does avdl this work? i think you need to specify that a field can be null.
@namespace("sample")
protocol SampleAvro {
record Sample {
union { null, string } foo;
union { null, Sample } bar;
}
}
On Mon, Jan 16, 2017 at 1:01 PM, Rabe, Jens <[email protected]>
wrote:
> Hello again,
>
>
>
> it turns out I was wrong in first place. I re-tested it in Scala and get
> the same error.
>
>
>
> Gues I’ll have to redesign the schema then to avoid the nulls.
>
>
>
> *Von:* Rabe, Jens [mailto:[email protected]]
> *Gesendet:* Montag, 16. Januar 2017 18:13
> *An:* [email protected]
> *Betreff:* When using the SpecificWriter with .net, I get an exception
> when a referenced object in my schema is null
>
>
>
> Hello Avro community,
>
>
>
> I want to use my Avro serialized data with .net and I stumbled upon a
> strange problem. When a record in my schema references another record, and
> I set it to null, when serializing this in .net this throws an exception.
>
>
>
> Here is what I did:
>
>
>
> First, I created a simple protocol. This is my avdl file:
>
>
>
> @namespace("sample")
>
>
>
> protocol SampleAvro {
>
>
>
> record Sample {
>
>
>
> string foo;
>
> Sample bar;
>
> }
>
> }
>
>
>
> Now, I generated C# classes out of it:
>
>
>
> java -jar avro-tools-1.8.0.jar idl sample.avdl >sample.json
>
> avrogen -p sample.json .
>
>
>
> I then copied the .cs files into a project, and tried to serialize a
> sample object where the “bar” reference is null:
>
>
>
> using(var ms = new MemoryStream()) {
>
> var sw = new SpecificWriter<Sample>(Sample._SCHEMA);
>
> sw.Write(new Sample { foo = "bar" }, new BinaryEncoder(ms));
>
> }
>
>
>
> I get the following exception: *Record object is not derived from
> ISpecificRecord in field bar*
>
>
>
> When looking at the source code, this happens in the SpecificWriter.cs in
> the following method (I made the relevant lines bold):
>
>
>
> protected override void WriteRecord(RecordSchema schema, object
> value, Encoder encoder)
>
> {
>
> * var rec = value as ISpecificRecord;*
>
> * if (rec == null)*
>
> * throw new AvroTypeException("Record object is not derived
> from ISpecificRecord");*
>
>
>
> foreach (Field field in schema)
>
> {
>
> try
>
> {
>
> Write(field.Schema, rec.Get(field.Pos), encoder);
>
> }
>
> catch (Exception ex)
>
> {
>
> throw new AvroException(ex.Message + " in field " +
> field.Name);
>
> }
>
> }
>
> }
>
>
>
> The “value as ISpecificRecord” returns null here because the reference is
> null. This is intended in my schema, but throws an exception here.
>
>
>
> Is this a bug or is this intended behavior, and either way, how should I
> work around this? I need situations where the “bar” is null, and on the
> JVM/Scala side this is no problem and working flawlessly.
>
>
>
> Regards,
>
> Jens
>
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