Merge branch 'mc-1.19.x' into mc-1.20.x

Only an issue on the latest FAPI, so we also bump that.

.github/workflows/main-ci.yml

@@ -8,16 +8,16 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - name: Clone repository
+    - name: 📥 Clone repository
       uses: actions/checkout@v3
 
-    - name: Set up Java
+    - name: 📥 Set up Java
       uses: actions/setup-java@v3
       with:
         java-version: 17
         distribution: 'temurin'
 
-    - name: Setup Gradle
+    - name: 📥 Setup Gradle
       uses: gradle/gradle-build-action@v2
       with:
         cache-read-only: ${{ !startsWith(github.ref, 'refs/heads/mc-') }}
@@ -27,39 +27,45 @@ jobs:
         mkdir -p ~/.gradle
         echo "org.gradle.daemon=false" >> ~/.gradle/gradle.properties
 
-    - name: Build with Gradle
-      run: |
-        ./gradlew assemble || ./gradlew assemble
-        ./gradlew downloadAssets || ./gradlew downloadAssets
-        ./gradlew build
+    - name: ⚒️ Build
+      run: ./gradlew assemble || ./gradlew assemble
 
-    - name: Run client tests
+    - name: 💡 Lint
+      uses: pre-commit/action@v3.0.0
+
+    - name: 🧪 Run tests
+      run: ./gradlew test validateMixinNames checkChangelog
+
+    - name: 📥 Download assets for game tests
+      run: ./gradlew downloadAssets || ./gradlew downloadAssets
+
+    - name: 🧪 Run integration tests
+      run: ./gradlew runGametest
+
+    - name: 🧪 Run client tests
       run: ./gradlew runGametestClient # Not checkClient, as no point running rendering tests.
       # These are a little flaky on GH actions: its useful to run them, but don't break the build.
       continue-on-error: true
 
-    - name: Prepare Jars
+    - name: 🧪 Parse test reports
+      run: ./tools/parse-reports.py
+      if: ${{ failure() }}
+
+    - name: 📦 Prepare Jars
       run: |
         # Find the main jar and append the git hash onto it.
         mkdir -p jars
         find projects/forge/build/libs projects/fabric/build/libs -type f -regex '.*[0-9.]+\(-SNAPSHOT\)?\.jar$' -exec bash -c 'cp {} "jars/$(basename {} .jar)-$(git rev-parse HEAD).jar"' \;
 
-    - name: Upload Jar
+    - name: 📤 Upload Jar
       uses: actions/upload-artifact@v3
       with:
         name: CC-Tweaked
         path: ./jars
 
-    - name: Upload coverage
+    - name: 📤 Upload coverage
       uses: codecov/codecov-action@v3
 
-    - name: Parse test reports
-      run: ./tools/parse-reports.py
-      if: ${{ failure() }}
-
-    - name: Run linters
-      uses: pre-commit/action@v3.0.0
-
   build-core:
     strategy:
       fail-fast: false

.github/workflows/make-doc.yml

@@ -4,6 +4,7 @@ on:
   push:
     branches:
     - mc-1.19.x
+    - mc-1.20.x
 
 jobs:
   make_doc:

.reuse/dep5

@@ -6,6 +6,7 @@ Upstream-Contact: Jonathan Coates <git@squiddev.cc>
 Files:
   projects/common/src/main/resources/assets/computercraft/sounds.json
   projects/common/src/main/resources/assets/computercraft/sounds/empty.ogg
+  projects/common/src/testMod/resources/data/cctest/computercraft/turtle_upgrades/*
   projects/common/src/testMod/resources/data/cctest/structures/*
   projects/fabric/src/generated/*
   projects/forge/src/generated/*
@@ -47,6 +48,7 @@ License: MPL-2.0
 
 Files:
   doc/logo.png
+  doc/logo-darkmode.png
   projects/common/src/main/resources/assets/computercraft/models/*
   projects/common/src/main/resources/assets/computercraft/textures/*
   projects/common/src/main/resources/pack.mcmeta

CONTRIBUTING.md

@@ -6,7 +6,7 @@ SPDX-License-Identifier: MPL-2.0
 
 # Contributing to CC: Tweaked
 As with many open source projects, CC: Tweaked thrives on contributions from other people! This document (hopefully)
-provides an introduction as to how to get started in helping out.
+provides an introduction as to how to get started with helping out.
 
 If you've any other questions, [just ask the community][community] or [open an issue][new-issue].
 
@@ -28,7 +28,7 @@ automatically with GitHub, so please don't submit PRs adding/changing translatio
 ## Setting up a development environment
 In order to develop CC: Tweaked, you'll need to download the source code and then run it.
 
- - Make sure you've got the following software instealled:
+ - Make sure you've got the following software installed:
    - Java Development Kit (JDK) installed. This can be downloaded from [Adoptium].
    - [Git](https://git-scm.com/).
    - If you want to work on documentation, [NodeJS][node].
@@ -51,10 +51,10 @@ If you want to run CC:T in a normal Minecraft instance, run `./gradlew assemble`
 ## Developing CC: Tweaked
 Before making any major changes to CC: Tweaked, I'd recommend you have a read of the [the architecture
 document][architecture] first. While it's not a comprehensive document, it gives a good hint of where you should start
-looking to make your changes. As always, if you're not sure [do ask the community][community]!
+looking to make your changes. As always, if you're not sure, [do ask the community][community]!
 
 ### Testing
-When making larger changes, it's may be useful to write a test to make sure your code works as expected.
+When making larger changes, it may be useful to write a test to make sure your code works as expected.
 
 CC: Tweaked has several test suites, each designed to test something different:
 
@@ -91,11 +91,11 @@ file.
 
 Documentation is built using [illuaminate] which, while not currently documented (somewhat ironic), is largely the same
 as [ldoc][ldoc]. Documentation comments are written in Markdown, though note that we do not support many GitHub-specific
-markdown features - if you can, do check what the documentation looks like locally!
+markdown features. If you can, do check what the documentation looks like locally!
 
 When writing long-form documentation (such as the guides in [doc/guides](doc/guides)), I find it useful to tell a
-narrative. Think of what you want the user to learn or achieve, then start introducing a simple concept and then talk
-about how you can build on that, until you've covered everything!
+narrative. Think of what you want the user to learn or achieve, then start introducing a simple concept, and then talk
+about how you can build on that until you've covered everything!
 
 [new-issue]: https://github.com/cc-tweaked/CC-Tweaked/issues/new/choose "Create a new issue"
 [community]: README.md#community "Get in touch with the community."

README.md

@@ -4,7 +4,12 @@ SPDX-FileCopyrightText: 2017 The CC: Tweaked Developers
 SPDX-License-Identifier: MPL-2.0
 -->
 
-# ![CC: Tweaked](doc/logo.png)
+<picture>
+  <source media="(prefers-color-scheme: dark)" srcset="./doc/logo-darkmode.png">
+  <source media="(prefers-color-scheme: light)" srcset="./doc/logo.png">
+  <img alt="CC: Tweaked" src="./doc/logo.png">
+</picture>
+
 [![Current build status](https://github.com/cc-tweaked/CC-Tweaked/workflows/Build/badge.svg)](https://github.com/cc-tweaked/CC-Tweaked/actions "Current build status")
 [![Download CC: Tweaked on CurseForge](https://img.shields.io/static/v1?label=Download&message=CC:%20Tweaked&color=E04E14&logoColor=E04E14&logo=CurseForge)][CurseForge]
 [![Download CC: Tweaked on Modrinth](https://img.shields.io/static/v1?label=Download&color=00AF5C&logoColor=00AF5C&logo=Modrinth&message=CC:%20Tweaked)][Modrinth]
@@ -44,7 +49,7 @@ repositories {
 
 dependencies {
   // Vanilla (i.e. for multi-loader systems)
-  compileOnly("cc.tweaked:cc-tweaked-$mcVersion-common-api")
+  compileOnly("cc.tweaked:cc-tweaked-$mcVersion-common-api:$cctVersion")
 
