Paper/Spigot-Server-Patches/0493-Fix-numerous-item-duplication-issues-and-teleport-is.patch
Aikar f37381ea8a
Optimize Network Manager to not need synchronization
Removes synchronization from sending packets
Makes normal packet sends no longer need to be wrapped and queued like it use to work.
Adds more packet queue immunities on top of keep alive to let the following scenarios go out
without delay:
  - Keep Alive
  - Chat
  - Kick
  - All of the packets during the Player Joined World event

Hoping that latter one helps join timeout issues more too for slow connections.

Removes processing packet queue off of main thread
  - for the few cases where it is allowed, order is not necessary nor
    should it even be happening concurrently in first place (handshaking/login/status)

Ensures packets sent asynchronously are dispatched on main thread

This helps ensure safety for ProtocolLib as packet listeners
are commonly accessing world state. This will allow you to schedule
a packet to be sent async, but itll be dispatched sync for packet
listeners to process.

This should solve some deadlock risks

This may provide a decent performance improvement because thread synchronization incurs a cache reset
so by avoiding ever entering a synchronized block, we get to avoid that, and packet sending is a really
hot activity.
2020-05-06 05:28:47 -04:00

98 lines
5.7 KiB
Diff

From c8d61cc54c9cf1c1cca1e6f6d615b0218e6fbdb7 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sat, 25 Apr 2020 06:46:35 -0400
Subject: [PATCH] Fix numerous item duplication issues and teleport issues
This notably fixes the newest "Donkey Dupe", but also fixes a lot
of dupe bugs in general around nether portals and entity world transfer
We also fix item duplication generically by anytime we clone an item
to drop it on the ground, destroy the source item.
This avoid an itemstack ever existing twice in the world state pre
clean up stage.
So even if something NEW comes up, it would be impossible to drop the
same item twice because the source was destroyed.
diff --git a/src/main/java/net/minecraft/server/Entity.java b/src/main/java/net/minecraft/server/Entity.java
index 9bb5a4bcf1e..14ba037c1dc 100644
--- a/src/main/java/net/minecraft/server/Entity.java
+++ b/src/main/java/net/minecraft/server/Entity.java
@@ -1966,11 +1966,12 @@ public abstract class Entity implements INamableTileEntity, ICommandListener, Ke
} else {
// CraftBukkit start - Capture drops for death event
if (this instanceof EntityLiving && !((EntityLiving) this).forceDrops) {
- ((EntityLiving) this).drops.add(org.bukkit.craftbukkit.inventory.CraftItemStack.asBukkitCopy(itemstack));
+ ((EntityLiving) this).drops.add(org.bukkit.craftbukkit.inventory.CraftItemStack.asCraftMirror(itemstack)); // Paper - mirror so we can destroy it later
return null;
}
// CraftBukkit end
- EntityItem entityitem = new EntityItem(this.world, this.locX(), this.locY() + (double) f, this.locZ(), itemstack);
+ EntityItem entityitem = new EntityItem(this.world, this.locX(), this.locY() + (double) f, this.locZ(), itemstack.cloneItemStack()); // Paper - clone so we can destroy original
+ itemstack.setCount(0); // Paper - destroy this item - if this ever leaks due to game bugs, ensure it doesn't dupe
entityitem.defaultPickupDelay();
// CraftBukkit start
@@ -2632,6 +2633,12 @@ public abstract class Entity implements INamableTileEntity, ICommandListener, Ke
@Nullable
public Entity teleportTo(DimensionManager dimensionmanager, BlockPosition location) {
// CraftBukkit end
+ // Paper start - fix bad state entities causing dupes
+ if (!isAlive() || !valid) {
+ LOGGER.warn("Illegal Entity Teleport " + this + " to " + dimensionmanager + ":" + location, new Throwable());
+ return null;
+ }
+ // Paper end
if (!this.world.isClientSide && !this.dead) {
this.world.getMethodProfiler().enter("changeDimension");
MinecraftServer minecraftserver = this.getMinecraftServer();
@@ -2757,7 +2764,7 @@ public abstract class Entity implements INamableTileEntity, ICommandListener, Ke
}
public boolean canPortal() {
- return true;
+ return isAlive() && valid; // Paper
}
public float a(Explosion explosion, IBlockAccess iblockaccess, BlockPosition blockposition, IBlockData iblockdata, Fluid fluid, float f) {
diff --git a/src/main/java/net/minecraft/server/EntityArmorStand.java b/src/main/java/net/minecraft/server/EntityArmorStand.java
index 8ad131e4fc2..d35a0b2d94e 100644
--- a/src/main/java/net/minecraft/server/EntityArmorStand.java
+++ b/src/main/java/net/minecraft/server/EntityArmorStand.java
@@ -557,7 +557,7 @@ public class EntityArmorStand extends EntityLiving {
for (i = 0; i < this.handItems.size(); ++i) {
itemstack = (ItemStack) this.handItems.get(i);
if (!itemstack.isEmpty()) {
- drops.add(org.bukkit.craftbukkit.inventory.CraftItemStack.asBukkitCopy(itemstack)); // CraftBukkit - add to drops
+ drops.add(org.bukkit.craftbukkit.inventory.CraftItemStack.asCraftMirror(itemstack)); // CraftBukkit - add to drops // Paper - mirror so we can destroy it later - though this call site was safe
this.handItems.set(i, ItemStack.a);
}
}
@@ -565,7 +565,7 @@ public class EntityArmorStand extends EntityLiving {
for (i = 0; i < this.armorItems.size(); ++i) {
itemstack = (ItemStack) this.armorItems.get(i);
if (!itemstack.isEmpty()) {
- drops.add(org.bukkit.craftbukkit.inventory.CraftItemStack.asBukkitCopy(itemstack)); // CraftBukkit - add to drops
+ drops.add(org.bukkit.craftbukkit.inventory.CraftItemStack.asCraftMirror(itemstack)); // CraftBukkit - add to drops // Paper - mirror so we can destroy it later - though this call site was safe
this.armorItems.set(i, ItemStack.a);
}
}
diff --git a/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java b/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
index c3f7e461210..73b271f6f3e 100644
--- a/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
+++ b/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
@@ -776,7 +776,8 @@ public class CraftEventFactory {
for (org.bukkit.inventory.ItemStack stack : event.getDrops()) {
if (stack == null || stack.getType() == Material.AIR || stack.getAmount() == 0) continue;
- world.dropItem(entity.getLocation(), stack);
+ world.dropItem(entity.getLocation(), stack); // Paper - note: dropItem already clones due to this being bukkit -> NMS
+ if (stack instanceof CraftItemStack) stack.setAmount(0); // Paper - destroy this item - if this ever leaks due to game bugs, ensure it doesn't dupe, but don't nuke bukkit stacks of manually added items
}
return event;
--
2.26.2