Paper/patches/server/0205-Fix-CraftEntity-hashCode.patch
Spottedleaf 01a13871de
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.
2022-09-26 01:02:51 -07:00

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sun, 10 Jun 2018 20:20:15 -0400
Subject: [PATCH] Fix CraftEntity hashCode
hashCodes are not allowed to change, however bukkit used a value
that does change, the entityId.
When an entity is teleported dimensions, the entity reference is
replaced with a new one with a new entity ID.
For hashCode, we can simply use the UUID's hashCode to keep
the hashCode from changing.
equals() is ok to use getEntityId() because equals() should only
be true if both the left and right are the same reference.
Since entity ids can not duplicate during runtime, this
check is essentially the same as this.getHandle() == other.getHandle()
However, replaced it too to make it clearer of intent.
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
index d3a8c68f5186f69432fb8af8b34b174b04368fc1..2a4f26c5bae66121c5c21d7f1013b3b7753608a4 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
@@ -824,14 +824,15 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
return false;
}
final CraftEntity other = (CraftEntity) obj;
- return (this.getEntityId() == other.getEntityId());
+ return (this.getHandle() == other.getHandle()); // Paper - while logically the same, this is clearer
}
+ // Paper - Fix hashCode. entity ID's are not static.
+ // A CraftEntity can change reference to a new entity with a new ID, and hash codes should never change
@Override
public int hashCode() {
- int hash = 7;
- hash = 29 * hash + this.getEntityId();
- return hash;
+ return getUniqueId().hashCode();
+ // Paper end
}
@Override