[WIP] Syncable Data Attachments

[Technici4n]

Allows data attachments to opt into syncing. Still a rough PR, many details need to be figured out. Closes #335.

TODO:

• StreamCodec helper.
• AttachmentSyncReason looks kinda pointless. Remove?
• Related: too many parameters for IAttachmentSyncHandler maybe?
• Method to force syncing of attachments.
• Decide whether we sync immediately or at the end of the tick.
• Support for block entities.
• Support for chunks.
• Entities: server player data does not seem to get synced on initial connection.
• Entities: what about player respawns and entity copies?
• Support for levels.
• Entity syncing code already looks incredibly complicated.
• When attachments are set through indirect means (getData, deserialization, copying), we should probably sync automatically.
• deserializeAttachments: needs to attempt to sync?
• Properly handle sending the removal of an attachment.
• Maybe send a separate byte[] for each attachment type.
• Is there a way to keep server-wide data in sync? (even if it is e.g. stored in the overworld) Is there a point to that?
• What to do when force-syncing an attachment? Sending a removal to the client is probably good.
• Remove client command hacks...
• 1.21.1 backport?

[neoforged-pr-publishing]

• Publish PR to GitHub Packages

Last commit published: 8842c6223cb6226065c08dbd29acc7dbca016c8f.

PR Publishing

The artifacts published by this PR:

• 📦 net.neoforged:testframework:21.4.66-beta-pr-1823-attachment-sync
• 📦 net.neoforged:neoforge:21.4.66-beta-pr-1823-attachment-sync

Repository Declaration

In order to use the artifacts published by the PR, add the following repository to your buildscript:

repositories {
    maven {
        name 'Maven for PR #1823' // https://github.com/neoforged/NeoForge/pull/1823
        url 'https://prmaven.neoforged.net/NeoForge/pr1823'
        content {
            includeModule('net.neoforged', 'testframework')
            includeModule('net.neoforged', 'neoforge')
        }
    }
}

MDK installation

In order to setup a MDK using the latest PR version, run the following commands in a terminal.
The script works on both *nix and Windows as long as you have the JDK bin folder on the path.
The script will clone the MDK in a folder named NeoForge-pr1823.
On Powershell you will need to remove the -L flag from the curl invocation.

mkdir NeoForge-pr1823
cd NeoForge-pr1823
curl -L https://prmaven.neoforged.net/NeoForge/pr1823/net/neoforged/neoforge/21.4.66-beta-pr-1823-attachment-sync/mdk-pr1823.zip -o mdk.zip
jar xf mdk.zip
rm mdk.zip || del mdk.zip

To test a production environment, you can download the installer from here.

[neoforged-compatibility-checks]

@Technici4n, this PR introduces breaking changes.
Fortunately, this project is currently accepting breaking changes, but if they are not intentional, please revert them.
Last checked commit: 8842c6223cb6226065c08dbd29acc7dbca016c8f.

neoforge (:neoforge)

• net/minecraft/server/level/ServerEntity
  • sendPairingData(Lnet/minecraft/server/level/ServerPlayer;Lnet/neoforged/neoforge/network/bundle/PacketAndPayloadAcceptor;)V: ❗ API method was removed
• net/neoforged/neoforge/network/bundle/PacketAndPayloadAcceptor
  • ⚠ API class no longer exists