Schema change results in exception - java.lang.ClassCastException

Following exception was seen with parquet 1.8.1 (and in parquet 1.12.0, when trying to reproduce it).

Exception in thread "main" java.lang.ClassCastException: optional binary phone_number (STRING) is not a group
at com.uber.komondor.shaded.org.apache.parquet.schema.Type.asGroupType(Type.java:250)
at com.uber.komondor.shaded.org.apache.parquet.avro.AvroRecordConverter.newConverter(AvroRecordConverter.java:279)
at com.uber.komondor.shaded.org.apache.parquet.avro.AvroRecordConverter.newConverter(AvroRecordConverter.java:232)
at com.uber.komondor.shaded.org.apache.parquet.avro.AvroRecordConverter.access$100(AvroRecordConverter.java:78)
at org.apache.parquet.avro.AvroRecordConverter$AvroCollectionConverter$ElementConverter.(AvroRecordConverter.java:536)
at org.apache.parquet.avro.AvroRecordConverter$AvroCollectionConverter.(AvroRecordConverter.java:486)
at org.apache.parquet.avro.AvroRecordConverter.newConverter(AvroRecordConverter.java:289)
at org.apache.parquet.avro.AvroRecordConverter.(AvroRecordConverter.java:141)
at org.apache.parquet.avro.AvroRecordConverter.newConverter(AvroRecordConverter.java:279)
at org.apache.parquet.avro.AvroRecordConverter.(AvroRecordConverter.java:141)
at org.apache.parquet.avro.AvroRecordConverter.(AvroRecordConverter.java:95)
at org.apache.parquet.avro.AvroRecordMaterializer.(AvroRecordMaterializer.java:33)
at org.apache.parquet.avro.AvroReadSupport.prepareForRead(AvroReadSupport.java:138)
at org.apache.parquet.hadoop.InternalParquetRecordReader.initialize(InternalParquetRecordReader.java:183)
at org.apache.parquet.hadoop.ParquetReader.initReader(ParquetReader.java:156)
at org.apache.parquet.hadoop.ParquetReader.read(ParquetReader.java:135)
at util.ParquetToAvroSchemaConverter$.convert(ParquetToAvroSchemaConverter.scala:46)
at util.ParquetToAvroSchemaConverter$.main(ParquetToAvroSchemaConverter.scala:20)
at util.ParquetToAvroSchemaConverter.main(ParquetToAvroSchemaConverter.scala)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.apache.hadoop.util.RunJar.run(RunJar.java:221)
at org.apache.hadoop.util.RunJar.main(RunJar.java:136)

Original exception was triggered by the following schema change.
Schema Before change:
{
"default": null,
"name": "master_cluster",
"type": [
"null",
{
"fields": [
{
"name": "uuid",
"type": "string"
},
{
"name": "namespace",
"type": "string"
},
{
"name": "version",
"type": "long"
}
],
"name": "master_cluster",
"type": "record"
}
]
},

After schema change:
{
"default": null,
"name": "master_cluster",
"type": [
"null",
{
"fields": [
{
"default": null,
"name": "uuid",
"type": [
"null",
"string"
]
},
{
"default": null,
"name": "namespace",
"type": [
"null",
"string"
]
},
{
"default": null,
"name": "version",
"type": [
"null",
"long"
]
}
],
"name": "VORGmaster_cluster",
"type": "record"
}
]
},

We were suspecting PARQUET-1441 could be in play and tried to reproduce the issue on parquet-1.12.0 and seeing the same exception.

During the repro noticed that issue could be with avroSchema conversion (field name was substituted with generic name "array"). While we look into this further, want to get community input on whether this is a known issue and any thoughts on path forward.

19/09/12 22:34:37 DEBUG avro.SchemaCompatibility: Checking compatibility of reader {"type":"record","name":"IDphones_items","fields":[{"name":"phone_number","type":["null","string"],"default":null}]} with writer {"type":"record","name":"array","fields":[{"name":"phone_number","type":["null","string"],"default":null}]}

**Environment**: Hoodie/Parquet/Avro

Parquet-1.8.1

Avro-1.7.6
**Reporter**: [Balajee Nagasubramaniam](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=balajeeUber)
**Assignee**: [Xinli Shang](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=shangx@uber.com) / @shangxinli
#### Externally tracked issue: [https://issues.apache.org/jira/browse/PARQUET-1681](https://issues.apache.org/jira/browse/PARQUET-1681)

_{**Note**: *This issue was originally created as [PARQUET-1656](https://issues.apache.org/jira/browse/PARQUET-1656). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

Start with the stack-trace entry points in AvroRecordConverter and AvroReadSupport, then inspect util.ParquetToAvroSchemaConverter.scala at the reported conversion lines. Compare the before and after schemas and the logged reader/writer schemas, and check the externally tracked PARQUET-1681 issue to determine the current status and definition of done.

Written by the indexing model from the issue text.