[GitHub] [beam] lukemin89 opened a new issue, #23084: [BUG]: Java `Wait.OnSignal` does not set output coder.

[GitBox <gi...@apache.org>]

lukemin89 opened a new issue, #23084:
URL: https://github.com/apache/beam/issues/23084

   
   I spent a significant amount of time where the coder is missing or type is being erased, and located a single point.
   
   
   
   The issue is a combination of `ProtoCoder` and `MapElements`, as
   - `ProtoCoder` does not have `getEncodedTypeDescriptor()`, so it returns just `TypeDescriptor<Message>` instead of actual type.
   - `MapElements` only takes  `TypeDescriptor` as a parameter, and try to re-infer the coder.
   
   
   Proposed Fix:
   - set input coder to output coder in `Wait.OnSignal` after `MapElements`
   
   
   How to reproduce.
   
   ```
   import org.apache.beam.sdk.options.PipelineOptions.CheckEnabled;
   import org.apache.beam.sdk.testing.TestPipeline;
   import org.apache.beam.sdk.transforms.Create;
   import org.apache.beam.sdk.transforms.Wait;
   import org.junit.Rule;
   import org.junit.Test;
   
   import com.google.protobuf.Empty;
   
   public class EmptyMessageTest {
     @Rule
     public final TestPipeline pipeline = TestPipeline.create();
   
     @Test
     public void test() {
       pipeline.getOptions().setStableUniqueNames(CheckEnabled.OFF);
   
       var emptyMessage = pipeline.apply(Create.of(Empty.getDefaultInstance()));
       var singleNull = pipeline.apply(Create.of((Void) null));
   
       emptyMessage.apply(Wait.on(singleNull));
       pipeline.run();
     }
   }
   ```
   
   ```
   Caused by: java.lang.NoSuchMethodException: com.google.protobuf.Message.getDefaultInstance()
   	at java.base/java.lang.Class.getMethod(Class.java:2108)
   	at org.apache.beam.sdk.extensions.protobuf.ProtoCoder.getParser(ProtoCoder.java:297)
   	at org.apache.beam.sdk.extensions.protobuf.ProtoCoder.decode(ProtoCoder.java:205)
   	at org.apache.beam.sdk.extensions.protobuf.ProtoCoder.decode(ProtoCoder.java:108)
   	at org.apache.beam.sdk.util.CoderUtils.decodeFromSafeStream(CoderUtils.java:118)
   	at org.apache.beam.sdk.util.CoderUtils.decodeFromByteArray(CoderUtils.java:101)
   	at org.apache.beam.sdk.util.CoderUtils.decodeFromByteArray(CoderUtils.java:95)
   	at org.apache.beam.sdk.util.CoderUtils.clone(CoderUtils.java:144)
   	at org.apache.beam.sdk.util.MutationDetectors$CodedValueMutationDetector.<init>(MutationDetectors.java:118)
   	at org.apache.beam.sdk.util.MutationDetectors.forValueWithCoder(MutationDetectors.java:49)
   ```
   
   
   


-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: github-unsubscribe@beam.apache.org.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org

[GitHub] [beam] bradlet commented on issue #23084: [BUG]: Java `Wait.OnSignal` does not set output coder.

[GitBox <gi...@apache.org>]

bradlet commented on issue #23084:
URL: https://github.com/apache/beam/issues/23084#issuecomment-1248306623

   Ran into the same issue. Running into this bug report was immensely helpful, so thank you @lukemin89!
   
   I was trying to Wait.on a DoFn resulting in PCollection of com.google.datastore.v1.Entity objects. Same bug as above, so it isn't specific to Void! Since Entity also implements java.io.Serializable, my workaround was simply to use SerializableCoder instead of ProtoCoder, that works just fine!


-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: github-unsubscribe@beam.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org