MapStruct vs Immuto: Where the Records Gap Actually Is

Short summary

MapStruct, despite strong Record support, has specific friction in asymmetric mappings, unmapped component handling, Optional-returning methods, and sealed hierarchies. Immuto addresses these through stricter compile-time checking and Record-native design. Walk through five concrete gaps with real generated code showing where each library fails silently vs. loudly.

• •MapStruct silently passes null when inverting asymmetric mappings; Immuto fails at compile time with named errors
• •MapStruct defaults to WARN on unmapped targets; Immuto defaults to ERROR, forcing explicit decisions
• •MapStruct requires manual null checks at call sites for Optional returns; Immuto's @NullSafe automates this

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