Cannot read array values with ParquetIO

Hi Beam community,

 I am seeing an error when reading an array field using ParquetIO. I was using beam 2.25.  Both direct runner and spark runner testing is seeing this issue. This is a blocker issue to me for the beam adoption, so a prompt help would be appreciated.

 Below is the schema tree as a quick visualization. The array field name is "numbers" and the element type is int. 

 

root |

     \-- numbers: array (nullable = true) | |

           \-- element: integer (containsNull = true)

 

The beam code is very simple: pipeline.apply(ParquetIO.read(avroSchema).from(parquetPath));

 

Below is the error when running that code:

 
```

Exception in thread "main" org.apache.beam.sdk.Pipeline$PipelineExecutionException: java.lang.ClassCastException:
org.apache.avro.generic.GenericData$Record cannot be cast to java.lang.Number

                at
org.apache.beam.runners.direct.DirectRunner$DirectPipelineResult.waitUntilFinish(DirectRunner.java:353)

               
at org.apache.beam.runners.direct.DirectRunner$DirectPipelineResult.waitUntilFinish(DirectRunner.java:321)

               
at org.apache.beam.runners.direct.DirectRunner.run(DirectRunner.java:216)

                at org.apache.beam.runners.direct.DirectRunner.run(DirectRunner.java:67)

               
at org.apache.beam.sdk.Pipeline.run(Pipeline.java:317)

                at org.apache.beam.sdk.Pipeline.run(Pipeline.java:303)

Caused
by: java.lang.ClassCastException: org.apache.avro.generic.GenericData$Record cannot be cast to java.lang.Number

               
at org.apache.avro.generic.GenericDatumWriter.writeWithoutConversion(GenericDatumWriter.java:156)

               
at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:82)

                at
org.apache.avro.generic.GenericDatumWriter.writeArray(GenericDatumWriter.java:234)

               
at org.apache.avro.generic.GenericDatumWriter.writeWithoutConversion(GenericDatumWriter.java:136)

               
at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:82)

                at
org.apache.avro.generic.GenericDatumWriter.writeField(GenericDatumWriter.java:206)

               
at org.apache.avro.generic.GenericDatumWriter.writeRecord(GenericDatumWriter.java:195)

               
at org.apache.avro.generic.GenericDatumWriter.writeWithoutConversion(GenericDatumWriter.java:130)

               
at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:82)

                at
org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:72)

                at org.apache.beam.sdk.coders.AvroCoder.encode(AvroCoder.java:317)

               
at org.apache.beam.sdk.coders.Coder.encode(Coder.java:136)

                at org.apache.beam.sdk.util.CoderUtils.encodeToSafeStream(CoderUtils.java:82)

               
at org.apache.beam.sdk.util.CoderUtils.encodeToByteArray(CoderUtils.java:66)

                at org.apache.beam.sdk.util.CoderUtils.encodeToByteArray(CoderUtils.java:51)

               
at org.apache.beam.sdk.util.CoderUtils.clone(CoderUtils.java:141)

                at org.apache.beam.sdk.util.MutationDetectors$CodedValueMutationDetector.(MutationDetectors.java:115)

               
at org.apache.beam.sdk.util.MutationDetectors.forValueWithCoder(MutationDetectors.java:46)

               
at org.apache.beam.runners.direct.ImmutabilityCheckingBundleFactory$ImmutabilityEnforcingBundle.add(ImmutabilityCheckingBundleFactory.java:112)

               
at org.apache.beam.runners.direct.ParDoEvaluator$BundleOutputManager.output(ParDoEvaluator.java:301)

               
at org.apache.beam.repackaged.direct_java.runners.core.SimpleDoFnRunner.outputWindowedValue(SimpleDoFnRunner.java:267)

               
at org.apache.beam.repackaged.direct_java.runners.core.SimpleDoFnRunner.access$900(SimpleDoFnRunner.java:79)

               
at org.apache.beam.repackaged.direct_java.runners.core.SimpleDoFnRunner$DoFnProcessContext.output(SimpleDoFnRunner.java:413)

               
at org.apache.beam.repackaged.direct_java.runners.core.SimpleDoFnRunner$DoFnProcessContext.output(SimpleDoFnRunner.java:401)

               
at org.apache.beam.sdk.io.parquet.ParquetIO$ReadFiles$ReadFn.processElement(ParquetIO.java:646)

```

Imported from Jira [BEAM-11721](https://issues.apache.org/jira/browse/BEAM-11721). Original Jira may contain additional context.
Reported by: sekiforever.