KAFKA-8142: Fix NPE for nulls in Headers (#6484)

Reviewers: Bill Bejeck <bill@confluent.io>, Guozhang Wang <guozhang@confluent.io>

clients/src/main/java/org/apache/kafka/common/header/internals/RecordHeaders.java

@@ -16,16 +16,17 @@
  */
 package org.apache.kafka.common.header.internals;
 
+import org.apache.kafka.common.header.Header;
+import org.apache.kafka.common.header.Headers;
+import org.apache.kafka.common.record.Record;
+import org.apache.kafka.common.utils.AbstractIterator;
+
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.List;
-
-import org.apache.kafka.common.header.Header;
-import org.apache.kafka.common.header.Headers;
-import org.apache.kafka.common.record.Record;
-import org.apache.kafka.common.utils.AbstractIterator;
+import java.util.Objects;
 
 public class RecordHeaders implements Headers {
 
@@ -61,6 +62,7 @@ public class RecordHeaders implements Headers {
 
     @Override
     public Headers add(Header header) throws IllegalStateException {
+        Objects.requireNonNull(header, "Header cannot be null.");
         canWrite();
         headers.add(header);
         return this;

clients/src/test/java/org/apache/kafka/common/header/internals/RecordHeadersTest.java

@@ -16,19 +16,19 @@
  */
 package org.apache.kafka.common.header.internals;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
+import org.apache.kafka.common.header.Header;
+import org.apache.kafka.common.header.Headers;
+import org.junit.Test;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Iterator;
 
-import org.apache.kafka.common.header.Header;
-import org.apache.kafka.common.header.Headers;
-import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 public class RecordHeadersTest {
 
@@ -206,6 +206,11 @@ public class RecordHeadersTest {
         assertEquals(2, getCount(newHeaders));
     }
 
+    @Test(expected = NullPointerException.class)
+    public void shouldThrowNpeWhenAddingNullHeader() {
+        new RecordHeaders().add(null);
+    }
+
     private int getCount(Headers headers) {
         int count = 0;
         Iterator<Header> headerIterator = headers.iterator();

streams/src/main/java/org/apache/kafka/streams/processor/internals/ProcessorRecordContext.java

@@ -90,7 +90,10 @@ public class ProcessorRecordContext implements RecordContext {
         if (headers != null) {
             for (final Header header : headers) {
                 size += header.key().toCharArray().length;
-                size += header.value().length;
+                final byte[] value = header.value();
+                if (value != null) {
+                    size += value.length;
+                }
             }
         }
         return size;

streams/src/test/java/org/apache/kafka/streams/processor/internals/ProcessorRecordContextTest.java

@@ -0,0 +1,98 @@
+/*
+ * 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.kafka.streams.processor.internals;
+
+import org.apache.kafka.common.header.Headers;
+import org.apache.kafka.common.header.internals.RecordHeaders;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class ProcessorRecordContextTest {
+    // timestamp + offset + partition: 8 + 8 + 4
+    private final static long MIN_SIZE = 20L;
+
+    @Test
+    public void shouldEstimateNullTopicAndNullHeadersAsZeroLength() {
+        final Headers headers = new RecordHeaders();
+        final ProcessorRecordContext context = new ProcessorRecordContext(
+            42L,
+            73L,
+            0,
+            null,
+            null
+        );
+
+        assertEquals(MIN_SIZE, context.sizeBytes());
+    }
+
+    @Test
+    public void shouldEstimateEmptyHeaderAsZeroLength() {
+        final ProcessorRecordContext context = new ProcessorRecordContext(
+            42L,
+            73L,
+            0,
+            null,
+            new RecordHeaders()
+        );
+
+        assertEquals(MIN_SIZE, context.sizeBytes());
+    }
+
+    @Test
+    public void shouldEstimateTopicLength() {
+        final ProcessorRecordContext context = new ProcessorRecordContext(
+            42L,
+            73L,
+            0,
+            "topic",
+            null
+        );
+
+        assertEquals(MIN_SIZE + 5L, context.sizeBytes());
+    }
+
+    @Test
+    public void shouldEstimateHeadersLength() {
+        final Headers headers = new RecordHeaders();
+        headers.add("header-key", "header-value".getBytes());
+        final ProcessorRecordContext context = new ProcessorRecordContext(
+            42L,
+            73L,
+            0,
+            null,
+            headers
+        );
+
+        assertEquals(MIN_SIZE + 10L + 12L, context.sizeBytes());
+    }
+
+    @Test
+    public void shouldEstimateNullValueInHeaderAsZero() {
+        final Headers headers = new RecordHeaders();
+        headers.add("header-key", null);
+        final ProcessorRecordContext context = new ProcessorRecordContext(
+            42L,
+            73L,
+            0,
+            null,
+            headers
+        );
+
+        assertEquals(MIN_SIZE + 10L, context.sizeBytes());
+    }
+}