Merge branch 'master' into mc-1.14.x

Previously we were just returning the current tile. However, if someone
was holding a reference to this inventory (such as a GUI), then it'd be
outdated and invalid once the turtle had moved.

This caused a couple of issues:
 - turtle_inventory events would not be fired when moving items in the
   turtle GUI.
 - As of 75e2845c01, turtles would no
   longer share their inventory state after moving. Thus, removing items
   from a GUI using an invalid inventory would move them from an old
   tile, duplicating the items.

Fixes #298, fixes #300

.github/workflows/main-ci.yml

@@ -0,0 +1,18 @@
+name: Build
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v1
+
+    - name: Set up JDK 1.8
+      uses: actions/setup-java@v1
+      with:
+        java-version: 1.8
+
+    - name: Build with Gradle
+      run: ./gradlew build --no-daemon

.luacheckrc

@@ -17,7 +17,8 @@ ignore = {
 -- are largely unsupported.
 include_files = {
     'src/main/resources/assets/computercraft/lua/rom',
-    'src/main/resources/assets/computercraft/lua/bios.lua'
+    'src/main/resources/assets/computercraft/lua/bios.lua',
+    'src/test/resources/test-rom',
 }
 
 files['src/main/resources/assets/computercraft/lua/bios.lua'] = {

.travis.yml

@@ -1,14 +0,0 @@
-language: java
-
-script: ./gradlew build --no-daemon
-
-before_cache:
-  - rm -f  $HOME/.gradle/caches/modules-2/modules-2.lock
-  - rm -fr $HOME/.gradle/caches/*/plugin-resolution/
-cache:
-  directories:
-    - $HOME/.gradle/caches/
-    - $HOME/.gradle/wrapper/s
-
-jdk:
-    - oraclejdk8

README.md

@@ -1,5 +1,5 @@
 # ![CC: Tweaked](logo.png)
-[![Current build status](https://travis-ci.org/SquidDev-CC/CC-Tweaked.svg?branch=master)](https://travis-ci.org/SquidDev-CC/CC-Tweaked "Current build status") [![Download CC: Tweaked on CurseForge](https://cf.way2muchnoise.eu/title/cc-tweaked.svg)](https://minecraft.curseforge.com/projects/cc-tweaked "Download CC: Tweaked on CurseForge")
+[![Current build status](https://github.com/SquidDev-CC/CC-Tweaked/workflows/Build/badge.svg)](https://github.com/SquidDev-CC/CC-Tweaked/actions "Current build status") [![Download CC: Tweaked on CurseForge](http://cf.way2muchnoise.eu/title/cc-tweaked.svg)](https://minecraft.curseforge.com/projects/cc-tweaked "Download CC: Tweaked on CurseForge")
 
 CC: Tweaked is a fork of [ComputerCraft](https://github.com/dan200/ComputerCraft), adding programmable computers,
 turtles and more to Minecraft.

build.gradle

@@ -4,12 +4,12 @@ buildscript {
         mavenCentral()
         maven {
             name = "forge"
-            url = "http://files.minecraftforge.net/maven"
+            url = "https://files.minecraftforge.net/maven"
         }
     }
     dependencies {
         classpath 'com.google.code.gson:gson:2.8.1'
-        classpath 'net.minecraftforge.gradle:ForgeGradle:3.0.128'
+        classpath 'net.minecraftforge.gradle:ForgeGradle:3.0.147'
         classpath 'net.sf.proguard:proguard-gradle:6.1.0beta2'
         classpath 'org.ajoberstar.grgit:grgit-gradle:3.0.0'
     }
@@ -67,7 +67,7 @@ minecraft {
 repositories {
     maven {
         name "JEI"
-        url  "http://dvs1.progwml6.com/files/maven"
+        url "https://dvs1.progwml6.com/files/maven"
     }
     maven {
         name "SquidDev"
@@ -79,7 +79,7 @@ repositories {
     }
     maven {
         name "Amadornes"
-        url "http://maven.amadornes.com/"
+        url "https://maven.amadornes.com/"
     }
 }
 
@@ -94,16 +94,16 @@ dependencies {
 
     minecraft "net.minecraftforge:forge:${mc_version}-${forge_version}"
 
-    compileOnly fg.deobf("mezz.jei:jei-1.13.2:5.0.0.20:api")
+    compileOnly fg.deobf("mezz.jei:jei-1.14.4:6.0.0.10:api")
     // deobfProvided "pl.asie:Charset-Lib:0.5.4.6"
     // deobfProvided "MCMultiPart2:MCMultiPart:2.5.3"
 
-    // runtimeOnly fg.deobf("mezz.jei:jei-1.13.2:5.0.0.20")
+    runtimeOnly fg.deobf("mezz.jei:jei-1.14.4:6.0.0.10")
 
     shade 'org.squiddev:Cobalt:0.5.0-SNAPSHOT'
 
-    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.1.0'
-    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.1.0'
+    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.4.2'
+    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.4.2'
 
     deployerJars "org.apache.maven.wagon:wagon-ssh:3.0.0"
 }
@@ -117,6 +117,8 @@ sourceSets {
     }
 }
 
+// Compile tasks
+
 javadoc {
     include "dan200/computercraft/api/**/*.java"
 }
@@ -127,7 +129,7 @@ jar {
     manifest {
         attributes(["Specification-Title": "computercraft",
                     "Specification-Vendor": "SquidDev",
-                    "Specification-Version": "26.0",
+                    "Specification-Version": "1",
                     "Implementation-Title": "CC: Tweaked",
                     "Implementation-Version": "${mod_version}",
                     "Implementation-Vendor" :"SquidDev",
@@ -141,6 +143,14 @@ jar {
     from configurations.shade.collect { it.isDirectory() ? it : zipTree(it) }
 }
 
+[compileJava, compileTestJava].forEach {
+    it.configure {
+        options.compilerArgs << "-Xlint" << "-Xlint:-processing" << "-Werror"
+    }
+}
+
+
+
 import java.nio.charset.StandardCharsets
 import java.nio.file.*
 import java.util.zip.*
@@ -276,7 +286,14 @@ task compressJson(dependsOn: jar) {
 
 assemble.dependsOn compressJson
 
-/* Check tasks */
+// Check tasks
+
+test {
+    useJUnitPlatform()
+    testLogging {
+        events "skipped", "failed"
+    }
+}
 
 license {
     mapping("java", "SLASHSTAR_STYLE")
@@ -300,6 +317,13 @@ license {
     }
 }
 
+gradle.projectsEvaluated {
+    tasks.withType(LicenseFormat) {
+        outputs.upToDateWhen { false }
+    }
+}
+
+
 task licenseAPI(type: LicenseCheck);
 task licenseFormatAPI(type: LicenseFormat);
 [licenseAPI, licenseFormatAPI].forEach {
@@ -310,7 +334,7 @@ task licenseFormatAPI(type: LicenseFormat);
     }
 }
 
-/* Upload tasks */
+// Upload tasks
 
 task checkRelease {
     group "upload"
@@ -355,7 +379,7 @@ curseforge {
     apiKey = project.hasProperty('curseForgeApiKey') ? project.curseForgeApiKey : ''
     project {
         id = '282001'
-        releaseType = 'beta'
+        releaseType = 'release'
         changelog = "Release notes can be found on the GitHub repository (https://github.com/SquidDev-CC/CC-Tweaked/releases/tag/v${mc_version}-${mod_version})."
 
         relations {
@@ -431,7 +455,7 @@ githubRelease {
             .takeWhile { it != 'Type "help changelog" to see the full version history.' }
             .join("\n").trim()
     }
-    prerelease true
+    prerelease false
 }
 
 def uploadTasks = ["uploadArchives", "curseforge", "githubRelease"]
@@ -441,23 +465,3 @@ task uploadAll(dependsOn: uploadTasks) {
     group "upload"
     description "Uploads to all repositories (Maven, Curse, GitHub release)"
 }
-
-test {
-    useJUnitPlatform()
-    testLogging {
-        events "passed", "skipped", "failed"
-    }
-}
-
-gradle.projectsEvaluated {
-    reobfJar.dependsOn proguardMove
-
-    tasks.withType(JavaCompile) {
-        options.compilerArgs << "-Xlint" << "-Xlint:-processing" // Causes Forge build to fail << "-Werror"
-    }
-
-    tasks.withType(LicenseFormat) {
-        outputs.upToDateWhen { false }
-    }
-}
-

gradle.properties

@@ -1,7 +1,7 @@
 # Mod properties
-mod_version=1.83.1
+mod_version=1.85.0
 
 # Minecraft properties
-mc_version=1.14.3
-forge_version=27.0.3
-mappings_version=20190626-1.14.3
+mc_version=1.14.4
+forge_version=28.1.26
+mappings_version=20190912-1.14.3

src/main/java/dan200/computercraft/api/turtle/ITurtleAccess.java

@@ -144,7 +144,9 @@ public interface ITurtleAccess
     GameProfile getOwningPlayer();
 
     /**
-     * Get the inventory of this turtle
+     * Get the inventory of this turtle.
+     *
+     * Note: this inventory should only be accessed and modified on the server thread.
      *
      * @return This turtle's inventory
      * @see #getItemHandler()
@@ -155,6 +157,8 @@ public interface ITurtleAccess
     /**
      * Get the inventory of this turtle as an {@link IItemHandlerModifiable}.
      *
+     * Note: this inventory should only be accessed and modified on the server thread.
+     *
      * @return This turtle's inventory
      * @see #getInventory()
      * @see IItemHandlerModifiable

src/main/java/dan200/computercraft/api/turtle/ITurtleUpgrade.java

@@ -98,8 +98,8 @@ public interface ITurtleUpgrade
      * Will only be called for Tool turtle. Called when turtle.dig() or turtle.attack() is called
      * by the turtle, and the tool is required to do some work.
      *
-     * Conforming implementations should fire {@link BlockEvent.BreakEvent} and {@link TurtleBlockEvent.Dig}for digging,
-     * {@link AttackEntityEvent} and {@link TurtleAttackEvent} for attacking.
+     * Conforming implementations should fire {@link BlockEvent.BreakEvent} and {@link TurtleBlockEvent.Dig} for
+     * digging, {@link AttackEntityEvent} and {@link TurtleAttackEvent} for attacking.
      *
      * @param turtle    Access to the turtle that the tool resides on.
      * @param side      Which side of the turtle (left or right) the tool resides on.

src/main/java/dan200/computercraft/client/ClientRegistry.java

@@ -12,6 +12,7 @@ import dan200.computercraft.shared.common.IColouredItem;
 import dan200.computercraft.shared.media.items.ItemDisk;
 import dan200.computercraft.shared.pocket.items.ItemPocketComputer;
 import dan200.computercraft.shared.util.Colour;
+import net.minecraft.client.Minecraft;
 import net.minecraft.client.renderer.model.IBakedModel;
 import net.minecraft.client.renderer.model.IUnbakedModel;
 import net.minecraft.client.renderer.model.ModelResourceLocation;
@@ -58,8 +59,8 @@ public final class ClientRegistry
     };
 
     private static final String[] EXTRA_TEXTURES = new String[] {
-        // TODO: Gather these automatically from the model. I'm unable to get this working with Forge's current
-        //  model loading code.
+        // TODO: Gather these automatically from the model. Sadly the model loader isn't available
+        //  when stitching textures.
         "block/turtle_colour",
         "block/turtle_elf_overlay",
         "block/turtle_crafty_face",
@@ -77,13 +78,12 @@ public final class ClientRegistry
     @SubscribeEvent
     public static void onTextureStitchEvent( TextureStitchEvent.Pre event )
     {
-        /*
-        IResourceManager manager = Minecraft.getInstance().getResourceManager();
+        if( event.getMap() != Minecraft.getInstance().getTextureMap() ) return;
+
         for( String extra : EXTRA_TEXTURES )
         {
-            // TODO: event.getMap().registerSprite( manager, new ResourceLocation( ComputerCraft.MOD_ID, extra ) );
+            event.addSprite( new ResourceLocation( ComputerCraft.MOD_ID, extra ) );
         }
-        */
     }
 
     @SubscribeEvent

src/main/java/dan200/computercraft/client/FrameInfo.java

@@ -8,9 +8,9 @@ package dan200.computercraft.client;
 
 import dan200.computercraft.ComputerCraft;
 import net.minecraftforge.api.distmarker.Dist;
+import net.minecraftforge.event.TickEvent;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
 import net.minecraftforge.fml.common.Mod;
-import net.minecraftforge.fml.common.gameevent.TickEvent;
 
 @Mod.EventBusSubscriber( modid = ComputerCraft.MOD_ID, value = Dist.CLIENT )
 public final class FrameInfo

src/main/java/dan200/computercraft/client/gui/GuiComputer.java

@@ -176,11 +176,4 @@ public final class GuiComputer<T extends ContainerComputerBase> extends Containe
         return (getFocused() != null && getFocused().mouseDragged( x, y, button, deltaX, deltaY ))
             || super.mouseDragged( x, y, button, deltaX, deltaY );
     }
-
-    @Override
-    public boolean mouseReleased( double x, double y, int button )
-    {
-        return (getFocused() != null && getFocused().mouseReleased( x, y, button ))
-            || super.mouseReleased( x, y, button );
-    }
 }

src/main/java/dan200/computercraft/client/gui/GuiTurtle.java

@@ -129,4 +129,11 @@ public class GuiTurtle extends ContainerScreen<ContainerTurtle>
         super.render( mouseX, mouseY, partialTicks );
         renderHoveredToolTip( mouseX, mouseY );
     }
+
+    @Override
+    public boolean mouseDragged( double x, double y, int button, double deltaX, double deltaY )
+    {
+        return (getFocused() != null && getFocused().mouseDragged( x, y, button, deltaX, deltaY ))
+            || super.mouseDragged( x, y, button, deltaX, deltaY );
+    }
 }

src/main/java/dan200/computercraft/client/gui/widgets/WidgetTerminal.java

@@ -241,11 +241,12 @@ public class WidgetTerminal implements IGuiEventListener
             charX = Math.min( Math.max( charX, 0 ), term.getWidth() - 1 );
             charY = Math.min( Math.max( charY, 0 ), term.getHeight() - 1 );
 
-            computer.mouseDrag( button + 1, charX + 1, charY + 1 );
-
-            lastMouseX = charX;
-            lastMouseY = charY;
-            lastMouseButton = button;
+            if( button == lastMouseButton && (charX != lastMouseX || charY != lastMouseY) )
+            {
+                computer.mouseDrag( button + 1, charX + 1, charY + 1 );
+                lastMouseX = charX;
+                lastMouseY = charY;
+            }
         }
 
         return false;
@@ -427,4 +428,10 @@ public class WidgetTerminal implements IGuiEventListener
         ClientComputer computer = this.computer.get();
         if( computer != null ) computer.queueEvent( event, args );
     }
+
+    @Override
+    public boolean isMouseOver( double x, double y )
+    {
+        return true;
+    }
 }

src/main/java/dan200/computercraft/client/gui/widgets/WidgetWrapper.java

@@ -95,4 +95,11 @@ public class WidgetWrapper implements IGuiEventListener
     {
         return height;
     }
+
+    @Override
+    public boolean isMouseOver( double x, double y )
+    {
+        double dx = x - this.x, dy = y - this.y;
+        return dx >= 0 && dx < width && dy >= 0 && dy < height;
+    }
 }

src/main/java/dan200/computercraft/client/render/CableHighlightRenderer.java

@@ -15,7 +15,6 @@ import net.minecraft.block.BlockState;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.renderer.ActiveRenderInfo;
 import net.minecraft.client.renderer.WorldRenderer;
-import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.BlockRayTraceResult;
 import net.minecraft.util.math.RayTraceResult;
@@ -39,7 +38,7 @@ public final class CableHighlightRenderer
      * Draw an outline for a specific part of a cable "Multipart".
      *
      * @param event The event to observe
-     * @see WorldRenderer#drawSelectionBox(PlayerEntity, RayTraceResult, int, float)
+     * @see WorldRenderer#drawSelectionBox(ActiveRenderInfo, RayTraceResult, int)
      */
     @SubscribeEvent
     public static void drawHighlight( DrawBlockHighlightEvent event )
@@ -48,7 +47,7 @@ public final class CableHighlightRenderer
 
         BlockRayTraceResult hit = (BlockRayTraceResult) event.getTarget();
         BlockPos pos = hit.getPos();
-        World world = event.getInfo().func_216773_g().getEntityWorld();
+        World world = event.getInfo().getRenderViewEntity().getEntityWorld();
         ActiveRenderInfo info = event.getInfo();
 
         BlockState state = world.getBlockState( pos );

src/main/java/dan200/computercraft/client/render/MonitorHighlightRenderer.java

@@ -42,12 +42,12 @@ public final class MonitorHighlightRenderer
     @SubscribeEvent
     public static void drawHighlight( DrawBlockHighlightEvent event )
     {
-        if( event.getTarget().getType() != RayTraceResult.Type.BLOCK || event.getInfo().func_216773_g().isSneaking() )
+        if( event.getTarget().getType() != RayTraceResult.Type.BLOCK || event.getInfo().getRenderViewEntity().isSneaking() )
         {
             return;
         }
 
-        World world = event.getInfo().func_216773_g().getEntityWorld();
+        World world = event.getInfo().getRenderViewEntity().getEntityWorld();
         BlockPos pos = ((BlockRayTraceResult) event.getTarget()).getPos();
 
         TileEntity tile = world.getTileEntity( pos );

src/main/java/dan200/computercraft/client/render/TurtleMultiModel.java

@@ -119,6 +119,7 @@ public class TurtleMultiModel implements IBakedModel
 
     @Nonnull
     @Override
+    @Deprecated
     public TextureAtlasSprite getParticleTexture()
     {
         return m_baseModel.getParticleTexture();

src/main/java/dan200/computercraft/client/render/TurtleSmartItemModel.java

@@ -202,6 +202,7 @@ public class TurtleSmartItemModel implements IBakedModel
 
     @Nonnull
     @Override
+    @Deprecated
     public TextureAtlasSprite getParticleTexture()
     {
         return familyModel.getParticleTexture();

