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, 75 insertions, 0 deletions

diff --git a/patches/server/0765-More-vanilla-friendly-methods-to-update-trades.patch b/patches/server/0765-More-vanilla-friendly-methods-to-update-trades.patch
new file mode 100644
index 0000000000..5c30d5f82c
--- /dev/null
+++ b/patches/server/0765-More-vanilla-friendly-methods-to-update-trades.patch
@@ -0,0 +1,75 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Lulu13022002 <[email protected]>
+Date: Sun, 16 Oct 2022 16:12:49 +0200
+Subject: [PATCH] More vanilla friendly methods to update trades
+
+
+diff --git a/src/main/java/net/minecraft/world/entity/npc/Villager.java b/src/main/java/net/minecraft/world/entity/npc/Villager.java
+index 9d5a5a7fff7f75871e167f83edb0e9d5348748d7..393588661c41b490ee6bce2f687962f7ddeff7d4 100644
+--- a/src/main/java/net/minecraft/world/entity/npc/Villager.java
++++ b/src/main/java/net/minecraft/world/entity/npc/Villager.java
+@@ -921,6 +921,12 @@ public class Villager extends AbstractVillager implements ReputationEventHandler
+ 
+     @Override
+     protected void updateTrades() {
++        // Paper start - More vanilla friendly methods to update trades
++        updateTrades(TRADES_PER_LEVEL);
++    }
++
++    public boolean updateTrades(int amount) {
++        // Paper end - More vanilla friendly methods to update trades
+         VillagerData villagerdata = this.getVillagerData();
+         Int2ObjectMap int2objectmap;
+ 
+@@ -938,9 +944,11 @@ public class Villager extends AbstractVillager implements ReputationEventHandler
+             if (avillagertrades_imerchantrecipeoption != null) {
+                 MerchantOffers merchantrecipelist = this.getOffers();
+ 
+-                this.addOffersFromItemListings(merchantrecipelist, avillagertrades_imerchantrecipeoption, 2);
++                this.addOffersFromItemListings(merchantrecipelist, avillagertrades_imerchantrecipeoption, amount); // Paper - More vanilla friendly methods to update trades
++                return true; // Paper - More vanilla friendly methods to update trades
+             }
+         }
++        return false; // Paper - More vanilla friendly methods to update trades
+     }
+ 
+     public void gossip(ServerLevel world, Villager villager, long time) {
+diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftVillager.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftVillager.java
+index 52312bec840322d32ea845f0bd64eb3ca1380854..bd2987fa1fb194a581567134ed980e8fc043f435 100644
+--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftVillager.java
++++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftVillager.java
+@@ -97,6 +97,34 @@ public class CraftVillager extends CraftAbstractVillager implements Villager {
+     }
+ 
+     // Paper start
++    @Override
++    public boolean increaseLevel(int amount) {
++        Preconditions.checkArgument(amount > 0, "Level earned must be positive");
++        int supposedFinalLevel = this.getVillagerLevel() + amount;
++        Preconditions.checkArgument(net.minecraft.world.entity.npc.VillagerData.MIN_VILLAGER_LEVEL <= supposedFinalLevel && supposedFinalLevel <= net.minecraft.world.entity.npc.VillagerData.MAX_VILLAGER_LEVEL,
++            "Final level reached after the donation (%d) must be between [%d, %d]".formatted(supposedFinalLevel, net.minecraft.world.entity.npc.VillagerData.MIN_VILLAGER_LEVEL, net.minecraft.world.entity.npc.VillagerData.MAX_VILLAGER_LEVEL));
++
++        it.unimi.dsi.fastutil.ints.Int2ObjectMap<net.minecraft.world.entity.npc.VillagerTrades.ItemListing[]> trades =
++            net.minecraft.world.entity.npc.VillagerTrades.TRADES.get(this.getHandle().getVillagerData().getProfession());
++
++        if (trades == null || trades.isEmpty()) {
++            this.getHandle().setVillagerData(this.getHandle().getVillagerData().setLevel(supposedFinalLevel));
++            return false;
++        }
++
++        while (amount > 0) {
++            this.getHandle().increaseMerchantCareer();
++            amount--;
++        }
++        return true;
++    }
++
++    @Override
++    public boolean addTrades(int amount) {
++        Preconditions.checkArgument(amount > 0, "Number of trades unlocked must be positive");
++        return this.getHandle().updateTrades(amount);
++    }
++
+     @Override
+     public int getRestocksToday() {
+         return getHandle().numberOfRestocksToday;