From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: BillyGalbreath <blake.galbreath@gmail.com>
Date: Tue, 8 Dec 2020 20:14:20 -0600
Subject: [PATCH] Fix curing zombie villager discount exploit

This fixes the exploit used to gain absurd trading discounts with infecting
and curing a villager on repeat by simply resetting the relevant part of
the reputation when it is cured.

diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
index 7d3207a9af8360ddad228281d6aa65e1a0d24157..a3b3e3e04b7a5e3a351992e06870cc91fbd8adc8 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -717,4 +717,9 @@ public class PaperWorldConfig {
     private void fixClimbingBypassingCrammingRule() {
         fixClimbingBypassingCrammingRule = getBoolean("fix-climbing-bypassing-cramming-rule", fixClimbingBypassingCrammingRule);
     }
+
+    public boolean fixCuringZombieVillagerDiscountExploit = true;
+    private void fixCuringExploit() {
+        fixCuringZombieVillagerDiscountExploit = getBoolean("game-mechanics.fix-curing-zombie-villager-discount-exploit", fixCuringZombieVillagerDiscountExploit);
+    }
 }
diff --git a/src/main/java/net/minecraft/world/entity/ai/gossip/GossipContainer.java b/src/main/java/net/minecraft/world/entity/ai/gossip/GossipContainer.java
index 57832c392910d22aa81ac2b4816d043dd7ac867a..9a68201bab4fcbad69c85e2469a103634b65d7b3 100644
--- a/src/main/java/net/minecraft/world/entity/ai/gossip/GossipContainer.java
+++ b/src/main/java/net/minecraft/world/entity/ai/gossip/GossipContainer.java
@@ -223,6 +223,7 @@ public class GossipContainer {
 
         }
 
+        public final void removeReputationForType(GossipType reputationType) { this.remove(reputationType); } // Paper - OBFHELPER
         public void remove(GossipType gossipType) {
             this.entries.removeInt(gossipType);
         }
diff --git a/src/main/java/net/minecraft/world/entity/npc/Villager.java b/src/main/java/net/minecraft/world/entity/npc/Villager.java
index 415fa3591add1f1ab22dd5866e110dbfccd0ec93..7817071b1964b962c8f4017d5bb39d74ca0ca3e4 100644
--- a/src/main/java/net/minecraft/world/entity/npc/Villager.java
+++ b/src/main/java/net/minecraft/world/entity/npc/Villager.java
@@ -1013,6 +1013,15 @@ public class Villager extends AbstractVillager implements ReputationEventHandler
     @Override
     public void onReputationEventFrom(ReputationEventType interaction, Entity entity) {
         if (interaction == ReputationEventType.ZOMBIE_VILLAGER_CURED) {
+            // Paper start - fix MC-181190
+            if (level.paperConfig.fixCuringZombieVillagerDiscountExploit) {
+                final GossipContainer.EntityGossips playerReputation = this.getReputation().getReputations().get(entity.getUUID());
+                if (playerReputation != null) {
+                    playerReputation.removeReputationForType(GossipType.MAJOR_POSITIVE);
+                    playerReputation.removeReputationForType(GossipType.MINOR_POSITIVE);
+                }
+            }
+            // Paper end
             this.gossips.add(entity.getUUID(), GossipType.MAJOR_POSITIVE, 20);
             this.gossips.add(entity.getUUID(), GossipType.MINOR_POSITIVE, 25);
         } else if (interaction == ReputationEventType.TRADE) {