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https://issues.apache.org/jira/browse/FLINK-3974?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15346486#comment-15346486
]
ASF GitHub Bot commented on FLINK-3974:
---------------------------------------
Github user tillrohrmann commented on a diff in the pull request:
https://github.com/apache/flink/pull/2110#discussion_r68241018
--- Diff:
flink-streaming-java/src/test/java/org/apache/flink/streaming/runtime/operators/ChainingITCase.java
---
@@ -0,0 +1,354 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.flink.streaming.runtime.operators;
+
+import org.apache.flink.api.common.ExecutionConfig;
+import org.apache.flink.api.common.functions.MapFunction;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.configuration.Configuration;
+import org.apache.flink.runtime.accumulators.AccumulatorRegistry;
+import org.apache.flink.runtime.execution.Environment;
+import org.apache.flink.runtime.jobgraph.JobGraph;
+import org.apache.flink.runtime.jobgraph.JobVertex;
+import org.apache.flink.runtime.operators.testutils.MockEnvironment;
+import org.apache.flink.runtime.operators.testutils.MockInputSplitProvider;
+import org.apache.flink.runtime.state.AbstractStateBackend;
+import org.apache.flink.runtime.state.memory.MemoryStateBackend;
+import org.apache.flink.streaming.api.collector.selector.OutputSelector;
+import org.apache.flink.streaming.api.datastream.DataStream;
+import org.apache.flink.streaming.api.datastream.SplitStream;
+import
org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
+import org.apache.flink.streaming.api.functions.sink.SinkFunction;
+import org.apache.flink.streaming.api.graph.StreamConfig;
+import org.apache.flink.streaming.api.operators.StreamMap;
+import org.apache.flink.streaming.api.operators.StreamOperator;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+import org.apache.flink.streaming.runtime.tasks.OperatorChain;
+import org.apache.flink.streaming.runtime.tasks.StreamTask;
+import org.junit.Assert;
+import org.junit.Test;
+import org.mockito.invocation.InvocationOnMock;
+import org.mockito.stubbing.Answer;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import static org.hamcrest.Matchers.contains;
+import static org.mockito.Matchers.any;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+/**
+ * Tests for stream operator chaining behaviour.
+ */
+public class ChainingITCase {
--- End diff --
I think that this test case no longer needs to be an IT case.
> enableObjectReuse fails when an operator chains to multiple downstream
> operators
> --------------------------------------------------------------------------------
>
> Key: FLINK-3974
> URL: https://issues.apache.org/jira/browse/FLINK-3974
> Project: Flink
> Issue Type: Bug
> Components: DataStream API
> Affects Versions: 1.0.3
> Reporter: B Wyatt
> Attachments: ReproFLINK3974.java, bwyatt-FLINK3974.1.patch
>
>
> Given a topology that looks like this:
> {code:java}
> DataStream<A> input = ...
> input
> .map(MapFunction<A,B>...)
> .addSink(...);
> input
> .map(MapFunction<A,C>...)
> .addSink(...);
> {code}
> enableObjectReuse() will cause an exception in the form of
> {{"java.lang.ClassCastException: B cannot be cast to A"}} to be thrown.
> It looks like the input operator calls {{Output<StreamRecord<A>>.collect}}
> which attempts to loop over the downstream operators and process them.
> However, the first map operation will call {{StreamRecord<>.replace}} which
> mutates the value stored in the StreamRecord<>.
> As a result, when the {{Output<StreamRecord<A>>.collect}} call passes the
> {{StreamRecord<A>}} to the second map operation it is actually a
> {{StreamRecord<B>}} and behaves as if the two map operations were serial
> instead of parallel.
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