   // Forge Gradle
   compileOnly("cc.tweaked:cc-tweaked-$mcVersion-core-api:$cctVersion")
@@ -57,6 +62,19 @@ dependencies {
 }
 ```
 
+When using ForgeGradle, you may also need to add the following:
+
+```groovy
+minecraft {
+    runs {
+        configureEach {
+            property 'mixin.env.remapRefMap', 'true'
+            property 'mixin.env.refMapRemappingFile', "${buildDir}/createSrgToMcp/output.srg"
+        }
+    }
+}
+```
+
 You should also be careful to only use classes within the `dan200.computercraft.api` package. Non-API classes are
 subject to change at any point. If you depend on functionality outside the API, file an issue, and we can look into
 exposing more features.

buildSrc/src/main/kotlin/cc-tweaked.forge.gradle.kts

@@ -10,8 +10,9 @@ import cc.tweaked.gradle.IdeaRunConfigurations
 import cc.tweaked.gradle.MinecraftConfigurations
 
 plugins {
-    id("cc-tweaked.java-convention")
     id("net.minecraftforge.gradle")
+    // We must apply java-convention after Forge, as we need the fg extension to be present.
+    id("cc-tweaked.java-convention")
     id("org.parchmentmc.librarian.forgegradle")
 }
 

buildSrc/src/main/kotlin/cc-tweaked.java-convention.gradle.kts

@@ -37,22 +37,37 @@ java {
 
 repositories {
     mavenCentral()
-    maven("https://squiddev.cc/maven") {
+
+    val mainMaven = maven("https://squiddev.cc/maven") {
         name = "SquidDev"
         content {
-            includeGroup("org.squiddev")
-            includeGroup("cc.tweaked")
-            // Things we mirror
-            includeGroup("dev.architectury")
-            includeGroup("maven.modrinth")
-            includeGroup("me.shedaniel")
-            includeGroup("me.shedaniel.cloth")
-            includeGroup("mezz.jei")
-            includeModule("com.terraformersmc", "modmenu")
             // Until https://github.com/SpongePowered/Mixin/pull/593 is merged
             includeModule("org.spongepowered", "mixin")
         }
     }
+
+    exclusiveContent {
+        forRepositories(mainMaven)
+
+        // Include the ForgeGradle repository if present. This requires that ForgeGradle is already present, which we
+        // enforce in our Forge overlay.
+        val fg =
+            project.extensions.findByType(net.minecraftforge.gradle.userdev.DependencyManagementExtension::class.java)
+        if (fg != null) forRepositories(fg.repository)
+
+        filter {
+            includeGroup("cc.tweaked")
+            includeModule("org.squiddev", "Cobalt")
+            // Things we mirror
+            includeGroup("dev.architectury")
+            includeGroup("dev.emi")
+            includeGroup("maven.modrinth")
+            includeGroup("me.shedaniel.cloth")
+            includeGroup("me.shedaniel")
+            includeGroup("mezz.jei")
+            includeModule("com.terraformersmc", "modmenu")
+        }
+    }
 }
 
 dependencies {
@@ -104,6 +119,7 @@ tasks.withType(JavaCompile::class.java).configureEach {
 
 tasks.processResources {
     exclude("**/*.license")
+    exclude(".cache")
 }
 
 tasks.withType(AbstractArchiveTask::class.java).configureEach {

buildSrc/src/main/kotlin/cc/tweaked/gradle/ForgeExtensions.kt

@@ -0,0 +1,26 @@
+// SPDX-FileCopyrightText: 2023 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package cc.tweaked.gradle
+
+import net.minecraftforge.gradle.common.util.RunConfig
+import net.minecraftforge.gradle.common.util.runs.setRunConfigInternal
+import org.gradle.api.plugins.JavaPluginExtension
+import org.gradle.api.tasks.JavaExec
+import org.gradle.jvm.toolchain.JavaToolchainService
+import java.nio.file.Files
+
+/**
+ * Set [JavaExec] task to run a given [RunConfig].
+ */
+fun JavaExec.setRunConfig(config: RunConfig) {
+    dependsOn("prepareRuns")
+    setRunConfigInternal(project, this, config)
+    doFirst("Create working directory") { Files.createDirectories(workingDir.toPath()) }
+
+    javaLauncher.set(
+        project.extensions.getByType(JavaToolchainService::class.java)
+            .launcherFor(project.extensions.getByType(JavaPluginExtension::class.java).toolchain),
+    )
+}

buildSrc/src/main/kotlin/cc/tweaked/gradle/Illuaminate.kt

@@ -60,7 +60,7 @@ class IlluaminatePlugin : Plugin<Project> {
 
     /** Define a dependency for illuaminate from a version number and the current operating system. */
     private fun illuaminateArtifact(project: Project, version: String): Dependency {
-        val osName = System.getProperty("os.name").toLowerCase()
+        val osName = System.getProperty("os.name").lowercase()
         val (os, suffix) = when {
             osName.contains("windows") -> Pair("windows", ".exe")
             osName.contains("mac os") || osName.contains("darwin") -> Pair("macos", "")
@@ -68,7 +68,7 @@ class IlluaminatePlugin : Plugin<Project> {
             else -> error("Unsupported OS $osName for illuaminate")
         }
 
-        val osArch = System.getProperty("os.arch").toLowerCase()
+        val osArch = System.getProperty("os.arch").lowercase()
         val arch = when {
             // On macOS the x86_64 binary will work for both ARM and Intel Macs through Rosetta.
             os == "macos" -> "x86_64"

buildSrc/src/main/kotlin/cc/tweaked/gradle/MinecraftExec.kt

@@ -4,6 +4,7 @@
 
 package cc.tweaked.gradle
 
+import net.minecraftforge.gradle.common.util.RunConfig
 import org.gradle.api.GradleException
 import org.gradle.api.file.FileSystemOperations
 import org.gradle.api.invocation.Gradle
@@ -32,11 +33,14 @@ abstract class ClientJavaExec : JavaExec() {
         usesService(clientRunner)
     }
 
+    @get:Input
+    val renderdoc get() = project.hasProperty("renderdoc")
+
     /**
      * When [false], tests will not be run automatically, allowing the user to debug rendering.
      */
     @get:Input
-    val clientDebug get() = project.hasProperty("clientDebug")
+    val clientDebug get() = renderdoc || project.hasProperty("clientDebug")
 
     /**
      * When [false], tests will not run under a framebuffer.
@@ -50,6 +54,25 @@ abstract class ClientJavaExec : JavaExec() {
     @get:OutputFile
     val testResults = project.layout.buildDirectory.file("test-results/$name.xml")
 
+    private fun setTestProperties() {
+        if (!clientDebug) systemProperty("cctest.client", "")
+        if (renderdoc) environment("LD_PRELOAD", "/usr/lib/librenderdoc.so")
+        systemProperty("cctest.gametest-report", testResults.get().asFile.absoluteFile)
+        workingDir(project.buildDir.resolve("gametest").resolve(name))
+    }
+
+    init {
+        setTestProperties()
+    }
+
+    /**
+     * Set this task to run a given [RunConfig].
+     */
+    fun setRunConfig(config: RunConfig) {
+        (this as JavaExec).setRunConfig(config)
+        setTestProperties() // setRunConfig may clobber some properties, ensure everything is set.
+    }
+
     /**
      * Copy configuration from a task with the given name.
      */
@@ -61,10 +84,7 @@ abstract class ClientJavaExec : JavaExec() {
     fun copyFrom(task: JavaExec) {
         for (dep in task.dependsOn) dependsOn(dep)
         task.copyToFull(this)
-
-        if (!clientDebug) systemProperty("cctest.client", "")
-        systemProperty("cctest.gametest-report", testResults.get().asFile.absoluteFile)
-        workingDir(project.buildDir.resolve("gametest").resolve(name))
+        setTestProperties() // copyToFull may clobber some properties, ensure everything is set.
     }
 
     /**

buildSrc/src/main/kotlin/net/minecraftforge/gradle/common/util/runs/RunConfigSetup.kt

@@ -0,0 +1,51 @@
+// SPDX-FileCopyrightText: 2023 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package net.minecraftforge.gradle.common.util.runs
+
+import net.minecraftforge.gradle.common.util.RunConfig
+import org.gradle.api.Project
+import org.gradle.process.CommandLineArgumentProvider
+import org.gradle.process.JavaExecSpec
+import java.io.File
+import java.util.function.Supplier
+import java.util.stream.Collectors
+import java.util.stream.Stream
+
+/**
+ * Set up a [JavaExecSpec] to execute a [RunConfig].
+ *
+ * [MinecraftRunTask] sets up all its properties when the task is executed, rather than when configured. As such, it's
+ * not possible to use [cc.tweaked.gradle.copyToFull] like we do for Fabric. Instead, we set up the task manually.
+ *
+ * Unfortunately most of the functionality we need is package-private, and so we have to put our code into the package.
+ */
+internal fun setRunConfigInternal(project: Project, spec: JavaExecSpec, config: RunConfig) {
+    spec.workingDir = File(config.workingDirectory)
+
+    spec.mainClass.set(config.main)
+    for (source in config.allSources) spec.classpath(source.runtimeClasspath)
+
+    val originalTask = project.tasks.named(config.taskName, MinecraftRunTask::class.java)
+
+    // Add argument and JVM argument via providers, to be as lazy as possible with fetching artifacts.
+    val lazyTokens = RunConfigGenerator.configureTokensLazy(
+        project, config, RunConfigGenerator.mapModClassesToGradle(project, config),
+        originalTask.get().minecraftArtifacts,
+        originalTask.get().runtimeClasspathArtifacts,
+    )
+    spec.argumentProviders.add(
+        CommandLineArgumentProvider {
+            RunConfigGenerator.getArgsStream(config, lazyTokens, false).toList()
+        },
+    )
+    spec.jvmArgumentProviders.add(
+        CommandLineArgumentProvider {
+            (if (config.isClient) config.jvmArgs + originalTask.get().additionalClientArgs.get() else config.jvmArgs).map { config.replace(lazyTokens, it) } +
+                config.properties.map { (k, v) -> "-D${k}=${config.replace(lazyTokens, v)}" }
+        },
+    )
+
+    for ((key, value) in config.environment) spec.environment(key, config.replace(lazyTokens, value))
+}

doc/events/websocket_closed.md

@@ -13,6 +13,15 @@ The @{websocket_closed} event is fired when an open WebSocket connection is clos
 ## Return Values
 1. @{string}: The event name.
 2. @{string}: The URL of the WebSocket that was closed.
+3. <span class="type">@{string}|@{nil}</span>: The [server-provided reason][close_reason]
+   the websocket was closed. This will be @{nil} if the connection was closed
+   abnormally.
+4. <span class="type">@{number}|@{nil}</span>: The [connection close code][close_code],
+   indicating why the socket was closed. This will be @{nil} if the connection
+   was closed abnormally.
+
+[close_reason]: https://www.rfc-editor.org/rfc/rfc6455.html#section-7.1.6 "The WebSocket Connection Close Reason, RFC 6455"
+[close_code]: https://www.rfc-editor.org/rfc/rfc6455.html#section-7.1.5 "The WebSocket Connection Close Code, RFC 6455"
 
 ## Example
 Prints a message when a WebSocket is closed (this may take a minute):

gradle.properties

@@ -10,7 +10,7 @@ kotlin.jvm.target.validation.mode=error
 
 # Mod properties
 isUnstable=false
-modVersion=1.105.0
+modVersion=1.107.0
 
 # Minecraft properties: We want to configure this here so we can read it in settings.gradle
-mcVersion=1.20
+mcVersion=1.20.1

gradle/libs.versions.toml

@@ -7,20 +7,20 @@
 # Minecraft
 # MC version is specified in gradle.properties, as we need that in settings.gradle.
 # Remember to update corresponding versions in fabric.mod.json/mods.toml
-fabric-api = "0.83.0+1.20"
+fabric-api = "0.86.1+1.20.1"
 fabric-loader = "0.14.21"
-forge = "46.0.1"
+forge = "47.1.0"
 forgeSpi = "6.0.0"
 mixin = "0.8.5"
-parchment = "2023.03.12"
-parchmentMc = "1.19.3"
+parchment = "2023.06.26"
+parchmentMc = "1.19.4"
 
 # Normal dependencies
 asm = "9.3"
 autoService = "1.0.1"
 checkerFramework = "3.32.0"
-cobalt = "0.7.0"
-cobalt-next = "0.7.1" # Not a real version, used to constrain the version we accept.
+cobalt = "0.7.1"
+cobalt-next = "0.7.2" # Not a real version, used to constrain the version we accept.
 fastutil = "8.5.9"
 guava = "31.1-jre"
 jetbrainsAnnotations = "24.0.1"
@@ -33,13 +33,14 @@ nightConfig = "3.6.5"
 slf4j = "1.7.36"
 
 # Minecraft mods
-iris = "1.5.2+1.19.4"
-jei = "13.1.0.11"
-modmenu = "6.1.0-rc.1"
+emi = "1.0.8+1.20.1"
+iris = "1.6.4+1.20"
+jei = "15.2.0.22"
+modmenu = "7.1.0"
 oculus = "1.2.5"
-rei = "10.0.578"
+rei = "12.0.626"
 rubidium = "0.6.1"
-sodium = "mc1.19.4-0.4.10"
+sodium = "mc1.20-0.4.10"
 
 # Testing
 byteBuddy = "1.14.2"
@@ -53,16 +54,16 @@ checkstyle = "10.3.4"
 curseForgeGradle = "1.0.14"
 errorProne-core = "2.18.0"
 errorProne-plugin = "3.0.1"
-fabric-loom = "1.1.10"
-forgeGradle = "5.1.+"
+fabric-loom = "1.3.7"
+forgeGradle = "6.0.8"
 githubRelease = "2.2.12"
 ideaExt = "1.1.6"
-illuaminate = "0.1.0-24-gdb28902"
+illuaminate = "0.1.0-28-ga7efd71"
 librarian = "1.+"
 minotaur = "2.+"
 mixinGradle = "0.7.+"
 nullAway = "0.9.9"
-quiltflower = "1.8.0"
+quiltflower = "1.10.0"
 spotless = "6.17.0"
 taskTree = "2.1.1"
 vanillaGradle = "0.2.1-SNAPSHOT"
@@ -92,10 +93,11 @@ slf4j = { module = "org.slf4j:slf4j-api", version.ref = "slf4j" }
 # Minecraft mods
 fabric-api = { module = "net.fabricmc.fabric-api:fabric-api", version.ref = "fabric-api" }
 fabric-loader = { module = "net.fabricmc:fabric-loader", version.ref = "fabric-loader" }
+emi = { module = "dev.emi:emi-xplat-mojmap", version.ref = "emi" }
 iris = { module = "maven.modrinth:iris", version.ref = "iris" }
-jei-api = { module = "mezz.jei:jei-1.19.4-common-api", version.ref = "jei" }
-jei-fabric = { module = "mezz.jei:jei-1.19.4-fabric", version.ref = "jei" }
-jei-forge = { module = "mezz.jei:jei-1.19.4-forge", version.ref = "jei" }
+jei-api = { module = "mezz.jei:jei-1.20.1-common-api", version.ref = "jei" }
+jei-fabric = { module = "mezz.jei:jei-1.20.1-fabric", version.ref = "jei" }
+jei-forge = { module = "mezz.jei:jei-1.20.1-forge", version.ref = "jei" }
 mixin = { module = "org.spongepowered:mixin", version.ref = "mixin" }
 modmenu = { module = "com.terraformersmc:modmenu", version.ref = "modmenu" }
 oculus = { module = "maven.modrinth:oculus", version.ref = "oculus" }
@@ -150,10 +152,10 @@ kotlin = ["kotlin-stdlib", "kotlin-coroutines"]
 # Minecraft
 externalMods-common = ["jei-api", "nightConfig-core", "nightConfig-toml"]
 externalMods-forge-compile = ["oculus", "jei-api"]
-externalMods-forge-runtime = []
+externalMods-forge-runtime = ["jei-forge"]
 externalMods-fabric = ["nightConfig-core", "nightConfig-toml"]
 externalMods-fabric-compile = ["iris", "jei-api", "rei-api", "rei-builtin"]
-externalMods-fabric-runtime = []
+externalMods-fabric-runtime = ["jei-fabric", "modmenu"]
 
 # Testing
 test = ["junit-jupiter-api", "junit-jupiter-params", "hamcrest", "jqwik-api"]

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.6-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.1.1-bin.zip
+networkTimeout=10000
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

gradlew

@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -80,13 +80,10 @@ do
     esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
@@ -143,12 +140,16 @@ fi
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
     case $MAX_FD in #(
       max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
         MAX_FD=$( ulimit -H -n ) ||
             warn "Could not query maximum file descriptor limit"
     esac
     case $MAX_FD in  #(
       '' | soft) :;; #(
       *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045
         ulimit -n "$MAX_FD" ||
             warn "Could not set maximum file descriptor limit to $MAX_FD"
     esac
@@ -193,6 +194,10 @@ if "$cygwin" || "$msys" ; then
     done
 fi
 
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
 # Collect all arguments for the java command;
 #   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
 #     shell script including quotes and variable substitutions, so put them in

gradlew.bat

@@ -26,6 +26,7 @@ if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
 if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 

projects/common-api/src/client/java/dan200/computercraft/api/client/turtle/TurtleUpgradeModeller.java

@@ -11,9 +11,13 @@ import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleSide;
 import dan200.computercraft.api.turtle.TurtleUpgradeSerialiser;
 import net.minecraft.client.resources.model.ModelResourceLocation;
+import net.minecraft.client.resources.model.UnbakedModel;
+import net.minecraft.nbt.CompoundTag;
 import net.minecraft.resources.ResourceLocation;
 
 import javax.annotation.Nullable;
+import java.util.Collection;
+import java.util.List;
 
 /**
  * Provides models for a {@link ITurtleUpgrade}.
@@ -28,15 +32,45 @@ public interface TurtleUpgradeModeller<T extends ITurtleUpgrade> {
      * When the current turtle is {@literal null}, this function should be constant for a given upgrade and side.
      *
      * @param upgrade The upgrade that you're getting the model for.
-     * @param turtle  Access to the turtle that the upgrade resides on. This will be null when getting item models!
+     * @param turtle  Access to the turtle that the upgrade resides on. This will be null when getting item models, unless
+     *                {@link #getModel(ITurtleUpgrade, CompoundTag, TurtleSide)} is overriden.
      * @param side    Which side of the turtle (left or right) the upgrade resides on.
      * @return The model that you wish to be used to render your upgrade.
      */
     TransformedModel getModel(T upgrade, @Nullable ITurtleAccess turtle, TurtleSide side);
 
     /**
-     * A basic {@link TurtleUpgradeModeller} which renders using the upgrade's {@linkplain ITurtleUpgrade#getCraftingItem()
-     * crafting item}.
+     * Obtain the model to be used when rendering a turtle peripheral.
+     * <p>
+     * This is used when rendering the turtle's item model, and so no {@link ITurtleAccess} is available.
+     *
+     * @param upgrade The upgrade that you're getting the model for.
+     * @param data    Upgrade data instance for current turtle side.
+     * @param side    Which side of the turtle (left or right) the upgrade resides on.
+     * @return The model that you wish to be used to render your upgrade.
+     */
+    default TransformedModel getModel(T upgrade, CompoundTag data, TurtleSide side) {
+        return getModel(upgrade, (ITurtleAccess) null, side);
+    }
+
+
+    /**
+     * Get a list of models that this turtle modeller depends on.
+     * <p>
+     * Models included in this list will be loaded and baked alongside item and block models, and so may be referenced
+     * by {@link TransformedModel#of(ResourceLocation)}. You do not need to override this method if you will load models
+     * by other means.
+     *
+     * @return A list of models that this modeller depends on.
+     * @see UnbakedModel#getDependencies()
+     */
+    default Collection<ResourceLocation> getDependencies() {
+        return List.of();
+    }
+
+    /**
+     * A basic {@link TurtleUpgradeModeller} which renders using the upgrade's {@linkplain ITurtleUpgrade#getUpgradeItem(CompoundTag)}
+     * upgrade item}.
      * <p>
      * This uses appropriate transformations for "flat" items, namely those extending the {@literal minecraft:item/generated}
      * model type. It will not appear correct for 3D models with additional depth, such as blocks.
@@ -46,7 +80,7 @@ public interface TurtleUpgradeModeller<T extends ITurtleUpgrade> {
      */
     @SuppressWarnings("unchecked")
     static <T extends ITurtleUpgrade> TurtleUpgradeModeller<T> flatItem() {
-        return (TurtleUpgradeModeller<T>) TurtleUpgradeModellers.FLAT_ITEM;
+        return (TurtleUpgradeModeller<T>) TurtleUpgradeModellers.UPGRADE_ITEM;
     }
 
     /**
@@ -58,7 +92,8 @@ public interface TurtleUpgradeModeller<T extends ITurtleUpgrade> {
      * @return The constructed modeller.
      */
     static <T extends ITurtleUpgrade> TurtleUpgradeModeller<T> sided(ModelResourceLocation left, ModelResourceLocation right) {
-        return (upgrade, turtle, side) -> TransformedModel.of(side == TurtleSide.LEFT ? left : right);
+        // TODO(1.21.0): Remove this.
+        return sided((ResourceLocation) left, right);
     }
 
     /**
@@ -70,6 +105,16 @@ public interface TurtleUpgradeModeller<T extends ITurtleUpgrade> {
      * @return The constructed modeller.
      */
     static <T extends ITurtleUpgrade> TurtleUpgradeModeller<T> sided(ResourceLocation left, ResourceLocation right) {
-        return (upgrade, turtle, side) -> TransformedModel.of(side == TurtleSide.LEFT ? left : right);
+        return new TurtleUpgradeModeller<>() {
+            @Override
+            public TransformedModel getModel(T upgrade, @Nullable ITurtleAccess turtle, TurtleSide side) {
+                return TransformedModel.of(side == TurtleSide.LEFT ? left : right);
+            }
+
+            @Override
+            public Collection<ResourceLocation> getDependencies() {
+                return List.of(left, right);
+            }
+        };
     }
 }

projects/common-api/src/client/java/dan200/computercraft/api/client/turtle/TurtleUpgradeModellers.java

@@ -6,13 +6,20 @@ package dan200.computercraft.api.client.turtle;
 
 import com.mojang.math.Transformation;
 import dan200.computercraft.api.client.TransformedModel;
+import dan200.computercraft.api.turtle.ITurtleAccess;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleSide;
+import dan200.computercraft.impl.client.ClientPlatformHelper;
+import net.minecraft.client.Minecraft;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.world.item.ItemStack;
 import org.joml.Matrix4f;
 
+import javax.annotation.Nullable;
+
 class TurtleUpgradeModellers {
-    private static final Transformation leftTransform = getMatrixFor(-0.40625f);
-    private static final Transformation rightTransform = getMatrixFor(0.40625f);
+    private static final Transformation leftTransform = getMatrixFor(-0.4065f);
+    private static final Transformation rightTransform = getMatrixFor(0.4065f);
 
     private static Transformation getMatrixFor(float offset) {
         var matrix = new Matrix4f();
@@ -26,6 +33,23 @@ class TurtleUpgradeModellers {
         return new Transformation(matrix);
     }
 
-    static final TurtleUpgradeModeller<ITurtleUpgrade> FLAT_ITEM = (upgrade, turtle, side) ->
-        TransformedModel.of(upgrade.getCraftingItem(), side == TurtleSide.LEFT ? leftTransform : rightTransform);
+    static final TurtleUpgradeModeller<ITurtleUpgrade> UPGRADE_ITEM = new UpgradeItemModeller();
+
+    private static class UpgradeItemModeller implements TurtleUpgradeModeller<ITurtleUpgrade> {
+        @Override
+        public TransformedModel getModel(ITurtleUpgrade upgrade, @Nullable ITurtleAccess turtle, TurtleSide side) {
+            return getModel(turtle == null ? upgrade.getCraftingItem() : upgrade.getUpgradeItem(turtle.getUpgradeNBTData(side)), side);
+        }
+
+        @Override
+        public TransformedModel getModel(ITurtleUpgrade upgrade, CompoundTag data, TurtleSide side) {
+            return getModel(upgrade.getUpgradeItem(data), side);
+        }
+
+        private TransformedModel getModel(ItemStack stack, TurtleSide side) {
+            var model = Minecraft.getInstance().getItemRenderer().getItemModelShaper().getItemModel(stack);
+            if (stack.hasFoil()) model = ClientPlatformHelper.get().createdFoiledModel(model);
+            return new TransformedModel(model, side == TurtleSide.LEFT ? leftTransform : rightTransform);
+        }
+    }
 }

projects/common-api/src/client/java/dan200/computercraft/impl/client/ClientPlatformHelper.java

@@ -5,6 +5,7 @@
 package dan200.computercraft.impl.client;
 
 import dan200.computercraft.impl.Services;
+import net.minecraft.client.renderer.RenderType;
 import net.minecraft.client.resources.model.BakedModel;
 import net.minecraft.client.resources.model.ModelManager;
 import net.minecraft.client.resources.model.ModelResourceLocation;
@@ -24,6 +25,15 @@ public interface ClientPlatformHelper {
      */
     BakedModel getModel(ModelManager manager, ResourceLocation location);
 
+    /**
+     * Wrap this model in a version which renders a foil/enchantment glint.
+     *
+     * @param model The model to wrap.
+     * @return The wrapped model.
+     * @see RenderType#glint()
+     */
+    BakedModel createdFoiledModel(BakedModel model);
+
     static ClientPlatformHelper get() {
         var instance = Instance.INSTANCE;
         return instance == null ? Services.raise(ClientPlatformHelper.class, Instance.ERROR) : instance;

projects/common-api/src/main/java/dan200/computercraft/api/pocket/IPocketAccess.java

@@ -5,9 +5,11 @@
 package dan200.computercraft.api.pocket;
 
 import dan200.computercraft.api.peripheral.IPeripheral;
+import dan200.computercraft.api.upgrades.UpgradeBase;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.world.entity.Entity;
+import net.minecraft.world.item.ItemStack;
 
 import javax.annotation.Nullable;
 import java.util.Map;
@@ -69,6 +71,8 @@ public interface IPocketAccess {
      *
      * @return The upgrade's NBT.
      * @see #updateUpgradeNBTData()
+     * @see UpgradeBase#getUpgradeItem(CompoundTag)
+     * @see UpgradeBase#getUpgradeData(ItemStack)
      */
     CompoundTag getUpgradeNBTData();
 
@@ -80,7 +84,10 @@ public interface IPocketAccess {
     void updateUpgradeNBTData();
 
     /**
-     * Remove the current peripheral and create a new one. You may wish to do this if the methods available change.
+     * Remove the current peripheral and create a new one.
+     * <p>
+     * You may wish to do this if the methods available change, for instance when the {@linkplain #getEntity() owning
+     * entity} changes.
      */
     void invalidatePeripheral();
 
@@ -88,6 +95,8 @@ public interface IPocketAccess {
      * Get a list of all upgrades for the pocket computer.
      *
      * @return A collection of all upgrade names.
+     * @deprecated This is a relic of a previous API, which no longer makes sense with newer versions of ComputerCraft.
      */
+    @Deprecated(forRemoval = true)
     Map<ResourceLocation, IPeripheral> getUpgrades();
 }

projects/common-api/src/main/java/dan200/computercraft/api/turtle/ITurtleAccess.java

@@ -8,10 +8,13 @@ import com.mojang.authlib.GameProfile;
 import dan200.computercraft.api.lua.ILuaCallback;
 import dan200.computercraft.api.lua.MethodResult;
 import dan200.computercraft.api.peripheral.IPeripheral;
+import dan200.computercraft.api.upgrades.UpgradeBase;
+import dan200.computercraft.api.upgrades.UpgradeData;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.world.Container;
+import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.Level;
 import org.jetbrains.annotations.ApiStatus;
 
@@ -221,23 +224,51 @@ public interface ITurtleAccess {
     void playAnimation(TurtleAnimation animation);
 
     /**
-     * Returns the turtle on the specified side of the turtle, if there is one.
+     * Returns the upgrade on the specified side of the turtle, if there is one.
      *
      * @param side The side to get the upgrade from.
      * @return The upgrade on the specified side of the turtle, if there is one.
-     * @see #setUpgrade(TurtleSide, ITurtleUpgrade)
+     * @see #getUpgradeWithData(TurtleSide)
+     * @see #setUpgradeWithData(TurtleSide, UpgradeData)
      */
     @Nullable
     ITurtleUpgrade getUpgrade(TurtleSide side);
 
+    /**
+     * Returns the upgrade on the specified side of the turtle, along with its {@linkplain #getUpgradeNBTData(TurtleSide)
+     * update data}.
+     *
+     * @param side The side to get the upgrade from.
+     * @return The upgrade on the specified side of the turtle, along with its upgrade data, if there is one.
+     * @see #getUpgradeWithData(TurtleSide)
+     * @see #setUpgradeWithData(TurtleSide, UpgradeData)
+     */
+    default @Nullable UpgradeData<ITurtleUpgrade> getUpgradeWithData(TurtleSide side) {
+        var upgrade = getUpgrade(side);
+        return upgrade == null ? null : UpgradeData.of(upgrade, getUpgradeNBTData(side));
+    }
+
     /**
      * Set the upgrade for a given side, resetting peripherals and clearing upgrade specific data.
      *
      * @param side    The side to set the upgrade on.
      * @param upgrade The upgrade to set, may be {@code null} to clear.
      * @see #getUpgrade(TurtleSide)
+     * @deprecated Use {@link #setUpgradeWithData(TurtleSide, UpgradeData)}
      */
-    void setUpgrade(TurtleSide side, @Nullable ITurtleUpgrade upgrade);
+    @Deprecated
+    default void setUpgrade(TurtleSide side, @Nullable ITurtleUpgrade upgrade) {
+        setUpgradeWithData(side, upgrade == null ? null : UpgradeData.ofDefault(upgrade));
+    }
+
+    /**
+     * Set the upgrade for a given side and its upgrade data.
+     *
+     * @param side    The side to set the upgrade on.
+     * @param upgrade The upgrade to set, may be {@code null} to clear.
+     * @see #getUpgradeWithData(TurtleSide)
+     */
+    void setUpgradeWithData(TurtleSide side, @Nullable UpgradeData<ITurtleUpgrade> upgrade);
 
     /**
      * Returns the peripheral created by the upgrade on the specified side of the turtle, if there is one.
@@ -257,6 +288,8 @@ public interface ITurtleAccess {
      * @param side The side to get the upgrade data for.
      * @return The upgrade-specific data.
      * @see #updateUpgradeNBTData(TurtleSide)
+     * @see UpgradeBase#getUpgradeItem(CompoundTag)
+     * @see UpgradeBase#getUpgradeData(ItemStack)
      */
     CompoundTag getUpgradeNBTData(TurtleSide side);
 

projects/common-api/src/main/java/dan200/computercraft/api/turtle/ITurtleUpgrade.java

@@ -7,6 +7,7 @@ package dan200.computercraft.api.turtle;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.upgrades.UpgradeBase;
 import net.minecraft.core.Direction;
+import net.minecraft.nbt.CompoundTag;
 
 import javax.annotation.Nullable;
 
@@ -79,4 +80,17 @@ public interface ITurtleUpgrade extends UpgradeBase {
      */
     default void update(ITurtleAccess turtle, TurtleSide side) {
     }
+
+    /**
+     * Get upgrade data that should be persisted when the turtle was broken.
+     * <p>
+     * This method should be overridden when you don't need to store all upgrade data by default. For instance, if you
+     * store peripheral state in the upgrade data, which should be lost when the turtle is broken.
+     *
+     * @param upgradeData Data that currently stored for this upgrade
+     * @return Filtered version of this data.
+     */
+    default CompoundTag getPersistedData(CompoundTag upgradeData) {
+        return upgradeData;
+    }
 }

projects/common-api/src/main/java/dan200/computercraft/api/turtle/TurtleToolDurability.java

@@ -0,0 +1,49 @@
+// SPDX-FileCopyrightText: 2023 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.api.turtle;
+
+import net.minecraft.util.StringRepresentable;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.item.ItemStack;
+
+/**
+ * Indicates if an equipped turtle item will consume durability.
+ *
+ * @see TurtleUpgradeDataProvider.ToolBuilder#consumeDurability(TurtleToolDurability)
+ */
+public enum TurtleToolDurability implements StringRepresentable {
+    /**
+     * The equipped tool always consumes durability when using.
+     */
+    ALWAYS("always"),
