PaperMC/paper-server/patches/sources/net/minecraft/world/item/SnowballItem.java.patch

--- a/net/minecraft/world/item/SnowballItem.java
+++ b/net/minecraft/world/item/SnowballItem.java
@@ -25,13 +25,30 @@
     public InteractionResult use(Level world, Player user, InteractionHand hand) {
         ItemStack itemstack = user.getItemInHand(hand);
 
-        world.playSound((Player) null, user.getX(), user.getY(), user.getZ(), SoundEvents.SNOWBALL_THROW, SoundSource.NEUTRAL, 0.5F, 0.4F / (world.getRandom().nextFloat() * 0.4F + 0.8F));
+        // CraftBukkit start - moved down
+        // world.playSound((EntityHuman) null, entityhuman.getX(), entityhuman.getY(), entityhuman.getZ(), SoundEffects.SNOWBALL_THROW, SoundCategory.NEUTRAL, 0.5F, 0.4F / (world.getRandom().nextFloat() * 0.4F + 0.8F));
         if (world instanceof ServerLevel worldserver) {
-            Projectile.spawnProjectileFromRotation(Snowball::new, worldserver, itemstack, user, 0.0F, SnowballItem.PROJECTILE_SHOOT_POWER, 1.0F);
+            // Paper start - PlayerLaunchProjectileEvent
+            final Projectile.Delayed<Snowball> snowball = Projectile.spawnProjectileFromRotationDelayed(Snowball::new, worldserver, itemstack, user, 0.0F, SnowballItem.PROJECTILE_SHOOT_POWER, 1.0F);
+            com.destroystokyo.paper.event.player.PlayerLaunchProjectileEvent event = new com.destroystokyo.paper.event.player.PlayerLaunchProjectileEvent((org.bukkit.entity.Player) user.getBukkitEntity(), org.bukkit.craftbukkit.inventory.CraftItemStack.asCraftMirror(itemstack), (org.bukkit.entity.Projectile) snowball.projectile().getBukkitEntity());
+            if (event.callEvent() && snowball.attemptSpawn()) {
+                user.awardStat(Stats.ITEM_USED.get(this));
+                if (event.shouldConsume()) {
+                    itemstack.consume(1, user);
+                } else if (user instanceof net.minecraft.server.level.ServerPlayer) {
+                    ((net.minecraft.server.level.ServerPlayer) user).getBukkitEntity().updateInventory();
+                }
+            // Paper end - PlayerLaunchProjectileEvent
+
+                world.playSound((Player) null, user.getX(), user.getY(), user.getZ(), SoundEvents.SNOWBALL_THROW, SoundSource.NEUTRAL, 0.5F, 0.4F / (world.getRandom().nextFloat() * 0.4F + 0.8F));
+            } else { if (user instanceof net.minecraft.server.level.ServerPlayer) { // Paper - PlayerLaunchProjectileEvent - return fail
+                ((net.minecraft.server.level.ServerPlayer) user).getBukkitEntity().updateInventory();
+            } return InteractionResult.FAIL; } // Paper - PlayerLaunchProjectileEvent - return fail
+            // CraftBukkit end
         }
 
-        user.awardStat(Stats.ITEM_USED.get(this));
-        itemstack.consume(1, user);
+        // Paper - PlayerLaunchProjectileEvent - moved up
+        // itemstack.consume(1, entityhuman); // CraftBukkit - moved up
         return InteractionResult.SUCCESS;
     }