	// For PLAYER_PUNCH
+	ServerActiveObject *object = nullptr;
+	// For NODE_DAMAGE
+	std::string node;
+
 	inline bool hasLuaReference() const
 	{
 		return lua_reference >= 0;
@@ -450,7 +454,15 @@ struct PlayerHPChangeReason {
 		}
 	}
 
-	PlayerHPChangeReason(Type type, ServerActiveObject *object=NULL):
+	PlayerHPChangeReason(Type type):
+			type(type)
+	{}
+
+	PlayerHPChangeReason(Type type, ServerActiveObject *object):
 			type(type), object(object)
 	{}
+
+	PlayerHPChangeReason(Type type, std::string node):
+			type(type), node(node)
+	{}
 };

src/script/cpp_api/s_base.cpp

@@ -404,6 +404,10 @@ void ScriptApiBase::pushPlayerHPChangeReason(lua_State *L, const PlayerHPChangeR
 		objectrefGetOrCreate(L, reason.object);
 		lua_setfield(L, -2, "object");
 	}
+	if (!reason.node.empty()) {
+		lua_pushstring(L, reason.node.c_str());
+		lua_setfield(L, -2, "node");
+	}
 }
 
 Server* ScriptApiBase::getServer()

src/script/lua_api/l_object.cpp

@@ -170,8 +170,8 @@ int ObjectRef::l_punch(lua_State *L)
 	ObjectRef *puncher_ref = checkobject(L, 2);
 	ServerActiveObject *co = getobject(ref);
 	ServerActiveObject *puncher = getobject(puncher_ref);
-	if (co == NULL) return 0;
-	if (puncher == NULL) return 0;
+	if (!co || !puncher)
+		return 0;
 	v3f dir;
 	if (lua_type(L, 5) != LUA_TTABLE)
 		dir = co->getBasePosition() - puncher->getBasePosition();
@@ -192,7 +192,8 @@ int ObjectRef::l_punch(lua_State *L)
 	// If the punched is a player, and its HP changed
 	if (src_original_hp != co->getHP() &&
 			co->getType() == ACTIVEOBJECT_TYPE_PLAYER) {
-		getServer(L)->SendPlayerHPOrDie((PlayerSAO *)co, PlayerHPChangeReason(PlayerHPChangeReason::PLAYER_PUNCH, puncher));
+		getServer(L)->SendPlayerHPOrDie((PlayerSAO *)co,
+				PlayerHPChangeReason(PlayerHPChangeReason::PLAYER_PUNCH, puncher));
 	}
 
 	// If the puncher is a player, and its HP changed