+
+    /**
+     * The equipped tool consumes durability if it is {@linkplain ItemStack#isEnchanted() enchanted} or has
+     * {@linkplain ItemStack#getAttributeModifiers(EquipmentSlot) custom attribute modifiers}.
+     */
+    WHEN_ENCHANTED("when_enchanted"),
+
+    /**
+     * The equipped tool never consumes durability. Tools which have been damaged cannot be used as upgrades.
+     */
+    NEVER("never");
+
+    private final String serialisedName;
+
+    /**
+     * The codec which may be used for serialising/deserialising {@link TurtleToolDurability}s.
+     */
+    @SuppressWarnings("deprecation")
+    public static final StringRepresentable.EnumCodec<TurtleToolDurability> CODEC = StringRepresentable.fromEnum(TurtleToolDurability::values);
+
+    TurtleToolDurability(String serialisedName) {
+        this.serialisedName = serialisedName;
+    }
+
+    @Override
+    public String getSerializedName() {
+        return serialisedName;
+    }
+}

projects/common-api/src/main/java/dan200/computercraft/api/turtle/TurtleUpgradeDataProvider.java

@@ -13,8 +13,10 @@ import net.minecraft.data.DataGenerator;
 import net.minecraft.data.PackOutput;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.tags.TagKey;
+import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.entity.ai.attributes.Attributes;
 import net.minecraft.world.item.Item;
+import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.block.Block;
 
 import javax.annotation.Nullable;
@@ -61,6 +63,8 @@ public abstract class TurtleUpgradeDataProvider extends UpgradeDataProvider<ITur
         private @Nullable Item craftingItem;
         private @Nullable Float damageMultiplier = null;
         private @Nullable TagKey<Block> breakable;
+        private boolean allowEnchantments = false;
+        private TurtleToolDurability consumeDurability = TurtleToolDurability.NEVER;
 
         ToolBuilder(ResourceLocation id, TurtleUpgradeSerialiser<?> serialiser, Item toolItem) {
             this.id = id;
@@ -104,6 +108,28 @@ public abstract class TurtleUpgradeDataProvider extends UpgradeDataProvider<ITur
             return this;
         }
 
+        /**
+         * Indicate that this upgrade allows items which have been {@linkplain ItemStack#isEnchanted() enchanted} or have
+         * {@linkplain ItemStack#getAttributeModifiers(EquipmentSlot) custom attribute modifiers}.
+         *
+         * @return The tool builder, for further use.
+         */
+        public ToolBuilder allowEnchantments() {
+            allowEnchantments = true;
+            return this;
+        }
+
+        /**
+         * Set when the tool will consume durability.
+         *
+         * @param durability The durability predicate.
+         * @return The tool builder, for further use.
+         */
+        public ToolBuilder consumeDurability(TurtleToolDurability durability) {
+            consumeDurability = durability;
+            return this;
+        }
+
         /**
          * Provide a list of breakable blocks. If not given, the tool can break all blocks. If given, only blocks
          * in this tag, those in {@link ComputerCraftTags.Blocks#TURTLE_ALWAYS_BREAKABLE} and "insta-mine" ones can
@@ -132,6 +158,10 @@ public abstract class TurtleUpgradeDataProvider extends UpgradeDataProvider<ITur
                 }
                 if (damageMultiplier != null) s.addProperty("damageMultiplier", damageMultiplier);
                 if (breakable != null) s.addProperty("breakable", breakable.location().toString());
+                if (allowEnchantments) s.addProperty("allowEnchantments", true);
+                if (consumeDurability != TurtleToolDurability.NEVER) {
+                    s.addProperty("consumeDurability", consumeDurability.getSerializedName());
+                }
             }));
         }
     }

projects/common-api/src/main/java/dan200/computercraft/api/upgrades/UpgradeBase.java

@@ -4,10 +4,14 @@
 
 package dan200.computercraft.api.upgrades;
 
+import dan200.computercraft.api.pocket.IPocketAccess;
 import dan200.computercraft.api.pocket.IPocketUpgrade;
+import dan200.computercraft.api.turtle.ITurtleAccess;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
+import dan200.computercraft.api.turtle.TurtleSide;
 import dan200.computercraft.impl.PlatformHelper;
 import net.minecraft.Util;
+import net.minecraft.nbt.CompoundTag;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.world.item.ItemStack;
 
@@ -50,6 +54,42 @@ public interface UpgradeBase {
      */
     ItemStack getCraftingItem();
 
+    /**
+     * Returns the item stack representing a currently equipped turtle upgrade.
+     * <p>
+     * While upgrades can store upgrade data ({@link ITurtleAccess#getUpgradeNBTData(TurtleSide)} and
+     * {@link IPocketAccess#getUpgradeNBTData()}}, by default this data is discarded when an upgrade is unequipped,
+     * and the original item stack is returned.
+     * <p>
+     * By overriding this method, you can create a new {@link ItemStack} which contains enough data to
+     * {@linkplain #getUpgradeData(ItemStack) re-create the upgrade data} if the item is re-equipped.
+     * <p>
+     * When overriding this, you should override {@link #getUpgradeData(ItemStack)} and {@link #isItemSuitable(ItemStack)}
+     * at the same time,
+     *
+     * @param upgradeData The current upgrade data. This should <strong>NOT</strong> be mutated.
+     * @return The item stack returned when unequipping.
+     */
+    default ItemStack getUpgradeItem(CompoundTag upgradeData) {
+        return getCraftingItem();
+    }
+
+    /**
+     * Extract upgrade data from an {@link ItemStack}.
+     * <p>
+     * This upgrade data will be available with {@link ITurtleAccess#getUpgradeNBTData(TurtleSide)} or
+     * {@link IPocketAccess#getUpgradeNBTData()}.
+     * <p>
+     * This should be an inverse to {@link #getUpgradeItem(CompoundTag)}.
+     *
+     * @param stack The stack that was equipped by the turtle or pocket computer. This will have the same item as
+     *              {@link #getCraftingItem()}.
+     * @return The upgrade data that should be set on the turtle or pocket computer.
+     */
+    default CompoundTag getUpgradeData(ItemStack stack) {
+        return new CompoundTag();
+    }
+
     /**
      * Determine if an item is suitable for being used for this upgrade.
      * <p>

projects/common-api/src/main/java/dan200/computercraft/api/upgrades/UpgradeData.java

@@ -0,0 +1,82 @@
+// SPDX-FileCopyrightText: 2023 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.api.upgrades;
+
+import dan200.computercraft.api.pocket.IPocketUpgrade;
+import dan200.computercraft.api.turtle.ITurtleUpgrade;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.world.item.ItemStack;
+import org.jetbrains.annotations.Contract;
+
+import javax.annotation.Nullable;
+
+/**
+ * An upgrade (i.e. a {@link ITurtleUpgrade}) and its current upgrade data.
+ * <p>
+ * <strong>IMPORTANT:</strong> The {@link #data()} in an upgrade data is often a reference to the original upgrade data.
+ * Be careful to take a {@linkplain #copy() defensive copy} if you plan to use the data in this upgrade.
+ *
+ * @param upgrade The current upgrade.
+ * @param data    The upgrade's data.
+ * @param <T>     The type of upgrade, either {@link ITurtleUpgrade} or {@link IPocketUpgrade}.
+ */
+public record UpgradeData<T extends UpgradeBase>(T upgrade, CompoundTag data) {
+    /**
+     * A utility method to construct a new {@link UpgradeData} instance.
+     *
+     * @param upgrade An upgrade.
+     * @param data    The upgrade's data.
+     * @param <T>     The type of upgrade.
+     * @return The new {@link UpgradeData} instance.
+     */
+    public static <T extends UpgradeBase> UpgradeData<T> of(T upgrade, CompoundTag data) {
+        return new UpgradeData<>(upgrade, data);
+    }
+
+    /**
+     * Create an {@link UpgradeData} containing the default {@linkplain #data() data} for an upgrade.
+     *
+     * @param upgrade The upgrade instance.
+     * @param <T>     The type of upgrade.
+     * @return The default upgrade data.
+     */
+    public static <T extends UpgradeBase> UpgradeData<T> ofDefault(T upgrade) {
+        return of(upgrade, upgrade.getUpgradeData(upgrade.getCraftingItem()));
+    }
+
+    /**
+     * Take a copy of a (possibly {@code null}) {@link UpgradeData} instance.
+     *
+     * @param upgrade The copied upgrade data.
+     * @param <T>     The type of upgrade.
+     * @return The newly created upgrade data.
+     */
+    @Contract("!null -> !null; null -> null")
+    public static <T extends UpgradeBase> @Nullable UpgradeData<T> copyOf(@Nullable UpgradeData<T> upgrade) {
+        return upgrade == null ? null : upgrade.copy();
+    }
+
+    /**
+     * Get the {@linkplain UpgradeBase#getUpgradeItem(CompoundTag) upgrade item} for this upgrade.
+     * <p>
+     * This returns a defensive copy of the item, to prevent accidental mutation of the upgrade data or original
+     * {@linkplain UpgradeBase#getCraftingItem() upgrade stack}.
+     *
+     * @return This upgrade's item.
+     */
+    public ItemStack getUpgradeItem() {
+        return upgrade.getUpgradeItem(data).copy();
+    }
+
+    /**
+     * Take a copy of this {@link UpgradeData}. This returns a new instance with the same upgrade and a fresh copy of
+     * the upgrade data.
+     *
+     * @return A copy of the current instance.
+     */
+    public UpgradeData<T> copy() {
+        return new UpgradeData<>(upgrade(), data().copy());
+    }
+}

projects/common-api/src/main/java/dan200/computercraft/api/upgrades/UpgradeDataProvider.java

@@ -23,10 +23,7 @@ import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
 import javax.annotation.Nullable;
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
+import java.util.*;
 import java.util.concurrent.CompletableFuture;
 import java.util.function.Consumer;
 import java.util.function.Function;
@@ -104,7 +101,7 @@ public abstract class UpgradeDataProvider<T extends UpgradeBase, R extends Upgra
     protected abstract void addUpgrades(Consumer<Upgrade<R>> addUpgrade);
 
     @Override
-    public final CompletableFuture<?> run(CachedOutput cache) {
+    public CompletableFuture<?> run(CachedOutput cache) {
         var base = output.getOutputFolder().resolve("data");
 
         Set<ResourceLocation> seen = new HashSet<>();
@@ -127,7 +124,7 @@ public abstract class UpgradeDataProvider<T extends UpgradeBase, R extends Upgra
             }
         });
 
-        this.upgrades = upgrades;
+        this.upgrades = Collections.unmodifiableList(upgrades);
         return Util.sequenceFailFast(futures);
     }
 
@@ -166,5 +163,21 @@ public abstract class UpgradeDataProvider<T extends UpgradeBase, R extends Upgra
         public void add(Consumer<Upgrade<R>> add) {
             add.accept(this);
         }
+
+        /**
+         * Return a new {@link Upgrade} which requires the given mod to be present.
+         * <p>
+         * This uses mod-loader-specific hooks (Forge's crafting conditions and Fabric's resource conditions). If using
+         * this in a multi-loader setup, you must generate resources separately for the two loaders.
+         *
+         * @param modId The id of the mod.
+         * @return A new upgrade instance.
+         */
+        public Upgrade<R> requireMod(String modId) {
+            return new Upgrade<>(id, serialiser, json -> {
+                PlatformHelper.get().addRequiredModCondition(json, modId);
+                serialise.accept(json);
+            });
+        }
     }
 }

projects/common-api/src/main/java/dan200/computercraft/impl/PlatformHelper.java

@@ -4,6 +4,8 @@
 
 package dan200.computercraft.impl;
 
+import com.google.gson.JsonObject;
+import dan200.computercraft.api.upgrades.UpgradeDataProvider;
 import net.minecraft.core.Registry;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.resources.ResourceKey;
@@ -63,6 +65,15 @@ public interface PlatformHelper {
         return item.getTag();
     }
 
+    /**
+     * Add a resource condition which requires a mod to be loaded. This should be used by data providers such as
+     * {@link UpgradeDataProvider}.
+     *
+     * @param object The JSON object we're generating.
+     * @param modId  The mod ID that we require.
+     */
+    void addRequiredModCondition(JsonObject object, String modId);
+
     final class Instance {
         static final @Nullable PlatformHelper INSTANCE;
         static final @Nullable Throwable ERROR;

projects/common/build.gradle.kts

@@ -7,6 +7,7 @@ import cc.tweaked.gradle.clientClasses
 import cc.tweaked.gradle.commonClasses
 
 plugins {
+    id("cc-tweaked.publishing")
     id("cc-tweaked.vanilla")
     id("cc-tweaked.gametest")
 }
@@ -25,6 +26,7 @@ dependencies {
     clientImplementation(clientClasses(project(":common-api")))
 
     compileOnly(libs.bundles.externalMods.common)
+    clientCompileOnly(variantOf(libs.emi) { classifier("api") })
 
     compileOnly(libs.mixin)
     annotationProcessorEverywhere(libs.autoService)

projects/common/src/client/java/dan200/computercraft/client/ClientRegistry.java

@@ -13,6 +13,7 @@ import dan200.computercraft.client.render.RenderTypes;
 import dan200.computercraft.client.render.TurtleBlockEntityRenderer;
 import dan200.computercraft.client.render.monitor.MonitorBlockEntityRenderer;
 import dan200.computercraft.client.turtle.TurtleModemModeller;
+import dan200.computercraft.client.turtle.TurtleUpgradeModellers;
 import dan200.computercraft.core.util.Colour;
 import dan200.computercraft.shared.ModRegistry;
 import dan200.computercraft.shared.common.IColouredItem;
@@ -107,24 +108,6 @@ public final class ClientRegistry {
     }
 
     private static final String[] EXTRA_MODELS = new String[]{
-        // Turtle upgrades
-        "block/turtle_modem_normal_off_left",
-        "block/turtle_modem_normal_on_left",
-        "block/turtle_modem_normal_off_right",
-        "block/turtle_modem_normal_on_right",
-
-        "block/turtle_modem_advanced_off_left",
-        "block/turtle_modem_advanced_on_left",
-        "block/turtle_modem_advanced_off_right",
-        "block/turtle_modem_advanced_on_right",
-
-        "block/turtle_crafting_table_left",
-        "block/turtle_crafting_table_right",
-
-        "block/turtle_speaker_left",
-        "block/turtle_speaker_right",
-
-        // Turtle block renderer
         "block/turtle_colour",
         "block/turtle_elf_overlay",
         "block/turtle_rainbow_overlay",
@@ -133,6 +116,7 @@ public final class ClientRegistry {
 
     public static void registerExtraModels(Consumer<ResourceLocation> register) {
         for (var model : EXTRA_MODELS) register.accept(new ResourceLocation(ComputerCraftAPI.MOD_ID, model));
+        TurtleUpgradeModellers.getDependencies().forEach(register);
     }
 
     public static void registerItemColours(BiConsumer<ItemColor, ItemLike> register) {

projects/common/src/client/java/dan200/computercraft/client/gui/ItemToast.java

@@ -100,9 +100,9 @@ public class ItemToast implements Toast {
             graphics.renderFakeItem(stack, MARGIN, MARGIN + height() / 2 - IMAGE_SIZE);
         }
 
-        graphics.drawString(component.getMinecraft().font, title, textX, MARGIN, 0xff500050);
+        graphics.drawString(component.getMinecraft().font, title, textX, MARGIN, 0xff500050, false);
         for (var i = 0; i < message.size(); ++i) {
-            graphics.drawString(component.getMinecraft().font, message.get(i), textX, LINE_SPACING + (i + 1) * LINE_SPACING, 0xff000000);
+            graphics.drawString(component.getMinecraft().font, message.get(i), textX, LINE_SPACING + (i + 1) * LINE_SPACING, 0xff000000, false);
         }
 
         return time - firstDisplay < DISPLAY_TIME ? Visibility.SHOW : Visibility.HIDE;

projects/common/src/client/java/dan200/computercraft/client/gui/NoTermComputerScreen.java

@@ -42,7 +42,6 @@ public class NoTermComputerScreen<T extends AbstractComputerMenu> extends Screen
 
     @Override
     protected void init() {
-        // FIXME: passEvents = true; // Pass mouse vents through to the game's mouse handler.
         // First ensure we're still grabbing the mouse, so the user can look around. Then reset bits of state that
         // grabbing unsets.
         minecraft.mouseHandler.grabMouse();

projects/common/src/client/java/dan200/computercraft/client/gui/TurtleScreen.java

@@ -25,9 +25,11 @@ public class TurtleScreen extends AbstractComputerScreen<TurtleMenu> {
     private static final ResourceLocation BACKGROUND_NORMAL = new ResourceLocation(ComputerCraftAPI.MOD_ID, "textures/gui/turtle_normal.png");
     private static final ResourceLocation BACKGROUND_ADVANCED = new ResourceLocation(ComputerCraftAPI.MOD_ID, "textures/gui/turtle_advanced.png");
 
-    private static final int TEX_WIDTH = 254;
+    private static final int TEX_WIDTH = 278;
     private static final int TEX_HEIGHT = 217;
 
+    private static final int FULL_TEX_SIZE = 512;
+
     public TurtleScreen(TurtleMenu container, Inventory player, Component title) {
         super(container, player, title, BORDER);
 
@@ -44,15 +46,16 @@ public class TurtleScreen extends AbstractComputerScreen<TurtleMenu> {
     protected void renderBg(GuiGraphics graphics, float partialTicks, int mouseX, int mouseY) {
         var advanced = family == ComputerFamily.ADVANCED;
         var texture = advanced ? BACKGROUND_ADVANCED : BACKGROUND_NORMAL;
-        graphics.blit(texture, leftPos + AbstractComputerMenu.SIDEBAR_WIDTH, topPos, 0, 0, TEX_WIDTH, TEX_HEIGHT);
+        graphics.blit(texture, leftPos + AbstractComputerMenu.SIDEBAR_WIDTH, topPos, 0, 0, 0, TEX_WIDTH, TEX_HEIGHT, FULL_TEX_SIZE, FULL_TEX_SIZE);
 
+        // Render selected slot
         var slot = getMenu().getSelectedSlot();
         if (slot >= 0) {
             var slotX = slot % 4;
             var slotY = slot / 4;
             graphics.blit(texture,
-                leftPos + TURTLE_START_X - 2 + slotX * 18, topPos + PLAYER_START_Y - 2 + slotY * 18,
-                0, 217, 24, 24
+                leftPos + TURTLE_START_X - 2 + slotX * 18, topPos + PLAYER_START_Y - 2 + slotY * 18, 0,
+                0, 217, 24, 24, FULL_TEX_SIZE, FULL_TEX_SIZE
             );
         }
 

projects/common/src/client/java/dan200/computercraft/client/gui/widgets/DynamicImageButton.java

@@ -67,14 +67,11 @@ public class DynamicImageButton extends Button {
         graphics.blit(texture, getX(), getY(), xTexStart.getAsInt(), yTex, width, height, textureWidth, textureHeight);
     }
 
-    @Override
-    public Component getMessage() {
-        return message.get().message;
-    }
-
     @Override
     public void render(GuiGraphics graphics, int mouseX, int mouseY, float partialTicks) {
-        setTooltip(message.get().tooltip());
+        var message = this.message.get();
+        setMessage(message.message());
+        setTooltip(message.tooltip());
         super.render(graphics, mouseX, mouseY, partialTicks);
     }
 

projects/common/src/client/java/dan200/computercraft/client/integration/emi/EMIComputerCraft.java

@@ -0,0 +1,44 @@
+// SPDX-FileCopyrightText: 2023 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.client.integration.emi;
+
+import dan200.computercraft.api.turtle.TurtleSide;
+import dan200.computercraft.shared.ModRegistry;
+import dan200.computercraft.shared.pocket.items.PocketComputerItem;
+import dan200.computercraft.shared.turtle.items.TurtleItem;
+import dev.emi.emi.api.EmiEntrypoint;
+import dev.emi.emi.api.EmiPlugin;
+import dev.emi.emi.api.EmiRegistry;
+import dev.emi.emi.api.stack.Comparison;
+import net.minecraft.world.item.ItemStack;
+
+import java.util.function.BiPredicate;
+
+@EmiEntrypoint
+public class EMIComputerCraft implements EmiPlugin {
+    @Override
+    public void register(EmiRegistry registry) {
+        registry.setDefaultComparison(ModRegistry.Items.TURTLE_NORMAL.get(), turtleComparison);
+        registry.setDefaultComparison(ModRegistry.Items.TURTLE_ADVANCED.get(), turtleComparison);
+
+        registry.setDefaultComparison(ModRegistry.Items.POCKET_COMPUTER_NORMAL.get(), pocketComparison);
+        registry.setDefaultComparison(ModRegistry.Items.POCKET_COMPUTER_ADVANCED.get(), pocketComparison);
+    }
+
+    private static final Comparison turtleComparison = compareStacks((left, right) ->
+        left.getItem() instanceof TurtleItem turtle
+            && turtle.getUpgrade(left, TurtleSide.LEFT) == turtle.getUpgrade(right, TurtleSide.LEFT)
+            && turtle.getUpgrade(left, TurtleSide.RIGHT) == turtle.getUpgrade(right, TurtleSide.RIGHT));
+
+    private static final Comparison pocketComparison = compareStacks((left, right) ->
+        left.getItem() instanceof PocketComputerItem && PocketComputerItem.getUpgrade(left) == PocketComputerItem.getUpgrade(right));
+
+    private static Comparison compareStacks(BiPredicate<ItemStack, ItemStack> test) {
+        return Comparison.of((left, right) -> {
+            ItemStack leftStack = left.getItemStack(), rightStack = right.getItemStack();
+            return leftStack.getItem() == rightStack.getItem() && test.test(leftStack, rightStack);
+        });
+    }
+}

projects/common/src/client/java/dan200/computercraft/client/model/turtle/ModelTransformer.java

@@ -0,0 +1,103 @@
+// SPDX-FileCopyrightText: 2023 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.client.model.turtle;
+
+import com.mojang.blaze3d.vertex.DefaultVertexFormat;
+import com.mojang.blaze3d.vertex.VertexFormat;
+import com.mojang.blaze3d.vertex.VertexFormatElement;
+import com.mojang.math.Transformation;
+import net.minecraft.client.renderer.block.model.BakedQuad;
+import net.minecraft.client.resources.model.BakedModel;
+import net.minecraft.core.Direction;
+import org.joml.Matrix4f;
+import org.joml.Vector4f;
+
+import javax.annotation.Nullable;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Applies a {@link Transformation} (or rather a {@link Matrix4f}) to a list of {@link BakedQuad}s.
+ * <p>
+ * This does a little bit of magic compared with other system (i.e. Forge's {@code QuadTransformers}), as it needs to
+ * handle flipping models upside down.
+ * <p>
+ * This is typically used with a {@link BakedModel} subclass - see the loader-specific projects.
+ */
+public class ModelTransformer {
+    private static final int[] INVERSE_ORDER = new int[]{ 3, 2, 1, 0 };
+
+    private static final int STRIDE = DefaultVertexFormat.BLOCK.getIntegerSize();
+    private static final int POS_OFFSET = findOffset(DefaultVertexFormat.BLOCK, DefaultVertexFormat.ELEMENT_POSITION);
+
+    protected final Matrix4f transformation;
+    protected final boolean invert;
+    private @Nullable TransformedQuads cache;
+
+    public ModelTransformer(Transformation transformation) {
+        this.transformation = transformation.getMatrix();
+        invert = transformation.getMatrix().determinant() < 0;
+    }
+
+    public List<BakedQuad> transform(List<BakedQuad> quads) {
+        if (quads.isEmpty()) return List.of();
+
+        // We do some basic caching here to avoid recomputing every frame. Most turtle models don't have culled faces,
+        // so it's not worth being smarter here.
+        var cache = this.cache;
+        if (cache != null && quads.equals(cache.original())) return cache.transformed();
+
+        List<BakedQuad> transformed = new ArrayList<>(quads.size());
+        for (var quad : quads) transformed.add(transformQuad(quad));
+        this.cache = new TransformedQuads(quads, transformed);
+        return transformed;
+    }
+
+    private BakedQuad transformQuad(BakedQuad quad) {
+        var inputData = quad.getVertices();
+        var outputData = new int[inputData.length];
+        for (var i = 0; i < 4; i++) {
+            var inStart = STRIDE * i;
+            // Reverse the order of the quads if we're inverting
+            var outStart = getVertexOffset(i, invert);
+            System.arraycopy(inputData, inStart, outputData, outStart, STRIDE);
+
+            // Apply the matrix to our position
+            var inPosStart = inStart + POS_OFFSET;
+            var outPosStart = outStart + POS_OFFSET;
+
+            var x = Float.intBitsToFloat(inputData[inPosStart]);
+            var y = Float.intBitsToFloat(inputData[inPosStart + 1]);
+            var z = Float.intBitsToFloat(inputData[inPosStart + 2]);
+
+            // Transform the position
+            var pos = new Vector4f(x, y, z, 1);
+            transformation.transformProject(pos);
+
+            outputData[outPosStart] = Float.floatToRawIntBits(pos.x());
+            outputData[outPosStart + 1] = Float.floatToRawIntBits(pos.y());
+            outputData[outPosStart + 2] = Float.floatToRawIntBits(pos.z());
+        }
+
+        var direction = Direction.rotate(transformation, quad.getDirection());
+        return new BakedQuad(outputData, quad.getTintIndex(), direction, quad.getSprite(), quad.isShade());
+    }
+
+    public static int getVertexOffset(int vertex, boolean invert) {
+        return (invert ? ModelTransformer.INVERSE_ORDER[vertex] : vertex) * ModelTransformer.STRIDE;
+    }
+
+    private record TransformedQuads(List<BakedQuad> original, List<BakedQuad> transformed) {
+    }
+
+    private static int findOffset(VertexFormat format, VertexFormatElement element) {
+        var offset = 0;
+        for (var other : format.getElements()) {
+            if (other == element) return offset / Integer.BYTES;
+            offset += element.getByteSize();
+        }
+        throw new IllegalArgumentException("Cannot find " + element + " in " + format);
+    }
+}

projects/common/src/client/java/dan200/computercraft/client/model/turtle/TurtleModelParts.java

@@ -4,11 +4,13 @@
 
 package dan200.computercraft.client.model.turtle;
 
+import com.google.common.cache.CacheBuilder;
 import com.mojang.blaze3d.vertex.PoseStack;
 import com.mojang.math.Transformation;
 import dan200.computercraft.api.client.TransformedModel;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleSide;
+import dan200.computercraft.api.upgrades.UpgradeData;
 import dan200.computercraft.client.platform.ClientPlatformHelper;
 import dan200.computercraft.client.render.TurtleBlockEntityRenderer;
 import dan200.computercraft.client.turtle.TurtleUpgradeModellers;
@@ -21,15 +23,17 @@ import net.minecraft.world.item.ItemStack;
 
 import javax.annotation.Nullable;
 import java.util.ArrayList;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.TimeUnit;
 import java.util.function.Function;
 
 /**
  * Combines several individual models together to form a turtle.
+ *
+ * @param <T> The type of the resulting "baked model".
  */
-public final class TurtleModelParts {
+public final class TurtleModelParts<T> {
     private static final Transformation identity, flip;
 
     static {
@@ -42,33 +46,67 @@ public final class TurtleModelParts {
         flip = new Transformation(stack.last().pose());
     }
 
-    public record Combination(
+    private record Combination(
         boolean colour,
-        @Nullable ITurtleUpgrade leftUpgrade,
-        @Nullable ITurtleUpgrade rightUpgrade,
+        @Nullable UpgradeData<ITurtleUpgrade> leftUpgrade,
+        @Nullable UpgradeData<ITurtleUpgrade> rightUpgrade,
         @Nullable ResourceLocation overlay,
         boolean christmas,
         boolean flip
     ) {
+        Combination copy() {
+            if (leftUpgrade == null && rightUpgrade == null) return this;
+            return new Combination(
+                colour, UpgradeData.copyOf(leftUpgrade), UpgradeData.copyOf(rightUpgrade),
+                overlay, christmas, flip
+            );
+        }
     }
 
     private final BakedModel familyModel;
     private final BakedModel colourModel;
     private final Function<TransformedModel, BakedModel> transformer;
+    private final Function<Combination, T> buildModel;
 
     /**
      * A cache of {@link TransformedModel} to the transformed {@link BakedModel}. This helps us pool the transformed
      * instances, reducing memory usage and hopefully ensuring their caches are hit more often!
      */
-    private final Map<TransformedModel, BakedModel> transformCache = new HashMap<>();
+    private final Map<TransformedModel, BakedModel> transformCache = CacheBuilder.newBuilder()
+        .concurrencyLevel(1)
+        .expireAfterAccess(30, TimeUnit.SECONDS)
+        .<TransformedModel, BakedModel>build()
+        .asMap();
 
-    public TurtleModelParts(BakedModel familyModel, BakedModel colourModel, ModelTransformer transformer) {
+    /**
+     * A cache of {@link Combination}s to the combined model.
+     */
+    private final Map<Combination, T> modelCache = CacheBuilder.newBuilder()
+        .concurrencyLevel(1)
+        .expireAfterAccess(30, TimeUnit.SECONDS)
+        .<Combination, T>build()
+        .asMap();
+
+    public TurtleModelParts(BakedModel familyModel, BakedModel colourModel, ModelTransformer transformer, Function<List<BakedModel>, T> combineModel) {
         this.familyModel = familyModel;
         this.colourModel = colourModel;
         this.transformer = x -> transformer.transform(x.getModel(), x.getMatrix());
+        buildModel = x -> combineModel.apply(buildModel(x));
     }
 
-    public Combination getCombination(ItemStack stack) {
+    public T getModel(ItemStack stack) {
+        var combination = getCombination(stack);
+        var existing = modelCache.get(combination);
+        if (existing != null) return existing;
+
+        // Take a defensive copy of the upgrade data, and add it to the cache.
+        var newCombination = combination.copy();
+        var newModel = buildModel.apply(newCombination);
+        modelCache.put(newCombination, newModel);
+        return newModel;
+    }
+
+    private Combination getCombination(ItemStack stack) {
         var christmas = Holiday.getCurrent() == Holiday.CHRISTMAS;
 
         if (!(stack.getItem() instanceof TurtleItem turtle)) {
@@ -76,8 +114,8 @@ public final class TurtleModelParts {
         }
 
         var colour = turtle.getColour(stack);
-        var leftUpgrade = turtle.getUpgrade(stack, TurtleSide.LEFT);
-        var rightUpgrade = turtle.getUpgrade(stack, TurtleSide.RIGHT);
+        var leftUpgrade = turtle.getUpgradeWithData(stack, TurtleSide.LEFT);
+        var rightUpgrade = turtle.getUpgradeWithData(stack, TurtleSide.RIGHT);
         var overlay = turtle.getOverlay(stack);
         var label = turtle.getLabel(stack);
         var flip = label != null && (label.equals("Dinnerbone") || label.equals("Grumm"));
@@ -85,7 +123,7 @@ public final class TurtleModelParts {
         return new Combination(colour != -1, leftUpgrade, rightUpgrade, overlay, christmas, flip);
     }
 
-    public List<BakedModel> buildModel(Combination combo) {
+    private List<BakedModel> buildModel(Combination combo) {
         var mc = Minecraft.getInstance();
         var modelManager = mc.getItemRenderer().getItemModelShaper().getModelManager();
 
@@ -97,19 +135,20 @@ public final class TurtleModelParts {
