[AVRO-2888] Csharp - Specific reader fails when using c# keyword in namespace name

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 1.9.2
• Fix Version/s: 1.11.0
• Component/s: csharp
• Assignee: Zoltan Csizmadia
• Reporter: Vaibhav
• Created: 10/Jul/20 06:56
• Updated: 01/Mar/22 05:41
• Resolved: 28/Feb/22 14:11

Description

 Csharp specific reader fails when csharp language keyword is present in namespace and datatype for on one of the element is array of complex type.

 Steps to reproduce - Use following schema file to generate avro csharp classes using Apache.Avro.Tools tool (v 1.10.0)

{
  "name": "Parent",
  "type": "record",
  "namespace": "com.parent.event",
  "fields": [
    {
      "name": "children",
      "type": {
        "type": "array",
        "items": {
          "name": "Child",
          "type": "record",
          "fields": [
            {
              "name": "name",
              "type": "string"
            }
          ]
        }
      }
    }
  ]
}

Following classes will be generated. I have added link to files as content is relatively large.

https://github.com/vkhose/testcode/blob/master/com/parent/event/Parent.cs

https://github.com/vkhose/testcode/blob/master/com/parent/event/Child.cs

Please note that Avro generator tool adds an escape character "@" in namespace as event is a csharp keyword 

e.g. namespace com.parent.@event

Next, I have created a test case which tries to deserialize the Parent class object

https://github.com/vkhose/testcode/blob/master/testCaseToReproduceError.cs

 

 [Test]        
 public void TestNamespaceWithCSharpKeyword()        
 {            
        var srcRecord = new Parent
            {
                children = new List<Child>
                {
                    new Child
                    {
                        name = "test"
                    },
                    new Child
                    {
                        name = "test"
                    }
                }
            };
            var stream = serialize(Parent._SCHEMA, srcRecord);
            var dstRecord = deserialize<Parent>(stream,
                Parent._SCHEMA, Parent._SCHEMA);
            Assert.NotNull(dstRecord);
        }
}

 This test case throws following exception 

Unable to find type '[e-mail]' in all loaded assemblies in field children
----> Avro.AvroException : Unable to find type '[e-mail]' in all loaded assemblies
at Avro.Specific.SpecificDefaultReader.ReadRecord(Object reuse, RecordSchema writerSchema, Schema readerSchema, Decoder dec)

 

When I debug the code it seems like same util methods are used to generate code for specific record and read record during deserialization.
https://github.com/apache/avro/blob/c0094b5bb1abb79304ce42a56cc115186370d407/lang/csharp/src/apache/main/CodeGen/CodeGenUtil.cs#L99

if (ReservedKeywords.Contains(names[i]))
   builder.Append(At);

Appending At(@) while generating code is correct but it should not appended while deserializing. Deserialization fails as c# reflection does not expects At(@) in string value provided to create class instance.
https://github.com/apache/avro/blob/master/lang/csharp/src/apache/main/Specific/ObjectCreator.cs#L165

Type.GetType(string) string parameter passed should be without "@" character in namespace name.

 

It works if I modify code not to add "@" in CodeGenUtil.cs. I think we need a fix where "@" is only added while auto generating classes and should not be used during deserialization.

Thanks.

Vaibhav

Issue Links

• duplicates: AVRO-3075 Avro.AvroException namespaces with reserved words cause deserialisation issue when inside an array.