[AVRO-2830] Union with aliases fail on 'Duplicate in union'

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.9.2
• Component/s: java
• Assignee: Unassigned
• Reporter: Steven Aerts
• Created: 11/May/20 09:04
• Updated: 11/May/20 09:04

Description

When evolving an avro scheme I think it should be possible to merge multiple records in to one.

So with this union as writer type:

[ {
  "type" : "record",
  "name" : "A",
  "fields" : [ { "name" : "a", "type" : "boolean" } ]
}, {
  "type" : "record",
  "name" : "B",
  "fields" : [ { "name" : "b", "type" : "boolean" } ]
} ]

I want to ready it with the following reader schema:

[ {
  "type" : "record",
  "name" : "B",
  "aliases" : [ "A" ],
  "fields" : [
     { "name" : "a", "type" : "boolean", "default" : true},
     { "name" : "b", "type" : "boolean", "default" : true}
  ]
} ]

This however generates the following stacktrace when trying to read it:

org.apache.avro.AvroRuntimeException: Duplicate in union:B
	at org.apache.avro.Schema$UnionSchema.<init>(Schema.java:1165)
	at org.apache.avro.Schema.createUnion(Schema.java:224)
	at org.apache.avro.Schema.applyAliases(Schema.java:1846)
	at org.apache.avro.Schema.applyAliases(Schema.java:1802)
	at org.apache.avro.Resolver.resolve(Resolver.java:62)
	at org.apache.avro.Resolver.resolve(Resolver.java:69)
	at org.apache.avro.io.parsing.ResolvingGrammarGenerator.generate(ResolvingGrammarGenerator.java:64)
	at org.apache.avro.io.ResolvingDecoder.resolve(ResolvingDecoder.java:84)

We have a pull request coming up to fix this issue.