Updates version to 1.2.3

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>net.knarcraft</groupId>
     <artifactId>BooksWithoutBorders</artifactId>
-    <version>1.2.2</version>
+    <version>1.2.3</version>
     <packaging>jar</packaging>
 
     <licenses>
@@ -75,7 +75,7 @@
         <dependency>
             <groupId>org.spigotmc</groupId>
             <artifactId>spigot-api</artifactId>
-            <version>1.18.1-R0.1-SNAPSHOT</version>
+            <version>1.19.1-R0.1-SNAPSHOT</version>
             <scope>provided</scope>
         </dependency>
         <dependency>

src/main/java/net/knarcraft/bookswithoutborders/command/CommandSave.java

@@ -51,7 +51,7 @@ public class CommandSave implements TabExecutor {
         }
 
         ItemSlot holdingSlot = InventoryHelper.getHeldSlotBook(player, false, false, false, false);
-        if (holdingSlot != ItemSlot.NONE) {
+        if (holdingSlot != null && holdingSlot != ItemSlot.NONE) {
             ItemStack holdingItem = InventoryHelper.getHeldItem(player, holdingSlot == ItemSlot.MAIN_HAND);
             boolean duplicate = args.length == 1 && Boolean.parseBoolean(args[0]);
             saveBook(player, holdingItem, duplicate, savePublic);

src/main/java/net/knarcraft/bookswithoutborders/listener/SignEventListener.java

@@ -89,6 +89,9 @@ public class SignEventListener implements Listener {
             return;
         }
         ItemStack heldItem = playerInventory.getItem(hand);
+        if (heldItem == null) {
+            return;
+        }
         Material heldItemType = heldItem.getType();
 
         if (event.getAction() == Action.RIGHT_CLICK_BLOCK && (Tag.SIGNS.isTagged(clickedBlockType) ||

src/main/java/net/knarcraft/bookswithoutborders/utility/InventoryHelper.java

@@ -96,7 +96,7 @@ public final class InventoryHelper {
         if (state == BookHoldingState.SIGNED_BOTH_HANDS ||
                 state == BookHoldingState.UNSIGNED_BOTH_HANDS ||
                 state == BookHoldingState.NONE) {
-            return null;
+            return ItemSlot.NONE;
         }
         if (handMatters && typeMatters) {
             if (mainHand && mainHandItem.getType() == requiredMaterial) {