Don't send when rebuilding

src/main/java/refinedstorage/api/storage/IGroupedStorage.java

@@ -15,6 +15,11 @@ public interface IGroupedStorage {
      */
     void rebuild();
 
+    /**
+     * @return If this storage is currently rebuilding
+     */
+    boolean isRebuilding();
+
     /**
      * Adds an item to the network. Will merge it with another item if it already exists.
      *

src/main/java/refinedstorage/apiimpl/storage/GroupedStorage.java

@@ -15,6 +15,7 @@ import java.util.Collection;
 public class GroupedStorage implements IGroupedStorage {
     private INetworkMaster network;
     private Multimap<Item, ItemStack> stacks = ArrayListMultimap.create();
+    private boolean rebuilding;
 
     public GroupedStorage(INetworkMaster network) {
         this.network = network;
@@ -22,6 +23,8 @@ public class GroupedStorage implements IGroupedStorage {
 
     @Override
     public void rebuild() {
+        this.rebuilding = true;
+
         stacks.clear();
 
         for (IStorage storage : network.getStorages()) {
@@ -38,9 +41,16 @@ public class GroupedStorage implements IGroupedStorage {
             }
         }
 
+        this.rebuilding = false;
+
         network.sendStorageToClient();
     }
 
+    @Override
+    public boolean isRebuilding() {
+        return rebuilding;
+    }
+
     @Override
     public void add(ItemStack stack) {
         for (ItemStack otherStack : stacks.get(stack.getItem())) {

src/main/java/refinedstorage/tile/controller/TileController.java

@@ -410,16 +410,20 @@ public class TileController extends TileBase implements INetworkMaster, IEnergyR
 
     @Override
     public void sendStorageToClient() {
-        for (EntityPlayer player : worldObj.playerEntities) {
-            if (isWatchingGrid(player)) {
-                sendStorageToClient((EntityPlayerMP) player);
+        if (!storage.isRebuilding()) {
+            for (EntityPlayer player : worldObj.playerEntities) {
+                if (isWatchingGrid(player)) {
+                    sendStorageToClient((EntityPlayerMP) player);
+                }
             }
         }
     }
 
     @Override
     public void sendStorageToClient(EntityPlayerMP player) {
-        RefinedStorage.NETWORK.sendTo(new MessageGridItems(this), player);
+        if (!storage.isRebuilding()) {
+            RefinedStorage.NETWORK.sendTo(new MessageGridItems(this), player);
+        }
     }
 
     private boolean isWatchingGrid(EntityPlayer player) {