[1.15] Tighten logic for handling target tick times in tick scheduler (#4011)

No longer rely on world time as plugins like to screw it up.

Add a new flag -Dpaper.ticklist-max-tick-delay= that
will automatically drop any tick entries that have a delay
exceeding the specified amount. This is only useful
for cleaning up a world that has been corrupted by
certain blocks having a huge tick delay.

Also fix an issue with some rails connecting incorrectly
that I found when testing.

Co-authored-by: Spottedleaf <[email protected]>

5 files changed, 142 insertions, 9 deletions

diff --git a/Spigot-Server-Patches/0446-Optimise-TickListServer-by-rewriting-it.patch b/Spigot-Server-Patches/0446-Optimise-TickListServer-by-rewriting-it.patch
index 24d53ad14e..84a69e462f 100644
--- a/Spigot-Server-Patches/0446-Optimise-TickListServer-by-rewriting-it.patch
+++ b/Spigot-Server-Patches/0446-Optimise-TickListServer-by-rewriting-it.patch
@@ -61,10 +61,10 @@ index 74295466e53db06d0d019a13768f3575ac61d699..f1b41e16c8ce8323a896339c5d822f8f
          ConfigurationSection section;
 diff --git a/src/main/java/com/destroystokyo/paper/server/ticklist/PaperTickList.java b/src/main/java/com/destroystokyo/paper/server/ticklist/PaperTickList.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..ce653f6b4be3ab6c6d35cb3e9222e7f8c8759e25
+index 0000000000000000000000000000000000000000..466d4ae811e85fa95bca007ec3f533dabf8a1603
 --- /dev/null
 +++ b/src/main/java/com/destroystokyo/paper/server/ticklist/PaperTickList.java
-@@ -0,0 +1,622 @@
+@@ -0,0 +1,630 @@
 +package com.destroystokyo.paper.server.ticklist;
 +
 +import net.minecraft.server.MCUtil;
@@ -72,7 +72,6 @@ index 0000000000000000000000000000000000000000..ce653f6b4be3ab6c6d35cb3e9222e7f8
 +import it.unimi.dsi.fastutil.longs.Long2ObjectMap;
 +import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
 +import it.unimi.dsi.fastutil.objects.ObjectRBTreeSet;
-+import net.minecraft.server.BaseBlockPosition;
 +import net.minecraft.server.BlockPosition;
 +import net.minecraft.server.ChunkCoordIntPair;
 +import net.minecraft.server.ChunkProviderServer;
@@ -269,7 +268,7 @@ index 0000000000000000000000000000000000000000..ce653f6b4be3ab6c6d35cb3e9222e7f8
 +    }
 +
 +    private void prepare() {
-+        final long currentTick = this.world.getTime();
++        final long currentTick = this.nextTick;
 +
 +        final ChunkProviderServer chunkProvider = this.world.getChunkProvider();
 +
@@ -334,8 +333,18 @@ index 0000000000000000000000000000000000000000..ce653f6b4be3ab6c6d35cb3e9222e7f8
 +        }
 +    }
 +
++    private boolean warnedAboutDesync;
++
 +    @Override
 +    public void tick() {
++        ++this.nextTick;
++        if (this.nextTick != this.world.getTime()) {
++            if (!this.warnedAboutDesync) {
++                this.warnedAboutDesync = true;
++                MinecraftServer.LOGGER.error("World tick desync detected! Expected " + this.nextTick + " ticks, but got " + this.world.getTime() + " ticks for world '" + this.world.getWorld().getName() + "'", new Throwable());
++                MinecraftServer.LOGGER.error("Preventing redstone from breaking by refusing to accept new tick time");
++            }
++        }
 +        final ChunkProviderServer chunkProvider = this.world.getChunkProvider();
 +
 +        this.world.getMethodProfiler().enter("cleaning");
@@ -346,7 +355,6 @@ index 0000000000000000000000000000000000000000..ce653f6b4be3ab6c6d35cb3e9222e7f8
 +        // this must be done here in case something schedules in the tick code
 +        this.shortScheduled[this.shortScheduledIndex].clear();
 +        this.shortScheduledIndex = getNextIndex(this.shortScheduledIndex, SHORT_SCHEDULE_TICK_THRESHOLD);
-+        this.nextTick = this.world.getTime() + 1;
 +
 +        this.timingCleanup.stopTiming();
