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Posted to issues@avro.apache.org by "ASF subversion and git services (Jira)" <ji...@apache.org> on 2023/01/04 14:25:00 UTC
[jira] [Commented] (AVRO-3646) Serialization / deserialization for enum with mixed variants (with and without data)
[ https://issues.apache.org/jira/browse/AVRO-3646?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17654486#comment-17654486 ]
ASF subversion and git services commented on AVRO-3646:
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Commit 22fe1e12f0cb915992e408938db08b97ec39299f in avro's branch refs/heads/avro-3683-multiple-schemas from Martin Tzvetanov Grigorov
[ https://gitbox.apache.org/repos/asf?p=avro.git;h=22fe1e12f ]
AVRO-3646: Formatting
Signed-off-by: Martin Tzvetanov Grigorov <mg...@apache.org>
> Serialization / deserialization for enum with mixed variants (with and without data)
> ------------------------------------------------------------------------------------
>
> Key: AVRO-3646
> URL: https://issues.apache.org/jira/browse/AVRO-3646
> Project: Apache Avro
> Issue Type: Bug
> Components: rust
> Reporter: Lucas Javaudin
> Assignee: Martin Tzvetanov Grigorov
> Priority: Major
> Labels: pull-request-available, rust
> Time Spent: 5h
> Remaining Estimate: 0h
>
> Consider the following example of what I call an "enum with mixed variants":
> {code:java}
> enum MixedExternalEnum {
> Val1,
> Val2(f32),
> } {code}
> For the two variants, this enum can be properly serialized to and deserialized from a {{types::Value}} (using {{ser::to_value}} and {{{}de::from_value{}}}). The problem is that the way they are represented as a \{{types::Value}} cannot be represented using an Avro Schema.
> The serialized version of {{MixedExternalEnum::Val1}} is
> {code:java}
> Value::Record(vec![("a".to_owned(), Value::Enum(0, "Val1".to_owned()))])
> {code}
> while the serialized version of {{MixedExternalEnum::Val2(0.0)}} is
> {code:java}
> Value::Record(vec![(
> "a".to_owned(),
> Value::Record(vec![
> ("type".to_owned(), Value::Enum(1, "Val2".to_owned())),
> (
> "value".to_owned(),
> Value::Union(1, Box::new(Value::Float(0.0))),
> ),
> ]),
> )])
> {code}
> As far as I know, there is no Avro Schema compatible with both possible values.
> One solution I can think of is to change the serialization of {{MixedExternalEnum::Val1}} to
> {code:java}
> Value::Record(vec![(
> "a".to_owned(),
> Value::Record(vec![
> ("type".to_owned(), Value::Enum(0, "Val1".to_owned())),
> (
> "value".to_owned(),
> Value::Union(0, Box::new(Value::Null)),
> ),
> ]),
> )])
> {code}
>
> A workaround is to replace {{Val1}} by {{Val1(())}} in the enum definition (see AVRO-3645) but this can have undesirable effects for other parts of the code.
>
> Then, it's another story for adjacently tagged, internally tagged and untagged enum...
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