Unit cargo transport system

core/src/mindustry/entities/comp/BuildingComp.java

@@ -785,17 +785,19 @@ abstract class BuildingComp implements Posc, Teamc, Healthc, Buildingc, Timerc,
     }
 
     /** Dumps any item with an accumulator. May dump multiple times per frame. Use with care. */
-    public void dumpAccumulate(){
-        dumpAccumulate(null);
+    public boolean dumpAccumulate(){
+        return dumpAccumulate(null);
     }
 
     /** Dumps any item with an accumulator. May dump multiple times per frame. Use with care. */
-    public void dumpAccumulate(Item item){
+    public boolean dumpAccumulate(Item item){
+        boolean res = false;
         dumpAccum += delta();
         while(dumpAccum >= 1f){
-            dump(item);
+            res |= dump(item);
             dumpAccum -=1f;
         }
+        return res;
     }
 
     /** Try dumping any item near the building. */

core/src/mindustry/entities/comp/BuildingTetherComp.java

@@ -1,5 +1,6 @@
 package mindustry.entities.comp;
 
+import arc.util.*;
 import mindustry.annotations.Annotations.*;
 import mindustry.game.*;
 import mindustry.gen.*;
@@ -11,7 +12,7 @@ abstract class BuildingTetherComp implements Unitc{
     @Import UnitType type;
     @Import Team team;
 
-    public Building building;
+    public @Nullable Building building;
 
     @Override
     public void update(){