Correctly handle capability creation & invalidation

Also make cable part detection more consistent.

src/main/java/dan200/computercraft/ComputerCraftAPIImpl.java

@@ -43,6 +43,7 @@ public final class ComputerCraftAPIImpl implements IComputerCraftAPI
     {
     }
 
+    @Nonnull
     @Override
     public String getInstalledVersion()
     {
@@ -110,6 +111,7 @@ public final class ComputerCraftAPIImpl implements IComputerCraftAPI
         PocketUpgrades.register( upgrade );
     }
 
+    @Nonnull
     @Override
     public IPacketNetwork getWirelessNetwork()
     {
@@ -122,19 +124,18 @@ public final class ComputerCraftAPIImpl implements IComputerCraftAPI
         ApiFactories.register( factory );
     }
 
+    @Nonnull
     @Override
     public IWiredNode createWiredNodeForElement( @Nonnull IWiredElement element )
     {
         return new WiredNode( element );
     }
 
+    @Nonnull
     @Override
-    public IWiredElement getWiredElementAt( @Nonnull IBlockReader world, @Nonnull BlockPos pos, @Nonnull EnumFacing side )
+    public LazyOptional<IWiredElement> getWiredElementAt( @Nonnull IBlockReader world, @Nonnull BlockPos pos, @Nonnull EnumFacing side )
     {
         TileEntity tile = world.getTileEntity( pos );
-        if( tile == null ) return null;
+        return tile == null ? LazyOptional.empty() : tile.getCapability( CapabilityWiredElement.CAPABILITY, side );
-
-        LazyOptional<IWiredElement> element = tile.getCapability( CapabilityWiredElement.CAPABILITY, side );
-        return CapabilityWiredElement.unwrap( element );
     }
 }

src/main/java/dan200/computercraft/api/ComputerCraftAPI.java

@@ -24,6 +24,7 @@ import net.minecraft.util.EnumFacing;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.world.IBlockReader;
 import net.minecraft.world.World;
+import net.minecraftforge.common.util.LazyOptional;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -240,8 +241,8 @@ public final class ComputerCraftAPI
      * @return The element's node
      * @see IWiredElement#getNode()
      */
-    @Nullable
+    @Nonnull
-    public static IWiredElement getWiredElementAt( @Nonnull IBlockReader world, @Nonnull BlockPos pos, @Nonnull EnumFacing side )
+    public static LazyOptional<IWiredElement> getWiredElementAt( @Nonnull IBlockReader world, @Nonnull BlockPos pos, @Nonnull EnumFacing side )
     {
         return getInstance().getWiredElementAt( world, pos, side );
     }
@@ -266,12 +267,15 @@ public final class ComputerCraftAPI
 
     public interface IComputerCraftAPI
     {
+        @Nonnull
         String getInstalledVersion();
 
         int createUniqueNumberedSaveDir( @Nonnull World world, @Nonnull String parentSubPath );
 
+        @Nullable
         IWritableMount createSaveDirMount( @Nonnull World world, @Nonnull String subPath, long capacity );
 
+        @Nullable
         IMount createResourceMount( @Nonnull String domain, @Nonnull String subPath );
 
         void registerPeripheralProvider( @Nonnull IPeripheralProvider provider );
@@ -286,12 +290,15 @@ public final class ComputerCraftAPI
 
         void registerPocketUpgrade( @Nonnull IPocketUpgrade upgrade );
 
+        @Nonnull
         IPacketNetwork getWirelessNetwork();
 
         void registerAPIFactory( @Nonnull ILuaAPIFactory factory );
 
+        @Nonnull
         IWiredNode createWiredNodeForElement( @Nonnull IWiredElement element );
 
-        IWiredElement getWiredElementAt( @Nonnull IBlockReader world, @Nonnull BlockPos pos, @Nonnull EnumFacing side );
+        @Nonnull
+        LazyOptional<IWiredElement> getWiredElementAt( @Nonnull IBlockReader world, @Nonnull BlockPos pos, @Nonnull EnumFacing side );
     }
 }

