Fixed StackOverFlow exception thrown with certain block designs

core/src/io/anuke/mindustry/net/Packets.java

@@ -30,7 +30,7 @@ public class Packets {
 
     }
 
-    public static class SyncPacket implements Packet{
+    public static class SyncPacket implements Packet, UnimportantPacket{
         public byte[] data;
 
         @Override
@@ -99,7 +99,7 @@ public class Packets {
         }
     }
 
-    public static class StateSyncPacket implements Packet{
+    public static class StateSyncPacket implements Packet, UnimportantPacket{
         public int[] items;
         public float countdown, time;
         public int enemies, wave;

core/src/io/anuke/mindustry/world/Block.java

@@ -90,6 +90,8 @@ public class Block{
 	public Array<BlockBar> bars = Array.with(new BlockBar(Color.RED, false, tile -> tile.entity.health / (float)tile.block().health));
 	/**whether this block can be replaced in all cases*/
 	public boolean alwaysReplace = false;
+	/**whether this block has instant transfer checking. used for calculations to prevent infinite loops.*/
+	public boolean instantTransfer = false;
 
 	public Block(String name) {
 		this.name = name;

core/src/io/anuke/mindustry/world/blocks/types/distribution/Junction.java

@@ -16,6 +16,7 @@ public class Junction extends Block{
 		super(name);
 		update = true;
 		solid = true;
+		instantTransfer = true;
 	}
 	
 	@Override

core/src/io/anuke/mindustry/world/blocks/types/distribution/Sorter.java

@@ -24,6 +24,7 @@ public class Sorter extends Block{
 		super(name);
 		update = true;
 		solid = true;
+		instantTransfer = true;
 	}
 	
 	@Override
@@ -70,13 +71,17 @@ public class Sorter extends Block{
 		}else{
 			Tile a = dest.getNearby(Mathf.mod(dir - 1, 4));
 			Tile b = dest.getNearby(Mathf.mod(dir + 1, 4));
-			boolean ac = a.block().acceptItem(item, a, dest);
-			boolean bc = b.block().acceptItem(item, b, dest);
+			boolean ac = !(a.block().instantTransfer && source.block().instantTransfer) &&
+								a.block().acceptItem(item, a, dest);
+			boolean bc = !(b.block().instantTransfer && source.block().instantTransfer) &&
+								b.block().acceptItem(item, b, dest);
 			
 			if(ac && !bc){
 				to = a;
 			}else if(bc && !ac){
 				to = b;
+			}else if(!bc && !ac){
+				return null;
 			}else{
 				if(dest.getDump() == 0){
 					to = a;

core/src/io/anuke/mindustry/world/blocks/types/distribution/Splitter.java

@@ -9,6 +9,8 @@ public class Splitter extends Block{
 
     public Splitter(String name){
         super(name);
+        solid = true;
+        instantTransfer = true;
     }
 
     @Override

core/src/io/anuke/mindustry/world/blocks/types/distribution/TunnelConveyor.java

@@ -19,6 +19,7 @@ public class TunnelConveyor extends Block{
 		update = true;
 		solid = true;
 		health = 70;
+		instantTransfer = true;
 	}
 	
 	@Override