Paper/patches/server/0675-Fix-swamp-hut-cat-generation-deadlock.patch
Bjarne Koll c5a10665b8
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.
2024-09-19 16:36:07 +02:00

65 lines
4.3 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Sat, 12 Mar 2022 06:31:13 -0800
Subject: [PATCH] Fix swamp hut cat generation deadlock
The worldgen thread will attempt to get structure references
via the world's getChunkAt method, which is fine if the gen is
not cancelled - but if the chunk was unloaded, the call will block
indefinitely. Instead of using the world state, we use the already
supplied ServerLevelAccessor which will always have the chunk available.
diff --git a/src/main/java/net/minecraft/world/entity/animal/Cat.java b/src/main/java/net/minecraft/world/entity/animal/Cat.java
index f0e5428394f8de8f7ac05b8cbc34826d153eeaef..d44807c16712afd37efdbf434d1afb12a7c3d343 100644
--- a/src/main/java/net/minecraft/world/entity/animal/Cat.java
+++ b/src/main/java/net/minecraft/world/entity/animal/Cat.java
@@ -357,7 +357,7 @@ public class Cat extends TamableAnimal implements VariantHolder<Holder<CatVarian
BuiltInRegistries.CAT_VARIANT.getRandomElementOf(tagkey, world.getRandom()).ifPresent(this::setVariant);
ServerLevel worldserver = world.getLevel();
- if (worldserver.structureManager().getStructureWithPieceAt(this.blockPosition(), StructureTags.CATS_SPAWN_AS_BLACK).isValid()) {
+ if (worldserver.structureManager().getStructureWithPieceAt(this.blockPosition(), StructureTags.CATS_SPAWN_AS_BLACK, world).isValid()) { // Paper - Fix swamp hut cat generation deadlock
this.setVariant((Holder) BuiltInRegistries.CAT_VARIANT.getHolderOrThrow(CatVariant.ALL_BLACK));
this.setPersistenceRequired();
}
diff --git a/src/main/java/net/minecraft/world/level/StructureManager.java b/src/main/java/net/minecraft/world/level/StructureManager.java
index ceec33ced3d0b65a3e800378e250d0166d0c195f..54972cce2314eff774250101df43a9b7074e9604 100644
--- a/src/main/java/net/minecraft/world/level/StructureManager.java
+++ b/src/main/java/net/minecraft/world/level/StructureManager.java
@@ -48,7 +48,12 @@ public class StructureManager {
}
public List<StructureStart> startsForStructure(ChunkPos pos, Predicate<Structure> predicate) {
- Map<Structure, LongSet> map = this.level.getChunk(pos.x, pos.z, ChunkStatus.STRUCTURE_REFERENCES).getAllReferences();
+ // Paper start - Fix swamp hut cat generation deadlock
+ return this.startsForStructure(pos, predicate, null);
+ }
+ public List<StructureStart> startsForStructure(ChunkPos pos, Predicate<Structure> predicate, @Nullable ServerLevelAccessor levelAccessor) {
+ Map<Structure, LongSet> map = (levelAccessor == null ? this.level : levelAccessor).getChunk(pos.x, pos.z, ChunkStatus.STRUCTURE_REFERENCES).getAllReferences();
+ // Paper end - Fix swamp hut cat generation deadlock
Builder<StructureStart> builder = ImmutableList.builder();
for (Entry<Structure, LongSet> entry : map.entrySet()) {
@@ -116,10 +121,20 @@ public class StructureManager {
}
public StructureStart getStructureWithPieceAt(BlockPos pos, Predicate<Holder<Structure>> predicate) {
+ // Paper start - Fix swamp hut cat generation deadlock
+ return this.getStructureWithPieceAt(pos, predicate, null);
+ }
+
+ public StructureStart getStructureWithPieceAt(BlockPos pos, TagKey<Structure> tag, @Nullable ServerLevelAccessor levelAccessor) {
+ return this.getStructureWithPieceAt(pos, structure -> structure.is(tag), levelAccessor);
+ }
+
+ public StructureStart getStructureWithPieceAt(BlockPos pos, Predicate<Holder<Structure>> predicate, @Nullable ServerLevelAccessor levelAccessor) {
+ // Paper end - Fix swamp hut cat generation deadlock
Registry<Structure> registry = this.registryAccess().registryOrThrow(Registries.STRUCTURE);
for (StructureStart structureStart : this.startsForStructure(
- new ChunkPos(pos), structure -> registry.getHolder(registry.getId(structure)).map(predicate::test).orElse(false)
+ new ChunkPos(pos), structure -> registry.getHolder(registry.getId(structure)).map(predicate::test).orElse(false), levelAccessor // Paper - Fix swamp hut cat generation deadlock
)) {
if (this.structureHasPieceAt(pos, structureStart)) {
return structureStart;