Paper/patches/server/0694-Fix-MerchantOffer-BuyB-Only-AssertionError.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: thamid-gamer <60953955+thamid-gamer@users.noreply.github.com>
Date: Fri, 16 Jul 2021 16:00:17 -0400
Subject: [PATCH] Fix MerchantOffer BuyB-Only AssertionError


diff --git a/src/main/java/net/minecraft/world/item/trading/MerchantOffer.java b/src/main/java/net/minecraft/world/item/trading/MerchantOffer.java
index e0f1857dc100bc4d68e5e308b984e5eeaef976b5..12354b2fd411c57fd14dfca92cd2f1522fa6f050 100644
--- a/src/main/java/net/minecraft/world/item/trading/MerchantOffer.java
+++ b/src/main/java/net/minecraft/world/item/trading/MerchantOffer.java
@@ -231,6 +231,7 @@ public class MerchantOffer {
         if (!this.satisfiedBy(firstBuyStack, secondBuyStack)) {
             return false;
         } else {
+            if (!this.getCostA().isEmpty()) // Paper
             firstBuyStack.shrink(this.getCostA().getCount());
             if (!this.getCostB().isEmpty()) {
                 secondBuyStack.shrink(this.getCostB().getCount());