 +        this.world.getMethodProfiler().exitEnter("ticking");
@@ -473,7 +481,7 @@ index 0000000000000000000000000000000000000000..ce653f6b4be3ab6c6d35cb3e9222e7f8
 +
 +    @Override
 +    public void schedule(BlockPosition blockPosition, T t, int i, TickListPriority tickListPriority) {
-+        this.schedule(blockPosition, t, i + this.world.getTime(), tickListPriority);
++        this.schedule(blockPosition, t, i + this.nextTick, tickListPriority);
 +    }
 +
 +    public void schedule(final NextTickListEntry<T> entry) {
@@ -649,7 +657,7 @@ index 0000000000000000000000000000000000000000..ce653f6b4be3ab6c6d35cb3e9222e7f8
 +        // start copy from TickListServer  // TODO check on update
 +        List<NextTickListEntry<T>> list = this.getEntriesInChunk(chunkcoordintpair, false, true);
 +
-+        return TickListServer.serialize(this.getMinecraftKeyFrom, list, this.world.getTime());
++        return TickListServer.serialize(this.getMinecraftKeyFrom, list, this.nextTick);
 +        // end copy from TickListServer
 +    }
 +
@@ -883,7 +891,7 @@ index 0000000000000000000000000000000000000000..118988c39e58f28e8a2851792b9c014f
 +    }
 +}
 diff --git a/src/main/java/net/minecraft/server/BlockPosition.java b/src/main/java/net/minecraft/server/BlockPosition.java
-index 3fcfe416d26808fa1c9bfdc5b413b149764c544a..3bf17ccdaef21322b787db538d569e0bc614ef22 100644
+index 9fc34246a845168d158a6b2793d8e344f2d2b008..8c3e09a5a3b4e6c38790735db4b3b316d7cdd39a 100644
 --- a/src/main/java/net/minecraft/server/BlockPosition.java
 +++ b/src/main/java/net/minecraft/server/BlockPosition.java
 @@ -126,6 +126,7 @@ public class BlockPosition extends BaseBlockPosition implements MinecraftSeriali
@@ -895,7 +903,7 @@ index 3fcfe416d26808fa1c9bfdc5b413b149764c544a..3bf17ccdaef21322b787db538d569e0b
          return this.b(baseblockposition.getX(), baseblockposition.getY(), baseblockposition.getZ());
      }
 diff --git a/src/main/java/net/minecraft/server/ChunkProviderServer.java b/src/main/java/net/minecraft/server/ChunkProviderServer.java
-index 6688b1340e2cc8fb13a7e80c9b7c37b8822dcecd..d53b34ba552771bf271131ce0a56ebb992ccc84c 100644
+index e467cd8123dafc46a8c894f1ffa9440de0d45340..9e3471be219b5e061486c8a3e4b638a45e6f28f5 100644
 --- a/src/main/java/net/minecraft/server/ChunkProviderServer.java
 +++ b/src/main/java/net/minecraft/server/ChunkProviderServer.java
 @@ -200,6 +200,13 @@ public class ChunkProviderServer extends IChunkProvider {
@@ -1037,6 +1045,36 @@ index dbb565e74d211ef35d5d40b3d024e2f07cef9031..185658e230688a9939c89dae9167217c
      public boolean b(BaseBlockPosition baseblockposition) {
          return baseblockposition.getX() >= this.a && baseblockposition.getX() <= this.d && baseblockposition.getZ() >= this.c && baseblockposition.getZ() <= this.f && baseblockposition.getY() >= this.b && baseblockposition.getY() <= this.e;
      }
+diff --git a/src/main/java/net/minecraft/server/TickListChunk.java b/src/main/java/net/minecraft/server/TickListChunk.java
+index eb526530fba30c313482355b74a01258b9b79410..485a029790ea91e61c2bb1a43d75317ecf40b317 100644
+--- a/src/main/java/net/minecraft/server/TickListChunk.java
++++ b/src/main/java/net/minecraft/server/TickListChunk.java
+@@ -51,6 +51,8 @@ public class TickListChunk<T> implements TickList<T> {
+         return TickListServer.a(this.b, this.a, i);
+     }
+ 
++    private static final int MAX_TICK_DELAY = Integer.getInteger("paper.ticklist-max-tick-delay", -1).intValue(); // Paper - clean up broken entries
++
+     public static <T> TickListChunk<T> a(NBTTagList nbttaglist, Function<T, MinecraftKey> function, Function<MinecraftKey, T> function1) {
+         Set<NextTickListEntry<T>> set = Sets.newHashSet();
+ 
+@@ -59,7 +61,15 @@ public class TickListChunk<T> implements TickList<T> {
+             T t0 = function1.apply(new MinecraftKey(nbttagcompound.getString("i")));
