[KAFKA-3905] Check for null in KafkaConsumer#{subscribe, assign}

• Type: Wish
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.10.0.0
• Fix Version/s: 0.10.1.0
• Component/s: clients
• Assignee: Rekha Joshi
• Reporter: Xing Huang
• Reviewer: Ismael Juma
• Created: 27/Jun/16 08:21
• Updated: 14/Jul/16 09:57
• Resolved: 14/Jul/16 09:57

Description

Currently, KafkaConsumer's subscribe methods accept Collection<String> as topics to be subscribed, but a Collection may have null as its element. For example

            String topic = null;
            Collection<String> topics = Arrays.asList(topic);
            consumer.subscribe(topics)

When this happens, consumer will throw a puzzling NullPointerException:

	at org.apache.kafka.common.utils.Utils.utf8Length(Utils.java:245)
	at org.apache.kafka.common.protocol.types.Type$6.sizeOf(Type.java:248)
	at org.apache.kafka.common.protocol.types.ArrayOf.sizeOf(ArrayOf.java:85)
	at org.apache.kafka.common.protocol.types.Schema.sizeOf(Schema.java:89)
	at org.apache.kafka.common.protocol.types.Struct.sizeOf(Struct.java:244)
	at org.apache.kafka.common.requests.RequestSend.serialize(RequestSend.java:35)
	at org.apache.kafka.common.requests.RequestSend.<init>(RequestSend.java:29)
	at org.apache.kafka.clients.NetworkClient$DefaultMetadataUpdater.request(NetworkClient.java:616)
	at org.apache.kafka.clients.NetworkClient$DefaultMetadataUpdater.maybeUpdate(NetworkClient.java:639)
	at org.apache.kafka.clients.NetworkClient$DefaultMetadataUpdater.maybeUpdate(NetworkClient.java:552)
	at org.apache.kafka.clients.NetworkClient.poll(NetworkClient.java:258)
	at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.clientPoll(ConsumerNetworkClient.java:360)
	at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:224)
	at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:192)
	at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:163)
	at org.apache.kafka.clients.consumer.internals.AbstractCoordinator.ensureCoordinatorReady(AbstractCoordinator.java:179)
	at org.apache.kafka.clients.consumer.KafkaConsumer.pollOnce(KafkaConsumer.java:970)
	at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:934)

Maybe it's better to remove null when doing subscription.

Issue Links

• links to: GitHub Pull Request #1561
• links to: GitHub Pull Request #1564
• links to: GitHub Pull Request #1601