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https://issues.apache.org/jira/browse/AVRO-1340?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16888251#comment-16888251
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Suresh TL commented on AVRO-1340:
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I see from the unit tests for testing enum default value, that the writer
schema is still needed for the reader to understand / decode the data.
[https://github.com/apache/avro/blob/master/lang/java/avro/src/test/java/org/apache/avro/TestSchemaCompatibilityEnumDefaults.java#L122]
Is it possible for the reader to use enum default values, when data is sent
without schema ?
For eg:
Reader schema can have enum with \{ "A" , "B" } and enum default "A"
Writer schema can have enum with \{ "A", "B" , "C", "D" , "E" } and enum
default "A"
And value being sent is say "E"
> use default to allow old readers to specify default enum value when
> encountering new enum symbols
> -------------------------------------------------------------------------------------------------
>
> Key: AVRO-1340
> URL: https://issues.apache.org/jira/browse/AVRO-1340
> Project: Apache Avro
> Issue Type: Improvement
> Components: spec
> Environment: N/A
> Reporter: Jim Donofrio
> Assignee: Adam Bellemare
> Priority: Minor
> Fix For: 1.9.0
>
>
> The schema resolution page says:
> > if both are enums:
> > if the writer's symbol is not present in the reader's enum, then an
> error is signalled.
> This makes it difficult to use enum's because you can never add a enum value
> and keep old reader's compatible. Why not use the default option to refer to
> one of enum values so that when a old reader encounters a enum ordinal it
> does not recognize, it can default to the optional schema provided one. If
> the old schema does not provide a default then the older reader can continue
> to fail as it does today.
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