Address some comments

metadata/src/main/java/org/apache/kafka/controller/ElectionStrategizer.java

@@ -24,15 +24,16 @@
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.function.Function;
 
 
 class ElectionStrategizer {
     private static final Logger log = LoggerFactory.getLogger(ElectionStrategizer.class);
 
     private final int nodeId;
-    private Boolean nodeUncleanConfig = null;
-    private Boolean clusterUncleanConfig = null;
+    private Optional<Boolean> nodeUncleanConfig = null;
+    private Optional<Boolean> clusterUncleanConfig = null;
     private Function<String, String> topicUncleanConfigAccessor = __ -> "false";
     private Map<String, String> topicUncleanOverrides = new HashMap<>();
 
@@ -62,24 +63,24 @@ ElectionStrategizer setTopicUncleanOverride(String topicName, String value) {
     }
 
     boolean shouldBeUnclean(String topicName) {
-        Boolean topicConfig = (topicUncleanOverrides.containsKey(topicName)) ?
+        Optional<Boolean> topicConfig = (topicUncleanOverrides.containsKey(topicName)) ?
             parseBoolean("topic", topicUncleanOverrides.get(topicName)) :
             parseBoolean("topic", topicUncleanConfigAccessor.apply(topicName));
-        if (topicConfig != null) return topicConfig.booleanValue();
-        if (nodeUncleanConfig != null) return nodeUncleanConfig.booleanValue();
-        if (clusterUncleanConfig != null) return clusterUncleanConfig.booleanValue();
+        if (topicConfig.isPresent()) return topicConfig.get();
+        if (nodeUncleanConfig.isPresent()) return nodeUncleanConfig.get();
+        if (clusterUncleanConfig.isPresent()) return clusterUncleanConfig.get();
         return false;
     }
 
     // VisibleForTesting
-    Boolean parseBoolean(String what, String value) {
-        if (value == null) return null;
-        if (value.equalsIgnoreCase("true")) return true;
-        if (value.equalsIgnoreCase("false")) return false;
-        if (value.trim().isEmpty()) return null;
+    Optional<Boolean> parseBoolean(String what, String value) {
+        if (value == null) return Optional.empty();
+        if (value.equalsIgnoreCase("true")) return Optional.of(true);
+        if (value.equalsIgnoreCase("false")) return Optional.of(false);
+        if (value.trim().isEmpty()) return Optional.empty();
         log.warn("Invalid value for {} config {} on node {}: '{}'. Expected true or false.",
             what, TopicConfig.UNCLEAN_LEADER_ELECTION_ENABLE_CONFIG, nodeId, value);
-        return null;
+        return Optional.empty();
     }
 
     @Override

metadata/src/main/java/org/apache/kafka/controller/Replicas.java

@@ -43,18 +43,6 @@ public static List<Integer> toList(int[] array) {
         return list;
     }
 
-    /**
-     * Convert an array of integers to a list of ints and append a final element.
-     *
-     * @param array         The input array.
-     * @return              The output list.
-     */
-    public static List<Integer> toList(int[] array, int last) {
-        List<Integer> list = toList(array);
-        list.add(last);
-        return list;
-    }
-
     /**
      * Convert a list of integers to an array of ints.
      *

metadata/src/main/java/org/apache/kafka/controller/ReplicationControlManager.java

@@ -727,9 +727,9 @@ void handleBrokerFenced(int brokerId, List<ApiMessageAndVersion> records) {
         if (brokerRegistration == null) {
             throw new RuntimeException("Can't find broker registration for broker " + brokerId);
         }
-        handleNodeDeactivated(brokerId, records);
         records.add(new ApiMessageAndVersion(new FenceBrokerRecord().
             setId(brokerId).setEpoch(brokerRegistration.epoch()), (short) 0));
+        handleNodeDeactivated(brokerId, records);
     }
 
     /**

metadata/src/test/java/org/apache/kafka/controller/ElectionStrategizerTest.java

@@ -23,7 +23,6 @@
 import org.slf4j.LoggerFactory;
 
 import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 
@@ -68,13 +67,13 @@ public void testTopicUncleanOverride() {
     @Test
     public void testParseBoolean() {
         ElectionStrategizer strategizer = createElectionStrategizer();
-        assertFalse(strategizer.parseBoolean("testParseBoolean", "false"));
-        assertFalse(strategizer.parseBoolean("testParseBoolean", "FALSE"));
-        assertTrue(strategizer.parseBoolean("testParseBoolean", "true"));
-        assertTrue(strategizer.parseBoolean("testParseBoolean", "TRUE"));
-        assertNull(strategizer.parseBoolean("testParseBoolean", ""));
-        assertNull(strategizer.parseBoolean("testParseBoolean", " "));
-        assertNull(strategizer.parseBoolean("testParseBoolean", null));
-        assertNull(strategizer.parseBoolean("testParseBoolean", "foo"));
+        assertFalse(strategizer.parseBoolean("testParseBoolean", "false").get());
+        assertFalse(strategizer.parseBoolean("testParseBoolean", "FALSE").get());
+        assertTrue(strategizer.parseBoolean("testParseBoolean", "true").get());
+        assertTrue(strategizer.parseBoolean("testParseBoolean", "TRUE").get());
+        assertFalse(strategizer.parseBoolean("testParseBoolean", "").isPresent());
+        assertFalse(strategizer.parseBoolean("testParseBoolean", " ").isPresent());
+        assertFalse(strategizer.parseBoolean("testParseBoolean", null).isPresent());
+        assertFalse(strategizer.parseBoolean("testParseBoolean", "foo").isPresent());
     }
 }

metadata/src/test/java/org/apache/kafka/controller/ReplicasTest.java

@@ -35,8 +35,6 @@ public void testToList() {
         assertEquals(Arrays.asList(1, 2, 3, 4), Replicas.toList(new int[] {1, 2, 3, 4}));
         assertEquals(Arrays.asList(), Replicas.toList(Replicas.NONE));
         assertEquals(Arrays.asList(2), Replicas.toList(new int[] {2}));
-        assertEquals(Arrays.asList(2, 3), Replicas.toList(new int[] {2}, 3));
-        assertEquals(Arrays.asList(3), Replicas.toList(new int[] {}, 3));
     }
 
     @Test