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, 55 insertions, 0 deletions

diff --git a/patches/server/0518-Implement-methods-to-convert-between-Component-and-B.patch b/patches/server/0518-Implement-methods-to-convert-between-Component-and-B.patch
new file mode 100644
index 0000000000..614386ecde
--- /dev/null
+++ b/patches/server/0518-Implement-methods-to-convert-between-Component-and-B.patch
@@ -0,0 +1,55 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Jason Penilla <[email protected]>
+Date: Sat, 24 Apr 2021 02:09:32 -0700
+Subject: [PATCH] Implement methods to convert between Component and
+ Brigadier's Message
+
+
+diff --git a/src/main/java/io/papermc/paper/brigadier/PaperBrigadierProviderImpl.java b/src/main/java/io/papermc/paper/brigadier/PaperBrigadierProviderImpl.java
+new file mode 100644
+index 0000000000000000000000000000000000000000..dd6012b6a097575b2d1471be5069eccee4537c0a
+--- /dev/null
++++ b/src/main/java/io/papermc/paper/brigadier/PaperBrigadierProviderImpl.java
+@@ -0,0 +1,30 @@
++package io.papermc.paper.brigadier;
++
++import com.mojang.brigadier.Message;
++import io.papermc.paper.adventure.PaperAdventure;
++import net.kyori.adventure.text.Component;
++import net.kyori.adventure.text.ComponentLike;
++import net.minecraft.network.chat.ComponentUtils;
++import org.checkerframework.checker.nullness.qual.NonNull;
++
++import static java.util.Objects.requireNonNull;
++
++public enum PaperBrigadierProviderImpl implements PaperBrigadierProvider {
++    INSTANCE;
++
++    PaperBrigadierProviderImpl() {
++        PaperBrigadierProvider.initialize(this);
++    }
++
++    @Override
++    public @NonNull Message message(final @NonNull ComponentLike componentLike) {
++        requireNonNull(componentLike, "componentLike");
++        return PaperAdventure.asVanilla(componentLike.asComponent());
++    }
++
++    @Override
++    public @NonNull Component componentFromMessage(final @NonNull Message message) {
++        requireNonNull(message, "message");
++        return PaperAdventure.asAdventure(ComponentUtils.fromMessage(message));
++    }
++}
+diff --git a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
+index 764395fe8e49d811294ca82887fee91ca6cd01fc..4057ade698a227b4f6efd3aa30b16d78c777be83 100644
+--- a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
++++ b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
+@@ -227,6 +227,7 @@ public class DedicatedServer extends MinecraftServer implements ServerInterface
+         io.papermc.paper.command.PaperCommands.registerCommands(this); // Paper - setup /paper command
+         com.destroystokyo.paper.Metrics.PaperMetrics.startMetrics(); // Paper - start metrics
+         com.destroystokyo.paper.VersionHistoryManager.INSTANCE.getClass(); // Paper - load version history now
++        io.papermc.paper.brigadier.PaperBrigadierProviderImpl.INSTANCE.getClass(); // Paper - init PaperBrigadierProvider
+ 
+         this.setPvpAllowed(dedicatedserverproperties.pvp);
+         this.setFlightAllowed(dedicatedserverproperties.allowFlight);