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

@@ -34,8 +34,8 @@ import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.text.ITextComponent;
 import net.minecraft.util.text.StringTextComponent;
 import net.minecraft.util.text.TranslationTextComponent;
-import net.minecraft.world.ServerWorld;
 import net.minecraft.world.World;
+import net.minecraft.world.server.ServerWorld;
 
 import javax.annotation.Nonnull;
 import java.util.*;

src/main/java/dan200/computercraft/shared/common/BlockGeneric.java

@@ -89,4 +89,10 @@ public abstract class BlockGeneric extends Block
     {
         return type.create();
     }
+
+    @Override
+    public boolean canBeReplacedByLeaves( BlockState state, IWorldReader world, BlockPos pos )
+    {
+        return false;
+    }
 }

src/main/java/dan200/computercraft/shared/common/ContainerHeldItem.java

@@ -8,7 +8,6 @@ package dan200.computercraft.shared.common;
 
 import dan200.computercraft.shared.network.container.ContainerData;
 import dan200.computercraft.shared.network.container.HeldItemContainerData;
-import dan200.computercraft.shared.util.InventoryUtil;
 import net.minecraft.entity.player.PlayerEntity;
 import net.minecraft.entity.player.PlayerInventory;
 import net.minecraft.inventory.container.Container;
@@ -33,7 +32,7 @@ public class ContainerHeldItem extends Container
         super( type, id );
 
         this.hand = hand;
-        stack = InventoryUtil.copyItem( player.getHeldItem( hand ) );
+        stack = player.getHeldItem( hand ).copy();
     }
 
     private static ContainerHeldItem createPrintout( int id, PlayerInventory inventory, HeldItemContainerData data )

src/main/java/dan200/computercraft/shared/common/TileGeneric.java

@@ -35,7 +35,6 @@ public abstract class TileGeneric extends TileEntity
         markDirty();
         BlockPos pos = getPos();
         BlockState state = getBlockState();
-        getWorld().markForRerender( pos );
         getWorld().notifyBlockUpdate( pos, state, state, 3 );
     }
 

src/main/java/dan200/computercraft/shared/computer/apis/CommandAPI.java

@@ -85,7 +85,7 @@ public class CommandAPI implements ILuaAPI
         {
             receiver.clearOutput();
             int result = commandManager.handleCommand( m_computer.getSource(), command );
-            return new Object[] { result > 0, receiver.copyOutput() };
+            return new Object[] { result > 0, receiver.copyOutput(), result };
         }
         catch( Throwable t )
         {

src/main/java/dan200/computercraft/shared/computer/blocks/BlockComputerBase.java

@@ -25,8 +25,8 @@ import net.minecraft.util.ResourceLocation;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.RayTraceResult;
 import net.minecraft.world.IBlockReader;
-import net.minecraft.world.ServerWorld;
 import net.minecraft.world.World;
+import net.minecraft.world.server.ServerWorld;
 import net.minecraft.world.storage.loot.LootContext;
 import net.minecraft.world.storage.loot.LootParameters;
 

src/main/java/dan200/computercraft/shared/computer/blocks/TileCommandComputer.java

@@ -23,7 +23,7 @@ import net.minecraft.util.text.ITextComponent;
 import net.minecraft.util.text.StringTextComponent;
 import net.minecraft.util.text.TranslationTextComponent;
 import net.minecraft.world.GameRules;
-import net.minecraft.world.ServerWorld;
+import net.minecraft.world.server.ServerWorld;
 
 import javax.annotation.Nonnull;
 import java.util.HashMap;

src/main/java/dan200/computercraft/shared/computer/core/ServerComputer.java

@@ -311,13 +311,13 @@ public class ServerComputer extends ServerTerminal implements IComputer, IComput
     @Override
     public double getTimeOfDay()
     {
-        return (m_world.getGameTime() + 6000) % 24000 / 1000.0;
+        return (m_world.getDayTime() + 6000) % 24000 / 1000.0;
     }
 
     @Override
     public int getDay()
     {
-        return (int) ((m_world.getGameTime() + 6000) / 24000) + 1;
+        return (int) ((m_world.getDayTime() + 6000) / 24000) + 1;
     }
 
     @Override

src/main/java/dan200/computercraft/shared/media/items/RecordMedia.java

@@ -6,11 +6,16 @@
 
 package dan200.computercraft.shared.media.items;
 
+import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.media.IMedia;
-import dan200.computercraft.shared.util.RecordUtil;
+import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;
 import net.minecraft.item.MusicDiscItem;
 import net.minecraft.util.SoundEvent;
+import net.minecraft.util.text.TranslationTextComponent;
+import net.minecraftforge.fml.common.ObfuscationReflectionHelper;
+import net.minecraftforge.fml.common.ObfuscationReflectionHelper.UnableToAccessFieldException;
+import net.minecraftforge.fml.common.ObfuscationReflectionHelper.UnableToFindFieldException;
 
 import javax.annotation.Nonnull;
 
@@ -34,12 +39,26 @@ public final class RecordMedia implements IMedia
     @Override
     public String getAudioTitle( @Nonnull ItemStack stack )
     {
-        return RecordUtil.getRecordInfo( stack );
+        Item item = stack.getItem();
+        if( !(item instanceof MusicDiscItem) ) return null;
+
+        return new TranslationTextComponent( item.getTranslationKey() + ".desc" ).getString();
     }
 
     @Override
     public SoundEvent getAudio( @Nonnull ItemStack stack )
     {
-        return ((MusicDiscItem) stack.getItem()).getSound();
+        Item item = stack.getItem();
+        if( !(item instanceof MusicDiscItem) ) return null;
+
+        try
+        {
+            return ObfuscationReflectionHelper.getPrivateValue( MusicDiscItem.class, (MusicDiscItem) item, "field_185076_b" );
+        }
+        catch( UnableToAccessFieldException | UnableToFindFieldException e )
+        {
+            ComputerCraft.log.error( "Cannot get disk sound", e );
+            return null;
+        }
     }
 }

src/main/java/dan200/computercraft/shared/peripheral/diskdrive/DiskDrivePeripheral.java

@@ -11,6 +11,7 @@ import dan200.computercraft.api.lua.LuaException;
 import dan200.computercraft.api.media.IMedia;
 import dan200.computercraft.api.peripheral.IComputerAccess;
 import dan200.computercraft.api.peripheral.IPeripheral;
+import dan200.computercraft.shared.MediaProviders;
 import dan200.computercraft.shared.media.items.ItemDisk;
 import dan200.computercraft.shared.util.StringUtil;
 import net.minecraft.item.ItemStack;
@@ -19,11 +20,11 @@ import javax.annotation.Nonnull;
 
 import static dan200.computercraft.core.apis.ArgumentHelper.optString;
 
-public class DiskDrivePeripheral implements IPeripheral
+class DiskDrivePeripheral implements IPeripheral
 {
     private final TileDiskDrive m_diskDrive;
 
-    public DiskDrivePeripheral( TileDiskDrive diskDrive )
+    DiskDrivePeripheral( TileDiskDrive diskDrive )
     {
         m_diskDrive = diskDrive;
     }
@@ -55,7 +56,7 @@ public class DiskDrivePeripheral implements IPeripheral
     }
 
     @Override
-    public Object[] callMethod( @Nonnull IComputerAccess computer, @Nonnull ILuaContext context, int method, @Nonnull Object[] arguments ) throws LuaException
+    public Object[] callMethod( @Nonnull IComputerAccess computer, @Nonnull ILuaContext context, int method, @Nonnull Object[] arguments ) throws LuaException, InterruptedException
     {
         switch( method )
         {
@@ -63,21 +64,26 @@ public class DiskDrivePeripheral implements IPeripheral
                 return new Object[] { !m_diskDrive.getDiskStack().isEmpty() };
             case 1: // getDiskLabel
             {
-                IMedia media = m_diskDrive.getDiskMedia();
-                return media == null ? null : new Object[] { media.getLabel( m_diskDrive.getDiskStack() ) };
+                ItemStack stack = m_diskDrive.getDiskStack();
+                IMedia media = MediaProviders.get( stack );
+                return media == null ? null : new Object[] { media.getLabel( stack ) };
             }
             case 2: // setDiskLabel
             {
                 String label = optString( arguments, 0, null );
 
-                IMedia media = m_diskDrive.getDiskMedia();
-                if( media == null ) return null;
+                return context.executeMainThreadTask( () -> {
+                    ItemStack stack = m_diskDrive.getDiskStack();
+                    IMedia media = MediaProviders.get( stack );
+                    if( media == null ) return null;
 
-                ItemStack disk = m_diskDrive.getDiskStack();
-                label = StringUtil.normaliseLabel( label );
-                if( !media.setLabel( disk, label ) ) throw new LuaException( "Disk label cannot be changed" );
-                m_diskDrive.setDiskStack( disk );
-                return null;
+                    if( !media.setLabel( stack, StringUtil.normaliseLabel( label ) ) )
+                    {
+                        throw new LuaException( "Disk label cannot be changed" );
+                    }
+                    m_diskDrive.setDiskStack( stack );
+                    return null;
+                } );
             }
             case 3: // hasData
                 return new Object[] { m_diskDrive.getDiskMountPath( computer ) != null };
@@ -86,14 +92,16 @@ public class DiskDrivePeripheral implements IPeripheral
             case 5:
             {
                 // hasAudio
-                IMedia media = m_diskDrive.getDiskMedia();
-                return new Object[] { media != null && media.getAudio( m_diskDrive.getDiskStack() ) != null };
+                ItemStack stack = m_diskDrive.getDiskStack();
+                IMedia media = MediaProviders.get( stack );
+                return new Object[] { media != null && media.getAudio( stack ) != null };
             }
             case 6:
             {
                 // getAudioTitle
-                IMedia media = m_diskDrive.getDiskMedia();
-                return new Object[] { media != null ? media.getAudioTitle( m_diskDrive.getDiskStack() ) : false };
+                ItemStack stack = m_diskDrive.getDiskStack();
+                IMedia media = MediaProviders.get( stack );
+                return new Object[] { media != null ? media.getAudioTitle( stack ) : false };
             }
             case 7: // playAudio
                 m_diskDrive.playDiskAudio();
@@ -129,8 +137,7 @@ public class DiskDrivePeripheral implements IPeripheral
     @Override
     public boolean equals( IPeripheral other )
     {
-        if( this == other ) return true;
-        return other instanceof DiskDrivePeripheral && ((DiskDrivePeripheral) other).m_diskDrive == m_diskDrive;
+        return this == other || other instanceof DiskDrivePeripheral && ((DiskDrivePeripheral) other).m_diskDrive == m_diskDrive;
     }
 
     @Nonnull

src/main/java/dan200/computercraft/shared/peripheral/diskdrive/TileDiskDrive.java

@@ -320,35 +320,31 @@ public final class TileDiskDrive extends TileGeneric implements DefaultInventory
     }
 
     @Nonnull
-    public ItemStack getDiskStack()
+    ItemStack getDiskStack()
     {
         return getStackInSlot( 0 );
     }
 
-    public void setDiskStack( @Nonnull ItemStack stack )
+    void setDiskStack( @Nonnull ItemStack stack )
     {
         setInventorySlotContents( 0, stack );
     }
 
-    public IMedia getDiskMedia()
+    private IMedia getDiskMedia()
     {
         return MediaProviders.get( getDiskStack() );
     }
 
-    public String getDiskMountPath( IComputerAccess computer )
+    String getDiskMountPath( IComputerAccess computer )
     {
         synchronized( this )
         {
-            if( m_computers.containsKey( computer ) )
-            {
-                MountInfo info = m_computers.get( computer );
-                return info.mountPath;
-            }
+            MountInfo info = m_computers.get( computer );
+            return info != null ? info.mountPath : null;
         }
-        return null;
     }
 
-    public void mount( IComputerAccess computer )
+    void mount( IComputerAccess computer )
     {
         synchronized( this )
         {
@@ -357,7 +353,7 @@ public final class TileDiskDrive extends TileGeneric implements DefaultInventory
         }
     }
 
-    public void unmount( IComputerAccess computer )
+    void unmount( IComputerAccess computer )
     {
         synchronized( this )
         {
@@ -366,7 +362,7 @@ public final class TileDiskDrive extends TileGeneric implements DefaultInventory
         }
     }
 
-    public void playDiskAudio()
+    void playDiskAudio()
     {
         synchronized( this )
         {
@@ -379,7 +375,7 @@ public final class TileDiskDrive extends TileGeneric implements DefaultInventory
         }
     }
 
-    public void stopDiskAudio()
+    void stopDiskAudio()
     {
         synchronized( this )
         {
@@ -388,7 +384,7 @@ public final class TileDiskDrive extends TileGeneric implements DefaultInventory
         }
     }
 
-    public void ejectDisk()
+    void ejectDisk()
     {
         synchronized( this )
         {
@@ -509,28 +505,6 @@ public final class TileDiskDrive extends TileGeneric implements DefaultInventory
         if( !destroyed ) getWorld().playBroadcastSound( 1000, getPos(), 0 );
     }
 
-    @Override
-    protected void readDescription( @Nonnull CompoundNBT nbt )
-    {
-        super.readDescription( nbt );
-        customName = nbt.contains( NBT_NAME ) ? ITextComponent.Serializer.fromJson( nbt.getString( NBT_NAME ) ) : null;
-        m_diskStack = nbt.contains( NBT_ITEM ) ? ItemStack.read( nbt.getCompound( NBT_ITEM ) ) : ItemStack.EMPTY;
-        updateBlock();
-    }
-
-    @Override
-    protected void writeDescription( @Nonnull CompoundNBT nbt )
-    {
-        super.writeDescription( nbt );
-        if( customName != null ) nbt.putString( NBT_NAME, ITextComponent.Serializer.toJson( customName ) );
-        if( !m_diskStack.isEmpty() )
-        {
-            CompoundNBT item = new CompoundNBT();
-            m_diskStack.write( item );
-            nbt.put( NBT_ITEM, item );
-        }
-    }
-
     // Private methods
 
     private void playRecord()

src/main/java/dan200/computercraft/shared/peripheral/modem/wired/BlockCable.java

@@ -210,7 +210,7 @@ public class BlockCable extends BlockGeneric implements IWaterLoggable
 
         BlockPos offsetPos = pos.offset( facing );
         BlockState offsetState = world.getBlockState( offsetPos );
-        return Block.hasSolidSide( offsetState, world, offsetPos, facing.getOpposite() );
+        return hasSolidSide( offsetState, world, offsetPos, facing.getOpposite() );
     }
 
     @Nullable

src/main/java/dan200/computercraft/shared/peripheral/modem/wired/TileCable.java

@@ -201,8 +201,7 @@ public class TileCable extends TileGeneric implements IPeripheralTile
     public void onNeighbourChange( @Nonnull BlockPos neighbour )
     {
         Direction dir = getDirection();
-        if( neighbour.equals( getPos().offset( dir ) ) && hasModem()
-            && getBlockState().isValidPosition( world, pos ) )
+        if( neighbour.equals( getPos().offset( dir ) ) && hasModem() && !getBlockState().isValidPosition( getWorld(), getPos() ) )
         {
             if( hasCable() )
             {

src/main/java/dan200/computercraft/shared/peripheral/printer/ContainerPrinter.java

@@ -34,7 +34,7 @@ public class ContainerPrinter extends Container
         this.properties = properties;
         this.inventory = inventory;
 
-        func_216961_a( properties );
+        trackIntArray( properties );
 
         // Ink slot
         addSlot( new Slot( inventory, 0, 13, 35 ) );

src/main/java/dan200/computercraft/shared/peripheral/printer/PrinterPeripheral.java

@@ -11,6 +11,7 @@ import dan200.computercraft.api.lua.LuaException;
 import dan200.computercraft.api.peripheral.IComputerAccess;
 import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.core.terminal.Terminal;
+import dan200.computercraft.shared.util.StringUtil;
 
 import javax.annotation.Nonnull;
 
@@ -51,8 +52,13 @@ public class PrinterPeripheral implements IPeripheral
     }
 
     @Override
-    public Object[] callMethod( @Nonnull IComputerAccess computer, @Nonnull ILuaContext context, int method, @Nonnull Object[] args ) throws LuaException
+    public Object[] callMethod( @Nonnull IComputerAccess computer, @Nonnull ILuaContext context, int method, @Nonnull Object[] args ) throws LuaException, InterruptedException
     {
+        // FIXME: There's a theoretical race condition here between getCurrentPage and then using the page. Ideally
+        //  we'd lock on the page, consume it, and unlock.
+
+        // FIXME: None of our page modification functions actually mark the tile as dirty, so the page may not be
+        //  persisted correctly.
         switch( method )
         {
             case 0: // write
@@ -89,10 +95,13 @@ public class PrinterPeripheral implements IPeripheral
                 return new Object[] { width, height };
             }
             case 4: // newPage
-                return new Object[] { m_printer.startNewPage() };
+                return context.executeMainThreadTask( () -> new Object[] { m_printer.startNewPage() } );
             case 5: // endPage
                 getCurrentPage();
-                return new Object[] { m_printer.endCurrentPage() };
+                return context.executeMainThreadTask( () -> {
+                    getCurrentPage();
+                    return new Object[] { m_printer.endCurrentPage() };
+                } );
             case 6: // getInkLevel
                 return new Object[] { m_printer.getInkLevel() };
             case 7:
@@ -100,7 +109,7 @@ public class PrinterPeripheral implements IPeripheral
                 // setPageTitle
                 String title = optString( args, 0, "" );
                 getCurrentPage();
-                m_printer.setPageTitle( title );
+                m_printer.setPageTitle( StringUtil.normaliseLabel( title ) );
                 return null;
             }
             case 8: // getPaperLevel
@@ -123,13 +132,11 @@ public class PrinterPeripheral implements IPeripheral
         return m_printer;
     }
 
+    @Nonnull
     private Terminal getCurrentPage() throws LuaException
     {
         Terminal currentPage = m_printer.getCurrentPage();
-        if( currentPage == null )
-        {
-            throw new LuaException( "Page not started" );
-        }
+        if( currentPage == null ) throw new LuaException( "Page not started" );
         return currentPage;
     }
 }

src/main/java/dan200/computercraft/shared/peripheral/printer/TilePrinter.java

@@ -120,10 +120,7 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
         }
 
         // Read inventory
-        synchronized( m_inventory )
-        {
-            ItemStackHelper.loadAllItems( nbt, m_inventory );
-        }
+        ItemStackHelper.loadAllItems( nbt, m_inventory );
     }
 
     @Nonnull
@@ -141,30 +138,12 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
         }
 
         // Write inventory
-        synchronized( m_inventory )
-        {
-            ItemStackHelper.saveAllItems( nbt, m_inventory );
-        }
+        ItemStackHelper.saveAllItems( nbt, m_inventory );
 
         return super.write( nbt );
     }
 
-    @Override
-    protected void writeDescription( @Nonnull CompoundNBT nbt )
-    {
-        super.writeDescription( nbt );
-        if( customName != null ) nbt.putString( NBT_NAME, ITextComponent.Serializer.toJson( customName ) );
-    }
-
-    @Override
-    public void readDescription( @Nonnull CompoundNBT nbt )
-    {
-        super.readDescription( nbt );
-        customName = nbt.contains( NBT_NAME ) ? ITextComponent.Serializer.fromJson( nbt.getString( NBT_NAME ) ) : null;
-        updateBlock();
-    }
-
-    public boolean isPrinting()
+    boolean isPrinting()
     {
         return m_printing;
     }
@@ -188,73 +167,59 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
 
