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, 36 insertions, 0 deletions

diff --git a/patches/server/0314-Improve-java-version-check.patch b/patches/server/0314-Improve-java-version-check.patch
new file mode 100644
index 0000000000..3d9eed5372
--- /dev/null
+++ b/patches/server/0314-Improve-java-version-check.patch
@@ -0,0 +1,36 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Nassim Jahnke <[email protected]>
+Date: Wed, 16 Mar 2022 13:58:16 +0100
+Subject: [PATCH] Improve java version check
+
+Co-Authored-By: MiniDigger <[email protected]>
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/Main.java b/src/main/java/org/bukkit/craftbukkit/Main.java
+index 446403f73fb1b5687d587889e6f32dce464d05a6..ed167d0d399924d54d9ff99c10ab8ee093efc149 100644
+--- a/src/main/java/org/bukkit/craftbukkit/Main.java
++++ b/src/main/java/org/bukkit/craftbukkit/Main.java
+@@ -203,11 +203,20 @@ public class Main {
+                 return;
+             }
+ 
+-            float javaVersion = Float.parseFloat(System.getProperty("java.class.version"));
+-            if (javaVersion > 66.0) {
+-                System.err.println("Unsupported Java detected (" + javaVersion + "). Only up to Java 22 is supported.");
+-                return;
++            // Paper start - Improve java version check
++            boolean skip = Boolean.getBoolean("Paper.IgnoreJavaVersion");
++            String javaVersionName = System.getProperty("java.version");
++            // J2SE SDK/JRE Version String Naming Convention
++            boolean isPreRelease = javaVersionName.contains("-");
++            if (isPreRelease) {
++                if (!skip) {
++                    System.err.println("Unsupported Java detected (" + javaVersionName + "). You are running an unsupported, non official, version. Only general availability versions of Java are supported. Please update your Java version. See https://docs.papermc.io/paper/faq#unsupported-java-detected-what-do-i-do for more information.");
++                    return;
++                }
++
++                System.err.println("Unsupported Java detected ("+ javaVersionName + "), but the check was skipped. Proceed with caution! ");
+             }
++            // Paper end - Improve java version check
+ 
+             try {
+                 // Paper start - Handled by TerminalConsoleAppender