Here's a fun bug you can try at home:
- Create a new world
- Spawn in a pocket computer, turn it on, and place it in a chest.
- Reload the world - the pocket computer in the chest should now be
off.
- Spawn in a new pocket computer, and turn it on. The computer in chest
will also appear to be on!
This bug has been present since pocket computers were added (27th March,
2024).
When a pocket computer is added to a player's inventory, it is assigned
a unique *per-session* "instance id" , which is used to find the
associated computer. Note the "per-session" there - these ids will be
reused if you reload the world (or restart the server).
In the above bug, we see the following:
- The first pocket computer is assigned an instance id of 0.
- After reloading, the second pocket computer is assigned an instance
id of 0.
- If the first pocket computer was in our inventory, it'd be ticked and
assigned a new instance id. However, because it's in an inventory, it
keeps its old one.
- Both computers look up their client-side computer state and get the
same value, meaning the first pocket computer mirrors the second!
To fix this, we now ensure instance ids are entirely unique (not just
per-session). Rather than sequentially assigning an int, we now use a
random UUID (we probably could get away with a random long, but this
feels more idiomatic).
This has a couple of user-visible changes:
- /computercraft no longer lists instance ids outside of dumping an
individual computer.
- The @c[instance=...] selector uses UUIDs. We still use int instance
ids for the legacy selector, but that'll be removed in a later MC
version.
- Pocket computers now store a UUID rather than an int.
Related to this change (I made this change first, but then they got
kinda mixed up together), we now only create PocketComputerData when
receiving server data. This makes the code a little uglier in some
places (the data may now be null), but means we don't populate the
client-side pocket computer map with computers the server doesn't know
about.
This ensures the client decoder is in sync with the server. Well, mostly
- we don't handle the anti-jerk, but that should correct itself within a
few samples.
Fixes#1748
This adds support for computer selectors, in the style of entity
selectors. The long-term goal here is to replace our existing ad-hoc
selectors. However, to aid migration, we currently support both - the
previous one will most likely be removed in MC 1.21.
Computer selectors take the form @c[<key>=<value>,...]. Currently we
support filtering by id, instance id, label, family (as before) and
distance from the player (new!). The code also supports computers within
a bounding box, but there's no parsing support for that yet.
This commit also (finally) documents the /computercraft command. Well,
sort of - it's definitely not my best word, but I couldn't find better
words.
Everything old is new again!
CC's network message implementation has gone through several iterations:
- Originally network messages were implemented with a single class,
which held an packet id/type and and opaque blobs of data (as
string/int/byte/NBT arrays), and a big switch statement to decode and
process this data.
- In 42d3901ee37892e259de26ebb57cf59ce284416e, we split the messages
into different classes all inheriting from NetworkMessage - this bit
we've stuck with ever since.
Each packet had a `getId(): int` method, which returned the
discriminator for this packet.
- However, getId() was only used when registering the packet, not when
sending, and so in ce0685c31f7315d15d3250c6c8605171b33aa99f we
removed it, just passing in a constant integer at registration
instead.
- In 53abe5e56eec6840890770b6ec36a5d009357da7, we made some relatively
minor changes to make the code more multi-loader/split-source
friendly. However, this meant when we finally came to add Fabric
support (8152f19b6efd71b66c3821ad94aacaddb7d26298), we had to
re-implement a lot of Forge's network code.
In 1.20.4, Forge moves to a system much closer to Fabric's (and indeed,
Minecraft's own CustomPacketPayload), and so it makes sense to adapt to
that now. As such, we:
- Add a new MessageType interface. This is implemented by the
loader-specific modules, and holds whatever information is needed to
register the packet (e.g. discriminator, reader function).
- Each NetworkMessage now has a type(): MessageType<?> function. This
is used by the Fabric networking code (and for NeoForge's on 1.20.4)
instead of a class lookup.
- NetworkMessages now creates/stores these MessageType<T>s (much like
we'd do for registries), and provides getters for the
clientbound/serverbound messages. Mod initialisers then call these
getters to register packets.
- For Forge, this is relatively unchanged. For Fabric, we now
`FabricPacket`s.
The two implementations aren't entirely compatible - the implementation
returned by .of will throw an NPE on .contains(null), whereas the
Collections implementations just return false. However, we try to avoid
passing null to collections methods, so this should be safe.
There's no strong reason to do this, but it helps make the code a little
more consistent
We can't use FriendlyByte.readCollection to read to a
pre-allocated/array-backed NonNullList, as that doesn't implement
List.add. Instead, we just need to do a normal loop.
We add a couple of tests to round-trip our recipe specs. Unfortunately
we can't test the recipes themselves as our own registries aren't set
up, so this'll have to do for now.
- Prefer {read,write}Nullable when possible.
- Use SoundEvent.{writeTo,readFrom}Network, instead of sending the
registry entries. This allows playing discs which don't register
their SoundEvent on the server.
- Add a couple of tests for round-tripping these packets.
This adds SPDX license headers to all source code files, following the
REUSE[1] specification. This does not include any asset files (such as
generated JSON files, or textures). While REUSE does support doing so
with ".license" files, for now we define these licences using the
.reuse/dep5 file.
[1]: https://reuse.software/
Many thanks to Lem for managing to reproduce it. It was actually an easy
bug bug to spot on second look, but having a reliable way to verify was
super helpful.
Fixes#1338
- Separate FileMount into separate FileMount and WritableFileMount
classes. This separates the (relatively simple) read-only code from
the (soon to be even more complex) read/write code.
It also allows you to create read-only mounts which don't bother with
filesystem accounting, which is nice.
- Make openForWrite/openForAppend always return a SeekableFileHandle.
Appendable files still cannot be seeked within, but that check is now
done on the FS side.
- Refactor the various mount tests to live in test contract interfaces,
allowing us to reuse them between mounts.
- Clean up our error handling a little better. (Most) file-specific code
has been moved to FileMount, and ArchiveMount-derived classes now
throw correct path-localised exceptions.
Lots of minor changes, but nothing too nasty - just tedious.
Known bugs/issues:
- REI and JEI haven't been updated at the time of writing, so our usage
of their APIs may be incompatible.
- Crash when opening the config UI in Fabric, as forgeconfigapi-port
hasn't been updated yet.
Will hold off on doing a release until those mods have updated.
- Remove deprecated API members in prep for 1.19.3. This allows us to
remove the mc-stubs and forge-stubs projects.
- Make several methods take a MinecraftServer instead of a Level (or
nothing at all).
- Remove I prefixes from a whole bunch of interfaces, making things a
little more consistent with Java conventions.
This avoids touching the "main" interfaces people consume for now. I
want to do that another Minecraft version, to avoid making the update
too painful.
- Remove IFileSystem and associated getters. This has never worked very
well and I don't think has got much (any?) usage.
After several weeks of carefully arranging ribbons, we pull the string
and end up with, ... a bit of a messy bow. There were still some things
I'd missed.
- Split the mod into a common (vanilla-only) project and Forge-specific
project. This gives us room to add Fabric support later on.
- Split the project into main/client source sets. This is not currently
statically checked: we'll do that soon.
- Rename block/item/tile entities to use suffixes rather than prefixes.
