[kafka] branch trunk updated: KAFKA-8011: Fix for race condition causing concurrent modification exception (#6338)

[bbejeck]

This is an automated email from the ASF dual-hosted git repository.

bbejeck pushed a commit to branch trunk
in repository https://gitbox.apache.org/repos/asf/kafka.git


The following commit(s) were added to refs/heads/trunk by this push:
     new 45adc80  KAFKA-8011: Fix for race condition causing concurrent 
modification exception (#6338)
45adc80 is described below

commit 45adc80366e6e61187484d7e88467df05af2470f
Author: Bill Bejeck <bbej...@gmail.com>
AuthorDate: Thu Feb 28 18:54:25 2019 -0500

    KAFKA-8011: Fix for race condition causing concurrent modification 
exception (#6338)
    
    In the RegexSourceIntegrationTest#testRegexMatchesTopicsAWhenCreated() and 
RegexSourceIntegrationTest#testRegexMatchesTopicsAWhenDeleted() a race 
condition exists where the ConsumerRebalanceListener in the test modifies the 
list of subscribed topics when the condition for the test success is comparing 
the same array instance against expected values.
    
    This PR should fix this race condition by using a CopyOnWriteArrayList 
which guarantees safe traversal of the list even when a concurrent modification 
is happening.
    
    Reviewers: Guozhang Wang <wangg...@gmail.com>
---
 .../apache/kafka/streams/integration/RegexSourceIntegrationTest.java | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git 
a/streams/src/test/java/org/apache/kafka/streams/integration/RegexSourceIntegrationTest.java
 
b/streams/src/test/java/org/apache/kafka/streams/integration/RegexSourceIntegrationTest.java
index 264cd35..1cb9e0c 100644
--- 
a/streams/src/test/java/org/apache/kafka/streams/integration/RegexSourceIntegrationTest.java
+++ 
b/streams/src/test/java/org/apache/kafka/streams/integration/RegexSourceIntegrationTest.java
@@ -60,6 +60,7 @@ import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;
+import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.regex.Pattern;
 
@@ -152,7 +153,7 @@ public class RegexSourceIntegrationTest {
         final KStream<String, String> pattern1Stream = 
builder.stream(Pattern.compile("TEST-TOPIC-\\d"));
 
         pattern1Stream.to(DEFAULT_OUTPUT_TOPIC, Produced.with(stringSerde, 
stringSerde));
-        final List<String> assignedTopics = new ArrayList<>();
+        final List<String> assignedTopics = new CopyOnWriteArrayList<>();
         streams = new KafkaStreams(builder.build(), streamsConfiguration, new 
DefaultKafkaClientSupplier() {
             @Override
             public Consumer<byte[], byte[]> getConsumer(final Map<String, 
Object> config) {
@@ -190,7 +191,7 @@ public class RegexSourceIntegrationTest {
 
         pattern1Stream.to(DEFAULT_OUTPUT_TOPIC, Produced.with(stringSerde, 
stringSerde));
 
-        final List<String> assignedTopics = new ArrayList<>();
+        final List<String> assignedTopics = new CopyOnWriteArrayList<>();
         streams = new KafkaStreams(builder.build(), streamsConfiguration, new 
DefaultKafkaClientSupplier() {
             @Override
             public Consumer<byte[], byte[]> getConsumer(final Map<String, 
Object> config) {