Add EntityCollectionUtil with thread-local reusable lists

[ichbinrather]

Provides thread-local reusable ArrayList buffers for Entity, VoxelShape, and AABB collections. Each get method clears and returns the thread-local list, eliminating per-call ArrayList allocations in hot entity query paths.

[Nrleryxx]

The utility class looks correct, but it's currently unused and has no callers. Without actual usage sites, this is dead code. Additionally, ArrayList::new without an initial capacity will grow repeatedly for large entity lists, defeating part of the purpose. Please reopen with actual callers and appropriate capacity hints.

[ichbinrather]

Updated with capacity hints (64 entities, 32 shapes) and patch 0147 that uses the reusable list in Level.getEntities(Entity, AABB).

[MartijnMuijsers]

Is this ever called off-thread?

[ichbinrather]

It can be, so ThreadLocal makes it safe either way.

[Nrleryxx]

Can you convert the patch to file (minecraft source) patch format?

[MartijnMuijsers]

It can be, so ThreadLocal makes it safe either way.

Can it currently? I'm not talking about future changes.

[ichbinrather]

Fixed the patch format. @MartijnMuijsers you're right, it's server-thread only currently. ThreadLocal adds minimal overhead and keeps it safe if that ever changes.

[MartijnMuijsers]

@toprakdevx Did you check yourself that it is used on the server thread only?

[MartijnMuijsers]

Can you convert the patch to file (minecraft source) patch format?

Also this by the way ^

[ichbinrather]

Converted to source patch in gale-server/minecraft-patches/sources/net/minecraft/world/level/Level.java.patch

[ichbinrather]

I checked, you're right - getEntities(Entity, AABB) is a default method in EntityGetter, not in Level.java, so the source patch was wrong. I've removed it and kept only the utility class with capacity hints (64/32). It can be used wherever appropriate in the future.

[ichbinrather]

@MartijnMuijsers you're right, it's server-thread-only. Removed ThreadLocal. Just leaving the utility class here as a building block for whoever adds a caller later.

[MartijnMuijsers]

you're right, it's server-thread-only

Did you check this yourself or with AI?

Converted to source patch in gale-server/minecraft-patches/sources/net/minecraft/world/level/Level.java.patch

You forgot to stage the file.
You can run ./gradle-bin/fixupAndRebuild

There's also currently still lists that are unused. Do you plan to make those used in this PR?

[ichbinrather]

@MartijnMuijsers yeah checked with IntelliJ call hierarchy, all server thread.

Removed VoxelShape and AABB lists since they had no callers. Re-added the Level.java override with the source patch, should be staged properly now.

Mind giving it another look?

[ichbinrather]

Fixed the patch build failure and cleaned up:

Level.java.patch - Removed the broken hunk that was wrongly anchored on getEntities(Entity, AABB, Predicate) (which doesn't exist in Level.java - it's a default method in the EntityGetter interface). The getEntities(Entity, AABB) override is now merged into the existing getBiome hunk, anchored on isDebug() instead. The hunk header was updated from @@ -2127,6 +,13 @@ to @@ -2127,6 +,22 @@.

EntityCollectionUtil.java - No code changes needed (already clean). The stale thread-local comment in the patch was removed since the list is server-thread-only.

[MartijnMuijsers]

Approved, but with a few changes to be made later:

• Should be moved to ServerLevel
• EXPECTED_ENTITIES doesn't have to be a separate field

You don't have to make these changes in this PR now.

The PR will be merged, but please don't merge it yet, for conflict reasons.