PaperMC/paper-server/nms-patches/net/minecraft/world/item/ItemFishingRod.patch

--- a/net/minecraft/world/item/ItemFishingRod.java
+++ b/net/minecraft/world/item/ItemFishingRod.java
@@ -11,6 +11,8 @@
 import net.minecraft.world.level.World;
 import net.minecraft.world.level.gameevent.GameEvent;
 
+import org.bukkit.event.player.PlayerFishEvent; // CraftBukkit
+
 public class ItemFishingRod extends Item implements ItemVanishable {
 
     public ItemFishingRod(Item.Info item_info) {
@@ -33,12 +35,23 @@
             world.playSound((EntityHuman) null, entityhuman.getX(), entityhuman.getY(), entityhuman.getZ(), SoundEffects.FISHING_BOBBER_RETRIEVE, SoundCategory.NEUTRAL, 1.0F, 0.4F / (world.getRandom().nextFloat() * 0.4F + 0.8F));
             entityhuman.gameEvent(GameEvent.ITEM_INTERACT_FINISH);
         } else {
-            world.playSound((EntityHuman) null, entityhuman.getX(), entityhuman.getY(), entityhuman.getZ(), SoundEffects.FISHING_BOBBER_THROW, SoundCategory.NEUTRAL, 0.5F, 0.4F / (world.getRandom().nextFloat() * 0.4F + 0.8F));
+            // world.playSound((EntityHuman) null, entityhuman.getX(), entityhuman.getY(), entityhuman.getZ(), SoundEffects.FISHING_BOBBER_THROW, SoundCategory.NEUTRAL, 0.5F, 0.4F / (world.getRandom().nextFloat() * 0.4F + 0.8F));
             if (!world.isClientSide) {
                 i = EnchantmentManager.getFishingSpeedBonus(itemstack);
                 int j = EnchantmentManager.getFishingLuckBonus(itemstack);
 
-                world.addFreshEntity(new EntityFishingHook(entityhuman, world, j, i));
+                // CraftBukkit start
+                EntityFishingHook entityfishinghook = new EntityFishingHook(entityhuman, world, j, i);
+                PlayerFishEvent playerFishEvent = new PlayerFishEvent((org.bukkit.entity.Player) entityhuman.getBukkitEntity(), null, (org.bukkit.entity.FishHook) entityfishinghook.getBukkitEntity(), PlayerFishEvent.State.FISHING);
+                world.getCraftServer().getPluginManager().callEvent(playerFishEvent);
+
+                if (playerFishEvent.isCancelled()) {
+                    entityhuman.fishing = null;
+                    return InteractionResultWrapper.pass(itemstack);
+                }
+                world.playSound((EntityHuman) null, entityhuman.getX(), entityhuman.getY(), entityhuman.getZ(), SoundEffects.FISHING_BOBBER_THROW, SoundCategory.NEUTRAL, 0.5F, 0.4F / (world.getRandom().nextFloat() * 0.4F + 0.8F));
+                world.addFreshEntity(entityfishinghook);
+                // CraftBukkit end
             }
 
             entityhuman.awardStat(StatisticList.ITEM_USED.get(this));