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, 26 insertions, 0 deletions

diff --git a/patches/server/0909-Add-Structure-check-API.patch b/patches/server/0909-Add-Structure-check-API.patch
new file mode 100644
index 0000000000..6f901b1c7f
--- /dev/null
+++ b/patches/server/0909-Add-Structure-check-API.patch
@@ -0,0 +1,26 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Jake Potrebic <[email protected]>
+Date: Mon, 27 Mar 2023 10:20:00 -0700
+Subject: [PATCH] Add Structure check API
+
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+index 7200c336de27ffd4d37231768ff5192956ede972..cb85180daaa2b40cba2474784548d650bc4d639b 100644
+--- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
++++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+@@ -246,6 +246,15 @@ public class CraftWorld extends CraftRegionAccessor implements World {
+         };
+     }
+     // Paper end
++    // Paper start - structure check API
++    @Override
++    public boolean hasStructureAt(final io.papermc.paper.math.Position position, final Structure structure) {
++        return this.world.structureManager().getStructureWithPieceAt(
++            io.papermc.paper.util.MCUtil.toBlockPos(position),
++            CraftStructure.bukkitToMinecraft(structure)
++        ).isValid();
++    }
++    // Paper end
+ 
+     private static final Random rand = new Random();
+