Rewrite chunk system (#8177)

Patch documentation to come

Issues with the old system that are fixed now:
- World generation does not scale with cpu cores effectively.
- Relies on the main thread for scheduling and maintaining chunk state, dropping chunk load/generate rates at lower tps.
- Unreliable prioritisation of chunk gen/load calls that block the main thread.
- Shutdown logic is utterly unreliable, as it has to wait for all chunks to unload - is it guaranteed that the chunk system is in a state on shutdown that it can reliably do this? Watchdog shutdown also typically failed due to thread checks, which is now resolved.
- Saving of data is not unified (i.e can save chunk data without saving entity data, poses problems for desync if shutdown is really abnormal.
- Entities are not loaded with chunks. This caused quite a bit of headache for Chunk#getEntities API, but now the new chunk system loads entities with chunks so that they are ready whenever the chunk loads in. Effectively brings the behavior back to 1.16 era, but still storing entities in their own separate regionfiles.

The above list is not complete. The patch documentation will complete it.

New chunk system hard relies on starlight and dataconverter, and most importantly the new concurrent utilities in ConcurrentUtil.

Some of the old async chunk i/o interface (i.e the old file io thread reroutes _some_ calls to the new file io thread) is kept for plugin compat reasons. It will be removed in the next major version of minecraft.

The old legacy chunk system patches have been moved to the removed folder in case we need them again.

1 files changed, 66 insertions, 0 deletions

diff --git a/patches/server/0032-Prevent-tile-entity-and-entity-crashes.patch b/patches/server/0032-Prevent-tile-entity-and-entity-crashes.patch
new file mode 100644
index 0000000000..ce3f080af3
--- /dev/null
+++ b/patches/server/0032-Prevent-tile-entity-and-entity-crashes.patch
@@ -0,0 +1,66 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Aikar <[email protected]>
+Date: Tue, 1 Mar 2016 23:52:34 -0600
+Subject: [PATCH] Prevent tile entity and entity crashes
+
+
+diff --git a/src/main/java/net/minecraft/world/level/Level.java b/src/main/java/net/minecraft/world/level/Level.java
+index e4dfaec6a1efa7bb44c843a283dd3c3d3a4e199c..4c4dff95b88c4f228c9e0eb51613ed1094bec8a5 100644
+--- a/src/main/java/net/minecraft/world/level/Level.java
++++ b/src/main/java/net/minecraft/world/level/Level.java
+@@ -703,11 +703,11 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
+         try {
+             tickConsumer.accept(entity);
+         } catch (Throwable throwable) {
+-            CrashReport crashreport = CrashReport.forThrowable(throwable, "Ticking entity");
+-            CrashReportCategory crashreportsystemdetails = crashreport.addCategory("Entity being ticked");
+-
+-            entity.fillCrashReportCategory(crashreportsystemdetails);
+-            throw new ReportedException(crashreport);
++            // Paper start - Prevent tile entity and entity crashes
++            final String msg = String.format("Entity threw exception at %s:%s,%s,%s", entity.level.getWorld().getName(), entity.getX(), entity.getY(), entity.getZ());
++            MinecraftServer.LOGGER.error(msg, throwable);
++            entity.discard();
++            // Paper end
+         }
+     }
+ 
+diff --git a/src/main/java/net/minecraft/world/level/block/entity/BlockEntity.java b/src/main/java/net/minecraft/world/level/block/entity/BlockEntity.java
+index be08224c8107aab3e9a3645a20977dd14bfff782..c518704386f14cd033307dd976455c35760d7236 100644
+--- a/src/main/java/net/minecraft/world/level/block/entity/BlockEntity.java
++++ b/src/main/java/net/minecraft/world/level/block/entity/BlockEntity.java
+@@ -213,7 +213,12 @@ public abstract class BlockEntity {
+             return minecraftkey + " // " + this.getClass().getCanonicalName();
+         });
+         if (this.level != null) {
+-            CrashReportCategory.populateBlockDetails(crashReportSection, this.level, this.worldPosition, this.getBlockState());
++            // Paper start - Prevent TileEntity and Entity crashes
++            BlockState block = this.getBlockState();
++            if (block != null) {
++                CrashReportCategory.populateBlockDetails(crashReportSection, this.level, this.worldPosition, block);
++            }
++            // Paper end
+             CrashReportCategory.populateBlockDetails(crashReportSection, this.level, this.worldPosition, this.level.getBlockState(this.worldPosition));
+         }
+     }
+diff --git a/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java b/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java
+index 8b65e8361918b5e6fe936fec99ee63ff9eef66f0..a4594b6b28eab545694491bc547f05a971a6ffad 100644
+--- a/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java
++++ b/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java
+@@ -1166,11 +1166,11 @@ public class LevelChunk extends ChunkAccess {
+ 
+                         gameprofilerfiller.pop();
+                     } catch (Throwable throwable) {
+-                        CrashReport crashreport = CrashReport.forThrowable(throwable, "Ticking block entity");
+-                        CrashReportCategory crashreportsystemdetails = crashreport.addCategory("Block entity being ticked");
+-
+-                        this.blockEntity.fillCrashReportCategory(crashreportsystemdetails);
+-                        throw new ReportedException(crashreport);
++                        // Paper start - Prevent tile entity and entity crashes
++                        final String msg = String.format("BlockEntity threw exception at %s:%s,%s,%s", LevelChunk.this.getLevel().getWorld().getName(), this.getPos().getX(), this.getPos().getY(), this.getPos().getZ());
++                        net.minecraft.server.MinecraftServer.LOGGER.error(msg, throwable);
++                        LevelChunk.this.removeBlockEntity(this.getPos());
++                        // Paper end
+                         // Spigot start
+                     } finally {
+                         this.blockEntity.tickTimer.stopTiming();