From 7bc8c0dcd1db27465661e135cea8e800c337f19e Mon Sep 17 00:00:00 2001
From: John Roesler <vvcephei@users.noreply.github.com>
Date: Mon, 21 Oct 2019 16:25:41 -0500
Subject: [PATCH] MINOR: don't require key serde in join materialized (#7557)

Reviewers: Bill Bejeck <bill@confluent.io>, Guozhang Wang <guozhang@confluent.io>, Matthias J. Sax <matthias@confluent.io>
---
 .../apache/kafka/streams/kstream/internals/KTableImpl.java   | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
index 301710ddb44..f6f2ada6ce5 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
@@ -712,7 +712,10 @@ public class KTableImpl<K, S, V> extends AbstractStream<K, V> implements KTable<
         final StoreBuilder<TimestampedKeyValueStore<K, VR>> storeBuilder;
 
         if (materializedInternal != null) {
-            keySerde = materializedInternal.keySerde() != null ? materializedInternal.keySerde() : this.keySerde;
+            if (materializedInternal.keySerde() == null) {
+                materializedInternal.withKeySerde(this.keySerde);
+            }
+            keySerde = materializedInternal.keySerde();
             valueSerde = materializedInternal.valueSerde();
             queryableStoreName = materializedInternal.storeName();
             storeBuilder = new TimestampedKeyValueStoreMaterializer<>(materializedInternal).materialize();