[ https://issues.apache.org/jira/browse/KAFKA-16858?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Greg Harris resolved KAFKA-16858. --------------------------------- Resolution: Fixed > Flatten SMT throws NPE > ---------------------- > > Key: KAFKA-16858 > URL: https://issues.apache.org/jira/browse/KAFKA-16858 > Project: Kafka > Issue Type: Bug > Components: connect > Affects Versions: 3.6.0 > Environment: Kafka 3.6 by way of CP 7.6.0 > Reporter: Adam Strickland > Priority: Major > Fix For: 3.8.0, 3.9.0 > > Attachments: FlattenTest.java, proto.proto > > > {{ConnectSchema.expectedClassesFor}} sometimes will throw an NPE as part of a > call to an SMT chain. Stack trace snippet: > {{at > com.github.momenttechnology.kafka.connect.transforms.MomentFlatten.apply(MomentFlatten.java:84)}} > {{at > com.github.momenttechnology.kafka.connect.transforms.MomentFlatten.applyWithSchema(MomentFlatten.java:173)}} > {{at > com.github.momenttechnology.kafka.connect.transforms.MomentFlatten.buildWithSchema(MomentFlatten.java:280)}} > {{at > com.github.momenttechnology.kafka.connect.transforms.MomentFlatten.buildWithSchema(MomentFlatten.java:280)}} > {{at > com.github.momenttechnology.kafka.connect.transforms.MomentFlatten.buildWithSchema(MomentFlatten.java:280)}} > {{at > com.github.momenttechnology.kafka.connect.transforms.MomentFlatten.buildWithSchema(MomentFlatten.java:274)}} > {{at org.apache.kafka.connect.data.Struct.put(Struct.java:203)}} > {{at org.apache.kafka.connect.data.Struct.put(Struct.java:216)}} > {{at > org.apache.kafka.connect.data.ConnectSchema.validateValue(ConnectSchema.java:255)}} > {{at > org.apache.kafka.connect.data.ConnectSchema.validateValue(ConnectSchema.java:213)}} > {{at > org.apache.kafka.connect.data.ConnectSchema.validateValue(ConnectSchema.java:224)}} > {{at > org.apache.kafka.connect.data.ConnectSchema.expectedClassesFor(ConnectSchema.java:268)}} > (the above transform is a sub-class of > {{{}o.a.k.connect.transforms.Flatten{}}}; have confirmed that the error > occurs regardless). > The field being transformed is an array of structs. If the call to > {{Schema#valueSchema()}} (o.a.k.connect.data.ConnectSchema.java:255) returns > {{{}null{}}}, the subsequent call to {{Schema#name()}} at > o.a.k.connect.data.ConnectSchema:268 throws an NPE. > The strange thing that we have observed is that this doesn't always happen; > *sometimes* the struct's schema is found and sometimes it is not. We have > been unable to determine the root cause, but have constructed a test that > replicates the problem as observed (see attachment). > In our case we have worked around the issue with the aforementioned sub-class > of {{{}Flatten{}}}, catching and logging the NPE on that specific use-case. -- This message was sent by Atlassian Jira (v8.20.10#820010)