     @Nonnull
     @Override
-    public ItemStack getStackInSlot( int i )
+    public ItemStack getStackInSlot( int slot )
     {
-        return m_inventory.get( i );
+        return m_inventory.get( slot );
     }
 
     @Nonnull
     @Override
-    public ItemStack removeStackFromSlot( int i )
+    public ItemStack removeStackFromSlot( int slot )
     {
-        synchronized( m_inventory )
-        {
-            ItemStack result = m_inventory.get( i );
-            m_inventory.set( i, ItemStack.EMPTY );
-            markDirty();
-            updateBlockState();
-            return result;
-        }
+        ItemStack result = m_inventory.get( slot );
+        m_inventory.set( slot, ItemStack.EMPTY );
+        markDirty();
+        updateBlockState();
+        return result;
     }
 
     @Nonnull
     @Override
-    public ItemStack decrStackSize( int i, int j )
+    public ItemStack decrStackSize( int slot, int count )
     {
-        synchronized( m_inventory )
+        ItemStack stack = m_inventory.get( slot );
+        if( stack.isEmpty() ) return ItemStack.EMPTY;
+
+        if( stack.getCount() <= count )
         {
-            if( m_inventory.get( i ).isEmpty() ) return ItemStack.EMPTY;
-
-            if( m_inventory.get( i ).getCount() <= j )
-            {
-                ItemStack itemstack = m_inventory.get( i );
-                m_inventory.set( i, ItemStack.EMPTY );
-                markDirty();
-                updateBlockState();
-                return itemstack;
-            }
-
-            ItemStack part = m_inventory.get( i ).split( j );
-            if( m_inventory.get( i ).isEmpty() )
-            {
-                m_inventory.set( i, ItemStack.EMPTY );
-                updateBlockState();
-            }
-            markDirty();
-            return part;
+            setInventorySlotContents( slot, ItemStack.EMPTY );
+            return stack;
         }
+
+        ItemStack part = stack.split( count );
+        if( m_inventory.get( slot ).isEmpty() )
+        {
+            m_inventory.set( slot, ItemStack.EMPTY );
+            updateBlockState();
+        }
+        markDirty();
+        return part;
     }
 
     @Override
-    public void setInventorySlotContents( int i, @Nonnull ItemStack stack )
+    public void setInventorySlotContents( int slot, @Nonnull ItemStack stack )
     {
-        synchronized( m_inventory )
-        {
-            m_inventory.set( i, stack );
-            markDirty();
-            updateBlockState();
-        }
+        m_inventory.set( slot, stack );
+        markDirty();
+        updateBlockState();
     }
 
     @Override
     public void clear()
     {
-        synchronized( m_inventory )
-        {
-            for( int i = 0; i < m_inventory.size(); i++ ) m_inventory.set( i, ItemStack.EMPTY );
-            markDirty();
-            updateBlockState();
-        }
+        for( int i = 0; i < m_inventory.size(); i++ ) m_inventory.set( i, ItemStack.EMPTY );
+        markDirty();
+        updateBlockState();
     }
 
     @Override
@@ -305,14 +270,18 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
         return new PrinterPeripheral( this );
     }
 
-    public Terminal getCurrentPage()
+    @Nullable
+    Terminal getCurrentPage()
     {
-        return m_printing ? m_page : null;
+        synchronized( m_page )
+        {
+            return m_printing ? m_page : null;
+        }
     }
 
-    public boolean startNewPage()
+    boolean startNewPage()
     {
-        synchronized( m_inventory )
+        synchronized( m_page )
         {
             if( !canInputPage() ) return false;
             if( m_printing && !outputPage() ) return false;
@@ -320,49 +289,36 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
         }
     }
 
-    public boolean endCurrentPage()
+    boolean endCurrentPage()
     {
-        synchronized( m_inventory )
+        synchronized( m_page )
         {
-            if( m_printing && outputPage() )
-            {
-                return true;
-            }
-        }
-        return false;
-    }
-
-    public int getInkLevel()
-    {
-        synchronized( m_inventory )
-        {
-            ItemStack inkStack = m_inventory.get( 0 );
-            return isInk( inkStack ) ? inkStack.getCount() : 0;
+            return m_printing && outputPage();
         }
     }
 
-    public int getPaperLevel()
+    int getInkLevel()
+    {
+        ItemStack inkStack = m_inventory.get( 0 );
+        return isInk( inkStack ) ? inkStack.getCount() : 0;
+    }
+
+    int getPaperLevel()
     {
         int count = 0;
-        synchronized( m_inventory )
+        for( int i = 1; i < 7; i++ )
         {
-            for( int i = 1; i < 7; i++ )
-            {
-                ItemStack paperStack = m_inventory.get( i );
-                if( !paperStack.isEmpty() && isPaper( paperStack ) )
-                {
-                    count += paperStack.getCount();
-                }
-            }
+            ItemStack paperStack = m_inventory.get( i );
+            if( isPaper( paperStack ) ) count += paperStack.getCount();
         }
         return count;
     }
 
-    public void setPageTitle( String title )
+    void setPageTitle( String title )
     {
-        if( m_printing )
+        synchronized( m_page )
         {
-            m_pageTitle = title;
+            if( m_printing ) m_pageTitle = title;
         }
     }
 
@@ -380,116 +336,100 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
 
     private boolean canInputPage()
     {
-        synchronized( m_inventory )
-        {
-            ItemStack inkStack = m_inventory.get( 0 );
-            return !inkStack.isEmpty() && isInk( inkStack ) && getPaperLevel() > 0;
-        }
+        ItemStack inkStack = m_inventory.get( 0 );
+        return !inkStack.isEmpty() && isInk( inkStack ) && getPaperLevel() > 0;
     }
 
     private boolean inputPage()
     {
-        synchronized( m_inventory )
+        ItemStack inkStack = m_inventory.get( 0 );
+        if( !isInk( inkStack ) ) return false;
+
+        for( int i = 1; i < 7; i++ )
         {
-            ItemStack inkStack = m_inventory.get( 0 );
-            if( !isInk( inkStack ) ) return false;
+            ItemStack paperStack = m_inventory.get( i );
+            if( paperStack.isEmpty() || !isPaper( paperStack ) ) continue;
 
-            for( int i = 1; i < 7; i++ )
+            // Setup the new page
+            DyeColor dye = ColourUtils.getStackColour( inkStack );
+            m_page.setTextColour( dye != null ? dye.getId() : 15 );
+
+            m_page.clear();
+            if( paperStack.getItem() instanceof ItemPrintout )
             {
-                ItemStack paperStack = m_inventory.get( i );
-                if( !paperStack.isEmpty() && isPaper( paperStack ) )
+                m_pageTitle = ItemPrintout.getTitle( paperStack );
+                String[] text = ItemPrintout.getText( paperStack );
+                String[] textColour = ItemPrintout.getColours( paperStack );
+                for( int y = 0; y < m_page.getHeight(); y++ )
                 {
-                    // Setup the new page
-                    DyeColor dye = ColourUtils.getStackColour( inkStack );
-                    m_page.setTextColour( dye != null ? dye.getId() : 15 );
-
-                    m_page.clear();
-                    if( paperStack.getItem() instanceof ItemPrintout )
-                    {
-                        m_pageTitle = ItemPrintout.getTitle( paperStack );
-                        String[] text = ItemPrintout.getText( paperStack );
-                        String[] textColour = ItemPrintout.getColours( paperStack );
-                        for( int y = 0; y < m_page.getHeight(); y++ )
-                        {
-                            m_page.setLine( y, text[y], textColour[y], "" );
-                        }
-                    }
-                    else
-                    {
-                        m_pageTitle = "";
-                    }
-                    m_page.setCursorPos( 0, 0 );
-
-                    // Decrement ink
-                    inkStack.shrink( 1 );
-                    if( inkStack.isEmpty() ) m_inventory.set( 0, ItemStack.EMPTY );
-
-                    // Decrement paper
-                    paperStack.shrink( 1 );
-                    if( paperStack.isEmpty() )
-                    {
-                        m_inventory.set( i, ItemStack.EMPTY );
-                        updateBlockState();
-                    }
-
-                    markDirty();
-                    m_printing = true;
-                    return true;
+                    m_page.setLine( y, text[y], textColour[y], "" );
                 }
             }
-            return false;
+            else
+            {
+                m_pageTitle = "";
+            }
+            m_page.setCursorPos( 0, 0 );
+
+            // Decrement ink
+            inkStack.shrink( 1 );
+            if( inkStack.isEmpty() ) m_inventory.set( 0, ItemStack.EMPTY );
+
+            // Decrement paper
+            paperStack.shrink( 1 );
+            if( paperStack.isEmpty() )
+            {
+                m_inventory.set( i, ItemStack.EMPTY );
+                updateBlockState();
+            }
+
+            markDirty();
+            m_printing = true;
+            return true;
         }
+        return false;
     }
 
     private boolean outputPage()
     {
-        synchronized( m_page )
+        int height = m_page.getHeight();
+        String[] lines = new String[height];
+        String[] colours = new String[height];
+        for( int i = 0; i < height; i++ )
         {
-            int height = m_page.getHeight();
-            String[] lines = new String[height];
-            String[] colours = new String[height];
-            for( int i = 0; i < height; i++ )
-            {
-                lines[i] = m_page.getLine( i ).toString();
-                colours[i] = m_page.getTextColourLine( i ).toString();
-            }
-
-            ItemStack stack = ItemPrintout.createSingleFromTitleAndText( m_pageTitle, lines, colours );
-            synchronized( m_inventory )
-            {
-                for( int slot : BOTTOM_SLOTS )
-                {
-                    if( m_inventory.get( slot ).isEmpty() )
-                    {
-                        setInventorySlotContents( slot, stack );
-                        m_printing = false;
-                        return true;
-                    }
-                }
-            }
-            return false;
+            lines[i] = m_page.getLine( i ).toString();
+            colours[i] = m_page.getTextColourLine( i ).toString();
         }
+
+        ItemStack stack = ItemPrintout.createSingleFromTitleAndText( m_pageTitle, lines, colours );
+        for( int slot : BOTTOM_SLOTS )
+        {
+            if( m_inventory.get( slot ).isEmpty() )
+            {
+                setInventorySlotContents( slot, stack );
+                m_printing = false;
+                return true;
+            }
+        }
+        return false;
     }
 
     private void ejectContents()
     {
-        synchronized( m_inventory )
+        for( int i = 0; i < 13; i++ )
         {
-            for( int i = 0; i < 13; i++ )
+            ItemStack stack = m_inventory.get( i );
+            if( !stack.isEmpty() )
             {
-                ItemStack stack = m_inventory.get( i );
-                if( !stack.isEmpty() )
-                {
-                    // Remove the stack from the inventory
-                    setInventorySlotContents( i, ItemStack.EMPTY );
+                // Remove the stack from the inventory
+                setInventorySlotContents( i, ItemStack.EMPTY );
 
-                    // Spawn the item in the world
-                    BlockPos pos = getPos();
-                    double x = pos.getX() + 0.5;
-                    double y = pos.getY() + 0.75;
-                    double z = pos.getZ() + 0.5;
-                    WorldUtil.dropItemStack( stack, getWorld(), x, y, z );
-                }
+                // Spawn the item in the world
+                BlockPos pos = getPos();
+                double x = pos.getX() + 0.5;
+                double y = pos.getY() + 0.75;
+                double z = pos.getZ() + 0.5;
+                WorldUtil.dropItemStack( stack, getWorld(), x, y, z );
             }
         }
     }
@@ -497,25 +437,22 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
     private void updateBlockState()
     {
         boolean top = false, bottom = false;
-        synchronized( m_inventory )
+        for( int i = 1; i < 7; i++ )
         {
-            for( int i = 1; i < 7; i++ )
+            ItemStack stack = m_inventory.get( i );
+            if( !stack.isEmpty() && isPaper( stack ) )
             {
-                ItemStack stack = m_inventory.get( i );
-                if( !stack.isEmpty() && isPaper( stack ) )
-                {
-                    top = true;
-                    break;
-                }
+                top = true;
+                break;
             }
-            for( int i = 7; i < 13; i++ )
+        }
+        for( int i = 7; i < 13; i++ )
+        {
+            ItemStack stack = m_inventory.get( i );
+            if( !stack.isEmpty() && isPaper( stack ) )
             {
-                ItemStack stack = m_inventory.get( i );
-                if( !stack.isEmpty() && isPaper( stack ) )
-                {
-                    bottom = true;
-                    break;
-                }
+                bottom = true;
+                break;
             }
         }
 

src/main/java/dan200/computercraft/shared/proxy/ComputerCraftProxyCommon.java

@@ -34,11 +34,11 @@ import net.minecraft.tileentity.CommandBlockTileEntity;
 import net.minecraft.tileentity.TileEntity;
 import net.minecraft.util.ResourceLocation;
 import net.minecraft.world.storage.loot.conditions.LootConditionManager;
+import net.minecraftforge.event.TickEvent;
 import net.minecraftforge.event.entity.player.PlayerContainerEvent;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
 import net.minecraftforge.fml.client.event.ConfigChangedEvent;
 import net.minecraftforge.fml.common.Mod;
-import net.minecraftforge.fml.common.gameevent.TickEvent;
 import net.minecraftforge.fml.event.lifecycle.FMLCommonSetupEvent;
 import net.minecraftforge.fml.event.server.FMLServerStartedEvent;
 import net.minecraftforge.fml.event.server.FMLServerStartingEvent;
@@ -146,7 +146,7 @@ public final class ComputerCraftProxyCommon
                 IComputer computer = ((IContainerComputer) container).getComputer();
                 if( computer instanceof ServerComputer )
                 {
-                    ((ServerComputer) computer).sendTerminalState( event.getEntityPlayer() );
+                    ((ServerComputer) computer).sendTerminalState( event.getPlayer() );
                 }
             }
         }

src/main/java/dan200/computercraft/shared/turtle/FurnaceRefuelHandler.java

@@ -12,8 +12,7 @@ import dan200.computercraft.api.turtle.event.TurtleRefuelEvent;
 import dan200.computercraft.shared.util.InventoryUtil;
 import dan200.computercraft.shared.util.WorldUtil;
 import net.minecraft.item.ItemStack;
-import net.minecraft.tileentity.FurnaceTileEntity;
-import net.minecraftforge.event.ForgeEventFactory;
+import net.minecraftforge.common.ForgeHooks;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
 import net.minecraftforge.fml.common.Mod;
 
@@ -31,9 +30,13 @@ public final class FurnaceRefuelHandler implements TurtleRefuelEvent.Handler
     @Override
     public int refuel( @Nonnull ITurtleAccess turtle, @Nonnull ItemStack currentStack, int slot, int limit )
     {
-        ItemStack stack = turtle.getItemHandler().extractItem( slot, limit, false );
-        int fuelToGive = getFuelPerItem( stack ) * stack.getCount();
+        int fuelSpaceLeft = turtle.getFuelLimit() - turtle.getFuelLevel();
+        int fuelPerItem = getFuelPerItem( turtle.getItemHandler().getStackInSlot( slot ) );
+        int fuelItemLimit = (int) Math.ceil( fuelSpaceLeft / (double) fuelPerItem );
+        if( limit > fuelItemLimit ) limit = fuelItemLimit;
 
+        ItemStack stack = turtle.getItemHandler().extractItem( slot, limit, false );
+        int fuelToGive = fuelPerItem * stack.getCount();
         // Store the replacement item in the inventory
         ItemStack replacementStack = stack.getItem().getContainerItem( stack );
         if( !replacementStack.isEmpty() )
@@ -48,15 +51,9 @@ public final class FurnaceRefuelHandler implements TurtleRefuelEvent.Handler
         return fuelToGive;
     }
 
-
     private static int getFuelPerItem( @Nonnull ItemStack stack )
     {
-        int basicBurnTime = stack.getBurnTime();
-        int burnTime = ForgeEventFactory.getItemBurnTime(
-            stack,
-            basicBurnTime == -1 ? FurnaceTileEntity.getBurnTimes().getOrDefault( stack.getItem(), 0 ) : basicBurnTime
-        );
-        return (burnTime * 5) / 100;
+        return (ForgeHooks.getBurnTime( stack ) * 5) / 100;
     }
 
     @SubscribeEvent

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

@@ -335,9 +335,11 @@ public class TurtleAPI implements ILuaAPI
                 return tryCommand( context, new TurtleInspectCommand( InteractDirection.Up ) );
             case 40: // inspectDown
                 return tryCommand( context, new TurtleInspectCommand( InteractDirection.Down ) );
-            case 41:
+            case 41: // getItemDetail
             {
-                // getItemDetail
+                // FIXME: There's a race condition here if the stack is being modified (mutating NBT, etc...)
+                //  on another thread. The obvious solution is to move this into a command, but some programs rely
+                //  on this having a 0-tick delay.
                 int slot = parseOptionalSlotNumber( args, 0, m_turtle.getSelectedSlot() );
                 ItemStack stack = m_turtle.getInventory().getStackInSlot( slot );
                 if( stack.isEmpty() ) return new Object[] { null };

src/main/java/dan200/computercraft/shared/turtle/blocks/BlockTurtle.java

@@ -153,7 +153,7 @@ public class BlockTurtle extends BlockComputerBase<TileTurtle> implements IWater
     @Override
     public float getExplosionResistance( BlockState state, IWorldReader world, BlockPos pos, @Nullable Entity exploder, Explosion explosion )
     {
-        if( getFamily() == ComputerFamily.Advanced && (exploder instanceof LivingEntity || exploder instanceof DamagingProjectileEntity) )
+        if( getFamily() == ComputerFamily.Advanced || exploder instanceof LivingEntity || exploder instanceof DamagingProjectileEntity )
         {
             return 2000;
         }

src/main/java/dan200/computercraft/shared/turtle/blocks/TileTurtle.java

@@ -49,13 +49,12 @@ import net.minecraftforge.items.wrapper.InvWrapper;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
+import java.util.Collections;
 
 import static net.minecraftforge.items.CapabilityItemHandler.ITEM_HANDLER_CAPABILITY;
 
 public class TileTurtle extends TileComputerBase implements ITurtleTile, DefaultInventory
 {
-    // Statics
-
     public static final int INVENTORY_SIZE = 16;
     public static final int INVENTORY_WIDTH = 4;
     public static final int INVENTORY_HEIGHT = 4;
@@ -70,8 +69,6 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
         type -> new TileTurtle( type, ComputerFamily.Advanced )
     );
 
