[GitHub] [flink] pnowojski commented on a change in pull request #12034: [FLINK-17568][checkpointing] Fix the issue that task may consume input data after checkpoint barrier before checkpoint is performed for unaligned checkpoint

[GitBox <gi...@apache.org>]

pnowojski commented on a change in pull request #12034:
URL: https://github.com/apache/flink/pull/12034#discussion_r422469341



##########
File path: flink-streaming-java/src/test/java/org/apache/flink/streaming/runtime/io/StreamTaskNetworkInputTest.java
##########
@@ -74,29 +77,31 @@ public void tearDown() throws Exception {
 
 	@Test
 	public void testIsAvailableWithBufferedDataInDeserializer() throws Exception {
-		BufferBuilder bufferBuilder = BufferBuilderTestUtils.createEmptyBufferBuilder(PAGE_SIZE);
-		BufferConsumer bufferConsumer = bufferBuilder.createBufferConsumer();
-
-		serializeRecord(42L, bufferBuilder);
-		serializeRecord(44L, bufferBuilder);
-
-		List<BufferOrEvent> buffers = Collections.singletonList(new BufferOrEvent(bufferConsumer.build(), 0, false));
+		List<BufferOrEvent> buffers = Collections.singletonList(createDataBuffer());
 
 		VerifyRecordsDataOutput output = new VerifyRecordsDataOutput<>();
-		StreamTaskNetworkInput input = new StreamTaskNetworkInput<>(
-			new CheckpointedInputGate(
-				new MockInputGate(1, buffers, false),
-				new CheckpointBarrierTracker(1, new DummyCheckpointInvokable())),
-			LongSerializer.INSTANCE,
-			ioManager,
-			new StatusWatermarkValve(1, output),
-			0);
+		StreamTaskNetworkInput input = createStreamTaskNetworkInput(buffers, output);
 
 		assertHasNextElement(input, output);
 		assertHasNextElement(input, output);
 		assertEquals(2, output.getNumberOfEmittedRecords());
 	}
 
+	@Test

Review comment:
       nit: add an explanation comment:
   ```
   InputGate on CheckpointBarrier can enqueue a mailbox action to execute and StreamTaskNetworkInput must
   allow this action to execute before processing a following record.
   ```




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