         if (overlayModelLocation != null) {
             parts.add(transform(ClientPlatformHelper.get().getModel(modelManager, overlayModelLocation), transformation));
         }
-        if (combo.leftUpgrade() != null) {
-            var model = TurtleUpgradeModellers.getModel(combo.leftUpgrade(), null, TurtleSide.LEFT);
-            parts.add(transform(model.getModel(), transformation.compose(model.getMatrix())));
-        }
-        if (combo.rightUpgrade() != null) {
-            var model = TurtleUpgradeModellers.getModel(combo.rightUpgrade(), null, TurtleSide.RIGHT);
-            parts.add(transform(model.getModel(), transformation.compose(model.getMatrix())));
-        }
+
+        addUpgrade(parts, transformation, TurtleSide.LEFT, combo.leftUpgrade());
+        addUpgrade(parts, transformation, TurtleSide.RIGHT, combo.rightUpgrade());
 
         return parts;
     }
 
-    public BakedModel transform(BakedModel model, Transformation transformation) {
+    private void addUpgrade(List<BakedModel> parts, Transformation transformation, TurtleSide side, @Nullable UpgradeData<ITurtleUpgrade> upgrade) {
+        if (upgrade == null) return;
+        var model = TurtleUpgradeModellers.getModel(upgrade.upgrade(), upgrade.data(), side);
+        parts.add(transform(model.getModel(), transformation.compose(model.getMatrix())));
+    }
+
+    private BakedModel transform(BakedModel model, Transformation transformation) {
         if (transformation.equals(Transformation.identity())) return model;
         return transformCache.computeIfAbsent(new TransformedModel(model, transformation), transformer);
     }

projects/common/src/client/java/dan200/computercraft/client/platform/ClientPlatformHelper.java

@@ -4,8 +4,13 @@
 
 package dan200.computercraft.client.platform;
 
+import com.mojang.blaze3d.vertex.PoseStack;
 import dan200.computercraft.shared.network.NetworkMessage;
 import dan200.computercraft.shared.network.server.ServerNetworkContext;
+import net.minecraft.client.renderer.MultiBufferSource;
+import net.minecraft.client.resources.model.BakedModel;
+
+import javax.annotation.Nullable;
 
 public interface ClientPlatformHelper extends dan200.computercraft.impl.client.ClientPlatformHelper {
     static ClientPlatformHelper get() {
@@ -18,4 +23,16 @@ public interface ClientPlatformHelper extends dan200.computercraft.impl.client.C
      * @param message The message to send.
      */
     void sendToServer(NetworkMessage<ServerNetworkContext> message);
+
+    /**
+     * Render a {@link BakedModel}, using any loader-specific hooks.
+     *
+     * @param transform     The current matrix transformation to apply.
+     * @param buffers       The current pool of render buffers.
+     * @param model         The model to draw.
+     * @param lightmapCoord The current packed lightmap coordinate.
+     * @param overlayLight  The current overlay light.
+     * @param tints         Block colour tints to apply to the model.
+     */
+    void renderBakedModel(PoseStack transform, MultiBufferSource buffers, BakedModel model, int lightmapCoord, int overlayLight, @Nullable int[] tints);
 }

projects/common/src/client/java/dan200/computercraft/client/render/ModelRenderer.java

@@ -0,0 +1,103 @@
+// SPDX-FileCopyrightText: 2023 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.client.render;
+
+import com.mojang.blaze3d.vertex.PoseStack;
+import com.mojang.blaze3d.vertex.VertexConsumer;
+import dan200.computercraft.client.model.turtle.ModelTransformer;
+import dan200.computercraft.client.platform.ClientPlatformHelper;
+import net.minecraft.client.renderer.MultiBufferSource;
+import net.minecraft.client.renderer.block.model.BakedQuad;
+import net.minecraft.client.renderer.entity.ItemRenderer;
+import net.minecraft.client.resources.model.BakedModel;
+import net.minecraft.world.item.ItemStack;
+import org.joml.Vector4f;
+
+import javax.annotation.Nullable;
+import java.util.List;
+
+/**
+ * Utilities for rendering {@link BakedModel}s and {@link BakedQuad}s.
+ */
+public final class ModelRenderer {
+    private ModelRenderer() {
+    }
+
+    /**
+     * Render a list of {@linkplain BakedQuad quads} to a buffer.
+     * <p>
+     * This is not intended to be used directly, but instead by {@link ClientPlatformHelper#renderBakedModel(PoseStack, MultiBufferSource, BakedModel, int, int, int[])}. The
+     * implementation here is pretty similar to {@link ItemRenderer#renderQuadList(PoseStack, VertexConsumer, List, ItemStack, int, int)},
+     * but supports inverted quads (i.e. those with a negative scale).
+     *
+     * @param transform     The current matrix transformation to apply.
+     * @param buffer        The buffer to draw to.
+     * @param quads         The quads to draw.
+     * @param lightmapCoord The current packed lightmap coordinate.
+     * @param overlayLight  The current overlay light.
+     * @param tints         Block colour tints to apply to the model.
+     */
+    public static void renderQuads(PoseStack transform, VertexConsumer buffer, List<BakedQuad> quads, int lightmapCoord, int overlayLight, @Nullable int[] tints) {
+        var matrix = transform.last();
+        var inverted = matrix.pose().determinant() < 0;
+
+        for (var bakedquad : quads) {
+            var tint = -1;
+            if (tints != null && bakedquad.isTinted()) {
+                var idx = bakedquad.getTintIndex();
+                if (idx >= 0 && idx < tints.length) tint = tints[bakedquad.getTintIndex()];
+            }
+
+            var r = (float) (tint >> 16 & 255) / 255.0F;
+            var g = (float) (tint >> 8 & 255) / 255.0F;
+            var b = (float) (tint & 255) / 255.0F;
+            putBulkQuad(buffer, matrix, bakedquad, r, g, b, lightmapCoord, overlayLight, inverted);
+        }
+    }
+
+    /**
+     * A version of {@link VertexConsumer#putBulkData(PoseStack.Pose, BakedQuad, float, float, float, int, int)} which
+     * will reverse vertex order when the matrix is inverted.
+     *
+     * @param buffer        The buffer to draw to.
+     * @param pose          The current matrix stack.
+     * @param quad          The quad to draw.
+     * @param red           The red tint of this quad.
+     * @param green         The  green tint of this quad.
+     * @param blue          The blue tint of this quad.
+     * @param lightmapCoord The lightmap coordinate
+     * @param overlayLight  The overlay light.
+     * @param invert        Whether to reverse the order of this quad.
+     */
+    private static void putBulkQuad(VertexConsumer buffer, PoseStack.Pose pose, BakedQuad quad, float red, float green, float blue, int lightmapCoord, int overlayLight, boolean invert) {
+        var matrix = pose.pose();
+        // It's a little dubious to transform using this matrix rather than the normal matrix. This mirrors the logic in
+        // Direction.rotate (so not out of nowhere!), but is a little suspicious.
+        var dirNormal = quad.getDirection().getNormal();
+        var vector = new Vector4f();
+
+        matrix.transform(dirNormal.getX(), dirNormal.getY(), dirNormal.getZ(), 0.0f, vector).normalize();
+        float normalX = vector.x(), normalY = vector.y(), normalZ = vector.z();
+
+        var vertices = quad.getVertices();
+        for (var vertex = 0; vertex < 4; vertex++) {
+            var i = ModelTransformer.getVertexOffset(vertex, invert);
+
+            var x = Float.intBitsToFloat(vertices[i]);
+            var y = Float.intBitsToFloat(vertices[i + 1]);
+            var z = Float.intBitsToFloat(vertices[i + 2]);
+
+            matrix.transform(x, y, z, 1, vector);
+
+            var u = Float.intBitsToFloat(vertices[i + 4]);
+            var v = Float.intBitsToFloat(vertices[i + 5]);
+            buffer.vertex(
+                vector.x(), vector.y(), vector.z(),
+                red, green, blue, 1.0F, u, v, overlayLight, lightmapCoord,
+                normalX, normalY, normalZ
+            );
+        }
+    }
+}

projects/common/src/client/java/dan200/computercraft/client/render/TurtleBlockEntityRenderer.java

@@ -5,7 +5,6 @@
 package dan200.computercraft.client.render;
 
 import com.mojang.blaze3d.vertex.PoseStack;
-import com.mojang.blaze3d.vertex.VertexConsumer;
 import com.mojang.math.Axis;
 import com.mojang.math.Transformation;
 import dan200.computercraft.api.ComputerCraftAPI;
@@ -14,25 +13,20 @@ import dan200.computercraft.client.platform.ClientPlatformHelper;
 import dan200.computercraft.client.turtle.TurtleUpgradeModellers;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.turtle.blocks.TurtleBlockEntity;
-import dan200.computercraft.shared.util.DirectionUtil;
 import dan200.computercraft.shared.util.Holiday;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.Font;
 import net.minecraft.client.renderer.MultiBufferSource;
-import net.minecraft.client.renderer.Sheets;
-import net.minecraft.client.renderer.block.model.BakedQuad;
 import net.minecraft.client.renderer.blockentity.BlockEntityRenderDispatcher;
 import net.minecraft.client.renderer.blockentity.BlockEntityRenderer;
 import net.minecraft.client.renderer.blockentity.BlockEntityRendererProvider;
 import net.minecraft.client.resources.model.BakedModel;
 import net.minecraft.client.resources.model.ModelResourceLocation;
 import net.minecraft.resources.ResourceLocation;
-import net.minecraft.util.RandomSource;
 import net.minecraft.world.phys.BlockHitResult;
 import net.minecraft.world.phys.HitResult;
 
 import javax.annotation.Nullable;
-import java.util.List;
 
 public class TurtleBlockEntityRenderer implements BlockEntityRenderer<TurtleBlockEntity> {
     private static final ModelResourceLocation NORMAL_TURTLE_MODEL = new ModelResourceLocation(ComputerCraftAPI.MOD_ID, "turtle_normal", "inventory");
@@ -40,8 +34,6 @@ public class TurtleBlockEntityRenderer implements BlockEntityRenderer<TurtleBloc
     private static final ResourceLocation COLOUR_TURTLE_MODEL = new ResourceLocation(ComputerCraftAPI.MOD_ID, "block/turtle_colour");
     private static final ResourceLocation ELF_OVERLAY_MODEL = new ResourceLocation(ComputerCraftAPI.MOD_ID, "block/turtle_elf_overlay");
 
-    private final RandomSource random = RandomSource.create(0);
-
     private final BlockEntityRenderDispatcher renderer;
     private final Font font;
 
@@ -107,23 +99,22 @@ public class TurtleBlockEntityRenderer implements BlockEntityRenderer<TurtleBloc
         var family = turtle.getFamily();
         var overlay = turtle.getOverlay();
 
-        var buffer = buffers.getBuffer(Sheets.translucentCullBlockSheet());
-        renderModel(transform, buffer, lightmapCoord, overlayLight, getTurtleModel(family, colour != -1), colour == -1 ? null : new int[]{ colour });
+        renderModel(transform, buffers, lightmapCoord, overlayLight, getTurtleModel(family, colour != -1), colour == -1 ? null : new int[]{ colour });
 
         // Render the overlay
         var overlayModel = getTurtleOverlayModel(overlay, Holiday.getCurrent() == Holiday.CHRISTMAS);
         if (overlayModel != null) {
-            renderModel(transform, buffer, lightmapCoord, overlayLight, overlayModel, null);
+            renderModel(transform, buffers, lightmapCoord, overlayLight, overlayModel, null);
         }
 
         // Render the upgrades
-        renderUpgrade(transform, buffer, lightmapCoord, overlayLight, turtle, TurtleSide.LEFT, partialTicks);
-        renderUpgrade(transform, buffer, lightmapCoord, overlayLight, turtle, TurtleSide.RIGHT, partialTicks);
+        renderUpgrade(transform, buffers, lightmapCoord, overlayLight, turtle, TurtleSide.LEFT, partialTicks);
+        renderUpgrade(transform, buffers, lightmapCoord, overlayLight, turtle, TurtleSide.RIGHT, partialTicks);
 
         transform.popPose();
     }
 
-    private void renderUpgrade(PoseStack transform, VertexConsumer renderer, int lightmapCoord, int overlayLight, TurtleBlockEntity turtle, TurtleSide side, float f) {
+    private void renderUpgrade(PoseStack transform, MultiBufferSource buffers, int lightmapCoord, int overlayLight, TurtleBlockEntity turtle, TurtleSide side, float f) {
         var upgrade = turtle.getUpgrade(side);
         if (upgrade == null) return;
         transform.pushPose();
@@ -134,46 +125,33 @@ public class TurtleBlockEntityRenderer implements BlockEntityRenderer<TurtleBloc
         transform.translate(0.0f, -0.5f, -0.5f);
 
         var model = TurtleUpgradeModellers.getModel(upgrade, turtle.getAccess(), side);
-        pushPoseFromTransformation(transform, model.getMatrix());
-        renderModel(transform, renderer, lightmapCoord, overlayLight, model.getModel(), null);
-        transform.popPose();
+        applyTransformation(transform, model.getMatrix());
+        renderModel(transform, buffers, lightmapCoord, overlayLight, model.getModel(), null);
 
         transform.popPose();
     }
 
-    private void renderModel(PoseStack transform, VertexConsumer renderer, int lightmapCoord, int overlayLight, ResourceLocation modelLocation, @Nullable int[] tints) {
+    private void renderModel(PoseStack transform, MultiBufferSource buffers, int lightmapCoord, int overlayLight, ResourceLocation modelLocation, @Nullable int[] tints) {
         var modelManager = Minecraft.getInstance().getItemRenderer().getItemModelShaper().getModelManager();
-        renderModel(transform, renderer, lightmapCoord, overlayLight, ClientPlatformHelper.get().getModel(modelManager, modelLocation), tints);
+        renderModel(transform, buffers, lightmapCoord, overlayLight, ClientPlatformHelper.get().getModel(modelManager, modelLocation), tints);
     }
 
-    private void renderModel(PoseStack transform, VertexConsumer renderer, int lightmapCoord, int overlayLight, BakedModel model, @Nullable int[] tints) {
-        random.setSeed(0);
-        renderQuads(transform, renderer, lightmapCoord, overlayLight, model.getQuads(null, null, random), tints);
-        for (var facing : DirectionUtil.FACINGS) {
-            renderQuads(transform, renderer, lightmapCoord, overlayLight, model.getQuads(null, facing, random), tints);
-        }
+    /**
+     * Render a block model.
+     *
+     * @param transform     The current matrix stack.
+     * @param renderer      The buffer to write to.
+     * @param lightmapCoord The current lightmap coordinate.
+     * @param overlayLight  The overlay light.
+     * @param model         The model to render.
+     * @param tints         Tints for the quads, as an array of RGB values.
+     * @see net.minecraft.client.renderer.block.ModelBlockRenderer#renderModel
+     */
+    private void renderModel(PoseStack transform, MultiBufferSource renderer, int lightmapCoord, int overlayLight, BakedModel model, @Nullable int[] tints) {
+        ClientPlatformHelper.get().renderBakedModel(transform, renderer, model, lightmapCoord, overlayLight, tints);
     }
 
-    private static void renderQuads(PoseStack transform, VertexConsumer buffer, int lightmapCoord, int overlayLight, List<BakedQuad> quads, @Nullable int[] tints) {
-        var matrix = transform.last();
-
-        for (var bakedquad : quads) {
-            var tint = -1;
-            if (tints != null && bakedquad.isTinted()) {
-                var idx = bakedquad.getTintIndex();
-                if (idx >= 0 && idx < tints.length) tint = tints[bakedquad.getTintIndex()];
-            }
-
-            var r = (float) (tint >> 16 & 255) / 255.0F;
-            var g = (float) (tint >> 8 & 255) / 255.0F;
-            var b = (float) (tint & 255) / 255.0F;
-            buffer.putBulkData(matrix, bakedquad, r, g, b, lightmapCoord, overlayLight);
-        }
-    }
-
-    private static void pushPoseFromTransformation(PoseStack stack, Transformation transformation) {
-        stack.pushPose();
-
+    private static void applyTransformation(PoseStack stack, Transformation transformation) {
         var trans = transformation.getTranslation();
         stack.translate(trans.x(), trans.y(), trans.z());
 

projects/common/src/client/java/dan200/computercraft/client/turtle/TurtleModemModeller.java

@@ -13,6 +13,9 @@ import dan200.computercraft.shared.turtle.upgrades.TurtleModem;
 import net.minecraft.resources.ResourceLocation;
 import org.jetbrains.annotations.Nullable;
 
+import java.util.Collection;
+import java.util.List;
+
 /**
  * A {@link TurtleUpgradeModeller} for modems, providing different models depending on if the modem is on/off.
  */
@@ -48,4 +51,9 @@ public class TurtleModemModeller implements TurtleUpgradeModeller<TurtleModem> {
             ? TransformedModel.of(active ? leftOnModel : leftOffModel)
             : TransformedModel.of(active ? rightOnModel : rightOffModel);
     }
+
+    @Override
+    public Collection<ResourceLocation> getDependencies() {
+        return List.of(leftOffModel, rightOffModel, leftOnModel, rightOnModel);
+    }
 }

projects/common/src/client/java/dan200/computercraft/client/turtle/TurtleUpgradeModellers.java

@@ -14,11 +14,13 @@ import dan200.computercraft.api.turtle.TurtleUpgradeSerialiser;
 import dan200.computercraft.impl.TurtleUpgrades;
 import dan200.computercraft.impl.UpgradeManager;
 import net.minecraft.client.Minecraft;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.resources.ResourceLocation;
 
-import javax.annotation.Nullable;
 import java.util.Map;
 import java.util.WeakHashMap;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.stream.Stream;
 
 /**
  * A registry of {@link TurtleUpgradeModeller}s.
@@ -52,12 +54,18 @@ public final class TurtleUpgradeModellers {
         }
     }
 
-    public static TransformedModel getModel(ITurtleUpgrade upgrade, @Nullable ITurtleAccess access, TurtleSide side) {
+    public static TransformedModel getModel(ITurtleUpgrade upgrade, ITurtleAccess access, TurtleSide side) {
         @SuppressWarnings("unchecked")
         var modeller = (TurtleUpgradeModeller<ITurtleUpgrade>) modelCache.computeIfAbsent(upgrade, TurtleUpgradeModellers::getModeller);
         return modeller.getModel(upgrade, access, side);
     }
 
+    public static TransformedModel getModel(ITurtleUpgrade upgrade, CompoundTag data, TurtleSide side) {
+        @SuppressWarnings("unchecked")
+        var modeller = (TurtleUpgradeModeller<ITurtleUpgrade>) modelCache.computeIfAbsent(upgrade, TurtleUpgradeModellers::getModeller);
+        return modeller.getModel(upgrade, data, side);
+    }
+
     private static TurtleUpgradeModeller<?> getModeller(ITurtleUpgrade upgradeA) {
         var wrapper = TurtleUpgrades.instance().getWrapper(upgradeA);
         if (wrapper == null) return NULL_TURTLE_MODELLER;
@@ -65,4 +73,8 @@ public final class TurtleUpgradeModellers {
         var modeller = turtleModels.get(wrapper.serialiser());
         return modeller == null ? NULL_TURTLE_MODELLER : modeller;
     }
+
+    public static Stream<ResourceLocation> getDependencies() {
+        return turtleModels.values().stream().flatMap(x -> x.getDependencies().stream());
+    }
 }

projects/common/src/client/java/dan200/computercraft/data/client/ClientDataProviders.java

@@ -0,0 +1,34 @@
+// SPDX-FileCopyrightText: 2023 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.data.client;
+
+import dan200.computercraft.data.DataProviders;
+import dan200.computercraft.shared.turtle.inventory.UpgradeSlot;
+import net.minecraft.client.renderer.texture.atlas.SpriteSources;
+import net.minecraft.client.renderer.texture.atlas.sources.SingleFile;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.server.packs.PackType;
+
+import java.util.List;
+import java.util.Optional;
+
+/**
+ * A version of {@link DataProviders} which relies on client-side classes.
+ * <p>
+ * This is called from {@link DataProviders#add(DataProviders.GeneratorSink)}.
+ */
+public final class ClientDataProviders {
+    private ClientDataProviders() {
+    }
+
+    public static void add(DataProviders.GeneratorSink generator) {
+        generator.addFromCodec("Block atlases", PackType.CLIENT_RESOURCES, "atlases", SpriteSources.FILE_CODEC, out -> {
+            out.accept(new ResourceLocation("blocks"), List.of(
+                new SingleFile(UpgradeSlot.LEFT_UPGRADE, Optional.empty()),
+                new SingleFile(UpgradeSlot.RIGHT_UPGRADE, Optional.empty())
+            ));
+        });
+    }
+}

projects/common/src/main/java/dan200/computercraft/data/BlockModelProvider.java

@@ -37,6 +37,14 @@ import static net.minecraft.data.models.model.ModelLocationUtils.getModelLocatio
 import static net.minecraft.data.models.model.TextureMapping.getBlockTexture;
 
 class BlockModelProvider {
+    private static final TextureSlot CURSOR = TextureSlot.create("cursor");
+
+    private static final ModelTemplate COMPUTER_ON = new ModelTemplate(
+        Optional.of(new ResourceLocation(ComputerCraftAPI.MOD_ID, "block/computer_on")),
+        Optional.empty(),
+        TextureSlot.FRONT, TextureSlot.SIDE, TextureSlot.TOP, CURSOR
+    );
+
     private static final ModelTemplate MONITOR_BASE = new ModelTemplate(
         Optional.of(new ResourceLocation(ComputerCraftAPI.MOD_ID, "block/monitor_base")),
         Optional.empty(),
@@ -142,11 +150,18 @@ class BlockModelProvider {
     private static void registerComputer(BlockModelGenerators generators, ComputerBlock<?> block) {
         generators.blockStateOutput.accept(MultiVariantGenerator.multiVariant(block)
             .with(createHorizontalFacingDispatch())
-            .with(createModelDispatch(ComputerBlock.STATE, state -> ModelTemplates.CUBE_ORIENTABLE.createWithSuffix(
-                block, "_" + state.getSerializedName(),
-                TextureMapping.orientableCube(block).put(TextureSlot.FRONT, getBlockTexture(block, "_front" + state.getTexture())),
-                generators.modelOutput
-            )))
+            .with(createModelDispatch(ComputerBlock.STATE, state -> switch (state) {
+                case OFF -> ModelTemplates.CUBE_ORIENTABLE.createWithSuffix(
+                    block, "_" + state.getSerializedName(),
+                    TextureMapping.orientableCube(block),
+                    generators.modelOutput
+                );
+                case ON, BLINKING -> COMPUTER_ON.createWithSuffix(
+                    block, "_" + state.getSerializedName(),
+                    TextureMapping.orientableCube(block).put(CURSOR, new ResourceLocation(ComputerCraftAPI.MOD_ID, "block/computer" + state.getTexture())),
+                    generators.modelOutput
+                );
+            }))
         );
         generators.delegateItemModel(block, getModelLocation(block, "_blinking"));
     }

projects/common/src/main/java/dan200/computercraft/data/DataProviders.java

@@ -4,16 +4,20 @@
 
 package dan200.computercraft.data;
 
+import com.mojang.serialization.Codec;
 import net.minecraft.data.DataProvider;
 import net.minecraft.data.PackOutput;
 import net.minecraft.data.loot.LootTableProvider.SubProviderEntry;
 import net.minecraft.data.models.BlockModelGenerators;
 import net.minecraft.data.models.ItemModelGenerators;
 import net.minecraft.data.tags.TagsProvider;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.server.packs.PackType;
 import net.minecraft.world.item.Item;
 import net.minecraft.world.level.block.Block;
 
 import java.util.List;
+import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 
 /**
@@ -37,11 +41,22 @@ public final class DataProviders {
         generator.models(BlockModelProvider::addBlockModels, ItemModelProvider::addItemModels);
 
         generator.add(out -> new LanguageProvider(out, turtleUpgrades, pocketUpgrades));
+
+        // Unfortunately we rely on some client-side classes in this code. We just load in the client side data provider
+        // and invoke that.
+        try {
+            Class.forName("dan200.computercraft.data.client.ClientDataProviders")
+                .getMethod("add", GeneratorSink.class).invoke(null, generator);
+        } catch (ReflectiveOperationException e) {
+            throw new RuntimeException(e);
+        }
     }
 
-    interface GeneratorSink {
+    public interface GeneratorSink {
         <T extends DataProvider> T add(DataProvider.Factory<T> factory);
 
+        <T> void addFromCodec(String name, PackType type, String directory, Codec<T> codec, Consumer<BiConsumer<ResourceLocation, T>> output);
+
         void lootTable(List<SubProviderEntry> tables);
 
         TagsProvider<Block> blockTags(Consumer<TagProvider.TagConsumer<Block>> tags);

projects/common/src/main/java/dan200/computercraft/data/LanguageProvider.java

@@ -6,6 +6,7 @@ package dan200.computercraft.data;
 
 import com.google.gson.JsonObject;
 import dan200.computercraft.api.ComputerCraftAPI;
+import dan200.computercraft.api.ComputerCraftTags;
 import dan200.computercraft.api.pocket.PocketUpgradeDataProvider;
 import dan200.computercraft.api.turtle.TurtleUpgradeDataProvider;
 import dan200.computercraft.api.upgrades.UpgradeBase;
@@ -20,6 +21,7 @@ import dan200.computercraft.shared.platform.RegistryWrappers;
 import net.minecraft.data.CachedOutput;
 import net.minecraft.data.DataProvider;
 import net.minecraft.data.PackOutput;
+import net.minecraft.tags.TagKey;
 import net.minecraft.world.item.Item;
 import net.minecraft.world.level.block.Block;
 
@@ -97,6 +99,12 @@ public final class LanguageProvider implements DataProvider {
         add(ModRegistry.Items.POCKET_COMPUTER_ADVANCED.get(), "Advanced Pocket Computer");
         add(ModRegistry.Items.POCKET_COMPUTER_ADVANCED.get().getDescriptionId() + ".upgraded", "Advanced %s Pocket Computer");
 
+        // Tags (for EMI)
+        add(ComputerCraftTags.Items.COMPUTER, "Computers");
+        add(ComputerCraftTags.Items.TURTLE, "Turtles");
+        add(ComputerCraftTags.Items.WIRED_MODEM, "Wired modems");
+        add(ComputerCraftTags.Items.MONITOR, "Monitors");
+
         // Turtle/pocket upgrades
         add("upgrade.minecraft.diamond_sword.adjective", "Melee");
         add("upgrade.minecraft.diamond_shovel.adjective", "Digging");
@@ -150,9 +158,6 @@ public final class LanguageProvider implements DataProvider {
         add("commands.computercraft.track.dump.desc", "Dump the latest results of computer tracking.");
         add("commands.computercraft.track.dump.no_timings", "No timings available");
         add("commands.computercraft.track.dump.computer", "Computer");
-        add("commands.computercraft.reload.synopsis", "Reload the ComputerCraft config file");
-        add("commands.computercraft.reload.desc", "Reload the ComputerCraft config file");
-        add("commands.computercraft.reload.done", "Reloaded config");
         add("commands.computercraft.queue.synopsis", "Send a computer_command event to a command computer");
         add("commands.computercraft.queue.desc", "Send a computer_command event to a command computer, passing through the additional arguments. This is mostly designed for map makers, acting as a more computer-friendly version of /trigger. Any player can run the command, which would most likely be done through a text component's click event.");
 
@@ -214,6 +219,7 @@ public final class LanguageProvider implements DataProvider {
         addConfigEntry(ConfigSpec.defaultComputerSettings, "Default Computer settings");
         addConfigEntry(ConfigSpec.logComputerErrors, "Log computer errors");
         addConfigEntry(ConfigSpec.commandRequireCreative, "Command computers require creative");
+        addConfigEntry(ConfigSpec.disabledGenericMethods, "Disabled generic methods");
 
         addConfigGroup(ConfigSpec.serverSpec, "execution", "Execution");
         addConfigEntry(ConfigSpec.computerThreads, "Computer threads");
@@ -277,8 +283,8 @@ public final class LanguageProvider implements DataProvider {
             turtleUpgrades.getGeneratedUpgrades().stream().map(UpgradeBase::getUnlocalisedAdjective),
             pocketUpgrades.getGeneratedUpgrades().stream().map(UpgradeBase::getUnlocalisedAdjective),
             Metric.metrics().values().stream().map(x -> AggregatedMetric.TRANSLATION_PREFIX + x.name() + ".name"),
-            getConfigEntries(ConfigSpec.serverSpec).map(ConfigFile.Entry::translationKey),
-            getConfigEntries(ConfigSpec.clientSpec).map(ConfigFile.Entry::translationKey)
+            ConfigSpec.serverSpec.entries().map(ConfigFile.Entry::translationKey),
+            ConfigSpec.clientSpec.entries().map(ConfigFile.Entry::translationKey)
         ).flatMap(x -> x);
     }
 
@@ -298,6 +304,10 @@ public final class LanguageProvider implements DataProvider {
         add(AggregatedMetric.TRANSLATION_PREFIX + metric.name() + ".name", text);
     }
 
+    private void add(TagKey<Item> tag, String text) {
+        add("tag.item." + tag.location().getNamespace() + "." + tag.location().getPath(), text);
+    }
+
     private void addConfigGroup(ConfigFile spec, String path, String text) {
         var entry = spec.getEntry(path);
         if (!(entry instanceof ConfigFile.Group)) throw new IllegalArgumentException("Cannot find group " + path);
@@ -308,16 +318,4 @@ public final class LanguageProvider implements DataProvider {
         add(value.translationKey(), text);
         add(value.translationKey() + ".tooltip", value.comment());
     }
-
-    private static Stream<ConfigFile.Entry> getConfigEntries(ConfigFile spec) {
-        return spec.entries().flatMap(LanguageProvider::getConfigEntries);
-    }
-
-    private static Stream<ConfigFile.Entry> getConfigEntries(ConfigFile.Entry entry) {
-        if (entry instanceof ConfigFile.Value<?>) return Stream.of(entry);
-        if (entry instanceof ConfigFile.Group group) {
-            return Stream.concat(Stream.of(entry), group.children().flatMap(LanguageProvider::getConfigEntries));
-        }
-        throw new IllegalStateException("Invalid config entry " + entry);
-    }
 }

projects/common/src/main/java/dan200/computercraft/data/RecipeProvider.java

@@ -8,6 +8,7 @@ import com.google.gson.JsonObject;
 import dan200.computercraft.api.ComputerCraftAPI;
 import dan200.computercraft.api.pocket.PocketUpgradeDataProvider;
 import dan200.computercraft.api.turtle.TurtleUpgradeDataProvider;
+import dan200.computercraft.api.upgrades.UpgradeData;
 import dan200.computercraft.core.util.Colour;
 import dan200.computercraft.shared.ModRegistry;
 import dan200.computercraft.shared.common.IColouredItem;
@@ -110,7 +111,7 @@ class RecipeProvider extends net.minecraft.data.recipes.RecipeProvider {
             var nameId = turtleItem.getFamily().name().toLowerCase(Locale.ROOT);
 
             for (var upgrade : turtleUpgrades.getGeneratedUpgrades()) {
-                var result = turtleItem.create(-1, null, -1, null, upgrade, -1, null);
+                var result = turtleItem.create(-1, null, -1, null, UpgradeData.ofDefault(upgrade), -1, null);
                 ShapedRecipeBuilder
                     .shaped(RecipeCategory.REDSTONE, result.getItem())
                     .group(String.format("%s:turtle_%s", ComputerCraftAPI.MOD_ID, nameId))
@@ -146,7 +147,7 @@ class RecipeProvider extends net.minecraft.data.recipes.RecipeProvider {