-    // Members
-
     enum MoveState
     {
         NOT_MOVED,
@@ -79,25 +76,20 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
         MOVED
     }
 
-    private NonNullList<ItemStack> m_inventory;
-    private NonNullList<ItemStack> m_previousInventory;
+    private final NonNullList<ItemStack> m_inventory = NonNullList.withSize( INVENTORY_SIZE, ItemStack.EMPTY );
+    private final NonNullList<ItemStack> m_previousInventory = NonNullList.withSize( INVENTORY_SIZE, ItemStack.EMPTY );
     private final IItemHandlerModifiable m_itemHandler = new InvWrapper( this );
     private LazyOptional<IItemHandlerModifiable> itemHandlerCap;
-    private boolean m_inventoryChanged;
-    private TurtleBrain m_brain;
-    private MoveState m_moveState;
+    private boolean m_inventoryChanged = false;
+    private TurtleBrain m_brain = new TurtleBrain( this );
+    private MoveState m_moveState = MoveState.NOT_MOVED;
 
     public TileTurtle( TileEntityType<? extends TileGeneric> type, ComputerFamily family )
     {
         super( type, family );
-        m_inventory = NonNullList.withSize( INVENTORY_SIZE, ItemStack.EMPTY );
-        m_previousInventory = NonNullList.withSize( INVENTORY_SIZE, ItemStack.EMPTY );
-        m_inventoryChanged = false;
-        m_brain = new TurtleBrain( this );
-        m_moveState = MoveState.NOT_MOVED;
     }
 
-    public boolean hasMoved()
+    private boolean hasMoved()
     {
         return m_moveState == MoveState.MOVED;
     }
@@ -237,18 +229,15 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
     {
         super.tick();
         m_brain.update();
-        synchronized( m_inventory )
+        if( !getWorld().isRemote && m_inventoryChanged )
         {
-            if( !getWorld().isRemote && m_inventoryChanged )
-            {
-                ServerComputer computer = getServerComputer();
-                if( computer != null ) computer.queueEvent( "turtle_inventory" );
+            ServerComputer computer = getServerComputer();
+            if( computer != null ) computer.queueEvent( "turtle_inventory" );
 
-                m_inventoryChanged = false;
-                for( int n = 0; n < getSizeInventory(); n++ )
-                {
-                    m_previousInventory.set( n, InventoryUtil.copyItem( getStackInSlot( n ) ) );
-                }
+            m_inventoryChanged = false;
+            for( int n = 0; n < getSizeInventory(); n++ )
+            {
+                m_previousInventory.set( n, getStackInSlot( n ).copy() );
             }
         }
     }
@@ -288,8 +277,8 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
 
         // Read inventory
         ListNBT nbttaglist = nbt.getList( "Items", Constants.NBT.TAG_COMPOUND );
-        m_inventory = NonNullList.withSize( INVENTORY_SIZE, ItemStack.EMPTY );
-        m_previousInventory = NonNullList.withSize( INVENTORY_SIZE, ItemStack.EMPTY );
+        m_inventory.clear();
+        m_previousInventory.clear();
         for( int i = 0; i < nbttaglist.size(); i++ )
         {
             CompoundNBT tag = nbttaglist.getCompound( i );
@@ -297,7 +286,7 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
             if( slot < getSizeInventory() )
             {
                 m_inventory.set( slot, ItemStack.read( tag ) );
-                m_previousInventory.set( slot, InventoryUtil.copyItem( m_inventory.get( slot ) ) );
+                m_previousInventory.set( slot, m_inventory.get( slot ).copy() );
             }
         }
 
@@ -396,7 +385,7 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
         return m_brain.getToolRenderAngle( side, f );
     }
 
-    public void setOwningPlayer( GameProfile player )
+    void setOwningPlayer( GameProfile player )
     {
         m_brain.setOwningPlayer( player );
         markDirty();
@@ -424,109 +413,76 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
     @Override
     public ItemStack getStackInSlot( int slot )
     {
-        if( slot >= 0 && slot < INVENTORY_SIZE )
-        {
-            synchronized( m_inventory )
-            {
-                return m_inventory.get( slot );
-            }
-        }
-        return ItemStack.EMPTY;
+        return slot >= 0 && slot < INVENTORY_SIZE ? m_inventory.get( slot ) : ItemStack.EMPTY;
     }
 
     @Nonnull
     @Override
     public ItemStack removeStackFromSlot( int slot )
     {
-        synchronized( m_inventory )
-        {
-            ItemStack result = getStackInSlot( slot );
-            setInventorySlotContents( slot, ItemStack.EMPTY );
-            return result;
-        }
+        ItemStack result = getStackInSlot( slot );
+        setInventorySlotContents( slot, ItemStack.EMPTY );
+        return result;
     }
 
     @Nonnull
     @Override
     public ItemStack decrStackSize( int slot, int count )
     {
-        if( count == 0 )
+        if( count == 0 ) return ItemStack.EMPTY;
+
+        ItemStack stack = getStackInSlot( slot );
+        if( stack.isEmpty() ) return ItemStack.EMPTY;
+
+        if( stack.getCount() <= count )
         {
-            return ItemStack.EMPTY;
+            setInventorySlotContents( slot, ItemStack.EMPTY );
+            return stack;
         }
 
-        synchronized( m_inventory )
-        {
-            ItemStack stack = getStackInSlot( slot );
-            if( stack.isEmpty() )
-            {
-                return ItemStack.EMPTY;
-            }
-
-            if( stack.getCount() <= count )
-            {
-                setInventorySlotContents( slot, ItemStack.EMPTY );
-                return stack;
-            }
-
-            ItemStack part = stack.split( count );
-            onInventoryDefinitelyChanged();
-            return part;
-        }
+        ItemStack part = stack.split( count );
+        onInventoryDefinitelyChanged();
+        return part;
     }
 
     @Override
     public void setInventorySlotContents( int i, @Nonnull ItemStack stack )
     {
-        if( i >= 0 && i < INVENTORY_SIZE )
+        if( i >= 0 && i < INVENTORY_SIZE && !InventoryUtil.areItemsEqual( stack, m_inventory.get( i ) ) )
         {
-            synchronized( m_inventory )
-            {
-                if( !InventoryUtil.areItemsEqual( stack, m_inventory.get( i ) ) )
-                {
-                    m_inventory.set( i, stack );
-                    onInventoryDefinitelyChanged();
-                }
-            }
+            m_inventory.set( i, stack );
+            onInventoryDefinitelyChanged();
         }
     }
 
     @Override
     public void clear()
     {
-        synchronized( m_inventory )
+        boolean changed = false;
+        for( int i = 0; i < INVENTORY_SIZE; i++ )
         {
-            boolean changed = false;
-            for( int i = 0; i < INVENTORY_SIZE; i++ )
+            if( !m_inventory.get( i ).isEmpty() )
             {
-                if( !m_inventory.get( i ).isEmpty() )
-                {
-                    m_inventory.set( i, ItemStack.EMPTY );
-                    changed = true;
-                }
-            }
-            if( changed )
-            {
-                onInventoryDefinitelyChanged();
+                m_inventory.set( i, ItemStack.EMPTY );
+                changed = true;
             }
         }
+
+        if( changed ) onInventoryDefinitelyChanged();
     }
 
     @Override
     public void markDirty()
     {
         super.markDirty();
-        synchronized( m_inventory )
+        if( !m_inventoryChanged )
         {
-            if( !m_inventoryChanged )
+            for( int n = 0; n < getSizeInventory(); n++ )
             {
-                for( int n = 0; n < getSizeInventory(); n++ )
+                if( !ItemStack.areItemStacksEqual( getStackInSlot( n ), m_previousInventory.get( n ) ) )
                 {
-                    if( !ItemStack.areItemStacksEqual( getStackInSlot( n ), m_previousInventory.get( n ) ) )
-                    {
-                        m_inventoryChanged = true;
-                        break;
-                    }
+                    m_inventoryChanged = true;
+                    break;
                 }
             }
         }
@@ -563,7 +519,6 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
     {
         super.readDescription( nbt );
         m_brain.readDescription( nbt );
-        updateBlock();
     }
 
     // Privates
@@ -588,8 +543,8 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
     public void transferStateFrom( TileTurtle copy )
     {
         super.transferStateFrom( copy );
-        m_inventory = copy.m_inventory;
-        m_previousInventory = copy.m_previousInventory;
+        Collections.copy( m_inventory, copy.m_inventory );
+        Collections.copy( m_previousInventory, copy.m_previousInventory );
         m_inventoryChanged = copy.m_inventoryChanged;
         m_brain = copy.m_brain;
         m_brain.setOwner( this );

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

@@ -23,6 +23,7 @@ import dan200.computercraft.shared.turtle.blocks.TileTurtle;
 import dan200.computercraft.shared.util.Colour;
 import dan200.computercraft.shared.util.Holiday;
 import dan200.computercraft.shared.util.HolidayUtil;
+import dan200.computercraft.shared.util.InventoryDelegate;
 import net.minecraft.block.Block;
 import net.minecraft.block.BlockState;
 import net.minecraft.entity.Entity;
@@ -43,6 +44,7 @@ import net.minecraft.util.math.Vec3d;
 import net.minecraft.world.World;
 import net.minecraftforge.common.util.Constants;
 import net.minecraftforge.items.IItemHandlerModifiable;
+import net.minecraftforge.items.wrapper.InvWrapper;
 
 import javax.annotation.Nonnull;
 import java.util.*;
@@ -68,6 +70,9 @@ public class TurtleBrain implements ITurtleAccess
     private ComputerProxy m_proxy;
     private GameProfile m_owningPlayer;
 
+    private final IInventory m_inventory = (InventoryDelegate) () -> m_owner;
+    private final IItemHandlerModifiable m_inventoryWrapper = new InvWrapper( m_inventory );
+
     private Queue<TurtleCommandQueueEntry> m_commandQueue = new ArrayDeque<>();
     private int m_commandsIssued = 0;
 
@@ -439,14 +444,14 @@ public class TurtleBrain implements ITurtleAccess
     @Override
     public IInventory getInventory()
     {
-        return m_owner;
+        return m_inventory;
     }
 
     @Nonnull
     @Override
     public IItemHandlerModifiable getItemHandler()
     {
-        return m_owner.getItemHandler();
+        return m_inventoryWrapper;
     }
 
     @Override

src/main/java/dan200/computercraft/shared/turtle/core/TurtleCompareCommand.java

@@ -14,8 +14,8 @@ import net.minecraft.block.BlockState;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.Direction;
 import net.minecraft.util.math.BlockPos;
-import net.minecraft.world.ServerWorld;
 import net.minecraft.world.World;
+import net.minecraft.world.server.ServerWorld;
 import net.minecraftforge.fml.common.ObfuscationReflectionHelper;
 
 import javax.annotation.Nonnull;

src/main/java/dan200/computercraft/shared/turtle/core/TurtlePlayer.java

@@ -17,7 +17,7 @@ import net.minecraft.item.ItemStack;
 import net.minecraft.util.Direction;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.Vec3d;
-import net.minecraft.world.ServerWorld;
+import net.minecraft.world.server.ServerWorld;
 import net.minecraftforge.common.util.FakePlayer;
 
 import javax.annotation.Nonnull;

src/main/java/dan200/computercraft/shared/turtle/inventory/ContainerTurtle.java

@@ -44,7 +44,7 @@ public class ContainerTurtle extends ContainerComputerBase
         super( TYPE, id, canUse, computer, family );
         this.properties = properties;
 
-        func_216961_a( properties );
+        trackIntArray( properties );
 
         // Turtle inventory
         for( int y = 0; y < 4; y++ )

src/main/java/dan200/computercraft/shared/turtle/upgrades/TurtleInventoryCrafting.java

@@ -15,8 +15,8 @@ import net.minecraft.item.ItemStack;
 import net.minecraft.item.crafting.IRecipe;
 import net.minecraft.item.crafting.IRecipeType;
 import net.minecraft.util.NonNullList;
-import net.minecraft.world.ServerWorld;
 import net.minecraft.world.World;
+import net.minecraft.world.server.ServerWorld;
 import net.minecraftforge.common.ForgeHooks;
 import net.minecraftforge.fml.hooks.BasicEventHooks;
 

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

@@ -248,7 +248,7 @@ public class TurtleTool extends AbstractTurtleUpgrade
         boolean canHarvest = state.canHarvestBlock( world, blockPosition, turtlePlayer );
         boolean canBreak = state.removedByPlayer( world, blockPosition, turtlePlayer, canHarvest, fluidState );
         if( canBreak ) state.getBlock().onPlayerDestroy( world, blockPosition, state );
-        if( canHarvest )
+        if( canHarvest && canBreak )
         {
             state.getBlock().harvestBlock( world, turtlePlayer, blockPosition, state, tile, turtlePlayer.getHeldItemMainhand() );
         }

src/main/java/dan200/computercraft/shared/util/DropConsumer.java

@@ -14,8 +14,6 @@ import net.minecraft.util.math.AxisAlignedBB;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.world.World;
 import net.minecraftforge.event.entity.EntityJoinWorldEvent;
-import net.minecraftforge.event.entity.living.LivingDropsEvent;
-import net.minecraftforge.event.world.BlockEvent;
 import net.minecraftforge.eventbus.api.EventPriority;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
 import net.minecraftforge.fml.common.Mod;
@@ -36,7 +34,6 @@ public final class DropConsumer
     private static Function<ItemStack, ItemStack> dropConsumer;
     private static List<ItemStack> remainingDrops;
     private static WeakReference<World> dropWorld;
-    private static BlockPos dropPos;
     private static AxisAlignedBB dropBounds;
     private static WeakReference<Entity> dropEntity;
 
@@ -46,7 +43,6 @@ public final class DropConsumer
         remainingDrops = new ArrayList<>();
         dropEntity = new WeakReference<>( entity );
         dropWorld = new WeakReference<>( entity.world );
-        dropPos = null;
         dropBounds = new AxisAlignedBB( entity.getPosition() ).grow( 2, 2, 2 );
 
         entity.captureDrops( new ArrayList<>() );
@@ -55,10 +51,9 @@ public final class DropConsumer
     public static void set( World world, BlockPos pos, Function<ItemStack, ItemStack> consumer )
     {
         dropConsumer = consumer;
-        remainingDrops = new ArrayList<>();
+        remainingDrops = new ArrayList<>( 2 );
         dropEntity = null;
         dropWorld = new WeakReference<>( world );
-        dropPos = pos;
         dropBounds = new AxisAlignedBB( pos ).grow( 2, 2, 2 );
     }
 
@@ -83,7 +78,6 @@ public final class DropConsumer
         remainingDrops = null;
         dropEntity = null;
         dropWorld = null;
-        dropPos = null;
         dropBounds = null;
 
         return remainingStacks;
@@ -95,34 +89,7 @@ public final class DropConsumer
         if( !remaining.isEmpty() ) remainingDrops.add( remaining );
     }
 
-    @SubscribeEvent( priority = EventPriority.LOWEST )
-    public static void onEntityLivingDrops( LivingDropsEvent event )
-    {
-        // Capture any mob drops for the current entity
-        if( dropEntity != null && event.getEntity() == dropEntity.get() )
-        {
-            Collection<ItemEntity> drops = event.getDrops();
-            for( ItemEntity entityItem : drops ) handleDrops( entityItem.getItem() );
-            drops.clear();
-        }
-    }
-
-    @SubscribeEvent( priority = EventPriority.LOWEST )
-    public static void onHarvestDrops( BlockEvent.HarvestDropsEvent event )
-    {
-        // Capture block drops for the current entity
-        if( dropWorld != null && dropWorld.get() == event.getWorld()
-            && dropPos != null && dropPos.equals( event.getPos() ) )
-        {
-            for( ItemStack item : event.getDrops() )
-            {
-                if( event.getWorld().getRandom().nextFloat() < event.getDropChance() ) handleDrops( item );
-            }
-            event.getDrops().clear();
-        }
-    }
-
-    @SubscribeEvent( priority = EventPriority.LOWEST )
+    @SubscribeEvent( priority = EventPriority.HIGHEST )
     public static void onEntitySpawn( EntityJoinWorldEvent event )
     {
         // Capture any nearby item spawns

src/main/java/dan200/computercraft/shared/util/InventoryDelegate.java

@@ -0,0 +1,120 @@
+/*
+ * This file is part of ComputerCraft - http://www.computercraft.info
+ * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
+ * Send enquiries to dratcliffe@gmail.com
+ */
+
+package dan200.computercraft.shared.util;
+
+import net.minecraft.entity.player.PlayerEntity;
+import net.minecraft.inventory.IInventory;
+import net.minecraft.item.Item;
+import net.minecraft.item.ItemStack;
+
+import javax.annotation.Nonnull;
+import java.util.Set;
+
+/**
+ * Provides a delegate over inventories.
+ *
+ * This may be used both on {@link net.minecraft.tileentity.TileEntity}s to redirect the inventory to another tile,
+ * and by other interfaces to have inventories which change their backing store.
+ */
+@FunctionalInterface
+public interface InventoryDelegate extends IInventory
+{
+    IInventory getInventory();
+
+    @Override
+    default int getSizeInventory()
+    {
+        return getInventory().getSizeInventory();
+    }
+
+    @Override
+    default boolean isEmpty()
+    {
+        return getInventory().isEmpty();
+    }
+
+    @Nonnull
+    @Override
+    default ItemStack getStackInSlot( int slot )
+    {
+        return getInventory().getStackInSlot( slot );
+    }
+
+    @Nonnull
+    @Override
+    default ItemStack decrStackSize( int slot, int count )
+    {
+        return getInventory().decrStackSize( slot, count );
+    }
+
+    @Nonnull
+    @Override
+    default ItemStack removeStackFromSlot( int slot )
+    {
+        return getInventory().removeStackFromSlot( slot );
+    }
+
+    @Override
+    default void setInventorySlotContents( int slot, ItemStack stack )
+    {
+        getInventory().setInventorySlotContents( slot, stack );
+    }
+
+    @Override
+    default int getInventoryStackLimit()
+    {
+        return getInventory().getInventoryStackLimit();
+    }
+
+    @Override
+    default void markDirty()
+    {
+        getInventory().markDirty();
+    }
+
+    @Override
+    default boolean isUsableByPlayer( @Nonnull PlayerEntity player )
+    {
+        return getInventory().isUsableByPlayer( player );
+    }
+
+    @Override
+    default void openInventory( @Nonnull PlayerEntity player )
+    {
+        getInventory().openInventory( player );
+    }
+
+    @Override
+    default void closeInventory( @Nonnull PlayerEntity player )
+    {
+        getInventory().closeInventory( player );
+    }
+
+    @Override
+    default boolean isItemValidForSlot( int slot, @Nonnull ItemStack stack )
+    {
+        return getInventory().isItemValidForSlot( slot, stack );
+    }
+
+    @Override
+    default void clear()
+    {
+        getInventory().clear();
+    }
+
+    @Override
+    default int count( @Nonnull Item stack )
+    {
+        return getInventory().count( stack );
+    }
+
+    @Override
+    default boolean hasAny( @Nonnull Set<Item> set )
+    {
+        return getInventory().hasAny( set );
+    }
+}

src/main/java/dan200/computercraft/shared/util/InventoryUtil.java

@@ -70,12 +70,6 @@ public final class InventoryUtil
         return shareTagA.equals( shareTagB );
     }
 