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

@@ -74,7 +74,8 @@ public final class RenderOverlayCable
         double z = player.lastTickPosZ + (player.posZ - player.lastTickPosZ) * partialTicks;
 
         VoxelShape shape = WorldUtil.isVecInside( CableShapes.getModemShape( state ), event.getTarget().hitVec.subtract( pos.getX(), pos.getY(), pos.getZ() ) )
-            ? CableShapes.getModemShape( state ) : CableShapes.getCableShape( state );
+            ? CableShapes.getModemShape( state )
+            : CableShapes.getCableShape( state );
 
         WorldRenderer.drawShape( shape, pos.getX() - x, pos.getY() - y, pos.getZ() - z, 0.0F, 0.0F, 0.0F, 0.4F );
 

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

@@ -11,6 +11,7 @@ import dan200.computercraft.shared.peripheral.modem.wired.BlockCable;
 import dan200.computercraft.shared.peripheral.modem.wired.CableModemVariant;
 import dan200.computercraft.shared.peripheral.modem.wired.CableShapes;
 import dan200.computercraft.shared.peripheral.modem.wired.TileCable;
+import dan200.computercraft.shared.util.WorldUtil;
 import net.minecraft.block.Block;
 import net.minecraft.block.state.IBlockState;
 import net.minecraft.client.Minecraft;
@@ -25,7 +26,6 @@ import net.minecraft.client.renderer.vertex.DefaultVertexFormats;
 import net.minecraft.util.BlockRenderLayer;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.RayTraceResult;
-import net.minecraft.util.math.shapes.VoxelShape;
 import net.minecraft.world.World;
 import net.minecraftforge.client.ForgeHooksClient;
 import net.minecraftforge.client.MinecraftForgeClient;
@@ -60,8 +60,7 @@ public class TileEntityCableRenderer extends TileEntityRenderer<TileCable>
         Block block = state.getBlock();
         if( block != ComputerCraft.Blocks.cable ) return;
 
-        VoxelShape shape = CableShapes.getModemShape( state );
+        state = WorldUtil.isVecInside( CableShapes.getModemShape( state ), hit.hitVec.subtract( pos.getX(), pos.getY(), pos.getZ() ) )
-        state = te.hasModem() && shape.getBoundingBox().grow( 0.02, 0.02, 0.02 ).contains( hit.hitVec.subtract( pos.getX(), pos.getY(), pos.getZ() ) )
             ? block.getDefaultState().with( BlockCable.MODEM, state.get( BlockCable.MODEM ) )
             : state.with( BlockCable.MODEM, CableModemVariant.None );
 

src/main/java/dan200/computercraft/core/computer/Computer.java

@@ -7,7 +7,6 @@
 package dan200.computercraft.core.computer;
 
 import com.google.common.base.Objects;
-import dan200.computercraft.api.filesystem.IWritableMount;
 import dan200.computercraft.api.lua.ILuaAPI;
 import dan200.computercraft.api.peripheral.IWorkMonitor;
 import dan200.computercraft.core.apis.IAPIEnvironment;

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

@@ -62,7 +62,7 @@ public final class TileDiskDrive extends TileGeneric implements DefaultInventory
 
     @Nonnull
     private ItemStack m_diskStack = ItemStack.EMPTY;
-    private final LazyOptional<IItemHandlerModifiable> m_itemCap = LazyOptional.of( () -> new InvWrapper( this ) );
+    private LazyOptional<IItemHandlerModifiable> itemHandlerCap;
     private IMount m_diskMount = null;
 
     private boolean m_recordQueued = false;
@@ -82,6 +82,17 @@ public final class TileDiskDrive extends TileGeneric implements DefaultInventory
         if( m_recordPlaying ) stopRecord();
     }
 
