[AVRO-2885] Providing a decimal number in an int field doesn't return an error

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.8.2, 1.10.0, 1.9.2
• Fix Version/s: 1.12.0
• Component/s: java
• Labels: pull-request-available
• Assignee: Christophe Le Saec
• Reporter: Federico Ragona
• Created: 09/Jul/20 12:06
• Updated: 17/Aug/23 19:23
• Resolved: 17/Aug/23 12:02

Description

I defined a schema with an int field and I'm then using the Java GenericDatumReader to decode records from JSON: I have noticed that the reader also accepts numbers with decimal digits and the resulting record contains the same numbers, coerced to integer values.Here is a runnable example:

import org.apache.avro.Schema;
import org.apache.avro.SchemaBuilder;
import org.apache.avro.generic.GenericDatumReader;
import org.apache.avro.generic.GenericRecord;
import org.apache.avro.io.Decoder;
import org.apache.avro.io.DecoderFactory;

public class AvroIntTest {

    public static GenericRecord readFromJson(Schema schema, String record) throws Exception {
        GenericDatumReader<GenericRecord> reader = new GenericDatumReader<>(schema, schema);
        Decoder decoder = DecoderFactory.get().jsonDecoder(schema, record);
        return reader.read(null, decoder);
    }

    public static void main(String[] args) throws Exception {
        Schema schema = SchemaBuilder
                .builder("test")
                .record("example")
                .fields()
                .requiredInt("id")
                .endRecord();
        String record = "{ \"id\": -1.2 }";

        System.out.println(readFromJson(schema, record)); // prints: { "id": -1 }
    }

}

The schema generated by the builder looks like this:

{
  "type" : "record",
  "name" : "example",
  "namespace" : "test",
  "fields" : [ {
    "name" : "id",
    "type" : "int"
  } ]
}

I would expect the reader to fail because the type of the value doesn't match the type of the field but it instead "silently" succeeds, converting -1.2 to -1: is this behaviour intended? am I doing something wrong?

Edit: Digging into it further, I think that the observed behavior is an effect of this line: https://github.com/apache/avro/blob/release-1.8.2/lang/java/avro/src/main/java/org/apache/avro/io/JsonDecoder.java#L168)

A similar test with the JS implementation seems to confirm that it's not intended behavior:

var avro = require('avro-js');

var schema = avro.parse('{ "type" : "record", "name" : "example", "namespace" : "test", "fields" : [ { "name" : "id", "type" : "int" } ] }');
var data = {id: -1.2};

schema.toBuffer(data);

returns, when run:

Error: invalid "int": -1.2

Issue Links

• links to: GitHub Pull Request #2401