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, 21 insertions, 0 deletions

diff --git a/patches/server/1041-Add-skipping-world-symlink-scan.patch b/patches/server/1041-Add-skipping-world-symlink-scan.patch
new file mode 100644
index 0000000000..edbbf7edf8
--- /dev/null
+++ b/patches/server/1041-Add-skipping-world-symlink-scan.patch
@@ -0,0 +1,21 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: mja00 <[email protected]>
+Date: Mon, 12 Aug 2024 06:27:15 -0400
+Subject: [PATCH] Add skipping world symlink scan
+
+In worlds that are extremely large (greater than 1TB), it can take an insanely long time to walk the entire world for symlinks.
+This patch adds a system property to disable the symlink scan, which can be used to speed up world loading.
+
+diff --git a/src/main/java/net/minecraft/world/level/storage/LevelStorageSource.java b/src/main/java/net/minecraft/world/level/storage/LevelStorageSource.java
+index 427ee4d6f12a7abd8da0c65e0b9081b25824df40..85ba843ce7e1f62971e736fa2cc028c47b274ce4 100644
+--- a/src/main/java/net/minecraft/world/level/storage/LevelStorageSource.java
++++ b/src/main/java/net/minecraft/world/level/storage/LevelStorageSource.java
+@@ -420,7 +420,7 @@ public class LevelStorageSource {
+ 
+     public LevelStorageSource.LevelStorageAccess validateAndCreateAccess(String s, ResourceKey<LevelStem> dimensionType) throws IOException, ContentValidationException { // CraftBukkit
+         Path path = this.getLevelPath(s);
+-        List<ForbiddenSymlinkInfo> list = this.worldDirValidator.validateDirectory(path, true);
++        List<ForbiddenSymlinkInfo> list = Boolean.getBoolean("paper.disableWorldSymlinkValidation") ? List.of() : this.worldDirValidator.validateDirectory(path, true); // Paper - add skipping of symlinks scan
+ 
+         if (!list.isEmpty()) {
+             throw new ContentValidationException(path, list);