-    @Nonnull
-    public static ItemStack copyItem( @Nonnull ItemStack a )
-    {
-        return a.copy();
-    }
-
     // Methods for finding inventories:
 
     public static IItemHandler getInventory( World world, BlockPos pos, Direction side )

src/main/java/dan200/computercraft/shared/util/NamedTileEntityType.java

@@ -6,16 +6,10 @@
 
 package dan200.computercraft.shared.util;
 
-import com.mojang.datafixers.DataFixUtils;
-import com.mojang.datafixers.types.Type;
-import dan200.computercraft.ComputerCraft;
 import net.minecraft.block.Block;
 import net.minecraft.tileentity.TileEntity;
 import net.minecraft.tileentity.TileEntityType;
 import net.minecraft.util.ResourceLocation;
-import net.minecraft.util.SharedConstants;
-import net.minecraft.util.datafix.DataFixesManager;
-import net.minecraft.util.datafix.TypeReferences;
 
 import javax.annotation.Nonnull;
 import java.util.Collections;
@@ -30,7 +24,7 @@ public final class NamedTileEntityType<T extends TileEntity> extends TileEntityT
 
     private NamedTileEntityType( ResourceLocation identifier, Supplier<? extends T> supplier )
     {
-        super( supplier, Collections.emptySet(), getDatafixer( identifier ) );
+        super( supplier, Collections.emptySet(), null );
         this.identifier = identifier;
         setRegistryName( identifier );
     }
@@ -62,22 +56,6 @@ public final class NamedTileEntityType<T extends TileEntity> extends TileEntityT
         return identifier;
     }
 
-    private static Type<?> getDatafixer( ResourceLocation id )
-    {
-        try
-        {
-            return DataFixesManager.getDataFixer()
-                .getSchema( DataFixUtils.makeKey( ComputerCraft.DATAFIXER_VERSION ) )
-                .getChoiceType( TypeReferences.BLOCK_ENTITY, id.toString() );
-        }
-        catch( IllegalArgumentException e )
-        {
-            if( SharedConstants.developmentMode ) throw e;
-            ComputerCraft.log.warn( "No data fixer registered for block entity " + id );
-            return null;
-        }
-    }
-
     private static final class FixedPointSupplier<T extends TileEntity> implements Supplier<T>
     {
         final NamedTileEntityType<T> factory;

src/main/java/dan200/computercraft/shared/util/RecordUtil.java

@@ -9,17 +9,11 @@ package dan200.computercraft.shared.util;
 import dan200.computercraft.shared.network.NetworkHandler;
 import dan200.computercraft.shared.network.NetworkMessage;
 import dan200.computercraft.shared.network.client.PlayRecordClientMessage;
-import net.minecraft.item.Item;
-import net.minecraft.item.ItemStack;
-import net.minecraft.item.MusicDiscItem;
 import net.minecraft.util.SoundEvent;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.Vec3d;
-import net.minecraft.util.text.TranslationTextComponent;
 import net.minecraft.world.World;
 
-import javax.annotation.Nonnull;
-
 public final class RecordUtil
 {
     private RecordUtil() {}
@@ -29,12 +23,4 @@ public final class RecordUtil
         NetworkMessage packet = record != null ? new PlayRecordClientMessage( pos, record, recordInfo ) : new PlayRecordClientMessage( pos );
         NetworkHandler.sendToAllAround( packet, world, new Vec3d( pos ), 64 );
     }
-
-    public static String getRecordInfo( @Nonnull ItemStack recordStack )
-    {
-        Item item = recordStack.getItem();
-        if( !(item instanceof MusicDiscItem) ) return null;
-
-        return new TranslationTextComponent( item.getTranslationKey() + ".desc" ).getString();
-    }
 }

src/main/java/dan200/computercraft/shared/util/TickScheduler.java

@@ -13,9 +13,9 @@ import net.minecraft.tileentity.TileEntity;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.world.ITickList;
 import net.minecraft.world.World;
+import net.minecraftforge.event.TickEvent;
 import net.minecraftforge.eventbus.api.SubscribeEvent;
 import net.minecraftforge.fml.common.Mod;
-import net.minecraftforge.fml.common.gameevent.TickEvent;
 
 import java.util.Collections;
 import java.util.Iterator;

src/main/java/dan200/computercraft/shared/util/WorldUtil.java

@@ -7,6 +7,7 @@
 package dan200.computercraft.shared.util;
 
 import com.google.common.base.Predicate;
+import com.google.common.collect.MapMaker;
 import net.minecraft.block.BlockState;
 import net.minecraft.entity.*;
 import net.minecraft.entity.item.ItemEntity;
@@ -20,25 +21,35 @@ import org.apache.commons.lang3.tuple.Pair;
 
 import javax.annotation.Nonnull;
 import java.util.List;
+import java.util.Map;
 
 public final class WorldUtil
 {
     @SuppressWarnings( "Guava" )
     private static final Predicate<Entity> CAN_COLLIDE = x -> x != null && x.isAlive() && x.canBeCollidedWith();
 
-    private static final Entity ENTITY = new ItemEntity( EntityType.ITEM, null )
-    {
-        @Override
-        public EntitySize getSize( Pose pose )
-        {
-            return EntitySize.fixed( 0, 0 );
-        }
-    };
+    private static final Map<World, Entity> entityCache = new MapMaker().weakKeys().weakValues().makeMap();
 
-    static
+    private static synchronized Entity getEntity( World world )
     {
-        ENTITY.noClip = true;
-        ENTITY.recalculateSize();
+        // TODO: It'd be nice if we could avoid this. Maybe always use the turtle player (if it's available).
+        Entity entity = entityCache.get( world );
+        if( entity != null ) return entity;
+
+        entity = new ItemEntity( EntityType.ITEM, world )
+        {
+            @Nonnull
+            @Override
+            public EntitySize getSize( Pose pose )
+            {
+                return EntitySize.fixed( 0, 0 );
+            }
+        };
+
+        entity.noClip = true;
+        entity.recalculateSize();
+        entityCache.put( world, entity );
+        return entity;
     }
 
     public static boolean isLiquidBlock( World world, BlockPos pos )
@@ -61,8 +72,9 @@ public final class WorldUtil
         Vec3d vecEnd = vecStart.add( vecDir.x * distance, vecDir.y * distance, vecDir.z * distance );
 
         // Raycast for blocks
-        ENTITY.setPosition( vecStart.x, vecStart.y, vecStart.z );
-        RayTraceContext context = new RayTraceContext( vecStart, vecEnd, RayTraceContext.BlockMode.COLLIDER, RayTraceContext.FluidMode.NONE, ENTITY );
+        Entity collisionEntity = getEntity( world );
+        collisionEntity.setPosition( vecStart.x, vecStart.y, vecStart.z );
+        RayTraceContext context = new RayTraceContext( vecStart, vecEnd, RayTraceContext.BlockMode.COLLIDER, RayTraceContext.FluidMode.NONE, collisionEntity );
         RayTraceResult result = world.rayTraceBlocks( context );
         if( result != null && result.getType() == RayTraceResult.Type.BLOCK )
         {

src/main/resources/META-INF/mods.toml

@@ -1,5 +1,5 @@
 modLoader="javafml"
-loaderVersion="[27,28)"
+loaderVersion="[28,29)"
 
 issueTrackerURL="https://github.com/SquidDev-CC/CC-Tweaked/issues"
 displayURL="https://github.com/SquidDev-CC/CC-Tweaked"
@@ -19,6 +19,6 @@ CC: Tweaked is a fork of ComputerCraft, adding programmable computers, turtles a
 [[dependencies.computercraft]]
     modId="forge"
     mandatory=true
-    versionRange="[27,28)"
+    versionRange="[28,29)"
     ordering="NONE"
     side="BOTH"

src/main/resources/data/computercraft/lua/bios.lua

@@ -1,48 +1,19 @@
-local native_select, native_type = select, type
-
---- Expect an argument to have a specific type.
+-- Load in expect from the module path.
 --
--- @tparam int index The 1-based argument index.
--- @param value The argument's value.
--- @tparam string ... The allowed types of the argument.
--- @throws If the value is not one of the allowed types.
-local function expect(index, value, ...)
-    local t = native_type(value)
-    for i = 1, native_select("#", ...) do
-        if t == native_select(i, ...) then return true end
-    end
+-- Ideally we'd use require, but that is part of the shell, and so is not
+-- available to the BIOS or any APIs. All APIs load this using dofile, but that
+-- has not been defined at this point.
+local expect
 
-    local types = table.pack(...)
-    for i = types.n, 1, -1 do
-        if types[i] == "nil" then table.remove(types, i) end
-    end
+do
+    local h = fs.open("rom/modules/main/cc/expect.lua", "r")
+    local f, err = loadstring(h.readAll(), "@expect.lua")
+    h.close()
 
-    local type_names
-    if #types <= 1 then
-        type_names = tostring(...)
-    else
-        type_names = table.concat(types, ", ", 1, #types - 1) .. " or " .. types[#types]
-    end
-
-    -- If we can determine the function name with a high level of confidence, try to include it.
-    local name
-    if native_type(debug) == "table" and native_type(debug.getinfo) == "function" then
-        local ok, info = pcall(debug.getinfo, 3, "nS")
-        if ok and info.name and #info.name ~= "" and info.what ~= "C" then name = info.name end
-    end
-
-    if name then
-        error( ("bad argument #%d to '%s' (expected %s, got %s)"):format(index, name, type_names, t), 3 )
-    else
-        error( ("bad argument #%d (expected %s, got %s)"):format(index, type_names, t), 3 )
-    end
+    if not f then error(err) end
+    expect = f().expect
 end
 
--- We expose expect in the global table as APIs need to access it, but give it
--- a non-identifier name - meaning it does not show up in auto-completion.
--- expect is an internal function, and should not be used by users.
-_G["~expect"] = expect
-
 if _VERSION == "Lua 5.1" then
     -- If we're on Lua 5.1, install parts of the Lua 5.2/5.3 API so that programs can be written against it
     local type = type
@@ -568,23 +539,28 @@ function read( _sReplaceChar, _tHistory, _fnComplete, _sDefault )
     return sLine
 end
 
-function loadfile( _sFile, _tEnv )
-    expect(1, _sFile, "string")
-    expect(2, _tEnv, "table", "nil")
-
-    local file = fs.open( _sFile, "r" )
-    if file then
-        local func, err = load( file.readAll(), "@" .. fs.getName( _sFile ), "t", _tEnv )
-        file.close()
-        return func, err
+function loadfile( filename, mode, env )
+    -- Support the previous `loadfile(filename, env)` form instead.
+    if type(mode) == "table" and env == nil then
+        mode, env = nil, mode
     end
-    return nil, "File not found"
+
+    expect(1, filename, "string")
+    expect(2, mode, "string", "nil")
+    expect(3, env, "table", "nil")
+
+    local file = fs.open( filename, "r" )
+    if not file then return nil, "File not found" end
+
+    local func, err = load( file.readAll(), "@" .. fs.getName( filename ), mode, env )
+    file.close()
+    return func, err
 end
 
 function dofile( _sFile )
     expect(1, _sFile, "string")
 
-    local fnFile, e = loadfile( _sFile, _G )
+    local fnFile, e = loadfile( _sFile, nil, _G )
     if fnFile then
         return fnFile()
     else
@@ -600,7 +576,7 @@ function os.run( _tEnv, _sPath, ... )
     local tArgs = table.pack( ... )
     local tEnv = _tEnv
     setmetatable( tEnv, { __index = _G } )
-    local fnFile, err = loadfile( _sPath, tEnv )
+    local fnFile, err = loadfile( _sPath, nil, tEnv )
     if fnFile then
         local ok, err = pcall( function()
             fnFile( table.unpack( tArgs, 1, tArgs.n ) )
@@ -634,7 +610,7 @@ function os.loadAPI( _sPath )
 
     local tEnv = {}
     setmetatable( tEnv, { __index = _G } )
-    local fnAPI, err = loadfile( _sPath, tEnv )
+    local fnAPI, err = loadfile( _sPath, nil, tEnv )
     if fnAPI then
         local ok, err = pcall( fnAPI )
         if not ok then

src/main/resources/data/computercraft/lua/rom/apis/colors.lua

@@ -1,4 +1,4 @@
-local expect = _G["~expect"]
+local expect = dofile("rom/modules/main/cc/expect.lua").expect
 
 -- Colors
 white = 1

src/main/resources/data/computercraft/lua/rom/apis/gps.lua

@@ -1,4 +1,4 @@
-local expect = _G["~expect"]
+local expect = dofile("rom/modules/main/cc/expect.lua").expect
 
 CHANNEL_GPS = 65534
 

src/main/resources/data/computercraft/lua/rom/apis/help.lua

@@ -1,4 +1,4 @@
-local expect = _G["~expect"]
+local expect = dofile("rom/modules/main/cc/expect.lua").expect
 
 local sPath = "/rom/help"
 

src/main/resources/data/computercraft/lua/rom/apis/io.lua

@@ -1,6 +1,6 @@
 -- Definition for the IO API
 
-local expect, typeOf = _G["~expect"], _G.type
+local expect, typeOf = dofile("rom/modules/main/cc/expect.lua").expect, _G.type
 
 --- If we return nil then close the file, as we've reached the end.
 -- We use this weird wrapper function as we wish to preserve the varargs

src/main/resources/data/computercraft/lua/rom/apis/keys.lua

@@ -8,7 +8,7 @@
 -- taught me anything, it's that emulating LWJGL's weird key handling is nigh-on
 -- impossible.
 
-local expect = _G["~expect"]
+local expect = dofile("rom/modules/main/cc/expect.lua").expect
 
 local tKeys = {}
 tKeys[32] = 'space'

src/main/resources/data/computercraft/lua/rom/apis/paintutils.lua

@@ -1,4 +1,4 @@
-local expect = _G["~expect"]
+local expect = dofile("rom/modules/main/cc/expect.lua").expect
 
 local function drawPixelInternal( xPos, yPos )
     term.setCursorPos( xPos, yPos )

src/main/resources/data/computercraft/lua/rom/apis/peripheral.lua

@@ -1,4 +1,4 @@
-local expect = _G["~expect"]
+local expect = dofile("rom/modules/main/cc/expect.lua").expect
 
 local native = peripheral
 

src/main/resources/data/computercraft/lua/rom/apis/rednet.lua

@@ -1,4 +1,4 @@
-local expect = _G["~expect"]
+local expect = dofile("rom/modules/main/cc/expect.lua").expect
 
 CHANNEL_BROADCAST = 65535
 CHANNEL_REPEAT = 65533

src/main/resources/data/computercraft/lua/rom/apis/settings.lua

@@ -1,4 +1,4 @@
-local expect = _G["~expect"]
+local expect = dofile("rom/modules/main/cc/expect.lua").expect
 
 local tSettings = {}
 

src/main/resources/data/computercraft/lua/rom/apis/term.lua

@@ -1,4 +1,4 @@
-local expect = _G["~expect"]
+local expect = dofile("rom/modules/main/cc/expect.lua").expect
 
 local native = (term.native and term.native()) or term
 local redirectTarget = native

src/main/resources/data/computercraft/lua/rom/apis/textutils.lua

@@ -1,4 +1,4 @@
-local expect = _G["~expect"]
+local expect = dofile("rom/modules/main/cc/expect.lua").expect
 
 function slowWrite( sText, nRate )
     expect(2, nRate, "number", "nil")

src/main/resources/data/computercraft/lua/rom/apis/window.lua

@@ -1,4 +1,4 @@
-local expect = _G["~expect"]
+local expect = dofile("rom/modules/main/cc/expect.lua").expect
 
 local tHex = {
     [ colors.white ] = "0",
@@ -388,6 +388,16 @@ function create( parent, nX, nY, nWidth, nHeight, bStartVisible )
         return nBackgroundColor
     end
 
+    function window.getLine(y)
+        if type(y) ~= "number" then expect(1, y, "number") end
+
+        if y < 1 or y > nHeight then
+            error("Line is out of range.", 2)
+        end
+
+        return tLines[y].text, tLines[y].textColor, tLines[y].backgroundColor
+    end
+
     -- Other functions
     function window.setVisible( bVis )
         if type(bVis) ~= "boolean" then expect(1, bVis, "boolean") end
@@ -421,16 +431,20 @@ function create( parent, nX, nY, nWidth, nHeight, bStartVisible )
         return nX, nY
     end
 
-    function window.reposition( nNewX, nNewY, nNewWidth, nNewHeight )
+    function window.reposition( nNewX, nNewY, nNewWidth, nNewHeight, newParent )
         if type(nNewX) ~= "number" then expect(1, nNewX, "number") end
         if type(nNewY) ~= "number" then expect(2, nNewY, "number") end
         if nNewWidth ~= nil or nNewHeight ~= nil then
             expect(3, nNewWidth, "number")
             expect(4, nNewHeight, "number")
         end
+        if newParent ~= nil and type(newParent) ~= "table" then expect(5, newParent, "table") end
 
         nX = nNewX
         nY = nNewY
+
+        if newParent then parent = newParent end
+
         if nNewWidth and nNewHeight then
             local tNewLines = {}
             createEmptyLines( nNewWidth )

src/main/resources/data/computercraft/lua/rom/help/changelog.txt

@@ -1,3 +1,37 @@
+# New features in CC: Tweaked 1.85.0
+
+* Window.reposition now allows changing the redirect buffer
+* Add cc.completion and cc.shell.completion modules
+* command.exec also returns the number of affected objects, when exposed by the game.
+
+And several bug fixes:
+* Change how turtle mining drops are handled, improving compatibility with some mods.
+* Fix several GUI desyncs after a turtle moves.
+* Fix os.day/os.time using the incorrect world time.
+* Prevent wired modems dropping incorrectly.
+* Fix mouse events not firing within the computer GUI.
+
+# New features in CC: Tweaked 1.84.1
+
+* Update to latest Forge
+
+# New features in CC: Tweaked 1.84.0
+
+* Improve validation in rename, copy and delete programs
+* Add window.getLine - the inverse of blit
+* turtle.refuel no longer consumes more fuel than needed
+* Add "cc.expect" module, for improved argument type checks
+* Mount the ROM from all mod jars, not just CC's
+
+And several bug fixes:
+* Ensure file error messages use the absolute correct path
+* Fix NPE when closing a file multiple times.
+* Do not load chunks when calling writeDescription.
+* Fix the signature of loadfile
+* Fix turtles harvesting blocks multiple times
+* Improve thread-safety of various peripherals
+* Prevent printed pages having massive/malformed titles
+
 # New features in CC: Tweaked 1.83.1
 
 * Add several new MOTD messages (JakobDev)

src/main/resources/data/computercraft/lua/rom/help/whatsnew.txt

@@ -1,10 +1,14 @@
-New features in CC: Tweaked 1.83.1
+New features in CC: Tweaked 1.85.0
 
-* Add several new MOTD messages (JakobDev)
+* Window.reposition now allows changing the redirect buffer
+* Add cc.completion and cc.shell.completion modules
+* command.exec also returns the number of affected objects, when exposed by the game.
 