+    @Override
+    protected void invalidateCaps()
+    {
+        super.invalidateCaps();
+        if( itemHandlerCap != null )
+        {
+            itemHandlerCap.invalidate();
+            itemHandlerCap = null;
+        }
+    }
+
     @Override
     public boolean onActivate( EntityPlayer player, EnumHand hand, EnumFacing side, float hitX, float hitY, float hitZ )
     {
@@ -540,7 +551,11 @@ public final class TileDiskDrive extends TileGeneric implements DefaultInventory
     @Override
     public <T> LazyOptional<T> getCapability( @Nonnull Capability<T> cap, @Nullable final EnumFacing side )
     {
-        if( cap == ITEM_HANDLER_CAPABILITY ) return m_itemCap.cast();
+        if( cap == ITEM_HANDLER_CAPABILITY )
+        {
+            if( itemHandlerCap == null ) itemHandlerCap = LazyOptional.of( () -> new InvWrapper( this ) );
+            return itemHandlerCap.cast();
+        }
         return super.getCapability( cap, side );
     }
 

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

@@ -86,7 +86,7 @@ public class BlockCable extends BlockGeneric implements WaterloggableBlock
     {
         if( !state.get( CABLE ) ) return false;
         if( state.get( MODEM ).getFacing() == direction ) return true;
-        return ComputerCraftAPI.getWiredElementAt( world, pos.offset( direction ), direction.getOpposite() ) != null;
+        return ComputerCraftAPI.getWiredElementAt( world, pos.offset( direction ), direction.getOpposite() ).isPresent();
     }
 
     @Nonnull
@@ -113,8 +113,7 @@ public class BlockCable extends BlockGeneric implements WaterloggableBlock
                     ItemStack item;
                     IBlockState newState;
 
-                    VoxelShape bb = CableShapes.getModemShape( state );
+                    if( WorldUtil.isVecInside( CableShapes.getModemShape( state ), hit.hitVec.subtract( pos.getX(), pos.getY(), pos.getZ() ) ) )
-                    if( WorldUtil.isVecInside( bb, hit.hitVec.subtract( pos.getX(), pos.getY(), pos.getZ() ) ) )
                     {
                         newState = state.with( MODEM, CableModemVariant.None );
                         item = new ItemStack( ComputerCraft.Items.wiredModem );
@@ -161,9 +160,7 @@ public class BlockCable extends BlockGeneric implements WaterloggableBlock
         if( modem == null ) return new ItemStack( ComputerCraft.Items.cable );
 
         // We've a modem and cable, so try to work out which one we're interacting with
-        TileEntity tile = world.getTileEntity( pos );
+        return hit != null && WorldUtil.isVecInside( CableShapes.getModemShape( state ), hit.hitVec.subtract( pos.getX(), pos.getY(), pos.getZ() ) )
-        return tile instanceof TileCable && hit != null &&
-            CableShapes.getModemShape( state ).getBoundingBox().contains( hit.hitVec.subtract( pos.getX(), pos.getY(), pos.getZ() ) )
             ? new ItemStack( ComputerCraft.Items.wiredModem )
             : new ItemStack( ComputerCraft.Items.cable );
 
@@ -202,21 +199,6 @@ public class BlockCable extends BlockGeneric implements WaterloggableBlock
             return getFluidState( state ).getBlockState();
         }
 
-        if( side == state.get( MODEM ).getFacing() && !state.isValidPosition( world, pos ) )
-        {
-            if( !state.get( CABLE ) ) return getFluidState( state ).getBlockState();
-
-            /* TODO:
-            TileEntity entity = world.getTileEntity( pos );
-            if( entity instanceof TileCable )
-            {
-                entity.modemChanged();
-                entity.connectionsChanged();
-            }
-            */
-            state = state.with( MODEM, CableModemVariant.None );
-        }
-
         return state.with( CONNECTIONS.get( side ), doesConnectVisually( state, world, pos, side ) );
     }
 

