testserver/patches/server/0421-Fix-sand-duping.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Fri, 12 Jun 2020 13:33:19 -0700
Subject: [PATCH] Fix sand duping

If the falling block dies during teleportation (entity#move), then we need
to detect that by placing a check after the move.

diff --git a/src/main/java/net/minecraft/world/entity/item/FallingBlockEntity.java b/src/main/java/net/minecraft/world/entity/item/FallingBlockEntity.java
index 108c9ea0eb4a7f381042bfe0203ac40a9c4f27a7..da00fab453f3fb580acc9de65a0853656f9b6fc4 100644
--- a/src/main/java/net/minecraft/world/entity/item/FallingBlockEntity.java
+++ b/src/main/java/net/minecraft/world/entity/item/FallingBlockEntity.java
@@ -126,6 +126,11 @@ public class FallingBlockEntity extends Entity {
 
     @Override
     public void tick() {
+        // Paper start - fix sand duping
+        if (this.isRemoved()) {
+            return;
+        }
+        // Paper end - fix sand duping
         if (this.blockState.isAir()) {
             this.discard();
         } else {
@@ -138,6 +143,12 @@ public class FallingBlockEntity extends Entity {
 
             this.move(MoverType.SELF, this.getDeltaMovement());
 
+            // Paper start - fix sand duping
+            if (this.isRemoved()) {
+                return;
+            }
+            // Paper end - fix sand duping
+
             // Paper start - Configurable EntityFallingBlock height nerf
             if (this.level.paperConfig().fixes.fallingBlockHeightNerf.test(v -> this.getY() > v)) {
                 if (this.dropItem && this.level.getGameRules().getBoolean(GameRules.RULE_DOENTITYDROPS)) {