             var nameId = pocket.getFamily().name().toLowerCase(Locale.ROOT);
 
             for (var upgrade : pocketUpgrades.getGeneratedUpgrades()) {
-                var result = pocket.create(-1, null, -1, upgrade);
+                var result = pocket.create(-1, null, -1, UpgradeData.ofDefault(upgrade));
                 ShapedRecipeBuilder
                     .shaped(RecipeCategory.REDSTONE, result.getItem())
                     .group(String.format("%s:pocket_%s", ComputerCraftAPI.MOD_ID, nameId))

projects/common/src/main/java/dan200/computercraft/data/TagProvider.java

@@ -88,6 +88,8 @@ class TagProvider {
             ModRegistry.Items.MONITOR_ADVANCED.get()
         );
 
+        tags.tag(ItemTags.BOOKSHELF_BOOKS).add(ModRegistry.Items.PRINTED_BOOK.get());
+
         tags.tag(ComputerCraftTags.Items.TURTLE_CAN_PLACE)
             .add(Items.GLASS_BOTTLE)
             .addTag(ItemTags.BOATS);

projects/common/src/main/java/dan200/computercraft/impl/AbstractComputerCraftAPI.java

@@ -19,8 +19,6 @@ import dan200.computercraft.api.pocket.PocketUpgradeSerialiser;
 import dan200.computercraft.api.redstone.BundledRedstoneProvider;
 import dan200.computercraft.api.turtle.TurtleRefuelHandler;
 import dan200.computercraft.api.turtle.TurtleUpgradeSerialiser;
-import dan200.computercraft.core.apis.ApiFactories;
-import dan200.computercraft.core.asm.GenericMethod;
 import dan200.computercraft.core.filesystem.WritableFileMount;
 import dan200.computercraft.impl.detail.DetailRegistryImpl;
 import dan200.computercraft.impl.network.wired.WiredNodeImpl;
@@ -79,7 +77,7 @@ public abstract class AbstractComputerCraftAPI implements ComputerCraftAPIServic
 
     @Override
     public final void registerGenericSource(GenericSource source) {
-        GenericMethod.register(source);
+        GenericSources.register(source);
     }
 
     @Override

projects/common/src/main/java/dan200/computercraft/impl/ApiFactories.java

@@ -2,7 +2,7 @@
 //
 // SPDX-License-Identifier: MPL-2.0
 
-package dan200.computercraft.core.apis;
+package dan200.computercraft.impl;
 
 import dan200.computercraft.api.lua.ILuaAPIFactory;
 
@@ -11,19 +11,24 @@ import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.Objects;
 
+/**
+ * The global factory for {@link ILuaAPIFactory}s.
+ *
+ * @see dan200.computercraft.core.ComputerContext.Builder#apiFactories(Collection)
+ * @see dan200.computercraft.api.ComputerCraftAPI#registerAPIFactory(ILuaAPIFactory)
+ */
 public final class ApiFactories {
     private ApiFactories() {
     }
 
     private static final Collection<ILuaAPIFactory> factories = new LinkedHashSet<>();
-    private static final Collection<ILuaAPIFactory> factoriesView = Collections.unmodifiableCollection(factories);
 
-    public static synchronized void register(ILuaAPIFactory factory) {
+    static synchronized void register(ILuaAPIFactory factory) {
         Objects.requireNonNull(factory, "provider cannot be null");
         factories.add(factory);
     }
 
-    public static Iterable<ILuaAPIFactory> getAll() {
-        return factoriesView;
+    public static Collection<ILuaAPIFactory> getAll() {
+        return Collections.unmodifiableCollection(factories);
     }
 }

projects/common/src/main/java/dan200/computercraft/impl/GenericSources.java

@@ -0,0 +1,41 @@
+// SPDX-FileCopyrightText: 2023 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.impl;
+
+import dan200.computercraft.api.lua.GenericSource;
+import dan200.computercraft.core.asm.GenericMethod;
+import dan200.computercraft.shared.config.ConfigSpec;
+
+import java.util.Collection;
+import java.util.LinkedHashSet;
+import java.util.Objects;
+import java.util.Set;
+
+/**
+ * The global registry for {@link GenericSource}s.
+ *
+ * @see dan200.computercraft.core.ComputerContext.Builder#genericMethods(Collection)
+ * @see dan200.computercraft.api.ComputerCraftAPI#registerGenericSource(GenericSource)
+ */
+public final class GenericSources {
+    private GenericSources() {
+    }
+
+    private static final Collection<GenericSource> sources = new LinkedHashSet<>();
+
+    static synchronized void register(GenericSource source) {
+        Objects.requireNonNull(source, "provider cannot be null");
+        sources.add(source);
+    }
+
+    public static Collection<GenericMethod> getAllMethods() {
+        var disabledMethods = Set.copyOf(ConfigSpec.disabledGenericMethods.get());
+        return sources.stream()
+            .filter(x -> !disabledMethods.contains(x.id()))
+            .flatMap(GenericMethod::getMethods)
+            .filter(x -> !disabledMethods.contains(x.id()))
+            .toList();
+    }
+}

projects/common/src/main/java/dan200/computercraft/impl/UpgradeManager.java

@@ -7,6 +7,7 @@ package dan200.computercraft.impl;
 import com.google.gson.*;
 import dan200.computercraft.api.ComputerCraftAPI;
 import dan200.computercraft.api.upgrades.UpgradeBase;
+import dan200.computercraft.api.upgrades.UpgradeData;
 import dan200.computercraft.api.upgrades.UpgradeSerialiser;
 import dan200.computercraft.shared.platform.PlatformHelper;
 import net.minecraft.core.Registry;
@@ -74,13 +75,13 @@ public class UpgradeManager<R extends UpgradeSerialiser<? extends T>, T extends
     }
 
     @Nullable
-    public T get(ItemStack stack) {
+    public UpgradeData<T> get(ItemStack stack) {
         if (stack.isEmpty()) return null;
 
         for (var wrapper : current.values()) {
             var craftingStack = wrapper.upgrade().getCraftingItem();
             if (!craftingStack.isEmpty() && craftingStack.getItem() == stack.getItem() && wrapper.upgrade().isItemSuitable(stack)) {
-                return wrapper.upgrade();
+                return UpgradeData.of(wrapper.upgrade, wrapper.upgrade.getUpgradeData(stack));
             }
         }
 

projects/common/src/main/java/dan200/computercraft/shared/CommonHooks.java

@@ -23,7 +23,11 @@ import net.minecraft.world.entity.Entity;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.chunk.LevelChunk;
 import net.minecraft.world.level.storage.loot.BuiltInLootTables;
+import net.minecraft.world.level.storage.loot.LootPool;
+import net.minecraft.world.level.storage.loot.entries.LootTableReference;
+import net.minecraft.world.level.storage.loot.providers.number.ConstantValue;
 
+import javax.annotation.Nullable;
 import java.util.Set;
 import java.util.function.BiConsumer;
 
@@ -71,7 +75,7 @@ public final class CommonHooks {
 
     public static final ResourceLocation TREASURE_DISK_LOOT = new ResourceLocation(ComputerCraftAPI.MOD_ID, "treasure_disk");
 
-    public static final Set<ResourceLocation> TREASURE_DISK_LOOT_TABLES = Set.of(
+    private static final Set<ResourceLocation> TREASURE_DISK_LOOT_TABLES = Set.of(
         BuiltInLootTables.SIMPLE_DUNGEON,
         BuiltInLootTables.ABANDONED_MINESHAFT,
         BuiltInLootTables.STRONGHOLD_CORRIDOR,
@@ -84,6 +88,16 @@ public final class CommonHooks {
         BuiltInLootTables.VILLAGE_CARTOGRAPHER
     );
 
+    public static @Nullable LootPool.Builder getExtraLootPool(ResourceLocation lootTable) {
+        if (!lootTable.getNamespace().equals("minecraft") || !TREASURE_DISK_LOOT_TABLES.contains(lootTable)) {
+            return null;
+        }
+
+        return LootPool.lootPool()
+            .add(LootTableReference.lootTableReference(TREASURE_DISK_LOOT))
+            .setRolls(ConstantValue.exactly(1));
+    }
+
     public static void onDatapackReload(BiConsumer<String, PreparableReloadListener> addReload) {
         addReload.accept("mounts", ResourceMount.RELOAD_LISTENER);
         addReload.accept("turtle_upgrades", TurtleUpgrades.instance());

projects/common/src/main/java/dan200/computercraft/shared/ModRegistry.java

@@ -11,6 +11,7 @@ import dan200.computercraft.api.detail.VanillaDetailRegistries;
 import dan200.computercraft.api.media.IMedia;
 import dan200.computercraft.api.pocket.PocketUpgradeSerialiser;
 import dan200.computercraft.api.turtle.TurtleUpgradeSerialiser;
+import dan200.computercraft.api.upgrades.UpgradeData;
 import dan200.computercraft.core.util.Colour;
 import dan200.computercraft.impl.PocketUpgrades;
 import dan200.computercraft.impl.TurtleUpgrades;
@@ -445,12 +446,12 @@ public final class ModRegistry {
     private static void addTurtle(CreativeModeTab.Output out, TurtleItem turtle) {
         out.accept(turtle.create(-1, null, -1, null, null, 0, null));
         TurtleUpgrades.getVanillaUpgrades()
-            .map(x -> turtle.create(-1, null, -1, null, x, 0, null))
+            .map(x -> turtle.create(-1, null, -1, null, UpgradeData.ofDefault(x), 0, null))
             .forEach(out::accept);
     }
 
     private static void addPocket(CreativeModeTab.Output out, PocketComputerItem pocket) {
         out.accept(pocket.create(-1, null, -1, null));
-        PocketUpgrades.getVanillaUpgrades().map(x -> pocket.create(-1, null, -1, x)).forEach(out::accept);
+        PocketUpgrades.getVanillaUpgrades().map(x -> pocket.create(-1, null, -1, UpgradeData.ofDefault(x))).forEach(out::accept);
     }
 }

projects/common/src/main/java/dan200/computercraft/shared/command/CommandComputerCraft.java

@@ -6,9 +6,12 @@ package dan200.computercraft.shared.command;
 
 import com.mojang.brigadier.CommandDispatcher;
 import com.mojang.brigadier.arguments.StringArgumentType;
+import com.mojang.brigadier.builder.RequiredArgumentBuilder;
 import com.mojang.brigadier.exceptions.CommandSyntaxException;
+import com.mojang.brigadier.suggestion.Suggestions;
 import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.core.metrics.Metrics;
+import dan200.computercraft.shared.command.arguments.ComputersArgumentType;
 import dan200.computercraft.shared.command.text.TableBuilder;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.computer.core.ServerComputer;
@@ -173,7 +176,10 @@ public final class CommandComputerCraft {
 
             .then(command("queue")
                 .requires(UserLevel.ANYONE)
-                .arg("computer", manyComputers())
+                .arg(
+                    RequiredArgumentBuilder.<CommandSourceStack, ComputersArgumentType.ComputersSupplier>argument("computer", manyComputers())
+                        .suggests((context, builder) -> Suggestions.empty())
+                )
                 .argManyValue("args", StringArgumentType.string(), Collections.emptyList())
                 .executes((ctx, args) -> {
                     var computers = getComputersArgument(ctx, "computer");

projects/common/src/main/java/dan200/computercraft/shared/command/UserLevel.java

@@ -49,6 +49,29 @@ public enum UserLevel implements Predicate<CommandSourceStack> {
         return source.hasPermission(toLevel());
     }
 
+    /**
+     * Take the union of two {@link UserLevel}s.
+     * <p>
+     * This satisfies the property that for all sources {@code s}, {@code a.test(s) || b.test(s) == (a ∪ b).test(s)}.
+     *
+     * @param left  The first user level to take the union of.
+     * @param right The second user level to take the union of.
+     * @return The union of two levels.
+     */
+    public static UserLevel union(UserLevel left, UserLevel right) {
+        if (left == right) return left;
+
+        // x ∪ ANYONE = ANYONE
+        if (left == ANYONE || right == ANYONE) return ANYONE;
+
+        // x ∪ OWNER = OWNER
+        if (left == OWNER) return right;
+        if (right == OWNER) return left;
+
+        // At this point, we have x != y and x, y ∈ { OP, OWNER_OP }.
+        return OWNER_OP;
+    }
+
     private static boolean isOwner(CommandSourceStack source) {
         var server = source.getServer();
         var sender = source.getEntity();

projects/common/src/main/java/dan200/computercraft/shared/command/arguments/ArgumentUtils.java

@@ -44,12 +44,12 @@ public class ArgumentUtils {
 
     @SuppressWarnings("unchecked")
     private static <A extends ArgumentType<?>, T extends ArgumentTypeInfo.Template<A>> void serializeToNetwork(FriendlyByteBuf buffer, ArgumentTypeInfo<A, T> type, ArgumentTypeInfo.Template<A> template) {
-        RegistryWrappers.writeId(buffer, RegistryWrappers.COMMAND_ARGUMENT_TYPES, type);
+        buffer.writeId(RegistryWrappers.COMMAND_ARGUMENT_TYPES, type);
         type.serializeToNetwork((T) template, buffer);
     }
 
     public static ArgumentTypeInfo.Template<?> deserialize(FriendlyByteBuf buffer) {
-        var type = RegistryWrappers.readId(buffer, RegistryWrappers.COMMAND_ARGUMENT_TYPES);
+        var type = buffer.readById(RegistryWrappers.COMMAND_ARGUMENT_TYPES);
         Objects.requireNonNull(type, "Unknown argument type");
         return type.deserializeFromNetwork(buffer);
     }

projects/common/src/main/java/dan200/computercraft/shared/command/arguments/ComputersArgumentType.java

@@ -18,7 +18,6 @@ import net.minecraft.commands.CommandBuildContext;
 import net.minecraft.commands.CommandSourceStack;
 import net.minecraft.commands.synchronization.ArgumentTypeInfo;
 import net.minecraft.network.FriendlyByteBuf;
-import org.jetbrains.annotations.NotNull;
 
 import java.util.*;
 import java.util.concurrent.CompletableFuture;
@@ -159,14 +158,14 @@ public final class ComputersArgumentType implements ArgumentType<ComputersArgume
         }
 
         @Override
-        public ComputersArgumentType.Template unpack(@NotNull ComputersArgumentType argumentType) {
+        public ComputersArgumentType.Template unpack(ComputersArgumentType argumentType) {
             return new ComputersArgumentType.Template(this, argumentType.requireSome);
         }
     }
 
     public record Template(Info info, boolean requireSome) implements ArgumentTypeInfo.Template<ComputersArgumentType> {
         @Override
-        public ComputersArgumentType instantiate(@NotNull CommandBuildContext context) {
+        public ComputersArgumentType instantiate(CommandBuildContext context) {
             return requireSome ? SOME : MANY;
         }
 

projects/common/src/main/java/dan200/computercraft/shared/command/arguments/RepeatArgumentType.java

@@ -17,7 +17,6 @@ import net.minecraft.commands.synchronization.ArgumentTypeInfo;
 import net.minecraft.commands.synchronization.ArgumentTypeInfos;
 import net.minecraft.network.FriendlyByteBuf;
 import net.minecraft.network.chat.Component;
-import org.jetbrains.annotations.NotNull;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -144,7 +143,7 @@ public final class RepeatArgumentType<T, U> implements ArgumentType<List<T>> {
     ) implements ArgumentTypeInfo.Template<RepeatArgumentType<?, ?>> {
         @Override
         @SuppressWarnings({ "unchecked", "rawtypes" })
-        public RepeatArgumentType<?, ?> instantiate(@NotNull CommandBuildContext commandBuildContext) {
+        public RepeatArgumentType<?, ?> instantiate(CommandBuildContext commandBuildContext) {
             var child = child().instantiate(commandBuildContext);
             return flatten ? RepeatArgumentType.someFlat((ArgumentType) child, some()) : RepeatArgumentType.some(child, some());
         }

projects/common/src/main/java/dan200/computercraft/shared/command/builder/CommandBuilder.java

@@ -48,11 +48,15 @@ public class CommandBuilder<S> implements CommandNodeBuilder<S, Command<S>> {
         return this;
     }
 
-    public CommandBuilder<S> arg(String name, ArgumentType<?> type) {
-        args.add(RequiredArgumentBuilder.argument(name, type));
+    public CommandBuilder<S> arg(ArgumentBuilder<S, ?> arg) {
+        args.add(arg);
         return this;
     }
 
+    public CommandBuilder<S> arg(String name, ArgumentType<?> type) {
+        return arg(RequiredArgumentBuilder.argument(name, type));
+    }
+
     public <T> CommandNodeBuilder<S, ArgCommand<S, List<T>>> argManyValue(String name, ArgumentType<T> type, List<T> empty) {
         return argMany(name, type, () -> empty);
     }
@@ -74,7 +78,7 @@ public class CommandBuilder<S> implements CommandNodeBuilder<S, Command<S>> {
 
         return command -> {
             // The node for no arguments
-            var tail = tail(ctx -> command.run(ctx, empty.get()));
+            var tail = setupTail(ctx -> command.run(ctx, empty.get()));
 
             // The node for one or more arguments
             ArgumentBuilder<S, ?> moreArg = RequiredArgumentBuilder
@@ -83,7 +87,7 @@ public class CommandBuilder<S> implements CommandNodeBuilder<S, Command<S>> {
 
             // Chain all of them together!
             tail.then(moreArg);
-            return link(tail);
+            return buildTail(tail);
         };
     }
 
@@ -94,20 +98,16 @@ public class CommandBuilder<S> implements CommandNodeBuilder<S, Command<S>> {
 
     @Override
     public CommandNode<S> executes(Command<S> command) {
-        if (args.isEmpty()) throw new IllegalStateException("Cannot have empty arg chain builder");
-
-        return link(tail(command));
+        return buildTail(setupTail(command));
     }
 
-    private ArgumentBuilder<S, ?> tail(Command<S> command) {
-        var defaultTail = args.get(args.size() - 1);
-        defaultTail.executes(command);
-        if (requires != null) defaultTail.requires(requires);
-        return defaultTail;
+    private ArgumentBuilder<S, ?> setupTail(Command<S> command) {
+        return args.get(args.size() - 1).executes(command);
     }
 
-    private CommandNode<S> link(ArgumentBuilder<S, ?> tail) {
+    private CommandNode<S> buildTail(ArgumentBuilder<S, ?> tail) {
         for (var i = args.size() - 2; i >= 0; i--) tail = args.get(i).then(tail);
+        if (requires != null) tail.requires(requires);
         return tail.build();
     }
 }

projects/common/src/main/java/dan200/computercraft/shared/command/builder/HelpingArgumentBuilder.java

@@ -10,6 +10,7 @@ import com.mojang.brigadier.builder.LiteralArgumentBuilder;
 import com.mojang.brigadier.context.CommandContext;
 import com.mojang.brigadier.tree.CommandNode;
 import com.mojang.brigadier.tree.LiteralCommandNode;
+import dan200.computercraft.shared.command.UserLevel;
 import net.minecraft.ChatFormatting;
 import net.minecraft.commands.CommandSourceStack;
 import net.minecraft.network.chat.ClickEvent;
@@ -18,6 +19,8 @@ import net.minecraft.network.chat.Component;
 import javax.annotation.Nullable;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.function.Predicate;
+import java.util.stream.Stream;
 
 import static dan200.computercraft.core.util.Nullability.assertNonNull;
 import static dan200.computercraft.shared.command.text.ChatHelpers.coloured;
@@ -37,6 +40,29 @@ public final class HelpingArgumentBuilder extends LiteralArgumentBuilder<Command
         return new HelpingArgumentBuilder(literal);
     }
 
+    @Override
+    public LiteralArgumentBuilder<CommandSourceStack> requires(Predicate<CommandSourceStack> requirement) {
+        throw new IllegalStateException("Cannot use requires on a HelpingArgumentBuilder");
+    }
+
+    @Override
+    public Predicate<CommandSourceStack> getRequirement() {
+        // The requirement of this node is the union of all child's requirements.
+        var requirements = Stream.concat(
+            children.stream().map(ArgumentBuilder::getRequirement),
+            getArguments().stream().map(CommandNode::getRequirement)
+        ).toList();
+
+        // If all requirements are a UserLevel, take the union of those instead.
+        var userLevel = UserLevel.OWNER;
+        for (var requirement : requirements) {
+            if (!(requirement instanceof UserLevel level)) return x -> requirements.stream().anyMatch(y -> y.test(x));
+            userLevel = UserLevel.union(userLevel, level);
+        }
+
+        return userLevel;
+    }
+
     @Override
     public LiteralArgumentBuilder<CommandSourceStack> executes(final Command<CommandSourceStack> command) {
         throw new IllegalStateException("Cannot use executes on a HelpingArgumentBuilder");
@@ -80,9 +106,7 @@ public final class HelpingArgumentBuilder extends LiteralArgumentBuilder<Command
         helpCommand.node = node;
 
         // Set up a /... help command
-        var helpNode = LiteralArgumentBuilder.<CommandSourceStack>literal("help")
-            .requires(x -> getArguments().stream().anyMatch(y -> y.getRequirement().test(x)))
-            .executes(helpCommand);
+        var helpNode = LiteralArgumentBuilder.<CommandSourceStack>literal("help").executes(helpCommand);
 
         // Add all normal command children to this and the help node
         for (var child : getArguments()) {

projects/common/src/main/java/dan200/computercraft/shared/computer/blocks/AbstractComputerBlockEntity.java

@@ -199,6 +199,11 @@ public abstract class AbstractComputerBlockEntity extends BlockEntity implements
         return localSide;
     }
 
+    private void updateRedstoneInputs(ServerComputer computer) {
+        var pos = getBlockPos();
+        for (var dir : DirectionUtil.FACINGS) updateRedstoneInput(computer, dir, pos.relative(dir));
+    }
+
     private void updateRedstoneInput(ServerComputer computer, Direction dir, BlockPos targetPos) {
         var offsetSide = dir.getOpposite();
         var localDir = remapToLocalSide(dir);
@@ -254,8 +259,7 @@ public abstract class AbstractComputerBlockEntity extends BlockEntity implements
 
         // If the position is not any adjacent one, update all inputs. This is pretty terrible, but some redstone mods
         // handle this incorrectly.
-        var pos = getBlockPos();
-        for (var dir : DirectionUtil.FACINGS) updateRedstoneInput(computer, dir, pos.relative(dir));
+        updateRedstoneInputs(computer);
         invalidSides = (1 << 6) - 1; // Mark all peripherals as dirty.
     }
 
@@ -264,9 +268,10 @@ public abstract class AbstractComputerBlockEntity extends BlockEntity implements
      */
     public void updateOutput() {
         BlockEntityHelpers.updateBlock(this);
-        for (var dir : DirectionUtil.FACINGS) {
-            RedstoneUtil.propagateRedstoneOutput(getLevel(), getBlockPos(), dir);
-        }
+        for (var dir : DirectionUtil.FACINGS) RedstoneUtil.propagateRedstoneOutput(getLevel(), getBlockPos(), dir);
+
+        var computer = getServerComputer();
+        if (computer != null) updateRedstoneInputs(computer);
     }
 
     protected abstract ServerComputer createComputer(int id);

projects/common/src/main/java/dan200/computercraft/shared/computer/core/ServerContext.java

@@ -9,13 +9,16 @@ import dan200.computercraft.api.ComputerCraftAPI;
 import dan200.computercraft.api.filesystem.Mount;
 import dan200.computercraft.api.network.PacketNetwork;
 import dan200.computercraft.core.ComputerContext;
-import dan200.computercraft.core.computer.ComputerThread;
 import dan200.computercraft.core.computer.GlobalEnvironment;
 import dan200.computercraft.core.computer.mainthread.MainThread;
 import dan200.computercraft.core.computer.mainthread.MainThreadConfig;
 import dan200.computercraft.core.lua.CobaltLuaMachine;
 import dan200.computercraft.core.lua.ILuaMachine;
+import dan200.computercraft.core.methods.MethodSupplier;
+import dan200.computercraft.core.methods.PeripheralMethod;
 import dan200.computercraft.impl.AbstractComputerCraftAPI;
+import dan200.computercraft.impl.ApiFactories;
+import dan200.computercraft.impl.GenericSources;
 import dan200.computercraft.shared.CommonHooks;
 import dan200.computercraft.shared.computer.metrics.GlobalMetrics;
 import dan200.computercraft.shared.config.ConfigSpec;
@@ -67,11 +70,13 @@ public final class ServerContext {
         this.server = server;
         storageDir = server.getWorldPath(FOLDER);
         mainThread = new MainThread(mainThreadConfig);
-        context = new ComputerContext(
-            new Environment(server),
-            new ComputerThread(ConfigSpec.computerThreads.get()),
-            mainThread, luaMachine
-        );
+        context = ComputerContext.builder(new Environment(server))
+            .computerThreads(ConfigSpec.computerThreads.get())
+            .mainThreadScheduler(mainThread)
+            .luaFactory(luaMachine)
+            .apiFactories(ApiFactories.getAll())
+            .genericMethods(GenericSources.getAllMethods())
+            .build();
         idAssigner = new IDAssigner(storageDir.resolve("ids.json"));
     }
 
@@ -133,6 +138,16 @@ public final class ServerContext {
         return context;
     }
 
+    /**
+     * Get the {@link MethodSupplier} used to find methods on peripherals.
+     *
+     * @return The {@link PeripheralMethod} method supplier.
+     * @see ComputerContext#peripheralMethods()
+     */
+    public MethodSupplier<PeripheralMethod> peripheralMethods() {
+        return context.peripheralMethods();
+    }
+
     /**
      * Tick all components of this server context. This should <em>NOT</em> be called outside of {@link CommonHooks}.
      */

projects/common/src/main/java/dan200/computercraft/shared/computer/upload/TransferredFile.java

@@ -7,7 +7,7 @@ package dan200.computercraft.shared.computer.upload;
 import dan200.computercraft.api.lua.LuaFunction;
 import dan200.computercraft.core.apis.handles.BinaryReadableHandle;
 import dan200.computercraft.core.apis.handles.ByteBufferChannel;
-import dan200.computercraft.core.asm.ObjectSource;
+import dan200.computercraft.core.methods.ObjectSource;
 
 import java.nio.ByteBuffer;
 import java.util.Collections;

projects/common/src/main/java/dan200/computercraft/shared/config/AddressRuleConfig.java

@@ -4,21 +4,19 @@
 
 package dan200.computercraft.shared.config;
 
+import com.electronwill.nightconfig.core.CommentedConfig;
 import com.electronwill.nightconfig.core.Config;
 import com.electronwill.nightconfig.core.InMemoryCommentedFormat;
 import com.electronwill.nightconfig.core.UnmodifiableConfig;
 import dan200.computercraft.core.apis.http.options.Action;
 import dan200.computercraft.core.apis.http.options.AddressRule;
+import dan200.computercraft.core.apis.http.options.InvalidRuleException;
 import dan200.computercraft.core.apis.http.options.PartialOptions;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import javax.annotation.Nullable;
-import java.util.Locale;
-import java.util.Optional;
-import java.util.OptionalInt;
-import java.util.OptionalLong;
-import java.util.concurrent.ConcurrentHashMap;
+import java.util.*;
+import java.util.function.Consumer;
 
 /**
  * Parses, checks and generates {@link Config}s for {@link AddressRule}.
@@ -26,49 +24,65 @@ import java.util.concurrent.ConcurrentHashMap;
 class AddressRuleConfig {
     private static final Logger LOG = LoggerFactory.getLogger(AddressRuleConfig.class);
 
-    public static UnmodifiableConfig makeRule(String host, Action action) {
-        var config = InMemoryCommentedFormat.defaultInstance().createConfig(ConcurrentHashMap::new);
-        config.add("host", host);
-        config.add("action", action.name().toLowerCase(Locale.ROOT));
+    private static final AddressRule REJECT_ALL = AddressRule.parse("*", OptionalInt.empty(), Action.DENY.toPartial());
 
-        if (host.equals("*") && action == Action.ALLOW) {
-            config.setComment("max_download", """
-                The maximum size (in bytes) that a computer can download in a single request.
-                Note that responses may receive more data than allowed, but this data will not
-                be returned to the client.""");
-            config.set("max_download", AddressRule.MAX_DOWNLOAD);
+    public static List<UnmodifiableConfig> defaultRules() {
+        return List.of(
+            makeRule(config -> {
+                config.setComment("host", """
+                    The magic "$private" host matches all private address ranges, such as localhost and 192.168.0.0/16.
+                    This rule prevents computers accessing internal services, and is strongly recommended.""");
+                config.add("host", "$private");
 
-            config.setComment("max_upload", """
-                The maximum size (in bytes) that a computer can upload in a single request. This
-                includes headers and POST text.""");
-            config.set("max_upload", AddressRule.MAX_UPLOAD);
+                config.setComment("action", "Deny all requests to private IP addresses.");
+                config.add("action", Action.DENY.name().toLowerCase(Locale.ROOT));
+            }),
+            makeRule(config -> {
+                config.setComment("host", """
+                    The wildcard "*" rule matches all remaining hosts.""");
+                config.add("host", "*");
 
-            config.setComment("max_websocket_message", "The maximum size (in bytes) that a computer can send or receive in one websocket packet.");
-            config.set("max_websocket_message", AddressRule.WEBSOCKET_MESSAGE);
+                config.setComment("action", "Allow all non-denied hosts.");
+                config.add("action", Action.ALLOW.name().toLowerCase(Locale.ROOT));
 
-            config.setComment("use_proxy", "Enable use of the HTTP/SOCKS proxy if it is configured.");
-            config.set("use_proxy", false);
-        }
+                config.setComment("max_download", """
+                    The maximum size (in bytes) that a computer can download in a single request.
+                    Note that responses may receive more data than allowed, but this data will not
+                    be returned to the client.""");
+                config.set("max_download", AddressRule.MAX_DOWNLOAD);
 
+                config.setComment("max_upload", """
+                    The maximum size (in bytes) that a computer can upload in a single request. This
+                    includes headers and POST text.""");
+                config.set("max_upload", AddressRule.MAX_UPLOAD);
+
+                config.setComment("max_websocket_message", "The maximum size (in bytes) that a computer can send or receive in one websocket packet.");
+                config.set("max_websocket_message", AddressRule.WEBSOCKET_MESSAGE);
+
+                config.setComment("use_proxy", "Enable use of the HTTP/SOCKS proxy if it is configured.");
+                config.set("use_proxy", false);
+            })
+        );
+    }
+
+    private static UnmodifiableConfig makeRule(Consumer<CommentedConfig> setup) {
+        var config = InMemoryCommentedFormat.defaultInstance().createConfig(LinkedHashMap::new);
+        setup.accept(config);
         return config;
     }
 
-    public static boolean checkRule(UnmodifiableConfig builder) {
-        var hostObj = get(builder, "host", String.class).orElse(null);
-        var port = unboxOptInt(get(builder, "port", Number.class));
-        return hostObj != null && checkEnum(builder, "action", Action.class)
-            && check(builder, "port", Number.class)
-            && check(builder, "max_upload", Number.class)
-            && check(builder, "max_download", Number.class)
-            && check(builder, "websocket_message", Number.class)
-            && check(builder, "use_proxy", Boolean.class)
-            && AddressRule.parse(hostObj, port, PartialOptions.DEFAULT) != null;
+    public static AddressRule parseRule(UnmodifiableConfig builder) {
+        try {