+ 
+             if (t0 != null) {
+-                set.add(new NextTickListEntry<>(new BlockPosition(nbttagcompound.getInt("x"), nbttagcompound.getInt("y"), nbttagcompound.getInt("z")), t0, (long) nbttagcompound.getInt("t"), TickListPriority.a(nbttagcompound.getInt("p"))));
++                // Paper start - clean up broken entries
++                NextTickListEntry<T> pending = new NextTickListEntry<>(new BlockPosition(nbttagcompound.getInt("x"), nbttagcompound.getInt("y"), nbttagcompound.getInt("z")), t0, (long) nbttagcompound.getInt("t"), TickListPriority.a(nbttagcompound.getInt("p")));
++                long delay = pending.getTargetTick();
++                if (MAX_TICK_DELAY > 0 && delay > MAX_TICK_DELAY) {
++                    MinecraftServer.LOGGER.warn("Dropping tick for pos " + pending.getPosition() + ", tick delay " + delay);
++                    continue;
++                }
++                set.add(pending);
++                // Paper end - clean up broken entries
+             }
+         }
+ 
 diff --git a/src/main/java/net/minecraft/server/TickListServer.java b/src/main/java/net/minecraft/server/TickListServer.java
 index f533860bbed19ff2915c90186c259b466f41ce90..3f1aa5ced697490b5481ba992cf5af5dc98b8166 100644
 --- a/src/main/java/net/minecraft/server/TickListServer.java
diff --git a/Spigot-Server-Patches/0551-Fix-some-rails-connecting-improperly.patch b/Spigot-Server-Patches/0551-Fix-some-rails-connecting-improperly.patch
new file mode 100644
index 0000000000..39bc7fef4d
--- /dev/null
+++ b/Spigot-Server-Patches/0551-Fix-some-rails-connecting-improperly.patch
@@ -0,0 +1,95 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Spottedleaf <[email protected]>
+Date: Fri, 24 Jul 2020 15:56:05 -0700
+Subject: [PATCH] Fix some rails connecting improperly
+
+
+diff --git a/src/main/java/net/minecraft/server/BlockMinecartDetector.java b/src/main/java/net/minecraft/server/BlockMinecartDetector.java
+index cbc19202465c128f22933df25661811cc9f99a8f..84e2d402cc749063cd83afb5ed2513d2168944bb 100644
+--- a/src/main/java/net/minecraft/server/BlockMinecartDetector.java
++++ b/src/main/java/net/minecraft/server/BlockMinecartDetector.java
+@@ -55,6 +55,7 @@ public class BlockMinecartDetector extends BlockMinecartTrackAbstract {
+     }
+ 
+     private void a(World world, BlockPosition blockposition, IBlockData iblockdata) {
++        if (iblockdata.getBlock() != this) { return; } // Paper - not our block, don't do anything
+         boolean flag = (Boolean) iblockdata.get(BlockMinecartDetector.POWERED);
+         boolean flag1 = false;
+         List<EntityMinecartAbstract> list = this.a(world, blockposition, EntityMinecartAbstract.class, (Predicate) null);
+diff --git a/src/main/java/net/minecraft/server/BlockMinecartTrackAbstract.java b/src/main/java/net/minecraft/server/BlockMinecartTrackAbstract.java
+index 18d60b85aa05bf5575ff65b202786f56deff5b51..4ad2e4932dcf60a90027e08ef037e9cca579dfc4 100644
+--- a/src/main/java/net/minecraft/server/BlockMinecartTrackAbstract.java
++++ b/src/main/java/net/minecraft/server/BlockMinecartTrackAbstract.java
+@@ -41,6 +41,7 @@ public abstract class BlockMinecartTrackAbstract extends Block {
+             iblockdata = this.a(world, blockposition, iblockdata, true);
+             if (this.c) {
+                 iblockdata.doPhysics(world, blockposition, this, blockposition, flag);
++                iblockdata = world.getType(blockposition); // Paper - don't desync, update again
+             }
+ 
+         }
+diff --git a/src/main/java/net/minecraft/server/MinecartTrackLogic.java b/src/main/java/net/minecraft/server/MinecartTrackLogic.java
+index 8f9eef8237932d78487e2a6c3c7302e1e233f3fd..f78321d4ff2f633d7291bc44c478068f384612ca 100644
+--- a/src/main/java/net/minecraft/server/MinecartTrackLogic.java
