Fix possible NPE and crashes

common/buildcraft/builders/ItemBlueprint.java

@@ -73,6 +73,9 @@ public abstract class ItemBlueprint extends ItemBuildCraft {
 
 	public static BlueprintId getId (ItemStack stack) {
 		NBTTagCompound nbt = NBTUtils.getItemData(stack);
+		if (nbt == null) {
+			return null;
+		}
 		BlueprintId id = new BlueprintId ();
 		id.read (nbt);
 

common/buildcraft/core/utils/NBTUtils.java

@@ -23,6 +23,9 @@ public final class NBTUtils {
 	}
 
 	public static NBTTagCompound getItemData(ItemStack stack) {
+		if (stack == null) {
+			return null;
+		}
 		NBTTagCompound nbt = stack.getTagCompound();
 		if (nbt == null) {
 			nbt = new NBTTagCompound();

common/buildcraft/silicon/TileAssemblyTable.java

@@ -149,6 +149,9 @@ public class TileAssemblyTable extends TileLaserTableBase implements IMachine, I
 			NBTTagCompound cpt = list.getCompoundTagAt(i);
 
 			ItemStack stack = ItemStack.loadItemStackFromNBT(cpt);
+			if (stack == null) {
+				continue;
+			}
 
 			for (AssemblyRecipe r : AssemblyRecipeManager.INSTANCE.getRecipes()) {
 				if (r.output.getItem() == stack.getItem() && r.output.getItemDamage() == stack.getItemDamage()) {

common/buildcraft/transport/ItemFacade.java

@@ -216,19 +216,23 @@ public class ItemFacade extends ItemBuildCraft {
 	}
 
 	private static boolean isBlockValidForFacade(Block block) {
-		if (block.getRenderType() != 0 && block.getRenderType() != 31) {
+		try {
+			if (block.getRenderType() != 0 && block.getRenderType() != 31) {
+				return false;
+			}
+
+			if (block.getBlockBoundsMaxX() != 1.0 || block.getBlockBoundsMaxY() != 1.0 || block.getBlockBoundsMaxZ() != 1.0) {
+				return false;
+			}
+
+			if (block instanceof BlockSpring || block instanceof BlockGenericPipe) {
+				return false;
+			}
+
+			return true;
+		} catch (Throwable ignored) {
 			return false;
 		}
-
-		if (block.getBlockBoundsMaxX() != 1.0 || block.getBlockBoundsMaxY() != 1.0 || block.getBlockBoundsMaxZ() != 1.0) {
-			return false;
-		}
-
-		if (block instanceof BlockSpring || block instanceof BlockGenericPipe) {
-			return false;
-		}
-
-		return true;
 	}
 
 	// GETTERS FOR FACADE DATA