[FLINK-36209] Remove redundant operations in the initialization of KafkaSourceEnumState

flink-connector-kafka/src/main/java/org/apache/flink/connector/kafka/dynamic/source/enumerator/DynamicKafkaSourceEnumerator.java

@@ -35,6 +35,7 @@
 import org.apache.flink.connector.kafka.source.KafkaPropertiesUtil;
 import org.apache.flink.connector.kafka.source.enumerator.KafkaSourceEnumState;
 import org.apache.flink.connector.kafka.source.enumerator.KafkaSourceEnumerator;
+import org.apache.flink.connector.kafka.source.enumerator.TopicPartitionAndAssignmentStatus;
 import org.apache.flink.connector.kafka.source.enumerator.initializer.OffsetsInitializer;
 import org.apache.flink.connector.kafka.source.enumerator.subscriber.KafkaSubscriber;
 import org.apache.flink.connector.kafka.source.split.KafkaPartitionSplit;
@@ -298,24 +299,16 @@ private void onHandleSubscribedStreamsFetch(Set<KafkaStream> fetchedKafkaStreams
                 final Set<String> activeTopics = activeClusterTopics.getValue();
 
                 // filter out removed topics
-                Set<TopicPartition> activeAssignedPartitions =
-                        kafkaSourceEnumState.assignedPartitions().stream()
-                                .filter(tp -> activeTopics.contains(tp.topic()))
-                                .collect(Collectors.toSet());
-                Set<TopicPartition> activeUnassignedInitialPartitions =
-                        kafkaSourceEnumState.unassignedInitialPartitions().stream()
-                                .filter(tp -> activeTopics.contains(tp.topic()))
+                Set<TopicPartitionAndAssignmentStatus> partitions =
+                        kafkaSourceEnumState.partitions().stream()
+                                .filter(tp -> activeTopics.contains(tp.topicPartition().topic()))
                                 .collect(Collectors.toSet());
 
                 newKafkaSourceEnumState =
                         new KafkaSourceEnumState(
-                                activeAssignedPartitions,
-                                activeUnassignedInitialPartitions,
-                                kafkaSourceEnumState.initialDiscoveryFinished());
+                                partitions, kafkaSourceEnumState.initialDiscoveryFinished());
             } else {
-                newKafkaSourceEnumState =
-                        new KafkaSourceEnumState(
-                                Collections.emptySet(), Collections.emptySet(), false);
+                newKafkaSourceEnumState = new KafkaSourceEnumState(Collections.emptySet(), false);
             }
 
             // restarts enumerator from state using only the active topic partitions, to avoid

flink-connector-kafka/src/main/java/org/apache/flink/connector/kafka/source/enumerator/KafkaSourceEnumState.java

@@ -32,7 +32,8 @@ public class KafkaSourceEnumState {
     /** Partitions with status: ASSIGNED or UNASSIGNED_INITIAL. */
     private final Set<TopicPartitionAndAssignmentStatus> partitions;
     /**
-     * this flag will be marked as true if inital partitions are discovered after enumerator starts.
+     * this flag will be marked as true if initial partitions are discovered after enumerator
+     * starts.
      */
     private final boolean initialDiscoveryFinished;
 

flink-connector-kafka/src/main/java/org/apache/flink/connector/kafka/source/enumerator/KafkaSourceEnumStateSerializer.java

@@ -89,9 +89,7 @@ public KafkaSourceEnumState deserialize(int version, byte[] serialized) throws I
             case CURRENT_VERSION:
                 return deserializeTopicPartitionAndAssignmentStatus(serialized);
             case VERSION_1:
-                final Set<TopicPartition> assignedPartitions =
-                        deserializeTopicPartitions(serialized);
-                return new KafkaSourceEnumState(assignedPartitions, new HashSet<>(), true);
+                return deserializeAssignedTopicPartitions(serialized);
             case VERSION_0:
                 Map<Integer, Set<KafkaPartitionSplit>> currentPartitionAssignment =
                         SerdeUtils.deserializeSplitAssignments(
@@ -113,23 +111,24 @@ public KafkaSourceEnumState deserialize(int version, byte[] serialized) throws I
         }
     }
 
-    private static Set<TopicPartition> deserializeTopicPartitions(byte[] serializedTopicPartitions)
-            throws IOException {
+    private static KafkaSourceEnumState deserializeAssignedTopicPartitions(
+            byte[] serializedTopicPartitions) throws IOException {
         try (ByteArrayInputStream bais = new ByteArrayInputStream(serializedTopicPartitions);
                 DataInputStream in = new DataInputStream(bais)) {
 
             final int numPartitions = in.readInt();
-            Set<TopicPartition> topicPartitions = new HashSet<>(numPartitions);
+            Set<TopicPartitionAndAssignmentStatus> partitions = new HashSet<>(numPartitions);
             for (int i = 0; i < numPartitions; i++) {
                 final String topic = in.readUTF();
                 final int partition = in.readInt();
-                topicPartitions.add(new TopicPartition(topic, partition));
+                partitions.add(
+                        new TopicPartitionAndAssignmentStatus(
+                                new TopicPartition(topic, partition), AssignmentStatus.ASSIGNED));
             }
             if (in.available() > 0) {
                 throw new IOException("Unexpected trailing bytes in serialized topic partitions");
             }
-
-            return topicPartitions;
+            return new KafkaSourceEnumState(partitions, true);
         }
     }
 

flink-connector-kafka/src/main/java/org/apache/flink/connector/kafka/source/enumerator/KafkaSourceEnumerator.java

@@ -112,7 +112,7 @@ public KafkaSourceEnumerator(
                 properties,
                 context,
                 boundedness,
-                new KafkaSourceEnumState(Collections.emptySet(), Collections.emptySet(), false));
+                new KafkaSourceEnumState(Collections.emptySet(), false));
     }
 
     public KafkaSourceEnumerator(