[jira] [Created] (KAFKA-13307) NPE in SyncGroup after an “empty” JoinGroup

["Jean-Baptiste Mazon (Jira)" <ji...@apache.org>]

Jean-Baptiste Mazon created KAFKA-13307:
-------------------------------------------

             Summary: NPE in SyncGroup after an “empty” JoinGroup
                 Key: KAFKA-13307
                 URL: https://issues.apache.org/jira/browse/KAFKA-13307
             Project: Kafka
          Issue Type: Bug
    Affects Versions: 2.8.0
         Environment: This is kafka_2.13-2.8.0, tarball from the website, on a single-host 3-node Linux 5.13.13 setup.
            Reporter: Jean-Baptiste Mazon
         Attachments: join_then_sync.raw

Got this while socket-hacking on my raw consumer (binary messages attached, but may not be that directly usable as there's a generated UUID involved).

 

Summary:
 # → JoinGroup Request v0 (groupId = "test-consumer", sessionTimeoutMs = 10000, memberId = empty string, protocolType = "consumer", protocols = empty array)
 # ← JoinGroup Response v0 (errorCode = 0 (None), generationId = 7, protocolName = empty string, leader = "null-cd85a8fc-b376-44aa-a4b0-641d01466d10", memberId =  "null-cd85a8fc-b376-44aa-a4b0-641d01466d10", members = [\{memberId = "null-cd85a8fc-b376-44aa-a4b0-641d01466d10", metadata = empty bytes}])
 # → SyncGroup Request v0  (groupId = "test-consumer", generationId = echo, memberId = echo, assignments = empty bytes)
 # ← SyncGroup Response v0 (errorCode = -1 (*UnknownServerError, with a NPE*), memberAssignment = empty bytes)

 

Server-side log:
{noformat}
[2021-09-16 21:46:15,979] ERROR [KafkaApi-0] Error when handling request: clientId=null, correlationId=67305986, api=SYNC_GROUP, version=0, body=SyncGroupRequestData(groupId='test-consumer', generationId=6, memberId='null-0e29c037-55b7-413a-9822-8b9d87b49a89', groupInstanceId=null, protocolType=null, protocolName=null, assignments=[]) (kafka.server.RequestHandlerHelper)
java.lang.NullPointerException: Cannot invoke "String.getBytes(java.nio.charset.Charset)" because "this.clientId" is null
 at kafka.internals.generated.GroupMetadataValue$MemberMetadata.addSize(GroupMetadataValue.java:643)
 at kafka.internals.generated.GroupMetadataValue.addSize(GroupMetadataValue.java:261)
 at org.apache.kafka.common.protocol.Message.size(Message.java:51)
 at org.apache.kafka.common.protocol.MessageUtil.toVersionPrefixedByteBuffer(MessageUtil.java:201)
 at org.apache.kafka.common.protocol.MessageUtil.toVersionPrefixedBytes(MessageUtil.java:210)
 at kafka.coordinator.group.GroupMetadataManager$.groupMetadataValue(GroupMetadataManager.scala:1065)
 at kafka.coordinator.group.GroupMetadataManager.storeGroup(GroupMetadataManager.scala:250)
 at kafka.coordinator.group.GroupCoordinator.$anonfun$doSyncGroup$1(GroupCoordinator.scala:421)
 at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.scala:18)
 at kafka.coordinator.group.GroupMetadata.inLock(GroupMetadata.scala:227)
 at kafka.coordinator.group.GroupCoordinator.handleSyncGroup(GroupCoordinator.scala:381)
 at kafka.server.KafkaApis.handleSyncGroupRequest(KafkaApis.scala:1555)
 at kafka.server.KafkaApis.handle(KafkaApis.scala:181)
 at kafka.server.KafkaRequestHandler.run(KafkaRequestHandler.scala:74)
 at java.base/java.lang.Thread.run(Thread.java:831){noformat}
 

A similar one can be triggered with DescribeGroups by launching {{kafka-consumer-groups.sh --describe --group test-consumer}} shortly after:
{noformat}
[2021-09-16 21:47:49,911] ERROR [KafkaApi-0] Error when handling request: clientId=adminclient-1, correlationId=4, api=DESCRIBE_GROUPS, version=5, body=DescribeGroupsRequestData(groups=[test-consumer], includeAuthorizedOperations=false) (kafka.server.RequestHandlerHelper)
java.lang.NullPointerException: Cannot invoke "String.getBytes(java.nio.charset.Charset)" because "this.clientId" is null
 at org.apache.kafka.common.message.DescribeGroupsResponseData$DescribedGroupMember.addSize(DescribeGroupsResponseData.java:1116)
 at org.apache.kafka.common.message.DescribeGroupsResponseData$DescribedGroup.addSize(DescribeGroupsResponseData.java:640)
 at org.apache.kafka.common.message.DescribeGroupsResponseData.addSize(DescribeGroupsResponseData.java:212)
 at org.apache.kafka.common.protocol.SendBuilder.buildSend(SendBuilder.java:218)
 at org.apache.kafka.common.protocol.SendBuilder.buildResponseSend(SendBuilder.java:200)
 at org.apache.kafka.common.requests.AbstractResponse.toSend(AbstractResponse.java:43)
 at org.apache.kafka.common.requests.RequestContext.buildResponseSend(RequestContext.java:111)
 at kafka.network.RequestChannel$Request.buildResponseSend(RequestChannel.scala:132)
 at kafka.server.RequestHandlerHelper.sendResponse(RequestHandlerHelper.scala:185)
 at kafka.server.RequestHandlerHelper.sendResponseMaybeThrottle(RequestHandlerHelper.scala:101)
 at kafka.server.KafkaApis.sendResponseCallback$3(KafkaApis.scala:1378)
 at kafka.server.KafkaApis.handleDescribeGroupRequest(KafkaApis.scala:1417)
 at kafka.server.KafkaApis.handle(KafkaApis.scala:182)
 at kafka.server.KafkaRequestHandler.run(KafkaRequestHandler.scala:74)
 at java.base/java.lang.Thread.run(Thread.java:831){noformat}



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