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/0576-Configurable-item-frame-map-cursor-update-interval.patch b/patches/server/0576-Configurable-item-frame-map-cursor-update-interval.patch
new file mode 100644
index 0000000000..a6389cdcbb
--- /dev/null
+++ b/patches/server/0576-Configurable-item-frame-map-cursor-update-interval.patch
@@ -0,0 +1,19 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Warrior <[email protected]>
+Date: Fri, 13 Aug 2021 01:14:38 +0200
+Subject: [PATCH] Configurable item frame map cursor update interval
+
+
+diff --git a/src/main/java/net/minecraft/server/level/ServerEntity.java b/src/main/java/net/minecraft/server/level/ServerEntity.java
+index 7e8a43ea1b32f444fb66e270a5f6b48bf7bcd2a0..f3f93710846ce0f6d53845e0b49331646a4e8332 100644
+--- a/src/main/java/net/minecraft/server/level/ServerEntity.java
++++ b/src/main/java/net/minecraft/server/level/ServerEntity.java
+@@ -116,7 +116,7 @@ public class ServerEntity {
+             if (true || this.tickCount % 10 == 0) { // CraftBukkit - Moved below, should always enter this block
+                 ItemStack itemstack = entityitemframe.getItem();
+ 
+-                if (this.tickCount % 10 == 0 && itemstack.getItem() instanceof MapItem) { // CraftBukkit - Moved this.tickCounter % 10 logic here so item frames do not enter the other blocks
++                if (this.level.paperConfig().maps.itemFrameCursorUpdateInterval > 0 && this.tickCount % this.level.paperConfig().maps.itemFrameCursorUpdateInterval == 0 && itemstack.getItem() instanceof MapItem) { // CraftBukkit - Moved this.tickCounter % 10 logic here so item frames do not enter the other blocks // Paper - Make item frame map cursor update interval configurable
+                     MapId mapid = (MapId) itemstack.get(DataComponents.MAP_ID);
+                     MapItemSavedData worldmap = MapItem.getSavedData(mapid, this.level);
+