ThriftRecordConverter throws NPE for unrecognized enum values

[asfimport]

currently:

    @Override
    public void addBinary(final Binary value) {
      final int id = enumLookup.get(value);
      events.add(new ParquetProtocol("readI32() enum") {
        @Override
        public int readI32() throws TException {
          return id;
        }
      });
    }

the auto-unboxing from Integer to into throws a NPE when enumLookup.get(value) == null – we should throw a better exception here that includes the value in question.

This was actually triggered by someone renaming an enum, and because parquet stores enums by name instead of ID it is not compatible. I'm not sure why we store enums as strings, but we might want to reconsider that.

Reporter: Alex Levenson / @isnotinvain
Assignee: Alex Levenson / @isnotinvain

Related issues:

• Backwards compat check should enforce enums are not renamed (is related to)

PRs and other links:

• PR-252

_{Note: This issue was originally created as PARQUET-350. Please see the migration documentation for further details.}

[asfimport]

Ryan Blue / @rdblue:
I think the reason why we store enums as strings instead of adding logic for explicit ordinals is that we can let the dictionary encoding do the conversion for us. Then we don't have to keep a known list of symbols.