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https://issues.apache.org/jira/browse/AVRO-1657?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14393848#comment-14393848
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David Korz commented on AVRO-1657:
----------------------------------
https://github.com/dkorz/avro-1657 contains a full project to show the problem.
> Namespaced reader schema w/field aliases can not read non-namespaced writer
> schema
> ----------------------------------------------------------------------------------
>
> Key: AVRO-1657
> URL: https://issues.apache.org/jira/browse/AVRO-1657
> Project: Avro
> Issue Type: Bug
> Components: java
> Affects Versions: 1.7.7
> Reporter: David Korz
>
> The writer uses a non-namespaced schema as follows:
> {noformat}
> {
> "type":"record",
> "name": "MyRecord",
> "fields":[
> {
> "type":"string",
> "name":"Name"
> },
> {
> "type":"double",
> "name":"Temperature"
> }
> ]
> }
> {noformat}
> The reader uses a namespaced schema with a field alias.
> {noformat}
> {
> "type":"record",
> "name": "MyRecord",
> "namespace": "com.example",
> "aliases": [".MyRecord"],
> "fields":[
> {
> "type":"string",
> "name":"Name"
> },
> {
> "type":"double",
> "name":"TemperatureC",
> "aliases": ["Temperature"]
> }
> ]
> }
> {noformat}
> The following reading code will fail.
> {noformat}
> DatumReader<MyRecord> datumReader = new SpecificDatumReader<>(MyRecord.class);
> FileReader<MyRecord> fileReader = DataFileReader.openReader(file,
> datumReader);
>
> MyRecord record = null;
> while (fileReader.hasNext()) {
> record = fileReader.next(record);
> CharSequence name = record.getName();
> Double temp = record.getTemperatureC();
> System.out.println(name + " " + temp);
> }
> {noformat}
> The reader's alias is not found.
> {noformat}
> Exception in thread "main" org.apache.avro.AvroTypeException: Found MyRecord,
> expecting com.example.MyRecord, missing required field TemperatureC
> at
> org.apache.avro.io.ResolvingDecoder.doAction(ResolvingDecoder.java:292)
> at org.apache.avro.io.parsing.Parser.advance(Parser.java:88)
> at
> org.apache.avro.io.ResolvingDecoder.readFieldOrder(ResolvingDecoder.java:130)
> at
> org.apache.avro.generic.GenericDatumReader.readRecord(GenericDatumReader.java:176)
> 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)
> {noformat}
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