 And several bug fixes:
-* Fix type check in `rednet.lookup`
-* Error if turtle and pocket computer programs are run on the wrong system (JakobDev)
-* Do not discard varargs after a nil.
+* Change how turtle mining drops are handled, improving compatibility with some mods.
+* Fix several GUI desyncs after a turtle moves.
+* Fix os.day/os.time using the incorrect world time.
+* Prevent wired modems dropping incorrectly.
+* Fix mouse events not firing within the computer GUI.
 
 Type "help changelog" to see the full version history.

src/main/resources/data/computercraft/lua/rom/help/window.txt

@@ -23,3 +23,4 @@ getPosition()
 reposition( x, y, width, height )
 getPaletteColor( color )
 setPaletteColor( color, r, g, b )
+getLine()

src/main/resources/data/computercraft/lua/rom/modules/main/cc/completion.lua

@@ -0,0 +1,105 @@
+--- A collection of helper methods for working with input completion, such
+-- as that require by @{read}.
+--
+-- @module craftos.completion
+-- @see cc.shell.completion For additional helpers to use with
+-- @{shell.setCompletionFunction}.
+
+local expect = require "cc.expect".expect
+
+local function choice_impl(text, choices, add_space)
+    local results = {}
+    for n = 1, #choices do
+        local option = choices[n]
+        if #option + (add_space and 1 or 0) > #text and option:sub(1, #text) == text then
+            local result = option:sub(#text + 1)
+            if add_space then
+                table.insert(results, result .. " ")
+            else
+                table.insert(results, result)
+            end
+        end
+    end
+    return results
+end
+
+--- Complete from a choice of one or more strings.
+--
+-- @tparam string text The input string to complete.
+-- @tparam { string... } choices The list of choices to complete from.
+-- @tparam[opt] boolean add_space Whether to add a space after the completed item.
+-- @treturn { string... } A list of suffixes of matching strings.
+-- @usage Call @{read}, completing the names of various animals.
+--
+--     local animals = { "dog", "cat", "lion", "unicorn" }
+--     read(nil, nil, function(text) return choice(text, animals) end)
+local function choice(text, choices, add_space)
+    expect(1, text, "string")
+    expect(2, choices, "table")
+    expect(3, add_space, "boolean", "nil")
+    return choice_impl(text, choices, add_space)
+end
+
+--- Complete the name of a currently attached peripheral.
+--
+-- @tparam string text The input string to complete.
+-- @tparam[opt] boolean add_space Whether to add a space after the completed name.
+-- @treturn { string... } A list of suffixes of matching peripherals.
+-- @usage read(nil, nil, peripheral)
+local function peripheral_(text, add_space)
+    expect(1, text, "string")
+    expect(2, add_space, "boolean", "nil")
+    return choice_impl(text, peripheral.getNames(), add_space)
+end
+
+local sides = redstone.getSides()
+
+--- Complete the side of a computer.
+--
+-- @tparam string text The input string to complete.
+-- @tparam[opt] boolean add_space Whether to add a space after the completed side.
+-- @treturn { string... } A list of suffixes of matching sides.
+-- @usage read(nil, nil, side)
+local function side(text, add_space)
+    expect(1, text, "string")
+    expect(2, add_space, "boolean", "nil")
+    return choice_impl(text, sides, add_space)
+end
+
+--- Complete a @{settings|setting}.
+--
+-- @tparam string text The input string to complete.
+-- @tparam[opt] boolean add_space Whether to add a space after the completed settings.
+-- @treturn { string... } A list of suffixes of matching settings.
+-- @usage read(nil, nil, setting)
+local function setting(text, add_space)
+    expect(1, text, "string")
+    expect(2, add_space, "boolean", "nil")
+    return choice_impl(text, settings.getNames(), add_space)
+end
+
+local command_list
+
+--- Complete the name of a Minecraft @{commands|command}.
+--
+-- @tparam string text The input string to complete.
+-- @tparam[opt] boolean add_space Whether to add a space after the completed command.
+-- @treturn { string... } A list of suffixes of matching commands.
+-- @usage read(nil, nil, command)
+local function command(text, add_space)
+    expect(1, text, "string")
+    expect(2, add_space, "boolean", "nil")
+    if command_list == nil then
+        command_list = commands and commands.list() or {}
+    end
+
+    return choice_impl(text, command_list, add_space)
+end
+
+return {
+    choice = choice,
+    peripheral = peripheral_,
+    side = side,
+    setting = setting,
+    command = command,
+}

src/main/resources/data/computercraft/lua/rom/modules/main/cc/expect.lua

@@ -0,0 +1,46 @@
+--- The @{craftos.expect} library provides helper functions for verifying that
+-- function arguments are well-formed and of the correct type.
+--
+-- @module craftos.expect
+
+local native_select, native_type = select, type
+
+--- Expect an argument to have a specific type.
+--
+-- @tparam int index The 1-based argument index.
+-- @param value The argument's value.
+-- @tparam string ... The allowed types of the argument.
+-- @throws If the value is not one of the allowed types.
+local function expect(index, value, ...)
+    local t = native_type(value)
+    for i = 1, native_select("#", ...) do
+        if t == native_select(i, ...) then return true end
+    end
+
+    local types = table.pack(...)
+    for i = types.n, 1, -1 do
+        if types[i] == "nil" then table.remove(types, i) end
+    end
+
+    local type_names
+    if #types <= 1 then
+        type_names = tostring(...)
+    else
+        type_names = table.concat(types, ", ", 1, #types - 1) .. " or " .. types[#types]
+    end
+
+    -- If we can determine the function name with a high level of confidence, try to include it.
+    local name
+    if native_type(debug) == "table" and native_type(debug.getinfo) == "function" then
+        local ok, info = pcall(debug.getinfo, 3, "nS")
+        if ok and info.name and #info.name ~= "" and info.what ~= "C" then name = info.name end
+    end
+
+    if name then
+        error( ("bad argument #%d to '%s' (expected %s, got %s)"):format(index, name, type_names, t), 3 )
+    else
+        error( ("bad argument #%d (expected %s, got %s)"):format(index, type_names, t), 3 )
+    end
+end
+
+return { expect = expect }

src/main/resources/data/computercraft/lua/rom/modules/main/cc/shell/completion.lua

@@ -0,0 +1,151 @@
+--- A collection of helper methods for working with shell completion.
+--
+-- Most programs may be completed using the @{build} helper method, rather than
+-- manually switching on the argument index.
+--
+-- Note, the helper functions within this module do not accept an argument index,
+-- and so are not directly usable with the @{shell.setCompletionFunction}. Instead,
+-- wrap them using @{build}, or your own custom function.
+--
+-- @module craftos.shell.completion
+-- @see cc.completion For more general helpers, suitable for use with @{read}.
+-- @see shell.setCompletionFunction
+
+local expect = require "cc.expect".expect
+local completion = require "cc.completion"
+
+--- Complete the name of a file relative to the current working directory.
+--
+-- @tparam shell shell The shell we're completing in
+-- @tparam { string... } choices The list of choices to complete from.
+-- @treturn { string... } A list of suffixes of matching files.
+local function file(shell, text)
+    return fs.complete(text, shell.dir(), true, false)
+end
+
+--- Complete the name of a directory relative to the current working directory.
+--
+-- @tparam shell shell The shell we're completing in
+-- @tparam { string... } choices The list of choices to complete from.
+-- @treturn { string... } A list of suffixes of matching directories.
+local function dir(shell, text)
+    return fs.complete(text, shell.dir(), false, true)
+end
+
+--- Complete the name of a file or directory relative to the current working
+-- directory.
+--
+-- @tparam shell shell The shell we're completing in
+-- @tparam { string... } choices The list of choices to complete from.
+-- @tparam { string... } previous The shell arguments before this one.
+-- @tparam[opt] boolean add_space Whether to add a space after the completed item.
+-- @treturn { string... } A list of suffixes of matching files and directories.
+local function dirOrFile(shell, text, previous, add_space)
+    local results = fs.complete(text, shell.dir(), true, true)
+    if add_space then
+        for n = 1, #results do
+            local result = results[n]
+            if result:sub(-1) ~= "/" then
+                results[n] = result .. " "
+            end
+        end
+    end
+    return results
+end
+
+local function wrap(func)
+    return function(shell, text, previous, ...)
+        return func(text, ...)
+    end
+end
+
+--- Complete the name of a program.
+--
+-- @tparam shell shell The shell we're completing in
+-- @tparam { string... } choices The list of choices to complete from.
+-- @treturn { string... } A list of suffixes of matching programs.
+local function program(shell, text)
+    return shell.completeProgram(text)
+end
+
+--- A helper function for building shell completion arguments.
+--
+-- This accepts a series of single-argument completion functions, and combines
+-- them into a function suitable for use with @{shell.setCompletionFunction}.
+--
+-- @tparam nil|table|function ... Every argument to @{build} represents an argument
+-- to the program you wish to complete. Each argument can be one of three types:
+--
+--  - `nil`: This argument will not be completed.
+--
+--  - A function: This argument will be completed with the given function. It is
+--    called with the @{shell} object, the string to complete and the arguments
+--    before this one.
+--
+--  - A table: This acts as a more powerful version of the function case. The table
+--    must have a function as the first item - this will be called with the shell,
+--    string and preceding arguments as above, but also followed by any additional
+--    items in the table. This provides a more convenient interface to pass
+--    options to your completion functions.
+--
+--    If this table is the last argument, it may also set the `many` key to true,
+--    which states this function should be used to complete any remaining arguments.
+--
+-- @usage Prompt for a choice of options, followed by a directory, and then multiple
+-- files.
+--
+--     complete.build(
+--       { complete.choice, { "get", "put" } },
+--       complete.dir,
+--       } complete.file, many = true }
+--     )
+local function build(...)
+    local arguments = table.pack(...)
+    for i = 1, arguments.n do
+        local arg = arguments[i]
+        if arg ~= nil then
+            expect(i, arg, "table", "function")
+            if type(arg) == "function" then
+                arg = { arg }
+                arguments[i] = arg
+            end
+
+            if type(arg[1]) ~= "function" then
+                error(("Bad table entry #1 at argument #%d (expected function, got %s)"):format(i, type(arg[1])), 2)
+            end
+
+            if arg.many and i < arguments.n then
+                error(("Unexpected 'many' field on argument #%d (should only occur on the last argument)"):format(i), 2)
+            end
+        end
+    end
+
+    return function(shell, index, text, previous)
+        local arg = arguments[index]
+        if not arg then
+            if index <= arguments.n then return end
+
+            arg = arguments[arguments.n]
+            if not arg or not arg.many then return end
+        end
+
+        return arg[1](shell, text, previous, table.unpack(arg, 2))
+    end
+end
+
+return {
+    file = file,
+    dir = dir,
+    dirOrFile = dirOrFile,
+    program = program,
+
+    -- Re-export various other functions
+    help = wrap(help.completeTopic),
+    choice = wrap(completion.choice),
+    peripheral = wrap(completion.peripheral),
+    side = wrap(completion.side),
+    setting = wrap(completion.setting),
+    command = wrap(completion.command),
+
+    build = build,
+}

src/main/resources/data/computercraft/lua/rom/programs/advanced/multishell.lua

@@ -1,4 +1,4 @@
-local expect = _G["~expect"]
+local expect = dofile("rom/modules/main/cc/expect.lua").expect
 
 -- Setup process switching
 local parentTerm = term.current()

src/main/resources/data/computercraft/lua/rom/programs/edit.lua

@@ -329,7 +329,7 @@ local tMenuFuncs = {
                 printer.setPageTitle( sName.." (page "..nPage..")" )
             end
 
-            while not printer.newPage()    do
+            while not printer.newPage() do
                 if printer.getInkLevel() < 1 then
                     sStatus = "Printer out of ink, please refill"
                 elseif printer.getPaperLevel() < 1 then
@@ -342,7 +342,6 @@ local tMenuFuncs = {
                 redrawMenu()
                 term.redirect( printerTerminal )
 
-                local timer = os.startTimer(0.5)
                 sleep(0.5)
             end
 

src/main/resources/data/computercraft/lua/rom/programs/help.lua

@@ -7,7 +7,7 @@ else
 end
 
 if sTopic == "index" then
-    print( "Help topics availiable:" )
+    print( "Help topics available:" )
     local tTopics = help.topics()
     textutils.pagedTabulate( tTopics )
     return

src/main/resources/data/computercraft/lua/rom/programs/shell.lua

@@ -1,4 +1,4 @@
-local expect = _G["~expect"]
+local expect = dofile("rom/modules/main/cc/expect.lua").expect
 
 local multishell = multishell
 local parentShell = shell
@@ -56,7 +56,7 @@ local function createShellEnv( sDir )
                     sPath = fs.combine(sDir, sPath)
                 end
                 if fs.exists(sPath) and not fs.isDir(sPath) then
-                    local fnFile, sError = loadfile( sPath, tEnv )
+                    local fnFile, sError = loadfile( sPath, nil, tEnv )
                     if fnFile then
                         return fnFile, sPath
                     else

src/main/resources/data/computercraft/lua/rom/startup.lua

@@ -1,3 +1,4 @@
+local completion = require "cc.shell.completion"
 
 -- Setup paths
 local sPath = ".:/rom/programs"
@@ -39,217 +40,86 @@ if term.isColor() then
 end
 
