Add PlayerUseBowWithoutProjectileEvent

paper-api/src/main/java/io/papermc/paper/event/player/PlayerUseBowWithoutProjectileEvent.java

@@ -0,0 +1,65 @@
+package io.papermc.paper.event.player;
+
+import org.bukkit.entity.Player;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.player.PlayerEvent;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * Called when a player tries to draw a bow or load a crossbow without having a suitable projectile in their inventory
+ */
+@NullMarked
+public class PlayerUseBowWithoutProjectileEvent extends PlayerEvent {
+
+    private static final HandlerList HANDLER_LIST = new HandlerList();
+
+    private final ItemStack item;
+    private ItemStack projectile;
+
+    @ApiStatus.Internal
+    public PlayerUseBowWithoutProjectileEvent(final Player player, final ItemStack item) {
+        super(player);
+        this.item = item;
+        this.projectile = ItemStack.empty();
+    }
+
+    /**
+     *  Gets the item which the player tries to use
+     *
+     * @return the item
+     */
+    public ItemStack getItem() {
+        return item.clone();
+    }
+
+    /**
+     * Gets the projectile that should be used
+     * 
+     * @return the projectile
+     */
+    public ItemStack getProjectile() {
+        return projectile.clone();
+    }
+
+    /**
+     * Sets the projectile that should be used
+     * <p>
+     * Note: setting this to {@link ItemStack#empty()} will prevent the player from using the bow/crossbow
+     * 
+     * @param projectile the projectile
+     */
+    public void setProjectile(ItemStack projectile) {
+        this.projectile = projectile.clone();
+    }
+
+    @Override
+    public HandlerList getHandlers() {
+        return HANDLER_LIST;
+    }
+
+    public static HandlerList getHandlerList() {
+        return HANDLER_LIST;
+    }
+}

paper-server/patches/sources/net/minecraft/world/entity/player/Player.java.patch

@@ -669,3 +669,20 @@
 
                  for (int i = 0; i < this.inventory.getContainerSize(); i++) {
                      ItemStack item = this.inventory.getItem(i);
+@@ -2007,7 +_,15 @@
+                     }
+                 }
+
+-                return this.abilities.instabuild ? new ItemStack(Items.ARROW) : ItemStack.EMPTY;
++                // Paper start - PlayerUseBowWithoutProjectileEvent
++                if (this.abilities.instabuild) {
++                    return new ItemStack(Items.ARROW);
++                } else {
++                    io.papermc.paper.event.player.PlayerUseBowWithoutProjectileEvent event = new io.papermc.paper.event.player.PlayerUseBowWithoutProjectileEvent((org.bukkit.entity.Player) getBukkitEntity(), org.bukkit.craftbukkit.inventory.CraftItemStack.asBukkitCopy(stack));
++                    event.callEvent();
++                    return org.bukkit.craftbukkit.inventory.CraftItemStack.asNMSCopy(event.getProjectile());
++                }
++                // Paper end - PlayerUseBowWithoutProjectileEvent
+             }
+         }
+     }