🧩 Your MapStruct Mappers Are Hiding Null Bugs

Short summary

MapStruct's default unmappedTargetPolicy = WARN allows target fields to remain null when source fields are missing, silently shipping bugs to production. Three configuration changes prevent this: set unmappedTargetPolicy = ERROR to fail the build when fields are unmapped, use MappingConstants.ComponentModel.SPRING with Mappers.getMapper() for Spring DI and lightweight unit tests, and leverage MapStruct's generated patterns for lists, enums, and composed mappers. These practices catch bugs at compile time instead of in production.

• •Set unmappedTargetPolicy = ERROR to catch missing fields at compile time and prevent silent null bugs
• •Use MappingConstants.ComponentModel.SPRING with Mappers.getMapper() for Spring DI and fast unit tests without container startup
• •Leverage generated list, enum, and composed mapper patterns to eliminate hand-written boilerplate and loops

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