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

@@ -35,6 +35,7 @@ import net.minecraft.util.text.TextComponentTranslation;
 import net.minecraft.world.World;
 import net.minecraftforge.common.capabilities.Capability;
 import net.minecraftforge.common.util.LazyOptional;
+import net.minecraftforge.common.util.NonNullConsumer;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -90,7 +91,7 @@ public class TileCable extends TileGeneric implements IPeripheralTile
     private boolean m_connectionsFormed = false;
 
     private final WiredModemElement m_cable = new CableElement();
-    private LazyOptional<IWiredElement> m_cableCapability = LazyOptional.of( () -> m_cable );
+    private LazyOptional<IWiredElement> elementCap;
     private final IWiredNode m_node = m_cable.getNode();
     private final WiredModemPeripheral m_modem = new WiredModemPeripheral(
         new ModemState( () -> TickScheduler.schedule( this ) ),
@@ -113,6 +114,8 @@ public class TileCable extends TileGeneric implements IPeripheralTile
         }
     };
 
+    private final NonNullConsumer<LazyOptional<IWiredElement>> connectedNodeChanged = x -> connectionsChanged();
+
     public TileCable()
     {
         super( FACTORY );
@@ -152,6 +155,17 @@ public class TileCable extends TileGeneric implements IPeripheralTile
         onRemove();
     }
 
+    @Override
+    protected void invalidateCaps()
+    {
+        super.invalidateCaps();
+        if( elementCap != null )
+        {
+            elementCap.invalidate();
+            elementCap = null;
+        }
+    }
+
     @Override
     public void onLoad()
     {
@@ -322,18 +336,20 @@ public class TileCable extends TileGeneric implements IPeripheralTile
             BlockPos offset = current.offset( facing );
             if( !world.isBlockLoaded( offset ) ) continue;
 
-            IWiredElement element = ComputerCraftAPI.getWiredElementAt( world, offset, facing.getOpposite() );
+            LazyOptional<IWiredElement> element = ComputerCraftAPI.getWiredElementAt( world, offset, facing.getOpposite() );
-            if( element == null ) continue;
+            if( !element.isPresent() ) continue;
 
+            element.addListener( connectedNodeChanged );
+            IWiredNode node = element.orElseThrow( NullPointerException::new ).getNode();
             if( BlockCable.canConnectIn( state, facing ) )
             {
                 // If we can connect to it then do so
-                m_node.connectTo( element.getNode() );
+                m_node.connectTo( node );
             }
-            else if( m_node.getNetwork() == element.getNode().getNetwork() )
+            else if( m_node.getNetwork() == node.getNetwork() )
             {
                 // Otherwise if we're on the same network then attempt to void it.
-                m_node.disconnectFrom( element.getNode() );
+                m_node.disconnectFrom( node );
             }
         }
     }
@@ -341,9 +357,11 @@ public class TileCable extends TileGeneric implements IPeripheralTile
     void modemChanged()
     {
         // Tell anyone who cares that the connection state has changed
-        // TODO: Be more restrictive about this.
+        if( elementCap != null )
-        m_cableCapability.invalidate();
+        {
-        m_cableCapability = LazyOptional.of( () -> m_cable );
+            elementCap.invalidate();
+            elementCap = null;
+        }
 
         if( getWorld().isRemote ) return;
 
@@ -405,8 +423,9 @@ public class TileCable extends TileGeneric implements IPeripheralTile
     {
         if( capability == CapabilityWiredElement.CAPABILITY )
         {
-            return !m_destroyed && BlockCable.canConnectIn( getBlockState(), facing )
+            if( m_destroyed || !BlockCable.canConnectIn( getBlockState(), facing ) ) return LazyOptional.empty();
-                ? m_cableCapability.cast() : LazyOptional.empty();
+            if( elementCap == null ) elementCap = LazyOptional.of( () -> m_cable );
+            return elementCap.cast();
         }
 
         return super.getCapability( capability, facing );
@@ -418,7 +437,7 @@ public class TileCable extends TileGeneric implements IPeripheralTile
         return !m_destroyed && hasModem() && side == getDirection() ? m_modem : null;
     }
 
