[AVRO-717] SpecificDatumWriter is using GenericData.resolveUnion sometimes

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.4.1
• Fix Version/s: 1.5.0
• Component/s: java

Environment

Mac, Java 6.

• Hadoop Flags: Reviewed
• Assignee: Joe Crobak
• Reporter: Joe Crobak
• Created: 21/Dec/10 20:14
• Updated: 12/Mar/11 00:32
• Resolved: 04/Jan/11 22:28

Description

From: avro-user

I've tried to use union of null and the enum-type, but I've run into an issue with this approach when using the AvroOutputFormat. The following code summarizes my issue:

   public void testDataWriteWithSchema() throws IOException {
     final DataFileWriter<Event writer =
       new DataFileWriter<Event>(new SpecificDatumWriter<Event>());

     writer.create(Event.SCHEMA$, new File("target/datafile-test.avro"));
     writer.append(getEvent());
     writer.close();
   }

   public void testDataWriteWithSchemaWithClass() throws IOException {
     final DataFileWriter<Event writer =
       new DataFileWriter<Event>(new SpecificDatumWriter<Event>(Event.class));

     writer.create(Event.SCHEMA$, new File("target/datafile-test.avro"));
     writer.append(getEvent());
     writer.close();
   }

When I don't pass in the Event.class to SpecificDatumWriter (the first test method), the above test fails with the following exception:

 Not in union ["null", {"type":"enum","name":"Suit","namespace":"foo","symbols":["SPADES","CLUBS","HEARS","DIAMONDS"]}]: SPADES
 at org.apache.avro.generic.GenericData.resolveUnion(GenericData.java:382)
 at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:67)
 at org.apache.avro.generic.GenericDatumWriter.writeRecord(GenericDatumWriter.java:100)
 at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:62)
 at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:54)
 at org.apache.avro.file.DataFileWriter.append(DataFileWriter.java:245)

Scott Carey's reply:

This looks like a bug. Can you file a ticket? In the first case, the constructor is not
initializing the SpecificData object, which means that it is using GenericData.resolveUnion()
instead of SpecificData.resolveUnion().

The empty param constructor in SpecificDatumWriter should be
public SpecificDatumWriter() { super(SpecificData.get()); }

public SpecificDatumWriter() { }