added movableTE's with help from @2No2Name

src/main/java/carpet/mixins/PistonBlockEntity_movableTEMixin.java

@@ -0,0 +1,139 @@
+package carpet.mixins;
+
+import carpet.CarpetSettings;
+import carpet.fakes.PistonBlockEntityInterface;
+import carpet.fakes.WorldInterface;
+import net.minecraft.block.Block;
+import net.minecraft.block.BlockEntityProvider;
+import net.minecraft.block.BlockState;
+import net.minecraft.block.Blocks;
+import net.minecraft.block.entity.BlockEntity;
+import net.minecraft.block.entity.BlockEntityType;
+import net.minecraft.block.entity.PistonBlockEntity;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.world.World;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.Redirect;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+@Mixin(PistonBlockEntity.class)
+public abstract class PistonBlockEntity_movableTEMixin extends BlockEntity implements PistonBlockEntityInterface
+{
+    @Shadow
+    private boolean source;
+    @Shadow
+    private BlockState pushedBlock;
+    
+    private BlockEntity carriedBlockEntity;
+    private boolean renderCarriedBlockEntity = false;
+    private boolean renderSet = false;
+    
+    public PistonBlockEntity_movableTEMixin(BlockEntityType<?> blockEntityType_1)
+    {
+        super(blockEntityType_1);
+    }
+    
+    
+    /**
+     * @author 2No2Name
+     */
+    public BlockEntity getCarriedBlockEntity()
+    {
+        return carriedBlockEntity;
+    }
+    
+    public void setCarriedBlockEntity(BlockEntity blockEntity)
+    {
+        this.carriedBlockEntity = blockEntity;
+        if (this.carriedBlockEntity != null)
+            this.carriedBlockEntity.setPos(this.pos);
+    }
+    
+    public boolean isRenderModeSet()
+    {
+        return renderSet;
+    }
+    
+    public boolean getRenderCarriedBlockEntity()
+    {
+        return renderCarriedBlockEntity;
+    }
+    
+    public void setRenderCarriedBlockEntity(boolean b)
+    {
+        renderCarriedBlockEntity = b;
+        renderSet = true;
+    }
+    
+    /**
+     * @author 2No2Name
+     */
+    @Redirect(method = "tick", at = @At(value = "INVOKE",
+              target = "Lnet/minecraft/world/World;setBlockState(Lnet/minecraft/util/math/BlockPos;Lnet/minecraft/block/BlockState;I)Z"))
+    private boolean movableTEsetBlockState0(World world, BlockPos blockPos_1, BlockState blockAState_2, int int_1)
+    {
+        if (!CarpetSettings.b_movableTileEntities)
+            return world.setBlockState(blockPos_1, blockAState_2, int_1);
+        else
+            return ((WorldInterface) (world)).setBlockStateWithBlockEntity(blockPos_1, blockAState_2, this.carriedBlockEntity, int_1);
+    }
+    
+    @Redirect(method = "finish", at = @At(value = "INVOKE",
+              target = "Lnet/minecraft/world/World;setBlockState(Lnet/minecraft/util/math/BlockPos;Lnet/minecraft/block/BlockState;I)Z"))
+    private boolean movableTEsetBlockState1(World world, BlockPos blockPos_1, BlockState blockState_2, int int_1)
+    {
+        if (!CarpetSettings.b_movableTileEntities)
+            return world.setBlockState(blockPos_1, blockState_2, int_1);
+        else
+        {
+            boolean ret = ((WorldInterface) (world)).setBlockStateWithBlockEntity(blockPos_1, blockState_2, this.carriedBlockEntity, int_1);
+            this.carriedBlockEntity = null; //this will cancel the finishHandleBroken
+            return ret;
+        }
+    }
+    
+    @Inject(method = "finish", at = @At(value = "RETURN"))
+    private void finishHandleBroken(CallbackInfo cir)
+    {
+        //Handle TNT Explosions or other ways the moving Block is broken
+        //Also /setblock will cause this to be called, and drop e.g. a moving chest's contents.
+        // This is MC-40380 (BlockEntities that aren't Inventories drop stuff when setblock is called )
+        if (CarpetSettings.b_movableTileEntities && this.carriedBlockEntity != null && !this.world.isClient && this.world.getBlockState(this.pos).getBlock() == Blocks.AIR)
+        {
+            BlockState blockState_2;
+            if (this.source)
+                blockState_2 = Blocks.AIR.getDefaultState();
+            else
+                blockState_2 = Block.getRenderingState(this.pushedBlock, this.world, this.pos);
+            ((WorldInterface) (this.world)).setBlockStateWithBlockEntity(this.pos, blockState_2, this.carriedBlockEntity, 3);
+            this.world.breakBlock(this.pos, true);
+        }
+    }
+    
+    @Inject(method = "fromTag", at = @At(value = "TAIL"))
+    private void onFromTag(CompoundTag compoundTag_1, CallbackInfo ci)
+    {
+        if (CarpetSettings.b_movableTileEntities && compoundTag_1.containsKey("carriedTileEntity", 10))
+        {
+            if (this.pushedBlock.getBlock() instanceof BlockEntityProvider)
+                this.carriedBlockEntity = ((BlockEntityProvider) (this.pushedBlock.getBlock())).createBlockEntity(this.world);
+            if (carriedBlockEntity != null) //Can actually be null, as BlockPistonMoving.createNewTileEntity(...) returns null
+                this.carriedBlockEntity.fromTag(compoundTag_1.getCompound("carriedTileEntity"));
+        }
+    }
+    
+    @Inject(method = "toTag", at = @At(value = "RETURN", shift = At.Shift.BEFORE))
+    private void onToTag(CompoundTag compoundTag_1, CallbackInfoReturnable<CompoundTag> cir)
+    {
+        if (CarpetSettings.b_movableTileEntities && this.carriedBlockEntity != null)
+        {
+            //Leave name "carriedTileEntity" instead of "carriedBlockEntity" for upgrade compatibility with 1.12 movable TE
+            compoundTag_1.put("carriedTileEntity", this.carriedBlockEntity.toTag(new CompoundTag()));
+        }
+    }
+}