+            return doParseRule(builder);
+        } catch (InvalidRuleException e) {
+            LOG.error("Malformed HTTP rule: {} HTTP will NOT work until this is fixed.", e.getMessage());
+            return REJECT_ALL;
+        }
     }
 
-    @Nullable
-    public static AddressRule parseRule(UnmodifiableConfig builder) {
+    public static AddressRule doParseRule(UnmodifiableConfig builder) {
         var hostObj = get(builder, "host", String.class).orElse(null);
-        if (hostObj == null) return null;
+        if (hostObj == null) throw new InvalidRuleException("No 'host' specified");
 
         var action = getEnum(builder, "action", Action.class).orElse(null);
         var port = unboxOptInt(get(builder, "port", Number.class));
@@ -88,38 +102,19 @@ class AddressRuleConfig {
         return AddressRule.parse(hostObj, port, options);
     }
 
-    private static <T> boolean check(UnmodifiableConfig config, String field, Class<T> klass) {
-        var value = config.get(field);
-        if (value == null || klass.isInstance(value)) return true;
-
-        LOG.warn("HTTP rule's {} is not a {}.", field, klass.getSimpleName());
-        return false;
-    }
-
-    private static <T extends Enum<T>> boolean checkEnum(UnmodifiableConfig config, String field, Class<T> klass) {
-        var value = config.get(field);
-        if (value == null) return true;
-
-        if (!(value instanceof String)) {
-            LOG.warn("HTTP rule's {} is not a string", field);
-            return false;
-        }
-
-        if (parseEnum(klass, (String) value) == null) {
-            LOG.warn("HTTP rule's {} is not a known option", field);
-            return false;
-        }
-
-        return true;
-    }
-
     private static <T> Optional<T> get(UnmodifiableConfig config, String field, Class<T> klass) {
         var value = config.get(field);
-        return klass.isInstance(value) ? Optional.of(klass.cast(value)) : Optional.empty();
+        if (value == null) return Optional.empty();
+        if (klass.isInstance(value)) return Optional.of(klass.cast(value));
+
+        throw new InvalidRuleException(String.format(
+            "Field '%s' should be a '%s' but is a %s.",
+            field, klass.getSimpleName(), value.getClass().getSimpleName()
+        ));
     }
 
     private static <T extends Enum<T>> Optional<T> getEnum(UnmodifiableConfig config, String field, Class<T> klass) {
-        return get(config, field, String.class).map(x -> parseEnum(klass, x));
+        return get(config, field, String.class).map(x -> parseEnum(field, klass, x));
     }
 
     private static OptionalLong unboxOptLong(Optional<? extends Number> value) {
@@ -130,11 +125,14 @@ class AddressRuleConfig {
         return value.map(Number::intValue).map(OptionalInt::of).orElse(OptionalInt.empty());
     }
 
-    @Nullable
-    private static <T extends Enum<T>> T parseEnum(Class<T> klass, String x) {
+    private static <T extends Enum<T>> T parseEnum(String field, Class<T> klass, String x) {
         for (var value : klass.getEnumConstants()) {
             if (value.name().equalsIgnoreCase(x)) return value;
         }
-        return null;
+
+        throw new InvalidRuleException(String.format(
+            "Field '%s' should be one of %s, but is '%s'.",
+            field, Arrays.stream(klass.getEnumConstants()).map(Enum::name).toList(), x
+        ));
     }
 }

projects/common/src/main/java/dan200/computercraft/shared/config/ConfigFile.java

@@ -54,12 +54,6 @@ public interface ConfigFile {
      * A group of config entries.
      */
     non-sealed interface Group extends Entry {
-        /**
-         * Get all entries in this group.
-         *
-         * @return All child entries.
-         */
-        Stream<Entry> children();
     }
 
     /**

projects/common/src/main/java/dan200/computercraft/shared/config/ConfigSpec.java

@@ -9,7 +9,6 @@ import dan200.computercraft.api.ComputerCraftAPI;
 import dan200.computercraft.core.CoreConfig;
 import dan200.computercraft.core.Logging;
 import dan200.computercraft.core.apis.http.NetworkUtils;
-import dan200.computercraft.core.apis.http.options.Action;
 import dan200.computercraft.core.apis.http.options.ProxyType;
 import dan200.computercraft.core.computer.mainthread.MainThreadConfig;
 import dan200.computercraft.shared.peripheral.monitor.MonitorRenderer;
@@ -20,9 +19,7 @@ import org.apache.logging.log4j.core.filter.MarkerFilter;
 
 import javax.annotation.Nullable;
 import java.nio.file.Path;
-import java.util.Arrays;
 import java.util.List;
-import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 
 public final class ConfigSpec {
@@ -38,6 +35,7 @@ public final class ConfigSpec {
     public static final ConfigFile.Value<Boolean> logComputerErrors;
     public static final ConfigFile.Value<Boolean> commandRequireCreative;
     public static final ConfigFile.Value<Integer> uploadMaxSize;
+    public static final ConfigFile.Value<List<? extends String>> disabledGenericMethods;
 
     public static final ConfigFile.Value<Integer> computerThreads;
     public static final ConfigFile.Value<Integer> maxMainGlobalTime;
@@ -142,6 +140,19 @@ public final class ConfigSpec {
                     Require players to be in creative mode and be opped in order to interact with
                     command computers. This is the default behaviour for vanilla's Command blocks.""")
                 .define("command_require_creative", Config.commandRequireCreative);
+
+            disabledGenericMethods = builder
+                .comment("""
+                    A list of generic methods or method sources to disable. Generic methods are
+                    methods added to a block/block entity when there is no explicit peripheral
+                    provider. This includes inventory methods (i.e. inventory.getItemDetail,
+                    inventory.pushItems), and (if on Forge), the fluid_storage and energy_storage
+                    methods.
+                    Methods in this list can either be a whole group of methods (computercraft:inventory)
+                    or a single method (computercraft:inventory#pushItems).
+                    """)
+                .worldRestart()
+                .defineList("disabled_generic_methods", List.of(), x -> x instanceof String);
         }
 
         {
@@ -182,9 +193,9 @@ public final class ConfigSpec {
 
             httpEnabled = builder
                 .comment("""
-                    Enable the "http" API on Computers. This also disables the "pastebin" and "wget"
-                    programs, that many users rely on. It's recommended to leave this on and use the
-                    "rules" config option to impose more fine-grained control.""")
+                    Enable the "http" API on Computers. Disabling this also disables the "pastebin" and
+                    "wget" programs, that many users rely on. It's recommended to leave this on and use
+                    the "rules" config option to impose more fine-grained control.""")
                 .define("enabled", CoreConfig.httpEnabled);
 
             httpWebsocketEnabled = builder
@@ -194,16 +205,23 @@ public final class ConfigSpec {
             httpRules = builder
                 .comment("""
                     A list of rules which control behaviour of the "http" API for specific domains or
-                    IPs. Each rule is an item with a 'host' to match against, and a series of
-                    properties. Rules are evaluated in order, meaning earlier rules override later
-                    ones.
-                    The host may be a domain name ("pastebin.com"), wildcard ("*.pastebin.com") or
-                    CIDR notation ("127.0.0.0/8").
-                    If no rules, the domain is blocked.""")
-                .defineList("rules", Arrays.asList(
-                    AddressRuleConfig.makeRule("$private", Action.DENY),
-                    AddressRuleConfig.makeRule("*", Action.ALLOW)
-                ), x -> x instanceof UnmodifiableConfig && AddressRuleConfig.checkRule((UnmodifiableConfig) x));
+                    IPs. Each rule matches against a hostname and an optional port, and then sets several
+                    properties for the request.  Rules are evaluated in order, meaning earlier rules override
+                    later ones.
+
+                    Valid properties:
+                     - "host" (required): The domain or IP address this rule matches. This may be a domain name
+                       ("pastebin.com"), wildcard ("*.pastebin.com") or CIDR notation ("127.0.0.0/8").
+                     - "port" (optional): Only match requests for a specific port, such as 80 or 443.
+
+                     - "action" (optional): Whether to allow or deny this request.
+                     - "max_download" (optional): The maximum size (in bytes) that a computer can download in this
+                       request.
+                     - "max_upload" (optional): The maximum size (in bytes) that a computer can upload in a this request.
+                     - "max_websocket_message" (optional): The maximum size (in bytes) that a computer can send or
+                       receive in one websocket packet.
+                     - "use_proxy" (optional): Enable use of the HTTP/SOCKS proxy if it is configured.""")
+                .defineList("rules", AddressRuleConfig.defaultRules(), x -> x instanceof UnmodifiableConfig);
 
             httpMaxRequests = builder
                 .comment("""
@@ -395,8 +413,8 @@ public final class ConfigSpec {
         // HTTP
         CoreConfig.httpEnabled = httpEnabled.get();
         CoreConfig.httpWebsocketEnabled = httpWebsocketEnabled.get();
-        CoreConfig.httpRules = httpRules.get().stream()
-            .map(AddressRuleConfig::parseRule).filter(Objects::nonNull).toList();
+
+        CoreConfig.httpRules = httpRules.get().stream().map(AddressRuleConfig::parseRule).toList();
 
         CoreConfig.httpMaxRequests = httpMaxRequests.get();
         CoreConfig.httpMaxWebsockets = httpMaxWebsockets.get();

projects/common/src/main/java/dan200/computercraft/shared/container/BasicContainer.java

@@ -7,7 +7,6 @@ package dan200.computercraft.shared.container;
 import net.minecraft.core.NonNullList;
 import net.minecraft.world.Container;
 import net.minecraft.world.ContainerHelper;
-import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.item.ItemStack;
 
 /**
@@ -16,24 +15,6 @@ import net.minecraft.world.item.ItemStack;
 public interface BasicContainer extends Container {
     NonNullList<ItemStack> getContents();
 
-    @Override
-    default int getMaxStackSize() {
-        return 64;
-    }
-
-    @Override
-    default void startOpen(Player player) {
-    }
-
-    @Override
-    default void stopOpen(Player player) {
-    }
-
-    @Override
-    default boolean canPlaceItem(int slot, ItemStack stack) {
-        return true;
-    }
-
     @Override
     default int getContainerSize() {
         return getContents().size();

projects/common/src/main/java/dan200/computercraft/shared/integration/RecipeModHelpers.java

@@ -5,6 +5,7 @@
 package dan200.computercraft.shared.integration;
 
 import dan200.computercraft.api.ComputerCraftAPI;
+import dan200.computercraft.api.upgrades.UpgradeData;
 import dan200.computercraft.impl.PocketUpgrades;
 import dan200.computercraft.impl.TurtleUpgrades;
 import dan200.computercraft.shared.ModRegistry;
@@ -56,14 +57,14 @@ public final class RecipeModHelpers {
         for (var turtleSupplier : TURTLES) {
             var turtle = turtleSupplier.get();
             for (var upgrade : TurtleUpgrades.instance().getUpgrades()) {
-                upgradeItems.add(turtle.create(-1, null, -1, null, upgrade, 0, null));
+                upgradeItems.add(turtle.create(-1, null, -1, null, UpgradeData.ofDefault(upgrade), 0, null));
             }
         }
 
         for (var pocketSupplier : POCKET_COMPUTERS) {
             var pocket = pocketSupplier.get();
             for (var upgrade : PocketUpgrades.instance().getUpgrades()) {
-                upgradeItems.add(pocket.create(-1, null, -1, upgrade));
+                upgradeItems.add(pocket.create(-1, null, -1, UpgradeData.ofDefault(upgrade)));
             }
         }
 

projects/common/src/main/java/dan200/computercraft/shared/integration/UpgradeRecipeGenerator.java

@@ -9,6 +9,7 @@ import dan200.computercraft.api.pocket.IPocketUpgrade;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleSide;
 import dan200.computercraft.api.upgrades.UpgradeBase;
+import dan200.computercraft.api.upgrades.UpgradeData;
 import dan200.computercraft.impl.PocketUpgrades;
 import dan200.computercraft.impl.TurtleUpgrades;
 import dan200.computercraft.shared.pocket.items.PocketComputerItem;
@@ -111,20 +112,22 @@ public class UpgradeRecipeGenerator<T> {
 
         if (stack.getItem() instanceof TurtleItem item) {
             // Suggest possible upgrades which can be applied to this turtle
-            var left = item.getUpgrade(stack, TurtleSide.LEFT);
-            var right = item.getUpgrade(stack, TurtleSide.RIGHT);
+            var left = item.getUpgradeWithData(stack, TurtleSide.LEFT);
+            var right = item.getUpgradeWithData(stack, TurtleSide.RIGHT);
             if (left != null && right != null) return Collections.emptyList();
 
             List<T> recipes = new ArrayList<>();
             var ingredient = Ingredient.of(stack);
             for (var upgrade : turtleUpgrades) {
+                if (upgrade.turtle == null) throw new NullPointerException();
+
                 // The turtle is facing towards us, so upgrades on the left are actually crafted on the right.
                 if (left == null) {
-                    recipes.add(turtle(ingredient, upgrade.ingredient, turtleWith(stack, upgrade.turtle, right)));
+                    recipes.add(turtle(ingredient, upgrade.ingredient, turtleWith(stack, UpgradeData.ofDefault(upgrade.turtle), right)));
                 }
 
                 if (right == null) {
-                    recipes.add(turtle(upgrade.ingredient, ingredient, turtleWith(stack, left, upgrade.turtle)));
+                    recipes.add(turtle(upgrade.ingredient, ingredient, turtleWith(stack, left, UpgradeData.ofDefault(upgrade.turtle))));
                 }
             }
 
@@ -137,7 +140,8 @@ public class UpgradeRecipeGenerator<T> {
             List<T> recipes = new ArrayList<>();
             var ingredient = Ingredient.of(stack);
             for (var upgrade : pocketUpgrades) {
-                recipes.add(pocket(upgrade.ingredient, ingredient, pocketWith(stack, upgrade.pocket)));
+                if (upgrade.pocket == null) throw new NullPointerException();
+                recipes.add(pocket(upgrade.ingredient, ingredient, pocketWith(stack, UpgradeData.ofDefault(upgrade.pocket))));
             }
 
             return Collections.unmodifiableList(recipes);
@@ -180,21 +184,21 @@ public class UpgradeRecipeGenerator<T> {
         if (stack.getItem() instanceof TurtleItem item) {
             List<T> recipes = new ArrayList<>(0);
 
-            var left = item.getUpgrade(stack, TurtleSide.LEFT);
-            var right = item.getUpgrade(stack, TurtleSide.RIGHT);
+            var left = item.getUpgradeWithData(stack, TurtleSide.LEFT);
+            var right = item.getUpgradeWithData(stack, TurtleSide.RIGHT);
 
             // The turtle is facing towards us, so upgrades on the left are actually crafted on the right.
             if (left != null) {
                 recipes.add(turtle(
                     Ingredient.of(turtleWith(stack, null, right)),
-                    Ingredient.of(left.getCraftingItem()),
+                    Ingredient.of(left.getUpgradeItem()),
                     stack
                 ));
             }
 
             if (right != null) {
                 recipes.add(turtle(
-                    Ingredient.of(right.getCraftingItem()),
+                    Ingredient.of(right.getUpgradeItem()),
                     Ingredient.of(turtleWith(stack, left, null)),
                     stack
                 ));
@@ -204,9 +208,9 @@ public class UpgradeRecipeGenerator<T> {
         } else if (stack.getItem() instanceof PocketComputerItem) {
             List<T> recipes = new ArrayList<>(0);
 
-            var back = PocketComputerItem.getUpgrade(stack);
+            var back = PocketComputerItem.getUpgradeWithData(stack);
             if (back != null) {
-                recipes.add(pocket(Ingredient.of(back.getCraftingItem()), Ingredient.of(pocketWith(stack, null)), stack));
+                recipes.add(pocket(Ingredient.of(back.getUpgradeItem()), Ingredient.of(pocketWith(stack, null)), stack));
             }
 
             return Collections.unmodifiableList(recipes);
@@ -215,7 +219,7 @@ public class UpgradeRecipeGenerator<T> {
         }
     }
 
-    private static ItemStack turtleWith(ItemStack stack, @Nullable ITurtleUpgrade left, @Nullable ITurtleUpgrade right) {
+    private static ItemStack turtleWith(ItemStack stack, @Nullable UpgradeData<ITurtleUpgrade> left, @Nullable UpgradeData<ITurtleUpgrade> right) {
         var item = (TurtleItem) stack.getItem();
         return item.create(
             item.getComputerID(stack), item.getLabel(stack), item.getColour(stack),
@@ -223,7 +227,7 @@ public class UpgradeRecipeGenerator<T> {
         );
     }
 
-    private static ItemStack pocketWith(ItemStack stack, @Nullable IPocketUpgrade back) {
+    private static ItemStack pocketWith(ItemStack stack, @Nullable UpgradeData<IPocketUpgrade> back) {
         var item = (PocketComputerItem) stack.getItem();
         return item.create(
             item.getComputerID(stack), item.getLabel(stack), item.getColour(stack), back
@@ -272,7 +276,7 @@ public class UpgradeRecipeGenerator<T> {
                     recipes.add(turtle(
                         ingredient, // Right upgrade, recipe on left
                         Ingredient.of(turtleItem.create(-1, null, -1, null, null, 0, null)),
-                        turtleItem.create(-1, null, -1, null, turtle, 0, null)
+                        turtleItem.create(-1, null, -1, null, UpgradeData.ofDefault(turtle), 0, null)
                     ));
                 }
             }
@@ -283,7 +287,7 @@ public class UpgradeRecipeGenerator<T> {
                     recipes.add(pocket(
                         ingredient,
                         Ingredient.of(pocketItem.create(-1, null, -1, null)),
-                        pocketItem.create(-1, null, -1, pocket)
+                        pocketItem.create(-1, null, -1, UpgradeData.ofDefault(pocket))
                     ));
                 }
             }

projects/common/src/main/java/dan200/computercraft/shared/peripheral/generic/GenericPeripheral.java

@@ -12,19 +12,23 @@ import dan200.computercraft.api.peripheral.IComputerAccess;
 import dan200.computercraft.api.peripheral.IDynamicPeripheral;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.shared.platform.RegistryWrappers;
+import net.minecraft.core.Direction;
 import net.minecraft.world.level.block.entity.BlockEntity;
 
 import javax.annotation.Nullable;
 import java.util.List;
 import java.util.Set;
 
-class GenericPeripheral implements IDynamicPeripheral {
+public final class GenericPeripheral implements IDynamicPeripheral {
+    private final BlockEntity tile;
+    private final Direction side;
+
     private final String type;
     private final Set<String> additionalTypes;
-    private final BlockEntity tile;
     private final List<SaturatedMethod> methods;
 
-    GenericPeripheral(BlockEntity tile, @Nullable String name, Set<String> additionalTypes, List<SaturatedMethod> methods) {
+    GenericPeripheral(BlockEntity tile, Direction side, @Nullable String name, Set<String> additionalTypes, List<SaturatedMethod> methods) {
+        this.side = side;
         var type = RegistryWrappers.BLOCK_ENTITY_TYPES.getKey(tile.getType());
         this.tile = tile;
         this.type = name != null ? name : type.toString();
@@ -32,6 +36,10 @@ class GenericPeripheral implements IDynamicPeripheral {
         this.methods = methods;
     }
 
+    public Direction side() {
+        return side;
+    }
+
     @Override
     public String[] getMethodNames() {
         var names = new String[methods.size()];
@@ -54,7 +62,6 @@ class GenericPeripheral implements IDynamicPeripheral {
         return additionalTypes;
     }
 
-    @Nullable
     @Override
     public Object getTarget() {
         return tile;

projects/common/src/main/java/dan200/computercraft/shared/peripheral/generic/GenericPeripheralBuilder.java

@@ -0,0 +1,63 @@
+// SPDX-FileCopyrightText: 2020 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.shared.peripheral.generic;
+
+import dan200.computercraft.api.peripheral.IPeripheral;
+import dan200.computercraft.api.peripheral.PeripheralType;
+import dan200.computercraft.core.methods.MethodSupplier;
+import dan200.computercraft.core.methods.NamedMethod;
+import dan200.computercraft.core.methods.PeripheralMethod;
+import dan200.computercraft.shared.computer.core.ServerContext;
+import net.minecraft.core.Direction;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.world.level.block.entity.BlockEntity;
+
+import javax.annotation.Nullable;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * A builder for a {@link GenericPeripheral}.
+ * <p>
+ * This handles building a list of {@linkplain SaturatedMethod methods} and computing the appropriate
+ * {@link PeripheralType} from the {@linkplain NamedMethod#genericType() methods' peripheral types}.
+ * <p>
+ * See the platform-specific peripheral providers for the usage of this.
+ */
+final class GenericPeripheralBuilder {
+    private final MethodSupplier<PeripheralMethod> peripheralMethods;
+
+    private @Nullable String name;
+    private final Set<String> additionalTypes = new HashSet<>(0);
+    private final ArrayList<SaturatedMethod> methods = new ArrayList<>();
+
+    GenericPeripheralBuilder(MinecraftServer server) {
+        peripheralMethods = ServerContext.get(server).peripheralMethods();
+    }
+
+    @Nullable
+    IPeripheral toPeripheral(BlockEntity blockEntity, Direction side) {
+        if (methods.isEmpty()) return null;
+
+        methods.trimToSize();
+        return new GenericPeripheral(blockEntity, side, name, additionalTypes, methods);
+    }
+
+    boolean addMethods(Object target) {
+        return peripheralMethods.forEachSelfMethod(target, (name, method, info) -> {
+            methods.add(new SaturatedMethod(target, name, method));
+
+            // If we have a peripheral type, use it. Always pick the smallest one, so it's consistent (assuming mods
+            // don't change).
+            var type = info == null ? null : info.genericType();
+            if (type != null && type.getPrimaryType() != null) {
+                var primaryType = type.getPrimaryType();
+                if (this.name == null || this.name.compareTo(primaryType) > 0) this.name = primaryType;
+            }
+            if (type != null) additionalTypes.addAll(type.getAdditionalTypes());
+        });
+    }
+}

projects/common/src/main/java/dan200/computercraft/shared/peripheral/generic/SaturatedMethod.java

@@ -9,18 +9,20 @@ import dan200.computercraft.api.lua.ILuaContext;
 import dan200.computercraft.api.lua.LuaException;
 import dan200.computercraft.api.lua.MethodResult;
 import dan200.computercraft.api.peripheral.IComputerAccess;
-import dan200.computercraft.core.asm.NamedMethod;
-import dan200.computercraft.core.asm.PeripheralMethod;
+import dan200.computercraft.core.methods.PeripheralMethod;
 
+/**
+ * A {@link PeripheralMethod} along with the method's target.
+ */
 final class SaturatedMethod {
     private final Object target;
     private final String name;
     private final PeripheralMethod method;
 
-    SaturatedMethod(Object target, NamedMethod<PeripheralMethod> method) {
+    SaturatedMethod(Object target, String name, PeripheralMethod method) {
         this.target = target;
-        name = method.getName();
-        this.method = method.getMethod();
+        this.name = name;
+        this.method = method;
     }
 
     MethodResult apply(ILuaContext context, IComputerAccess computer, IArguments args) throws LuaException {

projects/common/src/main/java/dan200/computercraft/shared/peripheral/modem/wired/WiredModemPeripheral.java

@@ -16,10 +16,12 @@ import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.peripheral.NotAttachedException;
 import dan200.computercraft.api.peripheral.WorkMonitor;
 import dan200.computercraft.core.apis.PeripheralAPI;
-import dan200.computercraft.core.asm.PeripheralMethod;
+import dan200.computercraft.core.methods.PeripheralMethod;
 import dan200.computercraft.core.util.LuaUtil;
+import dan200.computercraft.shared.computer.core.ServerContext;
 import dan200.computercraft.shared.peripheral.modem.ModemPeripheral;
 import dan200.computercraft.shared.peripheral.modem.ModemState;
+import net.minecraft.server.level.ServerLevel;
 import net.minecraft.world.level.Level;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -284,7 +286,8 @@ public abstract class WiredModemPeripheral extends ModemPeripheral implements Wi
 
     private void attachPeripheralImpl(IComputerAccess computer, ConcurrentMap<String, RemotePeripheralWrapper> peripherals, String periphName, IPeripheral peripheral) {
         if (!peripherals.containsKey(periphName) && !periphName.equals(getLocalPeripheral().getConnectedName())) {
-            var wrapper = new RemotePeripheralWrapper(modem, peripheral, computer, periphName);
+            var methods = ServerContext.get(((ServerLevel) getLevel()).getServer()).peripheralMethods().getSelfMethods(peripheral);
+            var wrapper = new RemotePeripheralWrapper(modem, peripheral, computer, periphName, methods);
             peripherals.put(periphName, wrapper);
             wrapper.attach();
         }
@@ -314,7 +317,7 @@ public abstract class WiredModemPeripheral extends ModemPeripheral implements Wi
         private volatile boolean attached;
         private final Set<String> mounts = new HashSet<>();
 
-        RemotePeripheralWrapper(WiredModemElement element, IPeripheral peripheral, IComputerAccess computer, String name) {
+        RemotePeripheralWrapper(WiredModemElement element, IPeripheral peripheral, IComputerAccess computer, String name, Map<String, PeripheralMethod> methods) {
             this.element = element;
             this.peripheral = peripheral;
             this.computer = computer;
@@ -322,7 +325,7 @@ public abstract class WiredModemPeripheral extends ModemPeripheral implements Wi
 
             type = Objects.requireNonNull(peripheral.getType(), "Peripheral type cannot be null");
             additionalTypes = peripheral.getAdditionalTypes();
-            methodMap = PeripheralAPI.getMethods(peripheral);
+            methodMap = methods;
         }
 
         public void attach() {

projects/common/src/main/java/dan200/computercraft/shared/peripheral/speaker/SpeakerPeripheral.java

@@ -190,7 +190,7 @@ public abstract class SpeakerPeripheral implements IPeripheral {
      * The speaker supports [all of Minecraft's noteblock instruments](https://minecraft.fandom.com/wiki/Note_Block#Instruments).
      * These are:
      * <p>
-     * {@code "harp"}, {@code "basedrum"}, {@code "snare"}, {@code "hat"}, {@code "bass"}, @code "flute"},
+     * {@code "harp"}, {@code "basedrum"}, {@code "snare"}, {@code "hat"}, {@code "bass"}, {@code "flute"},
      * {@code "bell"}, {@code "guitar"}, {@code "chime"}, {@code "xylophone"}, {@code "iron_xylophone"},
      * {@code "cow_bell"}, {@code "didgeridoo"}, {@code "bit"}, {@code "banjo"} and {@code "pling"}.
      *

projects/common/src/main/java/dan200/computercraft/shared/platform/FakePlayerConstants.java

@@ -0,0 +1,31 @@
+// SPDX-FileCopyrightText: 2023 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.shared.platform;
+
+import com.mojang.authlib.GameProfile;
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.Direction;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.world.item.ItemStack;
+
+/**
+ * Shared constants for {@linkplain PlatformHelper#createFakePlayer(ServerLevel, GameProfile) fake player}
+ * implementations.
+ *
+ * @see net.minecraft.server.level.ServerPlayer
+ * @see net.minecraft.world.entity.player.Player
+ */
+final class FakePlayerConstants {
+    private FakePlayerConstants() {
+    }
+
+    /**
+     * The maximum distance this player can reach.
+     * <p>
+     * This is used in the override of {@link net.minecraft.world.entity.player.Player#mayUseItemAt(BlockPos, Direction, ItemStack)},
+     * to prevent the fake player reaching more than 2 blocks away.
+     */
+    static final double MAX_REACH = 2;
+}

projects/common/src/main/java/dan200/computercraft/shared/platform/PlatformHelper.java

@@ -69,6 +69,13 @@ public interface PlatformHelper extends dan200.computercraft.impl.PlatformHelper
         return (PlatformHelper) dan200.computercraft.impl.PlatformHelper.get();
     }
 
+    /**
+     * Check if we're running in a development environment.
+     *
+     * @return If we're running in a development environment.
+     */
+    boolean isDevelopmentEnvironment();
+
     /**
      * Create a new config builder.
      *

projects/common/src/main/java/dan200/computercraft/shared/platform/RegistryWrappers.java

@@ -5,6 +5,7 @@
 package dan200.computercraft.shared.platform;
 
 import net.minecraft.commands.synchronization.ArgumentTypeInfo;
+import net.minecraft.core.IdMap;
 import net.minecraft.core.Registry;
 import net.minecraft.core.registries.Registries;
 import net.minecraft.network.FriendlyByteBuf;
@@ -36,9 +37,7 @@ public final class RegistryWrappers {
     public static final RegistryWrapper<RecipeSerializer<?>> RECIPE_SERIALIZERS = PlatformHelper.get().wrap(Registries.RECIPE_SERIALIZER);
     public static final RegistryWrapper<MenuType<?>> MENU = PlatformHelper.get().wrap(Registries.MENU);
 
-    public interface RegistryWrapper<T> extends Iterable<T> {
-        int getId(T object);
-
+    public interface RegistryWrapper<T> extends IdMap<T> {
         ResourceLocation getKey(T object);
 
         T get(ResourceLocation location);
@@ -46,8 +45,6 @@ public final class RegistryWrappers {
         @Nullable
         T tryGet(ResourceLocation location);
 
-        T get(int id);
-
         default Stream<T> stream() {
             return StreamSupport.stream(spliterator(), false);
         }
@@ -56,15 +53,6 @@ public final class RegistryWrappers {
     private RegistryWrappers() {
     }
 
-    public static <K> void writeId(FriendlyByteBuf buf, RegistryWrapper<K> registry, K object) {
-        buf.writeVarInt(registry.getId(object));
-    }
-
-    public static <K> K readId(FriendlyByteBuf buf, RegistryWrapper<K> registry) {
-        var id = buf.readVarInt();
-        return registry.get(id);
-    }
-
     public static <K> void writeKey(FriendlyByteBuf buf, RegistryWrapper<K> registry, K object) {
