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Philip Nee commented on KAFKA-14421: ------------------------------------ [~showuon] - should we close this issue as it is not supported. > OffsetFetchRequest throws NPE Exception > --------------------------------------- > > Key: KAFKA-14421 > URL: https://issues.apache.org/jira/browse/KAFKA-14421 > Project: Kafka > Issue Type: Bug > Components: clients > Affects Versions: 0.10.2.0, 0.10.2.1, 0.10.2.2 > Reporter: yws > Assignee: yws > Priority: Major > Attachments: image-2022-11-27-22-28-52-165.png, > image-2022-11-27-22-41-45-358.png > > > when I use 0.10.2 client send Metadata request to 0.10.0 server, NPE > exception happens, > !image-2022-11-27-22-28-52-165.png! > the NPE exception quite confused me, because if just send Metadata request > doest not cause the NPE exception occurs, after troubleshooting the problem, > It is the NetworkClient#poll call ConsumerNetworkClient#trySend and further > call NetworkClient#doSend when trying to build OffsetFetchRequest, because > the 0.10.0 server doest not support fetch all TopicPartitions, it throw > UnsupportedVersionException, > {code:java} > private void doSend(ClientRequest clientRequest, boolean isInternalRequest, > long now) { > String nodeId = clientRequest.destination(); > ...... > AbstractRequest request = null; > AbstractRequest.Builder<?> builder = clientRequest.requestBuilder(); > try { > NodeApiVersions versionInfo = nodeApiVersions.get(nodeId); > // Note: if versionInfo is null, we have no server version > information. This would be > // the case when sending the initial ApiVersionRequest which > fetches the version > // information itself. It is also the case when > discoverBrokerVersions is set to false. > if (versionInfo == null) { > if (discoverBrokerVersions && log.isTraceEnabled()) > log.trace("No version information found when sending > message of type {} to node {}. " + > "Assuming version {}.", clientRequest.apiKey(), > nodeId, builder.version()); > } else { > short version = > versionInfo.usableVersion(clientRequest.apiKey()); > builder.setVersion(version); > } > // The call to build may also throw UnsupportedVersionException, > if there are essential > // fields that cannot be represented in the chosen version. > request = builder.build(); > } catch (UnsupportedVersionException e) { > // If the version is not supported, skip sending the request over > the wire. > // Instead, simply add it to the local queue of aborted requests. > log.debug("Version mismatch when attempting to send {} to {}", > clientRequest.toString(), clientRequest.destination(), e); > ClientResponse clientResponse = new > ClientResponse(clientRequest.makeHeader(), > clientRequest.callback(), clientRequest.destination(), > now, now, > false, e, null); > abortedSends.add(clientResponse); > return; > } > {code} > !image-2022-11-27-22-41-45-358.png! > until now, all are expected, but unfortunately, in catch > UnsupportedVersionException code block, clientRequest.toString need to call > requestBuilder#toString, that is OffsetFetchRequest's Builder#toString, when > partition is ALL_TOPIC_PARTITIONS, it is null, therefore it cause the > unexpected NPE, and make the normal MetadataRequest failed.. > {code:java} > catch (UnsupportedVersionException e) { > > log.debug("Version mismatch when attempting to send {} to {}", > clientRequest.toString(), clientRequest.destination(), e); > ClientResponse clientResponse = new > ClientResponse(clientRequest.makeHeader(), > clientRequest.callback(), clientRequest.destination(), > now, now, > false, e, null); > abortedSends.add(clientResponse); > return; > } > ClientRequest#toString() > public String toString() { > return "ClientRequest(expectResponse=" + expectResponse + > ", callback=" + callback + > ", destination=" + destination + > ", correlationId=" + correlationId + > ", clientId=" + clientId + > ", createdTimeMs=" + createdTimeMs + > ", requestBuilder=" + requestBuilder + > ")"; > } > OffsetFetchRequest's Builder#toString > public String toString() { > StringBuilder bld = new StringBuilder(); > bld.append("(type=OffsetFetchRequest, "). > append("groupId=").append(groupId). > append(", partitions=").append(Utils.join(partitions, > ",")). // cause NPE > append(")"); > return bld.toString(); > } > {code} > I think the NPE is unexpected, when broker doest not support specific > protocal, It should not throw NPE instead of UnsupportedVersionException, > and I find in 0.11 or later version > it is fixed, but the OffsetFetchRequest support ALL_TOPIC_PARTITIONS is > introduced in 0.10.2 > [kIP88|https://cwiki.apache.org/confluence/display/KAFKA/KIP-88%3A+OffsetFetch+Protocol+Update], > Therefore, I think it should also be fixed in 0.10.2 client > look forward to any reply , Thanks~ > -- This message was sent by Atlassian Jira (v8.20.10#820010)