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https://issues.apache.org/jira/browse/AVRO-1532?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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O. Reißig updated AVRO-1532:
----------------------------
Attachment: RemovalOfUnionSubtype.java
Thanks for your suggestion with AvroAlias, that's a lot better than my first
try :-)
Explicitly stating the schema does indeed resolve the issue with removed
fields, but now I run into problems with union types. In my schema I have a Map
containing an abstract type, that has several possible implementations via
@Union. I'd like the rest of the serialized data to still be readable when
removing one of the Union subtypes.
I attached a test case to illustrate my example. In the real world, accessing
the removed type would yield ClassCastException, but of course I cannot
actually remove a class in this test case. As the stuff is stored in a Map, I
should still be able to access the rest of the map entries.
Did I make my use case clear? Is this realistic?
Why actually store the schema inside the serialized file, if it is overridden
anyway? I thought it's better to parse the serialized data with its according
schema.
> Field deletion not possible for ReflectData: NPE
> ------------------------------------------------
>
> Key: AVRO-1532
> URL: https://issues.apache.org/jira/browse/AVRO-1532
> Project: Avro
> Issue Type: Bug
> Components: java
> Affects Versions: 1.7.6
> Reporter: O. Reißig
> Labels: java, reflection
> Attachments: AVRO-1532.patch, ReflectDataFieldRemovalTest.java,
> ReflectDataFieldRemovalTest.java, RemovalOfUnionSubtype.java
>
>
> *Actual behaviour:*
> I have a field in my reflection-based schema like this:
> {code}
> @Nullable @AvroDefault("null")
> public Long someField;
> {code}
> When removing this field, parsing the previous serialized blob yields
> NullPointerException:
> {noformat}
> java.lang.NullPointerException
> at org.apache.avro.reflect.ReflectData.setField(ReflectData.java:128)
> at
> org.apache.avro.generic.GenericDatumReader.readField(GenericDatumReader.java:193)
> at
> org.apache.avro.reflect.ReflectDatumReader.readField(ReflectDatumReader.java:230)
> at
> org.apache.avro.generic.GenericDatumReader.readRecord(GenericDatumReader.java:183)
> at
> org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:151)
> at
> org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:142)
> at org.apache.avro.file.DataFileStream.next(DataFileStream.java:233)
> at org.apache.avro.file.DataFileStream.next(DataFileStream.java:220)
> at
> ReflectDataFieldRemovalTest.testFieldRemoval(ReflectDataFieldRemovalTest.java:41)
> {noformat}
> *Expected behaviour:*
> Field removal is crucial for schema evolution and must be possible with
> ReflectData.
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