Paper/patches/server/0439-Fix-villager-trading-demand-MC-163962.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: chickeneer <emcchickeneer@gmail.com>
Date: Fri, 5 Jun 2020 20:02:04 -0500
Subject: [PATCH] Fix villager trading demand - MC-163962

Prevent demand from going negative and tending to negative infinity

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 510730fecc8a88dd0588689512863bd30ac248c7..f3cf16ce1e1d6c8f76ca5823f532925253ae64aa 100644
--- a/src/main/java/net/minecraft/world/item/trading/MerchantOffer.java
+++ b/src/main/java/net/minecraft/world/item/trading/MerchantOffer.java
@@ -113,7 +113,7 @@ public class MerchantOffer {
     }
 
     public void updateDemand() {
-        this.demand = this.demand + this.uses - (this.maxUses - this.uses);
+        this.demand = Math.max(0, this.demand + this.uses - (this.maxUses - this.uses)); // Paper
     }
 
     public ItemStack assemble() {