-    public boolean hasCable()
+    boolean hasCable()
     {
         return getBlockState().get( BlockCable.CABLE );
     }
@@ -428,7 +447,7 @@ public class TileCable extends TileGeneric implements IPeripheralTile
         return getBlockState().get( BlockCable.MODEM ) != CableModemVariant.None;
     }
 
-    boolean canAttachPeripheral()
+    private boolean canAttachPeripheral()
     {
         return hasCable() && hasModem();
     }

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

@@ -8,7 +8,7 @@ package dan200.computercraft.shared.peripheral.modem.wired;
 
 import com.google.common.base.Objects;
 import dan200.computercraft.ComputerCraft;
-import dan200.computercraft.ComputerCraftAPIImpl;
+import dan200.computercraft.api.ComputerCraftAPI;
 import dan200.computercraft.api.network.wired.IWiredElement;
 import dan200.computercraft.api.network.wired.IWiredNode;
 import dan200.computercraft.api.peripheral.IPeripheral;
@@ -33,6 +33,7 @@ import net.minecraft.util.text.TextComponentTranslation;
 import net.minecraft.world.World;
 import net.minecraftforge.common.capabilities.Capability;
 import net.minecraftforge.common.util.LazyOptional;
+import net.minecraftforge.common.util.NonNullConsumer;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -105,10 +106,10 @@ public class TileWiredModemFull extends TileGeneric implements IPeripheralTile
 
     private final ModemState m_modemState = new ModemState( () -> TickScheduler.schedule( this ) );
     private final WiredModemElement m_element = new FullElement( this );
-    private final LazyOptional<WiredModemElement> m_elementCap = LazyOptional.of( () -> m_element );
+    private LazyOptional<IWiredElement> elementCap;
     private final IWiredNode m_node = m_element.getNode();
 
-    private int m_state = 0;
+    private final NonNullConsumer<LazyOptional<IWiredElement>> connectedNodeChanged = x -> connectionsChanged();
 
     public TileWiredModemFull()
     {
@@ -143,6 +144,17 @@ public class TileWiredModemFull extends TileGeneric implements IPeripheralTile
         doRemove();
     }
 
+    @Override
+    protected void invalidateCaps()
+    {
+        super.invalidateCaps();
+        if( elementCap != null )
+        {
+            elementCap.invalidate();
+            elementCap = null;
+        }
+    }
+
     @Override
     public void remove()
     {
@@ -275,11 +287,11 @@ public class TileWiredModemFull extends TileGeneric implements IPeripheralTile
             BlockPos offset = current.offset( facing );
             if( !world.isBlockLoaded( offset ) ) continue;
 
-            IWiredElement element = ComputerCraftAPIImpl.INSTANCE.getWiredElementAt( world, offset, facing.getOpposite() );
+            LazyOptional<IWiredElement> element = ComputerCraftAPI.getWiredElementAt( world, offset, facing.getOpposite() );
-            if( element == null ) continue;
+            if( !element.isPresent() ) continue;
 
-            // If we can connect to it then do so
+            element.addListener( connectedNodeChanged );
-            m_node.connectTo( element.getNode() );
+            m_node.connectTo( element.orElseThrow( NullPointerException::new ).getNode() );
         }
     }
 
@@ -350,7 +362,11 @@ public class TileWiredModemFull extends TileGeneric implements IPeripheralTile
     @Override
     public <T> LazyOptional<T> getCapability( @Nonnull Capability<T> capability, @Nullable EnumFacing facing )
     {
-        if( capability == CapabilityWiredElement.CAPABILITY ) return m_elementCap.cast();
+        if( capability == CapabilityWiredElement.CAPABILITY )
+        {
+            if( elementCap == null ) elementCap = LazyOptional.of( () -> m_element );
+            return elementCap.cast();
+        }
         return super.getCapability( capability, facing );
     }
 

src/main/java/dan200/computercraft/shared/peripheral/modem/wireless/TileWirelessModem.java