++++ b/src/main/java/net/minecraft/server/MinecartTrackLogic.java
+@@ -7,13 +7,19 @@ import javax.annotation.Nullable;
+ 
+ public class MinecartTrackLogic {
+ 
+-    private final World a;
+-    private final BlockPosition b;
++    private final World a; public final World getWorld() { return this.a; } // Paper - OBFHELPER
++    private final BlockPosition b; public final BlockPosition getPos() { return this.b; } // Paper - OBFHELPER
+     private final BlockMinecartTrackAbstract c;
+-    private IBlockData d;
++    private IBlockData d; public final IBlockData getRailState() { return this.d; } // Paper - OBFHELPER
+     private final boolean e;
+     private final List<BlockPosition> f = Lists.newArrayList();
+ 
++    // Paper start - prevent desync
++    public boolean isValid() {
++        return this.getWorld().getType(this.getPos()).getBlock() == this.getRailState().getBlock();
++    }
++    // Paper end - prevent desync
++
+     public MinecartTrackLogic(World world, BlockPosition blockposition, IBlockData iblockdata) {
+         this.a = world;
+         this.b = blockposition;
+@@ -148,6 +154,11 @@ public class MinecartTrackLogic {
+     }
+ 
+     private void c(MinecartTrackLogic minecarttracklogic) {
++        // Paper start - prevent desync
++        if (!this.isValid() || !minecarttracklogic.isValid()) {
++            return;
++        }
++        // Paper end - prevent desync
+         this.f.add(minecarttracklogic.b);
+         BlockPosition blockposition = this.b.north();
+         BlockPosition blockposition1 = this.b.south();
+@@ -342,11 +353,16 @@ public class MinecartTrackLogic {
+         this.d = (IBlockData) this.d.set(this.c.d(), blockpropertytrackposition1);
+         if (flag1 || this.a.getType(this.b) != this.d) {
+             this.a.setTypeAndData(this.b, this.d, 3);
++            // Paper start - prevent desync
++            if (!this.isValid()) {
++                return this;
++            }
++            // Paper end - prevent desync
+ 
+             for (int i = 0; i < this.f.size(); ++i) {
+                 MinecartTrackLogic minecarttracklogic = this.b((BlockPosition) this.f.get(i));
+ 
+-                if (minecarttracklogic != null) {
++                if (minecarttracklogic != null && minecarttracklogic.isValid()) { // Paper - prevent desync
+                     minecarttracklogic.d();
+                     if (minecarttracklogic.b(this)) {
+                         minecarttracklogic.c(this);
+@@ -359,6 +375,6 @@ public class MinecartTrackLogic {
+     }
+ 
+     public IBlockData c() {
+-        return this.d;
++        return this.getWorld().getType(this.getPos()); // Paper - prevent desync
+     }
+ }
diff --git a/Spigot-Server-Patches/0551-Optimize-the-advancement-data-player-iteration-to-be.patch b/Spigot-Server-Patches/0552-Optimize-the-advancement-data-player-iteration-to-be.patch
index 2f91d733b6..2f91d733b6 100644
--- a/Spigot-Server-Patches/0551-Optimize-the-advancement-data-player-iteration-to-be.patch
+++ b/Spigot-Server-Patches/0552-Optimize-the-advancement-data-player-iteration-to-be.patch
diff --git a/Spigot-Server-Patches/0552-Move-range-check-for-block-placing-up.patch b/Spigot-Server-Patches/0553-Move-range-check-for-block-placing-up.patch
index eba1279c74..eba1279c74 100644
--- a/Spigot-Server-Patches/0552-Move-range-check-for-block-placing-up.patch
+++ b/Spigot-Server-Patches/0553-Move-range-check-for-block-placing-up.patch
diff --git a/Spigot-Server-Patches/0553-Fix-AdvancementDataPlayer-leak-due-from-quitting-ear.patch b/Spigot-Server-Patches/0554-Fix-AdvancementDataPlayer-leak-due-from-quitting-ear.patch
index c8015fb604..c8015fb604 100644
--- a/Spigot-Server-Patches/0553-Fix-AdvancementDataPlayer-leak-due-from-quitting-ear.patch
+++ b/Spigot-Server-Patches/0554-Fix-AdvancementDataPlayer-leak-due-from-quitting-ear.patch