         buf.writeResourceLocation(registry.getKey(object));
     }

projects/common/src/main/java/dan200/computercraft/shared/pocket/apis/PocketAPI.java

@@ -7,6 +7,7 @@ package dan200.computercraft.shared.pocket.apis;
 import dan200.computercraft.api.lua.ILuaAPI;
 import dan200.computercraft.api.lua.LuaFunction;
 import dan200.computercraft.api.pocket.IPocketUpgrade;
+import dan200.computercraft.api.upgrades.UpgradeData;
 import dan200.computercraft.impl.PocketUpgrades;
 import dan200.computercraft.shared.pocket.core.PocketServerComputer;
 import net.minecraft.core.NonNullList;
@@ -14,6 +15,7 @@ import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.item.ItemStack;
 
 import javax.annotation.Nullable;
+import java.util.Objects;
 
 /**
  * Control the current pocket computer, adding or removing upgrades.
@@ -68,7 +70,7 @@ public class PocketAPI implements ILuaAPI {
         if (newUpgrade == null) return new Object[]{ false, "Cannot find a valid upgrade" };
 
         // Remove the current upgrade
-        if (previousUpgrade != null) storeItem(player, previousUpgrade.getCraftingItem().copy());
+        if (previousUpgrade != null) storeItem(player, previousUpgrade.getUpgradeItem());
 
         // Set the new upgrade
         computer.setUpgrade(newUpgrade);
@@ -93,7 +95,7 @@ public class PocketAPI implements ILuaAPI {
 
         computer.setUpgrade(null);
 
-        storeItem(player, previousUpgrade.getCraftingItem().copy());
+        storeItem(player, previousUpgrade.getUpgradeItem());
 
         return new Object[]{ true };
     }
@@ -105,13 +107,13 @@ public class PocketAPI implements ILuaAPI {
         }
     }
 
-    private static @Nullable IPocketUpgrade findUpgrade(NonNullList<ItemStack> inv, int start, @Nullable IPocketUpgrade previous) {
+    private static @Nullable UpgradeData<IPocketUpgrade> findUpgrade(NonNullList<ItemStack> inv, int start, @Nullable UpgradeData<IPocketUpgrade> previous) {
         for (var i = 0; i < inv.size(); i++) {
             var invStack = inv.get((i + start) % inv.size());
             if (!invStack.isEmpty()) {
                 var newUpgrade = PocketUpgrades.instance().get(invStack);
 
-                if (newUpgrade != null && newUpgrade != previous) {
+                if (newUpgrade != null && !Objects.equals(newUpgrade, previous)) {
                     // Consume an item from this stack and exit the loop
                     invStack = invStack.copy();
                     invStack.shrink(1);

projects/common/src/main/java/dan200/computercraft/shared/pocket/core/PocketServerComputer.java

@@ -7,6 +7,7 @@ package dan200.computercraft.shared.pocket.core;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.pocket.IPocketAccess;
 import dan200.computercraft.api.pocket.IPocketUpgrade;
+import dan200.computercraft.api.upgrades.UpgradeData;
 import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.shared.common.IColouredItem;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
@@ -104,12 +105,13 @@ public class PocketServerComputer extends ServerComputer implements IPocketAcces
     }
 
     @Override
+    @Deprecated(forRemoval = true)
     public Map<ResourceLocation, IPeripheral> getUpgrades() {
         return upgrade == null ? Collections.emptyMap() : Collections.singletonMap(upgrade.getUpgradeID(), getPeripheral(ComputerSide.BACK));
     }
 
-    public @Nullable IPocketUpgrade getUpgrade() {
-        return upgrade;
+    public @Nullable UpgradeData<IPocketUpgrade> getUpgrade() {
+        return upgrade == null ? null : UpgradeData.of(upgrade, getUpgradeNBTData());
     }
 
     /**
@@ -119,13 +121,11 @@ public class PocketServerComputer extends ServerComputer implements IPocketAcces
      *
      * @param upgrade The new upgrade to set it to, may be {@code null}.
      */
-    public void setUpgrade(@Nullable IPocketUpgrade upgrade) {
-        if (this.upgrade == upgrade) return;
-
+    public void setUpgrade(@Nullable UpgradeData<IPocketUpgrade> upgrade) {
         synchronized (this) {
             PocketComputerItem.setUpgrade(stack, upgrade);
             updateUpgradeNBTData();
-            this.upgrade = upgrade;
+            this.upgrade = upgrade == null ? null : upgrade.upgrade();
             invalidatePeripheral();
         }
     }

projects/common/src/main/java/dan200/computercraft/shared/pocket/items/PocketComputerItem.java

@@ -10,6 +10,7 @@ import dan200.computercraft.api.ComputerCraftAPI;
 import dan200.computercraft.api.filesystem.Mount;
 import dan200.computercraft.api.media.IMedia;
 import dan200.computercraft.api.pocket.IPocketUpgrade;
+import dan200.computercraft.api.upgrades.UpgradeData;
 import dan200.computercraft.core.computer.ComputerSide;
 import dan200.computercraft.impl.PocketUpgrades;
 import dan200.computercraft.shared.ModRegistry;
@@ -23,6 +24,7 @@ import dan200.computercraft.shared.pocket.apis.PocketAPI;
 import dan200.computercraft.shared.pocket.core.PocketServerComputer;
 import dan200.computercraft.shared.pocket.inventory.PocketComputerMenuProvider;
 import dan200.computercraft.shared.util.IDAssigner;
+import dan200.computercraft.shared.util.NBTUtil;
 import net.minecraft.ChatFormatting;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.network.chat.Component;
@@ -58,7 +60,7 @@ public class PocketComputerItem extends Item implements IComputerItem, IMedia, I
         this.family = family;
     }
 
-    public static ItemStack create(int id, @Nullable String label, int colour, ComputerFamily family, @Nullable IPocketUpgrade upgrade) {
+    public static ItemStack create(int id, @Nullable String label, int colour, ComputerFamily family, @Nullable UpgradeData<IPocketUpgrade> upgrade) {
         return switch (family) {
             case NORMAL -> ModRegistry.Items.POCKET_COMPUTER_NORMAL.get().create(id, label, colour, upgrade);
             case ADVANCED -> ModRegistry.Items.POCKET_COMPUTER_ADVANCED.get().create(id, label, colour, upgrade);
@@ -66,11 +68,14 @@ public class PocketComputerItem extends Item implements IComputerItem, IMedia, I
         };
     }
 
-    public ItemStack create(int id, @Nullable String label, int colour, @Nullable IPocketUpgrade upgrade) {
+    public ItemStack create(int id, @Nullable String label, int colour, @Nullable UpgradeData<IPocketUpgrade> upgrade) {
         var result = new ItemStack(this);
         if (id >= 0) result.getOrCreateTag().putInt(NBT_ID, id);
         if (label != null) result.setHoverName(Component.literal(label));
-        if (upgrade != null) result.getOrCreateTag().putString(NBT_UPGRADE, upgrade.getUpgradeID().toString());
+        if (upgrade != null) {
+            result.getOrCreateTag().putString(NBT_UPGRADE, upgrade.upgrade().getUpgradeID().toString());
+            if (!upgrade.data().isEmpty()) result.getOrCreateTag().put(NBT_UPGRADE_INFO, upgrade.data().copy());
+        }
         if (colour != -1) result.getOrCreateTag().putInt(NBT_COLOUR, colour);
         return result;
     }
@@ -208,7 +213,9 @@ public class PocketComputerItem extends Item implements IComputerItem, IMedia, I
             setInstanceID(stack, computer.register());
             setSessionID(stack, registry.getSessionID());
 
-            computer.updateValues(entity, stack, getUpgrade(stack));
+            var upgrade = getUpgrade(stack);
+
+            computer.updateValues(entity, stack, upgrade);
             computer.addAPI(new PocketAPI(computer));
 
             // Only turn on when initially creating the computer, rather than each tick.
@@ -245,7 +252,7 @@ public class PocketComputerItem extends Item implements IComputerItem, IMedia, I
     public ItemStack withFamily(ItemStack stack, ComputerFamily family) {
         return create(
             getComputerID(stack), getLabel(stack), getColour(stack),
-            family, getUpgrade(stack)
+            family, getUpgradeWithData(stack)
         );
     }
 
@@ -295,20 +302,27 @@ public class PocketComputerItem extends Item implements IComputerItem, IMedia, I
 
     public static @Nullable IPocketUpgrade getUpgrade(ItemStack stack) {
         var compound = stack.getTag();
-        return compound != null && compound.contains(NBT_UPGRADE)
-            ? PocketUpgrades.instance().get(compound.getString(NBT_UPGRADE)) : null;
+        if (compound == null || !compound.contains(NBT_UPGRADE)) return null;
+        return PocketUpgrades.instance().get(compound.getString(NBT_UPGRADE));
     }
 
-    public static void setUpgrade(ItemStack stack, @Nullable IPocketUpgrade upgrade) {
+    public static @Nullable UpgradeData<IPocketUpgrade> getUpgradeWithData(ItemStack stack) {
+        var compound = stack.getTag();
+        if (compound == null || !compound.contains(NBT_UPGRADE)) return null;
+        var upgrade = PocketUpgrades.instance().get(compound.getString(NBT_UPGRADE));
+        return upgrade == null ? null : UpgradeData.of(upgrade, NBTUtil.getCompoundOrEmpty(compound, NBT_UPGRADE_INFO));
+    }
+
+    public static void setUpgrade(ItemStack stack, @Nullable UpgradeData<IPocketUpgrade> upgrade) {
         var compound = stack.getOrCreateTag();
 
         if (upgrade == null) {
             compound.remove(NBT_UPGRADE);
+            compound.remove(NBT_UPGRADE_INFO);
         } else {
-            compound.putString(NBT_UPGRADE, upgrade.getUpgradeID().toString());
+            compound.putString(NBT_UPGRADE, upgrade.upgrade().getUpgradeID().toString());
+            compound.put(NBT_UPGRADE_INFO, upgrade.data().copy());
         }
-
-        compound.remove(NBT_UPGRADE_INFO);
     }
 
     public static CompoundTag getUpgradeInfo(ItemStack stack) {

projects/common/src/main/java/dan200/computercraft/shared/pocket/recipes/PocketComputerUpgradeRecipe.java

@@ -5,6 +5,7 @@
 package dan200.computercraft.shared.pocket.recipes;
 
 import dan200.computercraft.api.pocket.IPocketUpgrade;
+import dan200.computercraft.api.upgrades.UpgradeData;
 import dan200.computercraft.impl.PocketUpgrades;
 import dan200.computercraft.shared.ModRegistry;
 import dan200.computercraft.shared.pocket.items.PocketComputerItem;
@@ -62,7 +63,7 @@ public final class PocketComputerUpgradeRecipe extends CustomRecipe {
         if (PocketComputerItem.getUpgrade(computer) != null) return ItemStack.EMPTY;
 
         // Check for upgrades around the item
-        IPocketUpgrade upgrade = null;
+        UpgradeData<IPocketUpgrade> upgrade = null;
         for (var y = 0; y < inventory.getHeight(); y++) {
             for (var x = 0; x < inventory.getWidth(); x++) {
                 var item = inventory.getItem(x + y * inventory.getWidth());

projects/common/src/main/java/dan200/computercraft/shared/turtle/apis/TurtleAPI.java

@@ -555,7 +555,7 @@ public class TurtleAPI implements ILuaAPI {
      * @cc.usage Refuel a turtle from the currently selected slot.
      * <pre>{@code
      * local level = turtle.getFuelLevel()
-     * if new_level == "unlimited" then error("Turtle does not need fuel", 0) end
+     * if level == "unlimited" then error("Turtle does not need fuel", 0) end
      *
      * local ok, err = turtle.refuel()
      * if ok then

projects/common/src/main/java/dan200/computercraft/shared/turtle/blocks/TurtleBlock.java

@@ -5,7 +5,9 @@
 package dan200.computercraft.shared.turtle.blocks;
 
 import dan200.computercraft.annotations.ForgeOverride;
+import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleSide;
+import dan200.computercraft.api.upgrades.UpgradeData;
 import dan200.computercraft.shared.computer.blocks.AbstractComputerBlock;
 import dan200.computercraft.shared.computer.blocks.AbstractComputerBlockEntity;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
@@ -128,7 +130,7 @@ public class TurtleBlock extends AbstractComputerBlock<TurtleBlockEntity> implem
             if (stack.getItem() instanceof TurtleItem item) {
                 // Set Upgrades
                 for (var side : TurtleSide.values()) {
-                    turtle.getAccess().setUpgrade(side, item.getUpgrade(stack, side));
+                    turtle.getAccess().setUpgradeWithData(side, item.getUpgradeWithData(stack, side));
                 }
 
                 turtle.getAccess().setFuelLevel(item.getFuelLevel(stack));
@@ -161,11 +163,16 @@ public class TurtleBlock extends AbstractComputerBlock<TurtleBlockEntity> implem
         var access = turtle.getAccess();
         return TurtleItem.create(
             turtle.getComputerID(), turtle.getLabel(), access.getColour(), turtle.getFamily(),
-            access.getUpgrade(TurtleSide.LEFT), access.getUpgrade(TurtleSide.RIGHT),
+            withPersistedData(access.getUpgradeWithData(TurtleSide.LEFT)),
+            withPersistedData(access.getUpgradeWithData(TurtleSide.RIGHT)),
             access.getFuelLevel(), turtle.getOverlay()
         );
     }
 
+    private static @Nullable UpgradeData<ITurtleUpgrade> withPersistedData(@Nullable UpgradeData<ITurtleUpgrade> upgrade) {
+        return upgrade == null ? null : UpgradeData.of(upgrade.upgrade(), upgrade.upgrade().getPersistedData(upgrade.data()));
+    }
+
     @Override
     @Nullable
     public <U extends BlockEntity> BlockEntityTicker<U> getTicker(Level level, BlockState state, BlockEntityType<U> type) {

projects/common/src/main/java/dan200/computercraft/shared/turtle/core/TurtleBrain.java

@@ -13,8 +13,8 @@ import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleAnimation;
 import dan200.computercraft.api.turtle.TurtleCommand;
 import dan200.computercraft.api.turtle.TurtleSide;
+import dan200.computercraft.api.upgrades.UpgradeData;
 import dan200.computercraft.core.computer.ComputerSide;
-import dan200.computercraft.core.util.Colour;
 import dan200.computercraft.impl.TurtleUpgrades;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.computer.core.ServerComputer;
@@ -34,7 +34,6 @@ import net.minecraft.tags.FluidTags;
 import net.minecraft.world.Container;
 import net.minecraft.world.entity.Entity;
 import net.minecraft.world.entity.MoverType;
-import net.minecraft.world.item.DyeColor;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.Level;
 import net.minecraft.world.level.material.PushReaction;
@@ -141,17 +140,16 @@ public class TurtleBrain implements TurtleAccessInternal {
         overlay = nbt.contains(NBT_OVERLAY) ? new ResourceLocation(nbt.getString(NBT_OVERLAY)) : null;
 
         // Read upgrades
-        setUpgradeDirect(TurtleSide.LEFT, nbt.contains(NBT_LEFT_UPGRADE) ? TurtleUpgrades.instance().get(nbt.getString(NBT_LEFT_UPGRADE)) : null);
-        setUpgradeDirect(TurtleSide.RIGHT, nbt.contains(NBT_RIGHT_UPGRADE) ? TurtleUpgrades.instance().get(nbt.getString(NBT_RIGHT_UPGRADE)) : null);
+        setUpgradeDirect(TurtleSide.LEFT, readUpgrade(nbt, NBT_LEFT_UPGRADE, NBT_LEFT_UPGRADE_DATA));
+        setUpgradeDirect(TurtleSide.RIGHT, readUpgrade(nbt, NBT_RIGHT_UPGRADE, NBT_RIGHT_UPGRADE_DATA));
+    }
 
-        // NBT
-        upgradeNBTData.clear();
-        if (nbt.contains(NBT_LEFT_UPGRADE_DATA)) {
-            upgradeNBTData.put(TurtleSide.LEFT, nbt.getCompound(NBT_LEFT_UPGRADE_DATA).copy());
-        }
-        if (nbt.contains(NBT_RIGHT_UPGRADE_DATA)) {
-            upgradeNBTData.put(TurtleSide.RIGHT, nbt.getCompound(NBT_RIGHT_UPGRADE_DATA).copy());
-        }
+    private @Nullable UpgradeData<ITurtleUpgrade> readUpgrade(CompoundTag tag, String upgradeKey, String dataKey) {
+        if (!tag.contains(upgradeKey)) return null;
+        var upgrade = TurtleUpgrades.instance().get(tag.getString(upgradeKey));
+        if (upgrade == null) return null;
+
+        return UpgradeData.of(upgrade, tag.getCompound(dataKey));
     }
 
     private void writeCommon(CompoundTag nbt) {
@@ -463,23 +461,6 @@ public class TurtleBrain implements TurtleAccessInternal {
         }
     }
 
-    public @Nullable DyeColor getDyeColour() {
-        if (colourHex == -1) return null;
-        var colour = Colour.fromHex(colourHex);
-        return colour == null ? null : DyeColor.byId(15 - colour.ordinal());
-    }
-
-    public void setDyeColour(@Nullable DyeColor dyeColour) {
-        var newColour = -1;
-        if (dyeColour != null) {
-            newColour = Colour.values()[15 - dyeColour.getId()].getHex();
-        }
-        if (colourHex != newColour) {
-            colourHex = newColour;
-            BlockEntityHelpers.updateBlock(owner);
-        }
-    }
-
     @Override
     public void setColour(int colour) {
         if (colour >= 0 && colour <= 0xFFFFFF) {
@@ -514,7 +495,7 @@ public class TurtleBrain implements TurtleAccessInternal {
     }
 
     @Override
-    public void setUpgrade(TurtleSide side, @Nullable ITurtleUpgrade upgrade) {
+    public void setUpgradeWithData(TurtleSide side, @Nullable UpgradeData<ITurtleUpgrade> upgrade) {
         if (!setUpgradeDirect(side, upgrade) || owner.getLevel() == null) return;
 
         // This is a separate function to avoid updating the block when reading the NBT. We don't need to do this as
@@ -527,19 +508,18 @@ public class TurtleBrain implements TurtleAccessInternal {
         owner.updateInputsImmediately();
     }
 
-    private boolean setUpgradeDirect(TurtleSide side, @Nullable ITurtleUpgrade upgrade) {
+    private boolean setUpgradeDirect(TurtleSide side, @Nullable UpgradeData<ITurtleUpgrade> upgrade) {
         // Remove old upgrade
-        if (upgrades.containsKey(side)) {
-            if (upgrades.get(side) == upgrade) return false;
-            upgrades.remove(side);
-        } else {
-            if (upgrade == null) return false;
-        }
-
-        upgradeNBTData.remove(side);
+        var oldUpgrade = upgrades.remove(side);
+        if (oldUpgrade == null && upgrade == null) return false;
 
         // Set new upgrade
-        if (upgrade != null) upgrades.put(side, upgrade);
+        if (upgrade == null) {
+            upgradeNBTData.remove(side);
+        } else {
+            upgrades.put(side, upgrade.upgrade());
+            upgradeNBTData.put(side, upgrade.data().copy());
+        }
 
         // Notify clients and create peripherals
         if (owner.getLevel() != null && !owner.getLevel().isClientSide) {
@@ -593,7 +573,7 @@ public class TurtleBrain implements TurtleAccessInternal {
 
     public float getToolRenderAngle(TurtleSide side, float f) {
         return (side == TurtleSide.LEFT && animation == TurtleAnimation.SWING_LEFT_TOOL) ||
-            (side == TurtleSide.RIGHT && animation == TurtleAnimation.SWING_RIGHT_TOOL)
+               (side == TurtleSide.RIGHT && animation == TurtleAnimation.SWING_RIGHT_TOOL)
             ? 45.0f * (float) Math.sin(getAnimationFraction(f) * Math.PI)
             : 0.0f;
     }

projects/common/src/main/java/dan200/computercraft/shared/turtle/core/TurtleEquipCommand.java

@@ -5,6 +5,7 @@
 package dan200.computercraft.shared.turtle.core;
 
 import dan200.computercraft.api.turtle.*;
+import dan200.computercraft.api.upgrades.UpgradeData;
 import dan200.computercraft.impl.TurtleUpgrades;
 import dan200.computercraft.shared.turtle.TurtleUtil;
 
@@ -18,10 +19,10 @@ public class TurtleEquipCommand implements TurtleCommand {
     @Override
     public TurtleCommandResult execute(ITurtleAccess turtle) {
         // Determine the upgrade to replace
-        var oldUpgrade = turtle.getUpgrade(side);
+        var oldUpgrade = turtle.getUpgradeWithData(side);
 
         // Determine the upgrade to equipLeft
-        ITurtleUpgrade newUpgrade;
+        UpgradeData<ITurtleUpgrade> newUpgrade;
         var selectedStack = turtle.getInventory().getItem(turtle.getSelectedSlot());
         if (!selectedStack.isEmpty()) {
             newUpgrade = TurtleUpgrades.instance().get(selectedStack);
@@ -32,8 +33,8 @@ public class TurtleEquipCommand implements TurtleCommand {
 
         // Do the swapping:
         if (newUpgrade != null) turtle.getInventory().removeItem(turtle.getSelectedSlot(), 1);
-        if (oldUpgrade != null) TurtleUtil.storeItemOrDrop(turtle, oldUpgrade.getCraftingItem().copy());
-        turtle.setUpgrade(side, newUpgrade);
+        if (oldUpgrade != null) TurtleUtil.storeItemOrDrop(turtle, oldUpgrade.getUpgradeItem());
+        turtle.setUpgradeWithData(side, newUpgrade);
 
         // Animate
         if (newUpgrade != null || oldUpgrade != null) {

projects/common/src/main/java/dan200/computercraft/shared/turtle/core/TurtlePlaceCommand.java

@@ -75,18 +75,6 @@ public class TurtlePlaceCommand implements TurtleCommand {
         }
     }
 
-    public static boolean deployCopiedItem(
-        ItemStack stack, ITurtleAccess turtle, Direction direction, @Nullable Object[] extraArguments, @Nullable ErrorMessage outErrorMessage
-    ) {
-        // Create a fake player, and orient it appropriately
-        var playerPosition = turtle.getPosition().relative(direction);
-        var turtlePlayer = TurtlePlayer.getWithPosition(turtle, playerPosition, direction);
-        turtlePlayer.loadInventory(stack);
-        var result = deploy(stack, turtle, turtlePlayer, direction, extraArguments, outErrorMessage);
-        turtlePlayer.player().getInventory().clearContent();
-        return result;
-    }
-
     private static boolean deploy(
         ItemStack stack, ITurtleAccess turtle, TurtlePlayer turtlePlayer, Direction direction,
         @Nullable Object[] extraArguments, @Nullable ErrorMessage outErrorMessage
@@ -153,6 +141,22 @@ public class TurtlePlaceCommand implements TurtleCommand {
         return true;
     }
 
+    /**
+     * Calculate where a turtle would interact with a block.
+     *
+     * @param position The position of the block.
+     * @param side     The side the turtle is clicking on.
+     * @return The hit result.
+     */
+    public static BlockHitResult getHitResult(BlockPos position, Direction side) {
+        var hitX = 0.5 + side.getStepX() * 0.5;
+        var hitY = 0.5 + side.getStepY() * 0.5;
+        var hitZ = 0.5 + side.getStepZ() * 0.5;
+        if (Math.abs(hitY - 0.5) < 0.01) hitY = 0.45;
+
+        return new BlockHitResult(new Vec3(position.getX() + hitX, position.getY() + hitY, position.getZ() + hitZ), side, position, false);
+    }
+
     private static boolean deployOnBlock(
         ItemStack stack, ITurtleAccess turtle, TurtlePlayer turtlePlayer, BlockPos position, Direction side,
         @Nullable Object[] extraArguments, boolean adjacent, @Nullable ErrorMessage outErrorMessage
@@ -162,14 +166,8 @@ public class TurtlePlaceCommand implements TurtleCommand {
         var playerPosition = position.relative(side);
         turtlePlayer.setPosition(turtle, playerPosition, playerDir);
 
-        // Calculate where the turtle would hit the block
-        var hitX = 0.5f + side.getStepX() * 0.5f;
-        var hitY = 0.5f + side.getStepY() * 0.5f;
-        var hitZ = 0.5f + side.getStepZ() * 0.5f;
-        if (Math.abs(hitY - 0.5f) < 0.01f) hitY = 0.45f;
-
         // Check if there's something suitable to place onto
-        var hit = new BlockHitResult(new Vec3(position.getX() + hitX, position.getY() + hitY, position.getZ() + hitZ), side, position, false);
+        var hit = getHitResult(position, side);
         var context = new UseOnContext(turtlePlayer.player(), InteractionHand.MAIN_HAND, hit);
         if (!canDeployOnBlock(new BlockPlaceContext(context), turtle, turtlePlayer, position, side, adjacent, outErrorMessage)) {
             return false;

projects/common/src/main/java/dan200/computercraft/shared/turtle/inventory/TurtleMenu.java

@@ -4,6 +4,7 @@
 
 package dan200.computercraft.shared.turtle.inventory;
 
+import dan200.computercraft.api.turtle.TurtleSide;
 import dan200.computercraft.shared.ModRegistry;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.computer.core.ServerComputer;
@@ -29,12 +30,13 @@ public final class TurtleMenu extends AbstractComputerMenu {
     public static final int PLAYER_START_Y = 134;
     public static final int TURTLE_START_X = SIDEBAR_WIDTH + 175;
     public static final int PLAYER_START_X = SIDEBAR_WIDTH + BORDER;
+    public static final int UPGRADE_START_X = SIDEBAR_WIDTH + 254;
 
     private final ContainerData data;
 
     private TurtleMenu(
         int id, Predicate<Player> canUse, ComputerFamily family, @Nullable ServerComputer computer, @Nullable ComputerContainerData menuData,
-        Inventory playerInventory, Container inventory, ContainerData data
+        Inventory playerInventory, Container inventory, Container turtleUpgrades, ContainerData data
     ) {
         super(ModRegistry.Menus.TURTLE.get(), id, canUse, family, computer, menuData);
         this.data = data;
@@ -58,19 +60,24 @@ public final class TurtleMenu extends AbstractComputerMenu {
         for (var x = 0; x < 9; x++) {
             addSlot(new Slot(playerInventory, x, PLAYER_START_X + x * 18, PLAYER_START_Y + 3 * 18 + 5));
         }
+
+        // Turtle upgrades
+        addSlot(new UpgradeSlot(turtleUpgrades, TurtleSide.LEFT, 0, UPGRADE_START_X, PLAYER_START_Y + 1));
+        addSlot(new UpgradeSlot(turtleUpgrades, TurtleSide.RIGHT, 1, UPGRADE_START_X, PLAYER_START_Y + 1 + 18));
     }
 
     public static TurtleMenu ofBrain(int id, Inventory player, TurtleBrain turtle) {
         return new TurtleMenu(
             // Laziness in turtle.getOwner() is important here!
             id, p -> turtle.getOwner().stillValid(p), turtle.getFamily(), turtle.getOwner().createServerComputer(), null,
-            player, turtle.getInventory(), (SingleContainerData) turtle::getSelectedSlot
+            player, turtle.getInventory(), new UpgradeContainer(turtle), (SingleContainerData) turtle::getSelectedSlot
         );
     }
 
     public static TurtleMenu ofMenuData(int id, Inventory player, ComputerContainerData data) {
         return new TurtleMenu(
-            id, x -> true, data.family(), null, data, player, new SimpleContainer(TurtleBlockEntity.INVENTORY_SIZE), new SimpleContainerData(1)
+            id, x -> true, data.family(), null, data,
+            player, new SimpleContainer(TurtleBlockEntity.INVENTORY_SIZE), new SimpleContainer(2), new SimpleContainerData(1)
         );
     }
 

projects/common/src/main/java/dan200/computercraft/shared/turtle/inventory/UpgradeContainer.java

@@ -0,0 +1,117 @@
+// SPDX-FileCopyrightText: 2023 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.shared.turtle.inventory;
+
+import dan200.computercraft.api.turtle.ITurtleAccess;
+import dan200.computercraft.api.turtle.ITurtleUpgrade;
+import dan200.computercraft.api.turtle.TurtleSide;
+import dan200.computercraft.api.upgrades.UpgradeData;
+import dan200.computercraft.impl.TurtleUpgrades;
+import net.minecraft.core.NonNullList;
+import net.minecraft.world.Container;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.item.ItemStack;
+
+import javax.annotation.Nullable;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * A fake {@link Container} which exposes the {@linkplain ITurtleAccess#getUpgrade(TurtleSide) upgrades} a turtle has.
+ *
+ * @see TurtleMenu
+ * @see UpgradeSlot
+ */
+class UpgradeContainer implements Container {
+    private static final int SIZE = 2;
+
+    private final ITurtleAccess turtle;
+
+    private final List<UpgradeData<ITurtleUpgrade>> lastUpgrade = Arrays.asList(null, null);
+    private final NonNullList<ItemStack> lastStack = NonNullList.withSize(2, ItemStack.EMPTY);
+
+    UpgradeContainer(ITurtleAccess turtle) {
+        this.turtle = turtle;
+    }
+
+    private TurtleSide getSide(int slot) {
+        return switch (slot) {
+            case 0 -> TurtleSide.LEFT;
+            case 1 -> TurtleSide.RIGHT;
+            default -> throw new IllegalArgumentException("Invalid slot " + slot);
+        };
+    }
+
+    @Override
+    public ItemStack getItem(int slot) {
+        var side = getSide(slot);
+        var upgrade = turtle.getUpgradeWithData(side);
+        if (upgrade == null) return ItemStack.EMPTY;
+
+        // We don't want to return getUpgradeItem directly here, as we'd end up recreating the stack each tick. To
+        // avoid that, we maintain a simple cache.
+        if (upgrade.equals(lastUpgrade.get(slot))) return lastStack.get(slot);
+
+        return setUpgradeStack(slot, upgrade);
+    }
+
+    private ItemStack setUpgradeStack(int slot, @Nullable UpgradeData<ITurtleUpgrade> upgrade) {
+        var stack = upgrade == null ? ItemStack.EMPTY : upgrade.getUpgradeItem();
+        lastUpgrade.set(slot, UpgradeData.copyOf(upgrade));
+        lastStack.set(slot, stack);
+        return stack;
+    }
+
+    @Override
+    public void setItem(int slot, ItemStack itemStack) {
+        var upgrade = TurtleUpgrades.instance().get(itemStack);
+        turtle.setUpgradeWithData(getSide(slot), upgrade);
+        setUpgradeStack(slot, upgrade);
+    }
+
+    @Override
+    public int getContainerSize() {
+        return SIZE;
+    }
+
+    @Override
+    public int getMaxStackSize() {
+        return 1;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        for (var i = 0; i < SIZE; i++) {
+            if (!getItem(i).isEmpty()) return false;
+        }
+        return true;
+    }
+
+    @Override
+    public ItemStack removeItem(int slot, int count) {
+        return count <= 0 ? ItemStack.EMPTY : removeItemNoUpdate(slot);
+    }
+
+    @Override
+    public ItemStack removeItemNoUpdate(int slot) {
+        var current = getItem(slot);
+        setItem(slot, ItemStack.EMPTY);
+        return current;
+    }
+
+    @Override
+    public void setChanged() {
+    }
+
+    @Override
+    public boolean stillValid(Player player) {
+        return true;
+    }
+
+    @Override
+    public void clearContent() {
+        for (var i = 0; i < SIZE; i++) setItem(i, ItemStack.EMPTY);
+    }
+}

projects/common/src/main/java/dan200/computercraft/shared/turtle/inventory/UpgradeSlot.java

@@ -0,0 +1,50 @@
+// SPDX-FileCopyrightText: 2023 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.shared.turtle.inventory;
+
+import com.mojang.datafixers.util.Pair;
+import dan200.computercraft.api.ComputerCraftAPI;
+import dan200.computercraft.api.turtle.TurtleSide;
+import dan200.computercraft.impl.TurtleUpgrades;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.world.Container;
+import net.minecraft.world.inventory.InventoryMenu;
+import net.minecraft.world.inventory.Slot;
+import net.minecraft.world.item.ItemStack;
+
+import javax.annotation.Nullable;
+
+/**
+ * A slot in the turtle UI which holds the turtle's current upgrade.
+ *
+ * @see TurtleMenu
+ */
+public class UpgradeSlot extends Slot {
+    public static final ResourceLocation LEFT_UPGRADE = new ResourceLocation(ComputerCraftAPI.MOD_ID, "gui/turtle_upgrade_left");
+    public static final ResourceLocation RIGHT_UPGRADE = new ResourceLocation(ComputerCraftAPI.MOD_ID, "gui/turtle_upgrade_right");
+
+    private final TurtleSide side;
+
+    public UpgradeSlot(Container container, TurtleSide side, int slot, int xPos, int yPos) {
+        super(container, slot, xPos, yPos);
+        this.side = side;
+    }
+
+    @Override
+    public boolean mayPlace(ItemStack stack) {
+        return TurtleUpgrades.instance().get(stack) != null;
