Do not crash from invalid ingredient lists in VillagerAcquireTradeEvent

Spigot-Server-Patches/0622-Do-not-crash-from-invalid-ingredient-lists-in-Villag.patch

@@ -0,0 +1,24 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Shane Freeder <theboyetronic@gmail.com>
+Date: Sun, 27 Dec 2020 11:31:06 +0000
+Subject: [PATCH] Do not crash from invalid ingredient lists in
+ VillagerAcquireTradeEvent
+
+
+diff --git a/src/main/java/net/minecraft/server/EntityVillagerAbstract.java b/src/main/java/net/minecraft/server/EntityVillagerAbstract.java
+index 1fddf7c77488a5e53fc48d0db0a7b8acc71e2f42..8971dd013498e70c4e7a6ac6a218f62e599c86b9 100644
+--- a/src/main/java/net/minecraft/server/EntityVillagerAbstract.java
++++ b/src/main/java/net/minecraft/server/EntityVillagerAbstract.java
+@@ -245,7 +245,11 @@ public abstract class EntityVillagerAbstract extends EntityAgeable implements NP
+                     Bukkit.getPluginManager().callEvent(event);
+                 }
+                 if (!event.isCancelled()) {
+-                    merchantrecipelist.add(CraftMerchantRecipe.fromBukkit(event.getRecipe()).toMinecraft());
++                    // Paper start
++                    final CraftMerchantRecipe craftMerchantRecipe = CraftMerchantRecipe.fromBukkit(event.getRecipe());
++                    if (craftMerchantRecipe.getIngredients().isEmpty()) return;
++                    merchantrecipelist.add(craftMerchantRecipe.toMinecraft());
++                    // Paper end
+                 }
+                 // CraftBukkit end
+             }