{"id":"avro-missing-reader-field-requires-default","text":"During record resolution, a reader field absent from the writer schema must have a default value; missing defaults cause SchemaCompatibilityError, making defaults the mechanism for forward/backward compatibility.","truth_value":"IN","source":"entries/2026/05/29/avro-serializer-avro_serializer.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{"example":"if rf[\"name\"] not in writer_data:\n    if \"default\" not in rf:\n        raise SchemaCompatibilityError(\n            f\"Reader field {rf[\\\"name\\\"]} has no default\")"},"explanation":{"steps":[{"node":"avro-missing-reader-field-requires-default","truth_value":"IN","reason":"premise"}]}}