+    }
+
+    @Override
+    public int getMaxStackSize() {
+        return 1;
+    }
+
+    @Nullable
+    @Override
+    public Pair<ResourceLocation, ResourceLocation> getNoItemIcon() {
+        return Pair.of(InventoryMenu.BLOCK_ATLAS, side == TurtleSide.LEFT ? LEFT_UPGRADE : RIGHT_UPGRADE);
+    }
+}

projects/common/src/main/java/dan200/computercraft/shared/turtle/items/TurtleItem.java

@@ -8,12 +8,14 @@ import dan200.computercraft.annotations.ForgeOverride;
 import dan200.computercraft.api.ComputerCraftAPI;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleSide;
+import dan200.computercraft.api.upgrades.UpgradeData;
 import dan200.computercraft.impl.TurtleUpgrades;
 import dan200.computercraft.shared.ModRegistry;
 import dan200.computercraft.shared.common.IColouredItem;
 import dan200.computercraft.shared.computer.core.ComputerFamily;
 import dan200.computercraft.shared.computer.items.AbstractComputerItem;
 import dan200.computercraft.shared.turtle.blocks.TurtleBlock;
+import dan200.computercraft.shared.util.NBTUtil;
 import net.minecraft.core.cauldron.CauldronInteraction;
 import net.minecraft.network.chat.Component;
 import net.minecraft.resources.ResourceLocation;
@@ -32,7 +34,7 @@ public class TurtleItem extends AbstractComputerItem implements IColouredItem {
 
     public static ItemStack create(
         int id, @Nullable String label, int colour, ComputerFamily family,
-        @Nullable ITurtleUpgrade leftUpgrade, @Nullable ITurtleUpgrade rightUpgrade,
+        @Nullable UpgradeData<ITurtleUpgrade> leftUpgrade, @Nullable UpgradeData<ITurtleUpgrade> rightUpgrade,
         int fuelLevel, @Nullable ResourceLocation overlay
     ) {
         return switch (family) {
@@ -46,7 +48,7 @@ public class TurtleItem extends AbstractComputerItem implements IColouredItem {
 
     public ItemStack create(
         int id, @Nullable String label, int colour,
-        @Nullable ITurtleUpgrade leftUpgrade, @Nullable ITurtleUpgrade rightUpgrade,
+        @Nullable UpgradeData<ITurtleUpgrade> leftUpgrade, @Nullable UpgradeData<ITurtleUpgrade> rightUpgrade,
         int fuelLevel, @Nullable ResourceLocation overlay
     ) {
         // Build the stack
@@ -58,11 +60,15 @@ public class TurtleItem extends AbstractComputerItem implements IColouredItem {
         if (overlay != null) stack.getOrCreateTag().putString(NBT_OVERLAY, overlay.toString());
 
         if (leftUpgrade != null) {
-            stack.getOrCreateTag().putString(NBT_LEFT_UPGRADE, leftUpgrade.getUpgradeID().toString());
+            var tag = stack.getOrCreateTag();
+            tag.putString(NBT_LEFT_UPGRADE, leftUpgrade.upgrade().getUpgradeID().toString());
+            if (!leftUpgrade.data().isEmpty()) tag.put(NBT_LEFT_UPGRADE_DATA, leftUpgrade.data().copy());
         }
 
         if (rightUpgrade != null) {
-            stack.getOrCreateTag().putString(NBT_RIGHT_UPGRADE, rightUpgrade.getUpgradeID().toString());
+            var tag = stack.getOrCreateTag();
+            tag.putString(NBT_RIGHT_UPGRADE, rightUpgrade.upgrade().getUpgradeID().toString());
+            if (!rightUpgrade.data().isEmpty()) tag.put(NBT_RIGHT_UPGRADE_DATA, rightUpgrade.data().copy());
         }
 
         return stack;
@@ -117,7 +123,7 @@ public class TurtleItem extends AbstractComputerItem implements IColouredItem {
         return create(
             getComputerID(stack), getLabel(stack),
             getColour(stack), family,
-            getUpgrade(stack, TurtleSide.LEFT), getUpgrade(stack, TurtleSide.RIGHT),
+            getUpgradeWithData(stack, TurtleSide.LEFT), getUpgradeWithData(stack, TurtleSide.RIGHT),
             getFuelLevel(stack), getOverlay(stack)
         );
     }
@@ -127,7 +133,20 @@ public class TurtleItem extends AbstractComputerItem implements IColouredItem {
         if (tag == null) return null;
 
         var key = side == TurtleSide.LEFT ? NBT_LEFT_UPGRADE : NBT_RIGHT_UPGRADE;
-        return tag.contains(key) ? TurtleUpgrades.instance().get(tag.getString(key)) : null;
+        if (!tag.contains(key)) return null;
+        return TurtleUpgrades.instance().get(tag.getString(key));
+    }
+
+    public @Nullable UpgradeData<ITurtleUpgrade> getUpgradeWithData(ItemStack stack, TurtleSide side) {
+        var tag = stack.getTag();
+        if (tag == null) return null;
+
+        var key = side == TurtleSide.LEFT ? NBT_LEFT_UPGRADE : NBT_RIGHT_UPGRADE;
+        if (!tag.contains(key)) return null;
+        var upgrade = TurtleUpgrades.instance().get(tag.getString(key));
+        if (upgrade == null) return null;
+        var dataKey = side == TurtleSide.LEFT ? NBT_LEFT_UPGRADE_DATA : NBT_RIGHT_UPGRADE_DATA;
+        return UpgradeData.of(upgrade, NBTUtil.getCompoundOrEmpty(tag, dataKey));
     }
 
     public @Nullable ResourceLocation getOverlay(ItemStack stack) {

projects/common/src/main/java/dan200/computercraft/shared/turtle/recipes/TurtleOverlayRecipe.java

@@ -38,8 +38,8 @@ public class TurtleOverlayRecipe extends ShapelessRecipe {
             turtle.getComputerID(stack),
             turtle.getLabel(stack),
             turtle.getColour(stack),
-            turtle.getUpgrade(stack, TurtleSide.LEFT),
-            turtle.getUpgrade(stack, TurtleSide.RIGHT),
+            turtle.getUpgradeWithData(stack, TurtleSide.LEFT),
+            turtle.getUpgradeWithData(stack, TurtleSide.RIGHT),
             turtle.getFuelLevel(stack),
             overlay
         );

projects/common/src/main/java/dan200/computercraft/shared/turtle/recipes/TurtleUpgradeRecipe.java

@@ -6,6 +6,7 @@ package dan200.computercraft.shared.turtle.recipes;
 
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleSide;
+import dan200.computercraft.api.upgrades.UpgradeData;
 import dan200.computercraft.impl.TurtleUpgrades;
 import dan200.computercraft.shared.ModRegistry;
 import dan200.computercraft.shared.turtle.items.TurtleItem;
@@ -104,9 +105,10 @@ public final class TurtleUpgradeRecipe extends CustomRecipe {
         // At this point we have a turtle + 1 or 2 items
         // Get the turtle we already have
         var itemTurtle = (TurtleItem) turtle.getItem();
-        var upgrades = new ITurtleUpgrade[]{
-            itemTurtle.getUpgrade(turtle, TurtleSide.LEFT),
-            itemTurtle.getUpgrade(turtle, TurtleSide.RIGHT),
+        @SuppressWarnings({ "unchecked", "rawtypes" })
+        UpgradeData<ITurtleUpgrade>[] upgrades = new UpgradeData[]{
+            itemTurtle.getUpgradeWithData(turtle, TurtleSide.LEFT),
+            itemTurtle.getUpgradeWithData(turtle, TurtleSide.RIGHT),
         };
 
         // Get the upgrades for the new items

projects/common/src/main/java/dan200/computercraft/shared/turtle/upgrades/TurtleModem.java

@@ -9,6 +9,7 @@ import dan200.computercraft.api.turtle.*;
 import dan200.computercraft.shared.peripheral.modem.ModemState;
 import dan200.computercraft.shared.peripheral.modem.wireless.WirelessModemPeripheral;
 import net.minecraft.core.Direction;
+import net.minecraft.nbt.CompoundTag;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.Level;
@@ -77,4 +78,9 @@ public class TurtleModem extends AbstractTurtleUpgrade {
             }
         }
     }
+
+    @Override
+    public CompoundTag getPersistedData(CompoundTag upgradeData) {
+        return new CompoundTag();
+    }
 }

projects/common/src/main/java/dan200/computercraft/shared/turtle/upgrades/TurtleTool.java

@@ -14,16 +14,22 @@ import dan200.computercraft.shared.util.DropConsumer;
 import dan200.computercraft.shared.util.WorldUtil;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
+import net.minecraft.nbt.CompoundTag;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.server.level.ServerLevel;
+import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.tags.TagKey;
+import net.minecraft.world.InteractionHand;
 import net.minecraft.world.InteractionResult;
 import net.minecraft.world.entity.Entity;
+import net.minecraft.world.entity.LivingEntity;
+import net.minecraft.world.entity.MobType;
 import net.minecraft.world.entity.ai.attributes.Attributes;
 import net.minecraft.world.entity.decoration.ArmorStand;
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.item.Item;
 import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.enchantment.EnchantmentHelper;
 import net.minecraft.world.level.BlockGetter;
 import net.minecraft.world.level.Level;
 import net.minecraft.world.level.block.Block;
@@ -32,46 +38,127 @@ import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.world.phys.EntityHitResult;
 
 import javax.annotation.Nullable;
+import java.util.Objects;
+import java.util.function.Function;
 
 import static net.minecraft.nbt.Tag.TAG_COMPOUND;
 import static net.minecraft.nbt.Tag.TAG_LIST;
 
 public class TurtleTool extends AbstractTurtleUpgrade {
-    protected static final TurtleCommandResult UNBREAKABLE = TurtleCommandResult.failure("Cannot break unbreakable block");
-    protected static final TurtleCommandResult INEFFECTIVE = TurtleCommandResult.failure("Cannot break block with this tool");
+    private static final TurtleCommandResult UNBREAKABLE = TurtleCommandResult.failure("Cannot break unbreakable block");
+    private static final TurtleCommandResult INEFFECTIVE = TurtleCommandResult.failure("Cannot break block with this tool");
+
+    private static final String TAG_ITEM_TAG = "Tag";
 
     final ItemStack item;
     final float damageMulitiplier;
-    @Nullable
-    final TagKey<Block> breakable;
+    final boolean allowEnchantments;
+    final TurtleToolDurability consumeDurability;
+    final @Nullable TagKey<Block> breakable;
 
-    public TurtleTool(ResourceLocation id, String adjective, Item craftItem, ItemStack toolItem, float damageMulitiplier, @Nullable TagKey<Block> breakable) {
+    public TurtleTool(
+        ResourceLocation id, String adjective, Item craftItem, ItemStack toolItem, float damageMulitiplier,
+        boolean allowEnchantments, TurtleToolDurability consumeDurability, @Nullable TagKey<Block> breakable
+    ) {
         super(id, TurtleUpgradeType.TOOL, adjective, new ItemStack(craftItem));
         item = toolItem;
         this.damageMulitiplier = damageMulitiplier;
+        this.allowEnchantments = allowEnchantments;
+        this.consumeDurability = consumeDurability;
         this.breakable = breakable;
     }
 
     @Override
     public boolean isItemSuitable(ItemStack stack) {
-        var tag = stack.getTag();
-        if (tag == null || tag.isEmpty()) return true;
+        if (consumeDurability == TurtleToolDurability.NEVER && stack.isDamaged()) return false;
+        if (!allowEnchantments && isEnchanted(stack)) return false;
+        return true;
+    }
 
-        // Check we've not got anything vaguely interesting on the item. We allow other mods to add their
-        // own NBT, with the understanding such details will be lost to the mist of time.
-        if (stack.isDamaged() || stack.isEnchanted() || stack.hasCustomHoverName()) return false;
-        if (tag.contains("AttributeModifiers", TAG_LIST) && !tag.getList("AttributeModifiers", TAG_COMPOUND).isEmpty()) {
-            return false;
+    private static boolean isEnchanted(ItemStack stack) {
+        return !stack.isEmpty() && isEnchanted(stack.getTag());
+    }
+
+    private static boolean isEnchanted(@Nullable CompoundTag tag) {
+        if (tag == null || tag.isEmpty()) return false;
+        return (tag.contains(ItemStack.TAG_ENCH, TAG_LIST) && !tag.getList(ItemStack.TAG_ENCH, TAG_COMPOUND).isEmpty())
+            || (tag.contains("AttributeModifiers", TAG_LIST) && !tag.getList("AttributeModifiers", TAG_COMPOUND).isEmpty());
+    }
+
+    @Override
+    public CompoundTag getUpgradeData(ItemStack stack) {
+        var upgradeData = super.getUpgradeData(stack);
+
+        // Store the item's current tag.
+        var itemTag = stack.getTag();
+        if (itemTag != null) upgradeData.put(TAG_ITEM_TAG, itemTag);
+
+        return upgradeData;
+    }
+
+    @Override
+    public ItemStack getUpgradeItem(CompoundTag upgradeData) {
+        // Copy upgrade data back to the item.
+        var item = super.getUpgradeItem(upgradeData).copy();
+        item.setTag(upgradeData.contains(TAG_ITEM_TAG, TAG_COMPOUND) ? upgradeData.getCompound(TAG_ITEM_TAG) : null);
+        return item;
+    }
+
+    private ItemStack getToolStack(ITurtleAccess turtle, TurtleSide side) {
+        return getUpgradeItem(turtle.getUpgradeNBTData(side)).copy();
+    }
+
+    private void setToolStack(ITurtleAccess turtle, TurtleSide side, ItemStack stack) {
+        var upgradeData = turtle.getUpgradeNBTData(side);
+
+        var useDurability = switch (consumeDurability) {
+            case NEVER -> false;
+            case WHEN_ENCHANTED ->
+                upgradeData.contains(TAG_ITEM_TAG, TAG_COMPOUND) && isEnchanted(upgradeData.getCompound(TAG_ITEM_TAG));
+            case ALWAYS -> true;
+        };
+        if (!useDurability) return;
+
+        // If the tool has broken, remove the upgrade!
+        if (stack.isEmpty()) {
+            turtle.setUpgradeWithData(side, null);
+            return;
         }
 
-        return true;
+        // If the tool has changed, no clue what's going on.
+        if (stack.getItem() != item.getItem()) return;
+
+        var itemTag = stack.getTag();
+
+        // Early return if the item hasn't changed to avoid redundant syncs with the client.
+        if (Objects.equals(itemTag, upgradeData.get(TAG_ITEM_TAG))) return;
+
+        if (itemTag == null) {
+            upgradeData.remove(TAG_ITEM_TAG);
+        } else {
+            upgradeData.put(TAG_ITEM_TAG, itemTag);
+        }
+
+        turtle.updateUpgradeNBTData(side);
+    }
+
+    private <T> T withEquippedItem(ITurtleAccess turtle, TurtleSide side, Direction direction, Function<TurtlePlayer, T> action) {
+        var turtlePlayer = TurtlePlayer.getWithPosition(turtle, turtle.getPosition(), direction);
+        turtlePlayer.loadInventory(getToolStack(turtle, side));
+
+        var result = action.apply(turtlePlayer);
+
+        setToolStack(turtle, side, turtlePlayer.player().getItemInHand(InteractionHand.MAIN_HAND));
+        turtlePlayer.player().getInventory().clearContent();
+
+        return result;
     }
 
     @Override
     public TurtleCommandResult useTool(ITurtleAccess turtle, TurtleSide side, TurtleVerb verb, Direction direction) {
         return switch (verb) {
-            case ATTACK -> attack(turtle, direction);
-            case DIG -> dig(turtle, direction);
+            case ATTACK -> attack(turtle, side, direction);
+            case DIG -> dig(turtle, side, direction);
         };
     }
 
@@ -86,16 +173,14 @@ public class TurtleTool extends AbstractTurtleUpgrade {
     }
 
     /**
-     * Attack an entity. This is a <em>very</em> cut down version of {@link Player#attack(Entity)}, which doesn't handle
-     * enchantments, knockback, etc... Unfortunately we can't call attack directly as damage calculations are rather
-     * different (and we don't want to play sounds/particles).
+     * Attack an entity.
      *
      * @param turtle    The current turtle.
+     * @param side      The side the tool is on.
      * @param direction The direction we're attacking in.
      * @return Whether an attack occurred.
-     * @see Player#attack(Entity)
      */
-    private TurtleCommandResult attack(ITurtleAccess turtle, Direction direction) {
+    private TurtleCommandResult attack(ITurtleAccess turtle, TurtleSide side, Direction direction) {
         // Create a fake player, and orient it appropriately
         var world = turtle.getLevel();
         var position = turtle.getPosition();
@@ -107,10 +192,11 @@ public class TurtleTool extends AbstractTurtleUpgrade {
         var turtlePos = player.position();
         var rayDir = player.getViewVector(1.0f);
         var hit = WorldUtil.clip(world, turtlePos, rayDir, 1.5, null);
+        var attacked = false;
         if (hit instanceof EntityHitResult entityHit) {
             // Load up the turtle's inventory
-            var stackCopy = item.copy();
-            turtlePlayer.loadInventory(stackCopy);
+            var stack = getToolStack(turtle, side);
+            turtlePlayer.loadInventory(stack);
 
             var hitEntity = entityHit.getEntity();
 
@@ -118,62 +204,147 @@ public class TurtleTool extends AbstractTurtleUpgrade {
             DropConsumer.set(hitEntity, TurtleUtil.dropConsumer(turtle));
 
             // Attack the entity
-            var attacked = false;
             var result = PlatformHelper.get().canAttackEntity(player, hitEntity);
             if (result.consumesAction()) {
                 attacked = true;
             } else if (result == InteractionResult.PASS && hitEntity.isAttackable() && !hitEntity.skipAttackInteraction(player)) {
-                var damage = (float) player.getAttributeValue(Attributes.ATTACK_DAMAGE) * damageMulitiplier;
-                if (damage > 0.0f) {
-                    var source = player.damageSources().playerAttack(player);
-                    if (hitEntity instanceof ArmorStand) {
-                        // Special case for armor stands: attack twice to guarantee destroy
-                        hitEntity.hurt(source, damage);
-                        if (hitEntity.isAlive()) hitEntity.hurt(source, damage);
-                        attacked = true;
-                    } else {
-                        if (hitEntity.hurt(source, damage)) attacked = true;
-                    }
-                }
+                attacked = attack(player, direction, hitEntity);
             }
 
             // Stop claiming drops
             TurtleUtil.stopConsuming(turtle);
 
-            // Put everything we collected into the turtles inventory, then return
+            // Put everything we collected into the turtles inventory.
+            setToolStack(turtle, side, player.getItemInHand(InteractionHand.MAIN_HAND));
             player.getInventory().clearContent();
-            if (attacked) return TurtleCommandResult.success();
         }
 
-        return TurtleCommandResult.failure("Nothing to attack here");
+        return attacked ? TurtleCommandResult.success() : TurtleCommandResult.failure("Nothing to attack here");
     }
 
-    private TurtleCommandResult dig(ITurtleAccess turtle, Direction direction) {
-        if (PlatformHelper.get().hasToolUsage(item) && TurtlePlaceCommand.deployCopiedItem(item.copy(), turtle, direction, null, null)) {
-            return TurtleCommandResult.success();
+    /**
+     * Attack an entity. This is a copy of {@link Player#attack(Entity)}, with some unwanted features removed (sweeping
+     * edge). This is a little limited.
+     * <p>
+     * Ideally we'd use attack directly (if other mods mixin to that method, we won't support their features).
+     * Unfortunately,that doesn't give us any feedback to whether the attack occurred or not (and we don't want to play
+     * sounds/particles).
+     *
+     * @param player    The fake player doing the attacking.
+     * @param direction The direction the turtle is attacking.
+     * @param entity    The entity to attack.
+     * @return Whether we attacked or not.
+     * @see Player#attack(Entity)
+     */
+    private boolean attack(ServerPlayer player, Direction direction, Entity entity) {
+        var baseDamage = (float) player.getAttributeValue(Attributes.ATTACK_DAMAGE) * damageMulitiplier;
+        var bonusDamage = EnchantmentHelper.getDamageBonus(
+            player.getItemInHand(InteractionHand.MAIN_HAND), entity instanceof LivingEntity target ? target.getMobType() : MobType.UNDEFINED
+        );
+        var damage = baseDamage + bonusDamage;
+        if (damage <= 0) return false;
+
+        var knockBack = EnchantmentHelper.getKnockbackBonus(player);
+
+        // We follow the logic in Player.attack of setting the entity on fire before attacking, so it's burning when it
+        // (possibly) dies.
+        var fireAspect = EnchantmentHelper.getFireAspect(player);
+        var onFire = false;
+        if (entity instanceof LivingEntity target && fireAspect > 0 && !target.isOnFire()) {
+            onFire = true;
+            target.setSecondsOnFire(1);
         }
 
+        var source = player.damageSources().playerAttack(player);
+        if (!entity.hurt(source, damage)) {
+            // If we failed to damage the entity, undo us setting the entity on fire.
+            if (onFire) entity.clearFire();
+            return false;
+        }
+
+        // Special case for armor stands: attack twice to guarantee destroy
+        if (entity.isAlive() && entity instanceof ArmorStand) entity.hurt(source, damage);
+
+        // Apply knockback
+        if (knockBack > 0) {
+            if (entity instanceof LivingEntity target) {
+                target.knockback(knockBack * 0.5, -direction.getStepX(), -direction.getStepZ());
+            } else {
+                entity.push(direction.getStepX() * knockBack * 0.5, 0.1, direction.getStepZ() * knockBack * 0.5);
+            }
+        }
+
+        // Apply remaining enchantments
+        if (entity instanceof LivingEntity target) EnchantmentHelper.doPostHurtEffects(target, player);
+        EnchantmentHelper.doPostDamageEffects(player, entity);
+
+        // Damage the original item stack.
+        if (entity instanceof LivingEntity target) {
+            player.getItemInHand(InteractionHand.MAIN_HAND).hurtEnemy(target, player);
+        }
+
+        // Apply fire aspect
+        if (entity instanceof LivingEntity target && fireAspect > 0 && !target.isOnFire()) {
+            target.setSecondsOnFire(4 * fireAspect);
+        }
+
+        return true;
+    }
+
+    private TurtleCommandResult dig(ITurtleAccess turtle, TurtleSide side, Direction direction) {
         var level = (ServerLevel) turtle.getLevel();
-        var turtlePosition = turtle.getPosition();
 
-        var blockPosition = turtlePosition.relative(direction);
-        if (level.isEmptyBlock(blockPosition) || WorldUtil.isLiquidBlock(level, blockPosition)) {
-            return TurtleCommandResult.failure("Nothing to dig here");
+        return withEquippedItem(turtle, side, direction, turtlePlayer -> {
+            var stack = turtlePlayer.player().getItemInHand(InteractionHand.MAIN_HAND);
+
+            // Right-click the block when using a shovel/hoe. Important that we do this before checking the block is
+            // present, as we allow doing these actions from slightly further away.
+            if (PlatformHelper.get().hasToolUsage(stack) && useTool(level, turtle, turtlePlayer, stack, direction)) {
+                return TurtleCommandResult.success();
+            }
+
+            var blockPosition = turtle.getPosition().relative(direction);
+            if (level.isEmptyBlock(blockPosition) || WorldUtil.isLiquidBlock(level, blockPosition)) {
+                return TurtleCommandResult.failure("Nothing to dig here");
+            }
+
+            // Check if we can break the block
+            var breakable = checkBlockBreakable(level, blockPosition, turtlePlayer);
+            if (!breakable.isSuccess()) return breakable;
+
+            // And break it!
+            DropConsumer.set(level, blockPosition, TurtleUtil.dropConsumer(turtle));
+            var broken = !turtlePlayer.isBlockProtected(level, blockPosition) && turtlePlayer.player().gameMode.destroyBlock(blockPosition);
+            TurtleUtil.stopConsuming(turtle);
+
+            return broken ? TurtleCommandResult.success() : TurtleCommandResult.failure("Cannot break protected block");
+        });
+    }
+
+    /**
+     * Attempt to use a tool against a block instead.
+     *
+     * @param level        The current level.
+     * @param turtle       The current turtle.
+     * @param turtlePlayer The turtle player, already positioned and with a stack equipped.
+     * @param stack        The current tool's stack.
+     * @param direction    The direction this action occurs in.
+     * @return Whether the tool was successfully used.
+     * @see PlatformHelper#hasToolUsage(ItemStack)
+     */
+    private boolean useTool(ServerLevel level, ITurtleAccess turtle, TurtlePlayer turtlePlayer, ItemStack stack, Direction direction) {
+        var position = turtle.getPosition().relative(direction);
+        // Allow digging one extra block below the turtle, as you can't till dirt/flatten grass if there's a block
+        // above.
+        if (direction == Direction.DOWN && level.isEmptyBlock(position)) position = position.relative(direction);
+
+        if (!level.isInWorldBounds(position) || level.isEmptyBlock(position) || turtlePlayer.isBlockProtected(level, position)) {
+            return false;
         }
 
-        var turtlePlayer = TurtlePlayer.getWithPosition(turtle, turtlePosition, direction);
-        turtlePlayer.loadInventory(item.copy());
-
-        // Check if we can break the block
-        var breakable = checkBlockBreakable(level, blockPosition, turtlePlayer);
-        if (!breakable.isSuccess()) return breakable;
-
-        DropConsumer.set(level, blockPosition, TurtleUtil.dropConsumer(turtle));
-        var broken = !turtlePlayer.isBlockProtected(level, blockPosition) && turtlePlayer.player().gameMode.destroyBlock(blockPosition);
-        TurtleUtil.stopConsuming(turtle);
-
-        // Check spawn protection
-        return broken ? TurtleCommandResult.success() : TurtleCommandResult.failure("Cannot break protected block");
+        var hit = TurtlePlaceCommand.getHitResult(position, direction.getOpposite());
+        var result = PlatformHelper.get().useOn(turtlePlayer.player(), stack, hit, x -> false);
+        return result.consumesAction();
     }
 
     private static boolean isTriviallyBreakable(BlockGetter reader, BlockPos pos, BlockState state) {

projects/common/src/main/java/dan200/computercraft/shared/turtle/upgrades/TurtleToolSerialiser.java

@@ -5,6 +5,7 @@
 package dan200.computercraft.shared.turtle.upgrades;
 
 import com.google.gson.JsonObject;
+import dan200.computercraft.api.turtle.TurtleToolDurability;
 import dan200.computercraft.api.turtle.TurtleUpgradeSerialiser;
 import dan200.computercraft.api.upgrades.UpgradeBase;
 import dan200.computercraft.shared.platform.RegistryWrappers;
@@ -16,6 +17,8 @@ import net.minecraft.util.GsonHelper;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.level.block.Block;
 
+import java.util.Objects;
+
 public final class TurtleToolSerialiser implements TurtleUpgradeSerialiser<TurtleTool> {
     public static final TurtleToolSerialiser INSTANCE = new TurtleToolSerialiser();
 
@@ -28,6 +31,8 @@ public final class TurtleToolSerialiser implements TurtleUpgradeSerialiser<Turtl
         var toolItem = GsonHelper.getAsItem(object, "item");
         var craftingItem = GsonHelper.getAsItem(object, "craftingItem", toolItem);
         var damageMultiplier = GsonHelper.getAsFloat(object, "damageMultiplier", 3.0f);
+        var allowEnchantments = GsonHelper.getAsBoolean(object, "allowEnchantments", false);
+        var consumeDurability = TurtleToolDurability.CODEC.byName(GsonHelper.getAsString(object, "consumeDurability", null), TurtleToolDurability.NEVER);
 
         TagKey<Block> breakable = null;
         if (object.has("breakable")) {
@@ -35,28 +40,33 @@ public final class TurtleToolSerialiser implements TurtleUpgradeSerialiser<Turtl
             breakable = TagKey.create(Registries.BLOCK, tag);
         }
 
-        return new TurtleTool(id, adjective, craftingItem, new ItemStack(toolItem), damageMultiplier, breakable);
+        return new TurtleTool(id, adjective, craftingItem, new ItemStack(toolItem), damageMultiplier, allowEnchantments, consumeDurability, breakable);
     }
 
     @Override
     public TurtleTool fromNetwork(ResourceLocation id, FriendlyByteBuf buffer) {
         var adjective = buffer.readUtf();
-        var craftingItem = RegistryWrappers.readId(buffer, RegistryWrappers.ITEMS);
+        var craftingItem = buffer.readById(RegistryWrappers.ITEMS);
+        Objects.requireNonNull(craftingItem, "Unknown crafting item");
         var toolItem = buffer.readItem();
         // damageMultiplier and breakable aren't used by the client, but we need to construct the upgrade exactly
         // as otherwise syncing on an SP world will overwrite the (shared) upgrade registry with an invalid upgrade!
         var damageMultiplier = buffer.readFloat();
+        var allowsEnchantments = buffer.readBoolean();
+        var consumesDurability = buffer.readEnum(TurtleToolDurability.class);
 
         var breakable = buffer.readBoolean() ? TagKey.create(Registries.BLOCK, buffer.readResourceLocation()) : null;
-        return new TurtleTool(id, adjective, craftingItem, toolItem, damageMultiplier, breakable);
+        return new TurtleTool(id, adjective, craftingItem, toolItem, damageMultiplier, allowsEnchantments, consumesDurability, breakable);
     }
 
     @Override
     public void toNetwork(FriendlyByteBuf buffer, TurtleTool upgrade) {
         buffer.writeUtf(upgrade.getUnlocalisedAdjective());
-        RegistryWrappers.writeId(buffer, RegistryWrappers.ITEMS, upgrade.getCraftingItem().getItem());
+        buffer.writeId(RegistryWrappers.ITEMS, upgrade.getCraftingItem().getItem());
         buffer.writeItem(upgrade.item);
         buffer.writeFloat(upgrade.damageMulitiplier);
+        buffer.writeBoolean(upgrade.allowEnchantments);
+        buffer.writeEnum(upgrade.consumeDurability);
         buffer.writeBoolean(upgrade.breakable != null);
         if (upgrade.breakable != null) buffer.writeResourceLocation(upgrade.breakable.location());
     }

projects/common/src/main/java/dan200/computercraft/shared/util/ConsList.java

@@ -0,0 +1,56 @@
+// SPDX-FileCopyrightText: 2023 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package dan200.computercraft.shared.util;
+
+import org.jetbrains.annotations.Nullable;
+
+import java.util.AbstractList;
+import java.util.Iterator;
+import java.util.List;
+
+/**
+ * A list which prepends a single value to another list.
+ *
+ * @param <T> The type of item in the list.
+ */
+public final class ConsList<T> extends AbstractList<T> {
+    private final T head;
+    private final List<T> tail;
+
+    public ConsList(T head, List<T> tail) {
+        this.head = head;
+        this.tail = tail;
+    }
+
+    @Override
+    public T get(int index) {
+        return index == 0 ? head : tail.get(index - 1);
+    }
+
+    @Override
+    public int size() {
+        return 1 + tail.size();
+    }
+
+    @Override
+    public Iterator<T> iterator() {
+        return new Iterator<>() {
+            private @Nullable Iterator<T> tailIterator;
+
+            @Override
+            public boolean hasNext() {
+                return tailIterator == null || tailIterator.hasNext();
+            }
+
+            @Override
+            public T next() {
+                if (tailIterator != null) return tailIterator.next();
+
+                tailIterator = tail.iterator();
+                return head;
+            }
+        };
+    }
+}