 -- Setup completion functions
-local function completeMultipleChoice( sText, tOptions, bAddSpaces )
-    local tResults = {}
-    for n=1,#tOptions do
-        local sOption = tOptions[n]
-        if #sOption + (bAddSpaces and 1 or 0) > #sText and string.sub( sOption, 1, #sText ) == sText then
-            local sResult = string.sub( sOption, #sText + 1 )
-            if bAddSpaces then
-                table.insert( tResults, sResult .. " " )
-            else
-                table.insert( tResults, sResult )
-            end
-        end
-    end
-    return tResults
-end
-local function completePeripheralName( sText, bAddSpaces )
-    return completeMultipleChoice( sText, peripheral.getNames(), bAddSpaces )
-end
-local tRedstoneSides = redstone.getSides()
-local function completeSide( sText, bAddSpaces )
-    return completeMultipleChoice( sText, tRedstoneSides, bAddSpaces )
-end
-local function completeFile( shell, nIndex, sText, tPreviousText )
-    if nIndex == 1 then
-        return fs.complete( sText, shell.dir(), true, false )
+
+local function completePastebinPut(shell, text, previous)
+    if previous[2] == "put" then
+        return fs.complete(text, shell.dir(), true, false )
     end
 end
-local function completeFileMany( shell, nIndex, sText, tPreviousText )
-    return fs.complete( sText, shell.dir(), true, false )
-end
-local function completeDir( shell, nIndex, sText, tPreviousText )
-    if nIndex == 1 then
-        return fs.complete( sText, shell.dir(), false, true )
-    end
-end
-local function completeEither( shell, nIndex, sText, tPreviousText )
-    if nIndex == 1 then
-        return fs.complete( sText, shell.dir(), true, true )
-    end
-end
-local function completeEitherMany( shell, nIndex, sText, tPreviousText )
-    return fs.complete( sText, shell.dir(), true, true )
-end
-local function completeEitherEither( shell, nIndex, sText, tPreviousText )
-    if nIndex == 1 then
-        local tResults = fs.complete( sText, shell.dir(), true, true )
-        for n=1,#tResults do
-            local sResult = tResults[n]
-            if string.sub( sResult, #sResult, #sResult ) ~= "/" then
-                tResults[n] = sResult .. " "
-            end
-        end
-        return tResults
-    elseif nIndex == 2 then
-        return fs.complete( sText, shell.dir(), true, true )
-    end
-end
-local function completeProgram( shell, nIndex, sText, tPreviousText )
-    if nIndex == 1 then
-        return shell.completeProgram( sText )
-    end
-end
-local function completeHelp( shell, nIndex, sText, tPreviousText )
-    if nIndex == 1 then
-        return help.completeTopic( sText )
-    end
-end
-local function completeAlias( shell, nIndex, sText, tPreviousText )
-    if nIndex == 2 then
-        return shell.completeProgram( sText )
-    end
-end
-local function completePeripheral( shell, nIndex, sText, tPreviousText )
-    if nIndex == 1 then
-        return completePeripheralName( sText )
-    end
-end
-local tGPSOptions = { "host", "host ", "locate" }
-local function completeGPS( shell, nIndex, sText, tPreviousText )
-    if nIndex == 1 then
-        return completeMultipleChoice( sText, tGPSOptions )
-    end
-end
-local tLabelOptions = { "get", "get ", "set ", "clear", "clear " }
-local function completeLabel( shell, nIndex, sText, tPreviousText )
-    if nIndex == 1 then
-        return completeMultipleChoice( sText, tLabelOptions )
-    elseif nIndex == 2 then
-        return completePeripheralName( sText )
-    end
-end
-local function completeMonitor( shell, nIndex, sText, tPreviousText )
-    if nIndex == 1 then
-        return completePeripheralName( sText, true )
-    elseif nIndex == 2 then
-        return shell.completeProgram( sText )
-    end
-end
-local tRedstoneOptions = { "probe", "set ", "pulse " }
-local function completeRedstone( shell, nIndex, sText, tPreviousText )
-    if nIndex == 1 then
-        return completeMultipleChoice( sText, tRedstoneOptions )
-    elseif nIndex == 2 then
-        return completeSide( sText )
-    end
-end
-local tDJOptions = { "play", "play ", "stop " }
-local function completeDJ( shell, nIndex, sText, tPreviousText )
-    if nIndex == 1 then
-        return completeMultipleChoice( sText, tDJOptions )
-    elseif nIndex == 2 then
-        return completePeripheralName( sText )
-    end
-end
-local tPastebinOptions = { "put ", "get ", "run " }
-local function completePastebin( shell, nIndex, sText, tPreviousText )
-    if nIndex == 1 then
-        return completeMultipleChoice( sText, tPastebinOptions )
-    elseif nIndex == 2 then
-        if tPreviousText[2] == "put" then
-            return fs.complete( sText, shell.dir(), true, false )
-        end
-    end
-end
-local tChatOptions = { "host ", "join " }
-local function completeChat( shell, nIndex, sText, tPreviousText )
-    if nIndex == 1 then
-        return completeMultipleChoice( sText, tChatOptions )
-    end
-end
-local function completeSet( shell, nIndex, sText, tPreviousText )
-    if nIndex == 1 then
-        return completeMultipleChoice( sText, settings.getNames(), true )
-    end
-end
-local tCommands
-if commands then
-    tCommands = commands.list()
-end
-local function completeExec( shell, nIndex, sText, tPreviousText )
-    if nIndex == 1 and commands then
-        return completeMultipleChoice( sText, tCommands, true )
-    end
-end
-local tWgetOptions = { "run" }
-local function completeWget( shell, nIndex, sText, tPreviousText )
-    if nIndex == 1 then
-        return completeMultipleChoice( sText, tWgetOptions, true )
-    end
-end
-shell.setCompletionFunction( "rom/programs/alias.lua", completeAlias )
-shell.setCompletionFunction( "rom/programs/cd.lua", completeDir )
-shell.setCompletionFunction( "rom/programs/copy.lua", completeEitherEither )
-shell.setCompletionFunction( "rom/programs/delete.lua", completeEitherMany )
-shell.setCompletionFunction( "rom/programs/drive.lua", completeDir )
-shell.setCompletionFunction( "rom/programs/edit.lua", completeFile )
-shell.setCompletionFunction( "rom/programs/eject.lua", completePeripheral )
-shell.setCompletionFunction( "rom/programs/gps.lua", completeGPS )
-shell.setCompletionFunction( "rom/programs/help.lua", completeHelp )
-shell.setCompletionFunction( "rom/programs/id.lua", completePeripheral )
-shell.setCompletionFunction( "rom/programs/label.lua", completeLabel )
-shell.setCompletionFunction( "rom/programs/list.lua", completeDir )
-shell.setCompletionFunction( "rom/programs/mkdir.lua", completeFileMany )
-shell.setCompletionFunction( "rom/programs/monitor.lua", completeMonitor )
-shell.setCompletionFunction( "rom/programs/move.lua", completeEitherEither )
-shell.setCompletionFunction( "rom/programs/redstone.lua", completeRedstone )
-shell.setCompletionFunction( "rom/programs/rename.lua", completeEitherEither )
-shell.setCompletionFunction( "rom/programs/shell.lua", completeProgram )
-shell.setCompletionFunction( "rom/programs/type.lua", completeEither )
-shell.setCompletionFunction( "rom/programs/set.lua", completeSet )
-shell.setCompletionFunction( "rom/programs/advanced/bg.lua", completeProgram )
-shell.setCompletionFunction( "rom/programs/advanced/fg.lua", completeProgram )
-shell.setCompletionFunction( "rom/programs/fun/dj.lua", completeDJ )
-shell.setCompletionFunction( "rom/programs/fun/advanced/paint.lua", completeFile )
-shell.setCompletionFunction( "rom/programs/http/pastebin.lua", completePastebin )
-shell.setCompletionFunction( "rom/programs/rednet/chat.lua", completeChat )
-shell.setCompletionFunction( "rom/programs/command/exec.lua", completeExec )
-shell.setCompletionFunction( "rom/programs/http/wget.lua", completeWget )
+
+shell.setCompletionFunction( "rom/programs/alias.lua", completion.build(nil, completion.program) )
+shell.setCompletionFunction( "rom/programs/cd.lua", completion.build(completion.dir) )
+shell.setCompletionFunction( "rom/programs/copy.lua", completion.build(
+    { completion.dirOrFile, true },
+    completion.dirOrFile
+) )
+shell.setCompletionFunction( "rom/programs/delete.lua", completion.build({ completion.dirOrFile, many = true }) )
+shell.setCompletionFunction( "rom/programs/drive.lua", completion.build(completion.dir) )
+shell.setCompletionFunction( "rom/programs/edit.lua", completion.build(completion.file) )
+shell.setCompletionFunction( "rom/programs/eject.lua", completion.build(completion.peripheral) )
+shell.setCompletionFunction( "rom/programs/gps.lua", completion.build({ completion.choice, { "host", "host ", "locate" } }) )
+shell.setCompletionFunction( "rom/programs/help.lua", completion.build(completion.help) )
+shell.setCompletionFunction( "rom/programs/id.lua", completion.build(completion.peripheral) )
+shell.setCompletionFunction( "rom/programs/label.lua", completion.build(
+    { completion.choice, { "get", "get ", "set ", "clear", "clear " } },
+    completion.peripheral
+) )
+shell.setCompletionFunction( "rom/programs/list.lua", completion.build(completion.dir) )
+shell.setCompletionFunction( "rom/programs/mkdir.lua", completion.build({ completion.dir, many = true }) )
+shell.setCompletionFunction( "rom/programs/monitor.lua", completion.build(
+    { completion.peripheral, true },
+    completion.program
+) )
+shell.setCompletionFunction( "rom/programs/move.lua", completion.build(
+    { completion.dirOrFile, true },
+    completion.dirOrFile
+) )
+shell.setCompletionFunction( "rom/programs/redstone.lua", completion.build(
+    { completion.choice, { "probe", "set ", "pulse " } },
+    completion.side
+) )
+shell.setCompletionFunction( "rom/programs/rename.lua", completion.build(
+    { completion.dirOrFile, true },
+    completion.dirOrFile
+) )
+shell.setCompletionFunction( "rom/programs/shell.lua", completion.build(completion.program) )
+shell.setCompletionFunction( "rom/programs/type.lua", completion.build(completion.dirOrFile) )
+shell.setCompletionFunction( "rom/programs/set.lua", completion.build({ completion.setting, true }) )
+shell.setCompletionFunction( "rom/programs/advanced/bg.lua", completion.build(completion.program) )
+shell.setCompletionFunction( "rom/programs/advanced/fg.lua", completion.build(completion.program) )
+shell.setCompletionFunction( "rom/programs/fun/dj.lua", completion.build(
+    { completion.choice, { "play", "play ", "stop " } },
+    completion.peripheral
+) )
+shell.setCompletionFunction( "rom/programs/fun/advanced/paint.lua", completion.build(completion.file) )
+shell.setCompletionFunction( "rom/programs/http/pastebin.lua", completion.build(
+    { completion.choice, { "put ", "get ", "run " } },
+    completePastebinPut
+) )
+shell.setCompletionFunction( "rom/programs/rednet/chat.lua", completion.build({ completion.choice, { "host ", "join " } }) )
+shell.setCompletionFunction( "rom/programs/command/exec.lua", completion.build(completion.command) )
+shell.setCompletionFunction( "rom/programs/http/wget.lua", completion.build({ completion.choice, { "run " } }) )
 
 if turtle then
-    local tGoOptions = { "left", "right", "forward", "back", "down", "up" }
-    local function completeGo( shell, nIndex, sText )
-        return completeMultipleChoice( sText, tGoOptions, true)
-    end
-    local tTurnOptions = { "left", "right" }
-    local function completeTurn( shell, nIndex, sText )
-            return completeMultipleChoice( sText, tTurnOptions, true )
-    end
-    local tEquipOptions = { "left", "right" }
-    local function completeEquip( shell, nIndex, sText )
-        if nIndex == 2 then
-            return completeMultipleChoice( sText, tEquipOptions )
-        end
-    end
-    local function completeUnequip( shell, nIndex, sText )
-        if nIndex == 1 then
-            return completeMultipleChoice( sText, tEquipOptions )
-        end
-    end
-    shell.setCompletionFunction( "rom/programs/turtle/go.lua", completeGo )
-    shell.setCompletionFunction( "rom/programs/turtle/turn.lua", completeTurn )
-    shell.setCompletionFunction( "rom/programs/turtle/equip.lua", completeEquip )
-    shell.setCompletionFunction( "rom/programs/turtle/unequip.lua", completeUnequip )
+    shell.setCompletionFunction( "rom/programs/turtle/go.lua", completion.build(
+        { completion.choice, { "left", "right", "forward", "back", "down", "up" }, true, many = true }
+    ) )
+    shell.setCompletionFunction( "rom/programs/turtle/turn.lua", completion.build(
+        { completion.choice, { "left", "right" }, true, many = true }
+    ))
+    shell.setCompletionFunction( "rom/programs/turtle/equip.lua", completion.build(
+        nil,
+        { completion.choice, { "left", "right" } }
+    ) )
+    shell.setCompletionFunction( "rom/programs/turtle/unequip.lua", completion.build(
+        { completion.choice, { "left", "right" } }
+    ) )
 end
 
-
 -- Run autorun files
 if fs.exists( "/rom/autorun" ) and fs.isDir( "/rom/autorun" ) then
     local tFiles = fs.list( "/rom/autorun" )
-    table.sort( tFiles )
-    for n, sFile in ipairs( tFiles ) do
+    for _, sFile in ipairs( tFiles ) do
         if string.sub( sFile, 1, 1 ) ~= "." then
             local sPath = "/rom/autorun/"..sFile
             if not fs.isDir( sPath ) then

src/test/java/dan200/computercraft/core/ComputerTestDelegate.java

@@ -90,7 +90,7 @@ public class ComputerTestDelegate
         try( WritableByteChannel channel = mount.openChannelForWrite( "startup.lua" );
              Writer writer = Channels.newWriter( channel, StandardCharsets.UTF_8.newEncoder(), -1 ) )
         {
-            writer.write( "loadfile('test/mcfly.lua', _ENV)('test/spec') cct_test.finish()" );
+            writer.write( "loadfile('test/mcfly.lua', nil, _ENV)('test/spec') cct_test.finish()" );
         }
 
         computer = new Computer( new BasicEnvironment( mount ), term, 0 );

src/test/java/dan200/computercraft/core/computer/ComputerBootstrap.java

@@ -33,7 +33,7 @@ public class ComputerBootstrap
     {
         MemoryMount mount = new MemoryMount()
             .addFile( "test.lua", program )
-            .addFile( "startup", "assertion.assert(pcall(loadfile('test.lua', _ENV))) os.shutdown()" );
+            .addFile( "startup", "assertion.assert(pcall(loadfile('test.lua', nil, _ENV))) os.shutdown()" );
 
         run( mount, x -> { } );
     }

src/test/resources/test-rom/mcfly.lua

@@ -27,18 +27,58 @@ local function check(func, arg, ty, val)
     end
 end
 
+--- A stub - wraps a value within a a table,
+local stub_mt = {}
+stub_mt.__index = stub_mt
+
+--- Revert this stub, restoring the previous value.
+--
+-- Note, a stub can only be reverted once.
+function stub_mt:revert()
+    if not self.active then return end
+
+    self.active = false
+    rawset(self.stubbed_in, self.key, self.original)
+end
+
 local active_stubs = {}
 
---- Stub a global variable with a specific value
---
--- @tparam string var The variable to stub
--- @param value The value to stub it with
-local function stub(tbl, var, value)
-    check('stub', 1, 'table', tbl)
-    check('stub', 2, 'string', var)
+local function default_stub() end
 
-    table.insert(active_stubs, { tbl = tbl, var = var, value = tbl[var] })
-    rawset(tbl, var, value)
+--- Stub a table entry with a new value.
+--
+-- @tparam table
+-- @tparam string key The variable to stub
+-- @param[opt] value The value to stub it with. If this is a function, one can
+-- use the various stub expectation methods to determine what it was called
+-- with. Defaults to an empty function - pass @{nil} in explicitly to set the
+-- value to nil.
+-- @treturn Stub The resulting stub
+local function stub(tbl, key, ...)
+    check('stub', 1, 'table', tbl)
+    check('stub', 2, 'string', key)
+
+    local stub = setmetatable({
+        active = true,
+        stubbed_in = tbl,
+        key = key,
+        original = rawget(tbl, key),
+    }, stub_mt)
+
+    local value = ...
+    if select('#', ...) == 0 then value = default_stub end
+    if type(value) == "function" then
+        local arguments, delegate = {}, value
+        stub.arguments = arguments
+        value = function(...)
+            arguments[#arguments + 1] = table.pack(...)
+            return delegate(...)
+        end
+    end
+
+    table.insert(active_stubs, stub)
+    rawset(tbl, key, value)
+    return stub
 end
 
 --- Capture the current global state of the computer
@@ -51,16 +91,14 @@ local function push_state()
         output = io.output(),
         dir = shell.dir(),
         path = shell.path(),
+        aliases = shell.aliases(),
         stubs = stubs,
     }
 end
 
 --- Restore the global state of the computer to a previous version
 local function pop_state(state)
-    for i = #active_stubs, 1, -1 do
-        local stub = active_stubs[i]
-        rawset(stub.tbl, stub.var, stub.value)
-    end
+    for i = #active_stubs, 1, -1 do active_stubs[i]:revert() end
 
     active_stubs = state.stubs
 
@@ -69,6 +107,14 @@ local function pop_state(state)
     io.output(state.output)
     shell.setDir(state.dir)
     shell.setPath(state.path)
+
+    local aliases = shell.aliases()
+    for k in pairs(aliases) do
+        if not state.aliases[k] then shell.clearAlias(k) end
+    end
+    for k, v in pairs(state.aliases) do
+        if aliases[k] ~= v then shell.setAlias(k, v) end
+    end
 end
 
 local error_mt = { __tostring = function(self) return self.message end }
@@ -210,6 +256,16 @@ local function matches(eq, exact, left, right)
     return true
 end
 
+local function pairwise_equal(left, right)
+    if left.n ~= right.n then return false end
+
+    for i = 1, left.n do
+        if left[i] ~= right[i] then return false end
+    end
+
+    return true
+end
+
 --- Assert that this expectation is structurally equivalent to
 -- the provided object.
 --
@@ -236,6 +292,70 @@ function expect_mt:matches(value)
     return self
 end
 
+--- Assert that this stub was called a specific number of times.
+--
+-- @tparam[opt] number The exact number of times the function must be called.
+-- If not given just require the function to be called at least once.
+-- @raises If this function was not called the expected number of times.
+function expect_mt:called(times)
+    if getmetatable(self.value) ~= stub_mt or self.value.arguments == nil then
+        fail(("Expected stubbed function, got %s"):format(type(self.value)))
+    end
+
+    local called = #self.value.arguments
+
+    if times == nil then
+        if called == 0 then
+            fail("Expected stub to be called\nbut it was not.")
+        end
+    else
+        check('stub', 1, 'number', times)
+        if called ~= times then
+            fail(("Expected stub to be called %d times\nbut was called %d times."):format(times, called))
+        end
+    end
+
+    return self
+end
+
+local function called_with_check(eq, self, ...)
+    if getmetatable(self.value) ~= stub_mt or self.value.arguments == nil then
+        fail(("Expected stubbed function, got %s"):format(type(self.value)))
+    end
+
+    local exp_args = table.pack(...)
+    local actual_args = self.value.arguments
+    for i = 1, #actual_args do
+        if eq(actual_args[i], exp_args) then return self end
+    end
+
+    local head = ("Expected stub to be called with %s\nbut was"):format(format(exp_args))
+    if #actual_args == 0 then
+        fail(head .. " not called at all")
+    elseif #actual_args == 1 then
+        fail(("%s called with %s."):format(head, format(actual_args[1])))
+    else
+        local lines = { head .. " called with:" }
+        for i = 1, #actual_args do lines[i + 1] = " - " .. format(actual_args[i]) end
+
+        fail(table.concat(lines, "\n"))
+    end
+end
+
+--- Assert that this stub was called with a set of arguments
+--
+-- Arguments are compared using exact equality.
+function expect_mt:called_with(...)
+    return called_with_check(pairwise_equal, self, ...)
+end
+
+--- Assert that this stub was called with a set of arguments
+--
+-- Arguments are compared using matching.
+function expect_mt:called_with_matching(...)
+    return called_with_check(matches, self, ...)
+end
+
 local expect = setmetatable( {
     --- Construct an expectation on the error message calling this function
     -- produces
@@ -381,7 +501,7 @@ do
             if fs.isDir(file) then
                 run_in(file)
             elseif file:sub(-#suffix) == suffix then
-                local fun, err = loadfile(file, env)
+                local fun, err = loadfile(file, nil, env)
                 if not fun then
                     do_test { name = file:sub(#root_dir + 2), error = { message = err } }
                 else

src/test/resources/test-rom/spec/apis/window_spec.lua

@@ -118,6 +118,43 @@ describe("The window library", function()
             expect.error(w.reposition, 1, 1, false, 1):eq("bad argument #3 (expected number, got boolean)")
             expect.error(w.reposition, 1, 1, nil, 1):eq("bad argument #3 (expected number, got nil)")
             expect.error(w.reposition, 1, 1, 1, nil):eq("bad argument #4 (expected number, got nil)")
+            expect.error(w.reposition, 1, 1, 1, 1, true):eq("bad argument #5 (expected table, got boolean)")
+        end)
+
+        it("can change the buffer", function()
+            local a, b = mk(), mk()
+            local target = window.create(a, 1, 1, a.getSize())
+
+            target.write("Test")
+            expect((a.getLine(1))):equal("Test ")
+            expect({ a.getCursorPos() }):same { 5, 1 }
+
+            target.reposition(1, 1, nil, nil, b)
+
+            target.redraw()
+            expect((a.getLine(1))):equal("Test ")
+            expect({ a.getCursorPos() }):same { 5, 1 }
+
+            target.setCursorPos(1, 1) target.write("More")
+            expect((a.getLine(1))):equal("Test ")
+            expect((b.getLine(1))):equal("More ")
+        end)
+    end)
+
+    describe("Window.getLine", function()
+        it("validates arguments", function()
+            local w = mk()
+            w.getLine(1)
+            local _, y = w.getSize()
+            expect.error(w.getLine, nil):eq("bad argument #1 (expected number, got nil)")
+            expect.error(w.getLine, 0):eq("Line is out of range.")
+            expect.error(w.getLine, y + 1):eq("Line is out of range.")
+        end)
+
+        it("provides a line's contents", function()
+            local w = mk()
+            w.blit("test", "aaaa", "4444")
+            expect({ w.getLine(1) }):same { "test ", "aaaa0", "4444f" }
         end)
     end)
 end)

