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, 19 insertions, 0 deletions

diff --git a/patches/server/0503-forced-whitelist-use-configurable-kick-message.patch b/patches/server/0503-forced-whitelist-use-configurable-kick-message.patch
new file mode 100644
index 0000000000..96926fac4a
--- /dev/null
+++ b/patches/server/0503-forced-whitelist-use-configurable-kick-message.patch
@@ -0,0 +1,19 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Trigary <[email protected]>
+Date: Sat, 27 Mar 2021 09:24:23 +0100
+Subject: [PATCH] forced whitelist: use configurable kick message
+
+
+diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
+index 43b28b56c7949f95af5b7e99b04b93ed711d8880..6651afa50cfaf53959f89108904d4bf65a0fc495 100644
+--- a/src/main/java/net/minecraft/server/MinecraftServer.java
++++ b/src/main/java/net/minecraft/server/MinecraftServer.java
+@@ -2286,7 +2286,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
+                 ServerPlayer entityplayer = (ServerPlayer) iterator.next();
+ 
+                 if (!whitelist.isWhiteListed(entityplayer.getGameProfile()) && !this.getPlayerList().isOp(entityplayer.getGameProfile())) { // Paper - Fix kicking ops when whitelist is reloaded (MC-171420)
+-                    entityplayer.connection.disconnect((Component) Component.translatable("multiplayer.disconnect.not_whitelisted"));
++                    entityplayer.connection.disconnect(net.kyori.adventure.text.Component.text(org.spigotmc.SpigotConfig.whitelistMessage));
+                 }
+             }
+