@@ -8,6 +8,7 @@ package dan200.computercraft.shared.peripheral.modem.wireless;
 
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.peripheral.IPeripheral;
+import dan200.computercraft.api.peripheral.IPeripheralTile;
 import dan200.computercraft.shared.common.TileGeneric;
 import dan200.computercraft.shared.peripheral.modem.ModemPeripheral;
 import dan200.computercraft.shared.peripheral.modem.ModemState;
@@ -22,8 +23,9 @@ import net.minecraft.util.math.Vec3d;
 import net.minecraft.world.World;
 
 import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 
-public class TileWirelessModem extends TileGeneric
+public class TileWirelessModem extends TileGeneric implements IPeripheralTile
 {
     public static final NamedBlockEntityType<TileWirelessModem> FACTORY_NORMAL = NamedBlockEntityType.create(
         new ResourceLocation( ComputerCraft.MOD_ID, "wireless_modem_normal" ),
@@ -146,4 +148,13 @@ public class TileWirelessModem extends TileGeneric
             getWorld().setBlockState( getPos(), state.with( BlockWirelessModem.ON, on ) );
         }
     }
+
+
+    @Nullable
+    @Override
+    public IPeripheral getPeripheral( @Nonnull EnumFacing side )
+    {
+        updateDirection();
+        return side == modemDirection ? modem : null;
+    }
 }

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

@@ -61,8 +61,7 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
     ITextComponent customName;
 
     private final NonNullList<ItemStack> m_inventory = NonNullList.withSize( 13, ItemStack.EMPTY );
-    private IItemHandlerModifiable m_itemHandlerAll = new InvWrapper( this );
+    private LazyOptional<IItemHandlerModifiable>[] itemHandlerCaps;
-    private LazyOptional<IItemHandlerModifiable>[] m_itemHandlerSides;
 
     private final Terminal m_page = new Terminal( ItemPrintout.LINE_MAX_LENGTH, ItemPrintout.LINES_PER_PAGE );
     private String m_pageTitle = "";
@@ -79,6 +78,22 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
         ejectContents();
     }
 
+    @Override
+    protected void invalidateCaps()
+    {
+        super.invalidateCaps();
+
+        if( itemHandlerCaps != null )
+        {
+            for( int i = 0; i < itemHandlerCaps.length; i++ )
+            {
+                if( itemHandlerCaps[i] == null ) continue;
+                itemHandlerCaps[i].invalidate();
+                itemHandlerCaps[i] = null;
+            }
+        }
+    }
+
     @Override
     public boolean onActivate( EntityPlayer player, EnumHand hand, EnumFacing side, float hitX, float hitY, float hitZ )
     {
@@ -516,7 +531,6 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
         getWorld().setBlockState( getPos(), state.with( BlockPrinter.TOP, top ).with( BlockPrinter.BOTTOM, bottom ) );
     }
 
-
     @SuppressWarnings( { "unchecked", "rawtypes" } )
     @Nonnull
     @Override
@@ -524,28 +538,16 @@ public final class TilePrinter extends TileGeneric implements DefaultSidedInvent
     {
         if( capability == ITEM_HANDLER_CAPABILITY )
         {
-            LazyOptional<IItemHandlerModifiable>[] handlers = m_itemHandlerSides;
+            LazyOptional<IItemHandlerModifiable>[] handlers = itemHandlerCaps;
-            if( handlers == null ) handlers = m_itemHandlerSides = new LazyOptional[6];
+            if( handlers == null ) handlers = itemHandlerCaps = new LazyOptional[7];
 
