Treat shelves as containers in pipes

src/main/java/com/sk89q/craftbook/mechanics/pipe/Pipes.java

@@ -351,26 +351,18 @@ private void startPipe(Block block, List<ItemStack> items, boolean request) {
             Block fac = block.getRelative(p.getFacing());
             Material facType = fac.getType();
 
-            if (facType == Material.CHEST
-                    || facType == Material.TRAPPED_CHEST
-                    || facType == Material.DROPPER
-                    || facType == Material.DISPENSER
-                    || facType == Material.HOPPER
-                    || facType == Material.BARREL
-                    || facType == Material.CHISELED_BOOKSHELF
-                    || facType == Material.CRAFTER
-                    || facType == Material.DECORATED_POT
-                    || Tag.SHULKER_BOXES.isTagged(facType)) {
-                for (ItemStack stack : ((InventoryHolder) fac.getState()).getInventory().getContents()) {
+            if (InventoryUtil.hasGenericInventory(facType)) {
+                org.bukkit.block.BlockState facState = fac.getState();
+                for (ItemStack stack : ((InventoryHolder) facState).getInventory().getContents()) {
 
                     if (!ItemUtil.isStackValid(stack))
                         continue;
 
                     if(!ItemUtil.doesItemPassFilters(stack, filters, exceptions))
                         continue;
 
-                    items.add(stack);
-                    ((InventoryHolder) fac.getState()).getInventory().removeItem(stack);
+                    items.add(stack.clone());
+                    ((InventoryHolder) facState).getInventory().removeItem(stack);
                     if (pipeStackPerPull)
                         break;
                 }

src/main/java/com/sk89q/craftbook/util/InventoryUtil.java

@@ -1,6 +1,7 @@
 package com.sk89q.craftbook.util;
 
 import org.bukkit.Material;
+import org.bukkit.Tag;
 import org.bukkit.block.Block;
 import org.bukkit.block.BrewingStand;
 import org.bukkit.block.Chest;
@@ -339,13 +340,45 @@ public static boolean fitsInSlot(ItemStack stack, ItemStack slot) {
     public static boolean doesBlockHaveInventory(Block block) {
 
         switch(block.getType()) {
+            case FURNACE:
+            case BLAST_FURNACE:
+            case SMOKER:
+            case BREWING_STAND:
+                return true;
+            default:
+                return hasGenericInventory(block.getType());
+        }
+    }
+
+    /**
+     * Checks whether a material is a container whose whole inventory is plain
+     * item slots, safe to insert into or pull from generically. Furnaces,
+     * smokers, blast furnaces and brewing stands are containers too but have
+     * role-specific slots (fuel, ingredient, result), so their callers route
+     * them through dedicated branches instead of this family.
+     *
+     * @param type The material to check.
+     * @return If the material is a generic container.
+     */
+    public static boolean hasGenericInventory(Material type) {
+        switch(type) {
             case CHEST:
             case TRAPPED_CHEST:
             case DROPPER:
             case DISPENSER:
-            case FURNACE:
-            case BREWING_STAND:
             case HOPPER:
+            case BARREL:
+            case CHISELED_BOOKSHELF:
+            case DECORATED_POT:
+            case CRAFTER:
+            case COPPER_CHEST:
+            case EXPOSED_COPPER_CHEST:
+            case WEATHERED_COPPER_CHEST:
+            case OXIDIZED_COPPER_CHEST:
+            case WAXED_COPPER_CHEST:
+            case WAXED_EXPOSED_COPPER_CHEST:
+            case WAXED_WEATHERED_COPPER_CHEST:
+            case WAXED_OXIDIZED_COPPER_CHEST:
             case WHITE_SHULKER_BOX:
             case ORANGE_SHULKER_BOX:
             case MAGENTA_SHULKER_BOX:
@@ -363,15 +396,10 @@ public static boolean doesBlockHaveInventory(Block block) {
             case BLACK_SHULKER_BOX:
             case RED_SHULKER_BOX:
             case SHULKER_BOX:
-            case BLAST_FURNACE:
-            case SMOKER:
-            case BARREL:
-            case CHISELED_BOOKSHELF:
-            case DECORATED_POT:
-            case CRAFTER:
                 return true;
             default:
-                return false;
+                // Shelves are matched by tag because new wood types keep adding materials.
+                return Tag.WOODEN_SHELVES.isTagged(type);
         }
     }