Remove wall-time / unused skip tick protection (#11412)

Spigot still maintains some partial implementation of "tick skipping", a
practice in which the MinecraftServer.currentTick field is updated not
by an increment of one per actual tick, but instead set to
System.currentTimeMillis() / 50. This behaviour means that the tracked
tick may "skip" a tick value in case a previous tick took more than the
expected 50ms.

To compensate for this in important paths, spigot/craftbukkit
implements "wall-time". Instead of incrementing/decrementing ticks on
block entities/entities by one for each call to their tick() method,
they instead increment/decrement important values, like
an ItemEntity's age or pickupDelay, by the difference of
`currentTick - lastTick`, where `lastTick` is the value of
`currentTick` during the last tick() call.

These "fixes" however do not play nicely with minecraft's simulation
distance as entities/block entities implementing the above behaviour
would "catch up" their values when moving from a non-ticking chunk to a
ticking one as their `lastTick` value remains stuck on the last tick in
a ticking chunk and hence lead to a large "catch up" once ticked again.

Paper completely removes the "tick skipping" behaviour (See patch
"Further-improve-server-tick-loop"), making the above precautions
completely unnecessary, which also rids paper of the previous described
incompatibility with non-ticking chunks.

1 files changed, 27 insertions, 0 deletions

diff --git a/patches/server/0619-Preserve-overstacked-loot.patch b/patches/server/0619-Preserve-overstacked-loot.patch
new file mode 100644
index 0000000000..bd657ec906
--- /dev/null
+++ b/patches/server/0619-Preserve-overstacked-loot.patch
@@ -0,0 +1,27 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: lexikiq <[email protected]>
+Date: Mon, 21 Jun 2021 23:21:58 -0400
+Subject: [PATCH] Preserve overstacked loot
+
+Preserves overstacked items in loot tables, such as shulker box drops, to prevent the items
+from being deleted (as they'd overflow past the bounds of the container)-- or worse, causing
+chunk bans via the large amount of NBT created by unstacking the items.
+
+Fixes GH-5140 and GH-4748.
+
+diff --git a/src/main/java/net/minecraft/world/level/storage/loot/LootTable.java b/src/main/java/net/minecraft/world/level/storage/loot/LootTable.java
+index b231f90317fe7df9133674b12d47873520b481cb..edaf7f1692ae059581f3abc24bb228874e6d114b 100644
+--- a/src/main/java/net/minecraft/world/level/storage/loot/LootTable.java
++++ b/src/main/java/net/minecraft/world/level/storage/loot/LootTable.java
+@@ -72,9 +72,10 @@ public class LootTable {
+     }
+ 
+     public static Consumer<ItemStack> createStackSplitter(ServerLevel world, Consumer<ItemStack> consumer) {
++        boolean skipSplitter = world != null && !world.paperConfig().fixes.splitOverstackedLoot; // Paper - preserve overstacked items
+         return (itemstack) -> {
+             if (itemstack.isItemEnabled(world.enabledFeatures())) {
+-                if (itemstack.getCount() < itemstack.getMaxStackSize()) {
++                if (skipSplitter || itemstack.getCount() < itemstack.getMaxStackSize()) { // Paper - preserve overstacked items
+                     consumer.accept(itemstack);
+                 } else {
+                     int i = itemstack.getCount();