-            LazyOptional<IItemHandlerModifiable> handler;
+            int index = facing == null ? 0 : 1 + facing.getIndex();
-            if( facing == null )
+            LazyOptional<IItemHandlerModifiable> handler = handlers[index];
+            if( handler == null )
             {
-                int i = 6;
+                handler = handlers[index] = facing == null
-                handler = handlers[i];
+                    ? LazyOptional.of( () -> new InvWrapper( this ) )
-                if( handler == null )
+                    : LazyOptional.of( () -> new SidedInvWrapper( this, facing ) );
-                {
-                    handler = handlers[i] = LazyOptional.of( () -> m_itemHandlerAll );
-                }
-            }
-            else
-            {
-
-                int i = facing.ordinal();
-                handler = handlers[i];
-                if( handler == null )
-                {
-                    handler = handlers[i] = LazyOptional.of( () -> new SidedInvWrapper( this, facing ) );
-                }
             }
 
             return handler.cast();

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

@@ -12,8 +12,8 @@ import dan200.computercraft.api.peripheral.IPeripheral;
 import dan200.computercraft.api.turtle.ITurtleAccess;
 import dan200.computercraft.api.turtle.ITurtleUpgrade;
 import dan200.computercraft.api.turtle.TurtleSide;
-import dan200.computercraft.shared.common.TileGeneric;
 import dan200.computercraft.core.computer.ComputerSide;
+import dan200.computercraft.shared.common.TileGeneric;
 import dan200.computercraft.shared.computer.blocks.ComputerPeripheral;
 import dan200.computercraft.shared.computer.blocks.ComputerProxy;
 import dan200.computercraft.shared.computer.blocks.TileComputerBase;
@@ -79,7 +79,7 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
     private NonNullList<ItemStack> m_inventory;
     private NonNullList<ItemStack> m_previousInventory;
     private final IItemHandlerModifiable m_itemHandler = new InvWrapper( this );
-    private final LazyOptional<IItemHandlerModifiable> m_itemHandlerCap = LazyOptional.of( () -> m_itemHandler );
+    private LazyOptional<IItemHandlerModifiable> itemHandlerCap;
     private boolean m_inventoryChanged;
     private TurtleBrain m_brain;
     private MoveState m_moveState;
@@ -159,12 +159,20 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
         }
     }
 
+    @Override
+    protected void invalidateCaps()
+    {
+        super.invalidateCaps();
+        if( itemHandlerCap != null )
+        {
+            itemHandlerCap.invalidate();
+            itemHandlerCap = null;
+        }
+    }
+
     @Override
     public boolean onActivate( EntityPlayer player, EnumHand hand, EnumFacing side, float hitX, float hitY, float hitZ )
     {
-        // Request description from server
-        // requestTileEntityUpdate();
-
         // Apply dye
         ItemStack currentItem = player.getHeldItem( hand );
         if( !currentItem.isEmpty() )
@@ -613,7 +621,11 @@ public class TileTurtle extends TileComputerBase implements ITurtleTile, Default
     @Override
     public <T> LazyOptional<T> getCapability( @Nonnull Capability<T> cap, @Nullable EnumFacing side )
     {
-        if( cap == ITEM_HANDLER_CAPABILITY ) return m_itemHandlerCap.cast();
+        if( cap == ITEM_HANDLER_CAPABILITY )
+        {
+            if( itemHandlerCap == null ) itemHandlerCap = LazyOptional.of( () -> new InvWrapper( this ) );
+            return itemHandlerCap.cast();
+        }
         return super.getCapability( cap, side );
     }
 }

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

@@ -40,7 +40,7 @@ public final class WorldUtil
     public static boolean isVecInside( VoxelShape shape, Vec3d vec )
     {
         if( shape.isEmpty() ) return false;
-        // return shape.contains( pos.x, pos.y, pos.z );
+        // AxisAlignedBB.contains, but without strict inequalities.
         AxisAlignedBB bb = shape.getBoundingBox();
         return vec.x >= bb.minX && vec.x <= bb.maxX && vec.y >= bb.minY && vec.y <= bb.maxY && vec.z >= bb.minZ && vec.z <= bb.maxZ;
     }