Various net crashes fixed

core/src/io/anuke/mindustry/core/NetServer.java

@@ -169,7 +169,7 @@ public class NetServer extends Module{
             NetConnection connection = Net.getConnection(id);
             if(player == null || connection == null || packet.snapid < connection.lastRecievedClientSnapshot) return;
 
-            boolean verifyPosition = !player.isDead() && !debug && headless && !player.isMobile;
+            boolean verifyPosition = !player.isDead() && !debug && headless && !player.mech.flying;
 
             if(connection.lastRecievedClientTime == 0) connection.lastRecievedClientTime = TimeUtils.millis() - 16;
 

core/src/io/anuke/mindustry/entities/traits/BuilderTrait.java

@@ -99,8 +99,10 @@ public interface BuilderTrait {
     /**Return the build requests currently active, or the one at the top of the queue.
      * May return null.*/
     default BuildRequest getCurrentRequest(){
+        synchronized (getPlaceQueue()) {
             return getPlaceQueue().size == 0 ? null : getPlaceQueue().first();
         }
+    }
 
     /**Update building mechanism for this unit.
      * This includes mining.*/

core/src/io/anuke/mindustry/input/InputHandler.java

@@ -283,6 +283,8 @@ public abstract class InputHandler extends InputAdapter{
 			throw new ValidateException(player, "Player cannot transfer an item.");
 		}
 
+		if(player == null) return;
+
 		player.isTransferring = true;
 
 		ItemStack stack = player.inventory.getItem();

core/src/io/anuke/mindustry/type/Weapon.java

@@ -163,6 +163,8 @@ public class Weapon extends Upgrade {
 
 		AmmoType type = shooter.getInventory().getAmmo();
 
+		if(type == null) return;
+
 		weapon.tr.trns(rotation + 180f, type.recoil);
 
 		shooter.getVelocity().add(weapon.tr);

core/src/io/anuke/mindustry/world/blocks/BuildBlock.java

@@ -151,7 +151,7 @@ public class BuildBlock extends Block {
 
     @Remote(called = Loc.server, in = In.blocks)
     public static void onBuildFinish(Tile tile, Player lastBuilder){
-        if(tile.entity == null) return;
+        if(tile.entity == null || !(tile.entity instanceof BuildEntity)) return;
         BuildEntity entity = tile.entity();
 
         Team team = tile.getTeam();
@@ -179,6 +179,8 @@ public class BuildBlock extends Block {
 
     @Remote(called = Loc.server, targets = Loc.both, in = In.blocks, forward = true)
     public static void onBuildDeselect(Player player){
+        if(player == null) return;
+
         player.getPlaceQueue().clear();
     }