Tymur Hulua created AVRO-4137:
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Summary: C# SpecificWriter incorrectly assigns Enum type when
using Union containing identical value names
Key: AVRO-4137
URL: https://issues.apache.org/jira/browse/AVRO-4137
Project: Apache Avro
Issue Type: Bug
Components: csharp
Reporter: Tymur Hulua
At the moment, the C# library Avro matches Union types with Enum in the
following way:
{code:java}
// SpecificDefaultWriter.cs - LN159 - protected override bool Matches(Schema
sc, object obj)
case Schema.Type.Enumeration:
return obj.GetType().IsEnum && (sc as
EnumSchema).Symbols.Contains(obj.ToString());{code}
This leads to the scenario where several Enums declared within one Union schema
cannot have the same value names, because upon serialization, the Enum that is
declared earlier will be chosen, not the one that was originally passed.
It is further suggested to conduct a check on the type name and the schema
itself:
{code:java}
case Schema.Type.Enumeration:
return obj.GetType().IsEnum && (sc as
EnumSchema).Symbols.Contains(obj.ToString()) && sc.Name ==
obj.GetType().Name;{code}
If you believe that this could lead to unforeseen problems (such as breaking
backward compatibility), it is proposed to make the check optional, by default
turned off. There may be other, more reliable methods to solve this issue, but
the demonstrated one seemed the most optimal in my mind ;)
Thank you!
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