src/test/resources/test-rom/spec/base_spec.lua

@@ -1,36 +1,4 @@
 describe("The Lua base library", function()
-    describe("expect", function()
-        local e = _G["~expect"]
-
-        it("checks a single type", function()
-            expect(e(1, "test", "string")):eq(true)
-            expect(e(1, 2, "number")):eq(true)
-
-            expect.error(e, 1, nil, "string"):eq("bad argument #1 (expected string, got nil)")
-            expect.error(e, 2, 1, "nil"):eq("bad argument #2 (expected nil, got number)")
-        end)
-
-        it("checks multiple types", function()
-            expect(e(1, "test", "string", "number")):eq(true)
-            expect(e(1, 2, "string", "number")):eq(true)
-
-            expect.error(e, 1, nil, "string", "number"):eq("bad argument #1 (expected string or number, got nil)")
-            expect.error(e, 2, false, "string", "table", "number", "nil")
-                  :eq("bad argument #2 (expected string, table or number, got boolean)")
-        end)
-
-        it("includes the function name", function()
-            local function worker()
-                expect(e(1, nil, "string")):eq(true)
-            end
-            local function trampoline()
-                worker()
-            end
-
-            expect.error(trampoline):eq("base_spec.lua:27: bad argument #1 to 'worker' (expected string, got nil)")
-        end)
-    end)
-
     describe("sleep", function()
         it("validates arguments", function()
             sleep(0)
@@ -48,18 +16,43 @@ describe("The Lua base library", function()
     end)
 
     describe("loadfile", function()
+        local function make_file()
+            local tmp = fs.open("test-files/out.lua", "w")
+            tmp.write("return _ENV")
+            tmp.close()
+        end
+
         it("validates arguments", function()
             loadfile("")
-            loadfile("", {})
+            loadfile("", "")
+            loadfile("", "", {})
 
             expect.error(loadfile, nil):eq("bad argument #1 (expected string, got nil)")
-            expect.error(loadfile, "", false):eq("bad argument #2 (expected table, got boolean)")
+            expect.error(loadfile, "", false):eq("bad argument #2 (expected string, got boolean)")
+            expect.error(loadfile, "", "", false):eq("bad argument #3 (expected table, got boolean)")
         end)
 
         it("prefixes the filename with @", function()
             local info = debug.getinfo(loadfile("/rom/startup.lua"), "S")
             expect(info):matches { short_src = "startup.lua", source = "@startup.lua" }
         end)
+
+        it("loads a file with the global environment", function()
+            make_file()
+            expect(loadfile("test-files/out.lua")()):eq(_G)
+        end)
+
+        it("loads a file with a specific environment", function()
+            make_file()
+            local env = {}
+            expect(loadfile("test-files/out.lua", nil, env)()):eq(env)
+        end)
+
+        it("supports the old-style argument form", function()
+            make_file()
+            local env = {}
+            expect(loadfile("test-files/out.lua", env)()):eq(env)
+        end)
     end)
 
     describe("dofile", function()

src/test/resources/test-rom/spec/modules/cc/completion_spec.lua

@@ -0,0 +1,57 @@
+describe("cc.completion", function()
+    local c = require("cc.completion")
+
+    describe("choice", function()
+        it("provides all choices", function()
+            expect(c.choice("", { "some text", "some other", "other" }))
+                :same { "some text", "some other", "other" }
+        end)
+
+        it("provides a filtered list of choices", function()
+            expect(c.choice("som", { "some text", "some other", "other" }))
+                :same { "e text", "e other" }
+
+            expect(c.choice("none", { "some text", "some other", "other" }))
+                :same { }
+        end)
+
+        it("adds text if needed", function()
+            expect(c.choice("som", { "some text", "some other", "other" }, true))
+                :same { "e text ", "e other " }
+        end)
+    end)
+
+    describe("peripheral", function()
+        it("provides a choice of peripherals", function()
+            stub(peripheral, "getNames", function() return { "drive_0", "left" } end)
+
+            expect(c.peripheral("dri")):same { "ve_0" }
+            expect(c.peripheral("dri", true)):same { "ve_0 " }
+        end)
+    end)
+
+    describe("side", function()
+        it("provides a choice of sides", function()
+            expect(c.side("le")):same { "ft" }
+            expect(c.side("le", true)):same { "ft " }
+        end)
+    end)
+
+    describe("setting", function()
+        it("provides a choice of setting names", function()
+            stub(settings, "getNames", function() return { "shell.allow_startup", "list.show_hidden" } end)
+
+            expect(c.setting("li")):same { "st.show_hidden" }
+            expect(c.setting("li", true)):same { "st.show_hidden " }
+        end)
+    end)
+
+    describe("command", function()
+        it("provides a choice of command names", function()
+            stub(_G, "commands", { list = function() return { "list", "say" } end })
+
+            expect(c.command("li")):same { "st" }
+            expect(c.command("li", true)):same { "st " }
+        end)
+    end)
+end)

src/test/resources/test-rom/spec/modules/cc/expect_spec.lua

@@ -0,0 +1,31 @@
+describe("cc.expect", function()
+    local e = require("cc.expect")
+
+    it("checks a single type", function()
+        expect(e.expect(1, "test", "string")):eq(true)
+        expect(e.expect(1, 2, "number")):eq(true)
+
+        expect.error(e.expect, 1, nil, "string"):eq("bad argument #1 (expected string, got nil)")
+        expect.error(e.expect, 2, 1, "nil"):eq("bad argument #2 (expected nil, got number)")
+    end)
+
+    it("checks multiple types", function()
+        expect(e.expect(1, "test", "string", "number")):eq(true)
+        expect(e.expect(1, 2, "string", "number")):eq(true)
+
+        expect.error(e.expect, 1, nil, "string", "number"):eq("bad argument #1 (expected string or number, got nil)")
+        expect.error(e.expect, 2, false, "string", "table", "number", "nil")
+              :eq("bad argument #2 (expected string, table or number, got boolean)")
+    end)
+
+    it("includes the function name", function()
+        local function worker()
+            expect(e.expect(1, nil, "string")):eq(true)
+        end
+        local function trampoline()
+            worker()
+        end
+
+        expect.error(trampoline):eq("expect_spec.lua:26: bad argument #1 to 'worker' (expected string, got nil)")
+    end)
+end)

src/test/resources/test-rom/spec/modules/cc/shell/completion_spec.lua

@@ -0,0 +1,41 @@
+describe("cc.shell.completion", function()
+    local c = require "cc.shell.completion"
+
+    describe("dirOrFile", function()
+        it("completes both", function()
+            expect(c.dirOrFile(shell, "rom/")):same {
+                "apis/", "apis", "autorun/", "autorun", "help/", "help",
+                "modules/", "modules", "motd.txt", "programs/", "programs", "startup.lua"
+            }
+        end)
+
+        it("adds a space", function()
+            expect(c.dirOrFile(shell, "rom/", nil, true)):same {
+                "apis/", "apis ", "autorun/", "autorun ", "help/", "help ",
+                "modules/", "modules ", "motd.txt ", "programs/", "programs ", "startup.lua ",
+            }
+        end)
+    end)
+
+    describe("build", function()
+        it("completes multiple arguments", function()
+            local spec = c.build(
+                function() return { "a", "b", "c" } end,
+                nil,
+                { c.choice, { "d", "e", "f"} }
+            )
+
+            expect(spec(shell, 1, "")):same { "a", "b", "c" }
+            expect(spec(shell, 2, "")):same(nil)
+            expect(spec(shell, 3, "")):same { "d", "e", "f" }
+            expect(spec(shell, 4, "")):same(nil)
+        end)
+
+        it("supports variadic completions", function()
+            local spec = c.build({ function() return { "a", "b", "c" } end, many = true })
+
+            expect(spec(shell, 1, "")):same({ "a", "b", "c" })
+            expect(spec(shell, 2, "")):same({ "a", "b", "c" })
+        end)
+    end)
+end)

src/test/resources/test-rom/spec/programs/advanced/bg_spec.lua

@@ -0,0 +1,11 @@
+local capture = require "test_helpers".capture_program
+
+describe("The bg program", function()
+    it("opens a tab in the background", function()
+        local openTab = stub(shell, "openTab", function() return 12 end)
+        local switchTab = stub(shell, "switchTab")
+        capture(stub, "bg")
+        expect(openTab):called_with("shell")
+        expect(switchTab):called(0)
+    end)
+end)

src/test/resources/test-rom/spec/programs/advanced/fg_spec.lua

@@ -0,0 +1,11 @@
+local capture = require "test_helpers".capture_program
+
+describe("The fg program", function()
+    it("opens the shell in the foreground", function()
+        local openTab = stub(shell, "openTab", function() return 12 end)
+        local switchTab = stub(shell, "switchTab")
+        capture(stub, "fg")
+        expect(openTab):called_with("shell")
+        expect(switchTab):called_with(12)
+    end)
+end)

src/test/resources/test-rom/spec/programs/alias_spec.lua

@@ -0,0 +1,28 @@
+local capture = require "test_helpers".capture_program
+
+describe("The alias program", function()
+    it("displays its usage when given too many arguments", function()
+        expect(capture(stub, "alias a b c"))
+            :matches { ok = true, output = "Usage: alias <alias> <program>\n", error = "" }
+    end)
+
+    it("lists aliases", function()
+        local pagedTabulate = stub(textutils, "pagedTabulate", function(x) print(table.unpack(x)) end)
+        stub(shell, "aliases", function() return { cp = "copy" } end)
+        expect(capture(stub, "alias"))
+            :matches { ok = true, output = "cp:copy\n", error = "" }
+        expect(pagedTabulate):called_with_matching({ "cp:copy" })
+    end)
+
+    it("sets an alias", function()
+        local setAlias = stub(shell, "setAlias")
+        capture(stub, "alias test Hello")
+        expect(setAlias):called_with("test", "Hello")
+    end)
+
+    it("clears an alias", function()
+        local clearAlias = stub(shell, "clearAlias")
+        capture(stub, "alias test")
+        expect(clearAlias):called_with("test")
+    end)
+end)

src/test/resources/test-rom/spec/programs/cd_spec.lua

@@ -1,19 +1,18 @@
 local capture = require "test_helpers".capture_program
 
 describe("The cd program", function()
-
-    it("cd into a directory", function()
-        shell.run("cd /rom/programs")
-        
-        expect(shell.dir()):eq("rom/programs")
+    it("changes into a directory", function()
+        local setDir = stub(shell, "setDir")
+        capture(stub, "cd /rom/programs")
+        expect(setDir):called_with("rom/programs")
     end)
 
-    it("cd into a not existing directory", function()
+    it("does not move into a non-existent directory", function()
         expect(capture(stub, "cd /rom/nothing"))
             :matches { ok = true, output = "Not a directory\n", error = "" }
     end)
-    
-    it("displays the usage with no arguments", function()
+
+    it("displays the usage when given no arguments", function()
         expect(capture(stub, "cd"))
             :matches { ok = true, output = "Usage: cd <path>\n", error = "" }
     end)

src/test/resources/test-rom/spec/programs/clear_spec.lua

@@ -0,0 +1,13 @@
+local capture = require "test_helpers".capture_program
+
+describe("The clear program", function()
+    it("clears the screen", function()
+        local clear = stub(term, "clear")
+        local setCursorPos = stub(term, "setCursorPos")
+
+        capture(stub, "clear")
+
+        expect(clear):called(1)
+        expect(setCursorPos):called_with(1, 1)
+    end)
+end)

src/test/resources/test-rom/spec/programs/command/commands_spec.lua

@@ -0,0 +1,20 @@
+local capture = require "test_helpers".capture_program
+
+describe("The commands program", function()
+    it("displays an error without the commands api", function()
+        stub(_G, "commands", nil)
+        expect(capture(stub, "/rom/programs/command/commands.lua"))
+            :matches { ok = true, output = "", error = "Requires a Command Computer.\n" }
+    end)
+
+    it("lists commands", function()
+        local pagedTabulate = stub(textutils, "pagedTabulate", function(x) print(table.unpack(x)) end)
+        stub(_G, "commands", {
+            list = function() return { "computercraft" } end
+        })
+
+        expect(capture(stub, "/rom/programs/command/commands.lua"))
+            :matches { ok = true, output = "Available commands:\ncomputercraft\n", error = "" }
+        expect(pagedTabulate):called_with_matching({ "computercraft" })
+    end)
+end)

src/test/resources/test-rom/spec/programs/command/exec_spec.lua

@@ -0,0 +1,33 @@
+local capture = require "test_helpers".capture_program
+
+describe("The exec program", function()
+    it("displays an error without the commands api", function()
+        stub(_G, "commands", nil)
+        expect(capture(stub, "/rom/programs/command/exec.lua"))
+            :matches { ok = true, output = "", error = "Requires a Command Computer.\n" }
+    end)
+
+    it("displays its usage when given no argument", function()
+        stub(_G, "commands", {})
+        expect(capture(stub, "/rom/programs/command/exec.lua"))
+            :matches { ok = true, output = "", error = "Usage: exec <command>\n" }
+    end)
+
+    it("runs a command", function()
+        stub(_G, "commands", {
+            exec = function() return true, {"Hello World!"} end
+        })
+
+        expect(capture(stub, "/rom/programs/command/exec.lua computercraft"))
+            :matches { ok = true, output = "Success\nHello World!\n", error = "" }
+    end)
+
+    it("reports command failures", function()
+        stub(_G,"commands",{
+            exec = function() return false, {"Hello World!"} end
+        })
+
+        expect(capture(stub, "/rom/programs/command/exec.lua computercraft"))
+            :matches { ok = true, output = "Hello World!\n", error = "Failed\n" }
+    end)
+end)

src/test/resources/test-rom/spec/programs/drive_spec.lua

@@ -0,0 +1,16 @@
+local capture = require "test_helpers".capture_program
+
+describe("The drive program", function()
+    it("run the program", function()
+        local getFreeSpace = stub(fs, "getFreeSpace", function() return 1234e4 end)
+
+        expect(capture(stub, "drive"))
+            :matches { ok = true, output = "hdd (12.3MB remaining)\n", error = "" }
+        expect(getFreeSpace):called(1):called_with("")
+    end)
+
+    it("fails on a non-existent path", function()
+        expect(capture(stub, "drive /rom/nothing"))
+            :matches { ok = true, output = "No such path\n", error = "" }
+    end)
+end)

src/test/resources/test-rom/spec/programs/edit_spec.lua

@@ -1,10 +1,9 @@
 local capture = require "test_helpers".capture_program
+local testFile = require "test_helpers".testFile
 
 describe("The edit program", function()
 
-    it("displays its usage when given no argument", function()
-        multishell = nil
-        
+    it("displays its usage when given no argument", function()      
         expect(capture(stub, "edit"))
             :matches { ok = true, output = "Usage: edit <path>\n", error = "" }
     end)

src/test/resources/test-rom/spec/programs/eject_spec.lua

@@ -0,0 +1,13 @@
+local capture = require "test_helpers".capture_program
+
+describe("The eject program", function()
+    it("displays its usage when given no argument", function()
+        expect(capture(stub, "eject"))
+            :matches { ok = true, output = "Usage: eject <drive>\n", error = "" }
+    end)
+
+    it("fails when trying to eject a non-drive", function()
+        expect(capture(stub, "eject /rom"))
+            :matches { ok = true, output = "Nothing in /rom drive\n", error = "" }
+    end)
+end)

src/test/resources/test-rom/spec/programs/exit_spec.lua

@@ -0,0 +1,9 @@
+local capture = require "test_helpers".capture_program
+
+describe("The exit program", function()
+    it("exits the shell", function()
+        local exit = stub(shell, "exit")
+        expect(capture(stub, "exit")):matches { ok = true, combined = "" }
+        expect(exit):called(1)
+    end)
+end)

src/test/resources/test-rom/spec/programs/fun/advanced/paint_spec.lua

@@ -0,0 +1,8 @@
+local capture = require "test_helpers".capture_program
+
+describe("The paint program", function()
+    it("displays its usage when given no arguments", function()
+        expect(capture(stub, "paint"))
+            :matches { ok = true, output = "Usage: paint <path>\n", error = "" }
+    end)
+end)

src/test/resources/test-rom/spec/programs/fun/dj_spec.lua

@@ -0,0 +1,13 @@
+local capture = require "test_helpers".capture_program
+
+describe("The dj program", function()
+    it("displays its usage when given too many arguments", function()
+        expect(capture(stub, "dj a b c"))
+            :matches { ok = true, output = "Usages:\ndj play\ndj play <drive>\ndj stop\n", error = "" }
+    end)
+
+    it("fails when no disks are present", function()
+        expect(capture(stub, "dj"))
+            :matches { ok = true, output = "No Music Discs in attached disk drives\n", error = "" }
+    end)
+end)

src/test/resources/test-rom/spec/programs/fun/hello_spec.lua

@@ -0,0 +1,10 @@
+local capture = require "test_helpers".capture_program
+
+describe("The hello program", function()
+    it("says hello", function()
+        local slowPrint = stub(textutils, "slowPrint", function(...) return print(...) end)
+        expect(capture(stub, "hello"))
+            :matches { ok = true, output = "Hello World!\n", error = "" }
+        expect(slowPrint):called(1)
+    end)
+end)

src/test/resources/test-rom/spec/programs/gps_spec.lua

@@ -0,0 +1,23 @@
+local capture = require "test_helpers".capture_program
+
+describe("The gps program", function()
+    it("displays its usage when given no arguments", function()
+        expect(capture(stub, "gps"))
+            :matches { ok = true, output = "Usages:\ngps host\ngps host <x> <y> <z>\ngps locate\n", error = "" }
+    end)
+
+    it("fails on a pocket computer", function()
+        stub(_G, "pocket", {})
+
+        expect(capture(stub, "gps host"))
+            :matches { ok = true, output = "GPS Hosts must be stationary\n", error = "" }
+    end)
+
+    it("can locate the computer", function()
+        local locate = stub(gps, "locate", function() print("Some debugging information.") end)
+
+        expect(capture(stub, "gps locate"))
+            :matches { ok = true, output = "Some debugging information.\n", error = "" }
+        expect(locate):called_with(2, true)
+    end)
+end)