Deserializing an enum with a missing value does not result in the default enum value

[alycklama]

I'm trying to make the following scenario work:

TypeV1

• Contains an enum with initial 4 values: CAT, DOG, DUCK and UNKNOWN.
• Default value for the enum is UNKNOWN.

TypeV2

• Contains a subset of the previous enum: DOG and UNKNOWN.
• Default value for the enum is UNKNOWN.

I'm serializing an object of TypeV1 with value DUCK and I try to deserialize it with TypeV2. I expected the value to be UNKNOWN. Why wouldn't this work? It results in the error below:

./node_modules/avsc/lib/types.js:546
    throw new Error(f('cannot read %s as %s', type, this));
    ^

Error: cannot read {"type":"enum","symbols":["CAT","DOG","DUCK","UNKNOWN"]} as {"type":"enum","symbols":["DOG","UNKNOWN"]}
    at EnumType.Type.createResolver (./node_modules/avsc/lib/types.js:546:11)
    at RecordType._update (./node_modules/avsc/lib/types.js:2366:30)
    at RecordType.Type.createResolver (./node_modules/avsc/lib/types.js:542:10)
    at main (./main.js:46:31)
    at Object.<anonymous> (./main.js:52:5)
    at Module._compile (internal/modules/cjs/loader.js:1063:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
    at Module.load (internal/modules/cjs/loader.js:928:32)
    at Function.Module._load (internal/modules/cjs/loader.js:769:14)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:72:12)

const avro = require('avsc');

function main() {
    const typeV1 = avro.Type.forSchema({
        type: 'record',
        fields: [
            {
                name: 'kind',
                type: {
                    type: 'enum',
                    default: 'UNKNOWN',
                    symbols: [
                        'CAT',
                        'DOG',
                        'DUCK',
                        'UNKNOWN',
                    ]
                },
                default: 'UNKNOWN'
            }
        ]
    });

    const bufV1 = typeV1.toBuffer({kind: 'DUCK'}); // Encoded buffer.
    const valV1 = typeV1.fromBuffer(bufV1);
    console.log(valV1);

    const typeV2 = avro.Type.forSchema({
        type: 'record',
        fields: [
            {
                name: 'kind',
                type: {
                    type: 'enum',
                    default: 'UNKNOWN',
                    symbols: [
                        'DOG',
                        'UNKNOWN',
                    ]
                },
                default: 'UNKNOWN'
            }
        ]
    });

    const resolverV2 = typeV2.createResolver(typeV1);
    const valV2 = typeV2.fromBuffer(bufV1, resolverV2);
    console.log(valV2);
}

if (require.main === module) {
    main();
}

[mtth]

Hi @alycklama. avsc doesn't support enum defaults yet.

FTR: #238 (comment)

[mtth]

5.7.0, just released, supports enum defaults. Once you upgrade, the snippet above will produce the expected result.