[FLINK-6801] PojoSerializerConfigSnapshot cannot deal with missing Pojo fields

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.3.0, 1.4.0
• Fix Version/s: 1.3.1, 1.4.0
• Component/s: API / Type Serialization System
• Assignee: Tzu-Li (Gordon) Tai
• Reporter: Till Rohrmann
• Created: 01/Jun/17 14:00
• Updated: 13/Jun/17 05:58
• Resolved: 13/Jun/17 05:58

Description

The PojoSerializerConfigSnapshot tries to deserialize Pojo Fields. If the underlying Pojo class changed such that a formerly present field is not longer part of the Pojo, then the deserialization of the PojoSerializerConfigSnapshot will fail. As a consequence of this failure, there is no possibility to do state migration (e.g. skipping over this field when reading old data).

I think it is better to simply store the field name in the PojoSerializerConfigSnapshot and try to resolve the fields in the PojoSerializer#ensureCompatibility method. That way it is possible to construct a ConvertDeserializer allowing for state migration.