From dfed0e3b50a1124c603293cd60155e516b01c513 Mon Sep 17 00:00:00 2001
From: Joshua Kim <kimjos@amazon.com>
Date: Thu, 29 Apr 2021 17:10:55 -0700
Subject: [PATCH] Adding guardrails for duplicate shard responses

---
 .../kinesis/clientlibrary/proxies/KinesisProxy.java         | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/main/java/com/amazonaws/services/kinesis/clientlibrary/proxies/KinesisProxy.java b/src/main/java/com/amazonaws/services/kinesis/clientlibrary/proxies/KinesisProxy.java
index 3c890ed4..4ad2c508 100644
--- a/src/main/java/com/amazonaws/services/kinesis/clientlibrary/proxies/KinesisProxy.java
+++ b/src/main/java/com/amazonaws/services/kinesis/clientlibrary/proxies/KinesisProxy.java
@@ -22,6 +22,7 @@ import java.util.ArrayList;
 import java.util.Date;
 import java.util.EnumSet;
 import java.util.HashSet;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -485,10 +486,11 @@ public class KinesisProxy implements IKinesisProxyExtended {
                 }
             } while (response.getStreamDescription().isHasMoreShards());
         }
-        this.cachedShardMap = shards.stream().collect(Collectors.toMap(Shard::getShardId, Function.identity()));
+        final List<Shard> dedupedShards = new ArrayList<>(new LinkedHashSet<>(shards));
+        this.cachedShardMap = dedupedShards.stream().collect(Collectors.toMap(Shard::getShardId, Function.identity()));
         this.lastCacheUpdateTime = Instant.now();
 
-        return shards;
+        return dedupedShards;
     }
 
     /**