The Inheritance Chain Nobody Missed
The batch PR from earlier today shipped a composition refactor on CaseLedgerEntryRepository — breaking it free from JpaLedgerEntryRepository so tests could substitute an in-memory double without hitting native SQL tables. Clean separation. The kind of change that should only affect the module it touches.
CI disagreed. Eight unsatisfied LedgerEntryRepository injection points in casehub-engine-flow — a module that wasn’t touched in the PR.
The invisible coupling
CaseLedgerEntryRepository used to extend JpaLedgerEntryRepository, which implements LedgerEntryRepository. The class was @DefaultBean @ApplicationScoped — meaning it was discoverable by CDI and active by default. Every module on the test classpath that needed a LedgerEntryRepository got one for free through inheritance, whether or not it knew that’s where the bean came from.
The composition refactor removed extends JpaLedgerEntryRepository. The class kept its own methods and its @DefaultBean annotation. But it stopped being a LedgerEntryRepository.
The next question was obvious: why didn’t JpaLedgerEntryRepository itself — the actual implementation — satisfy the injection points? Claude ran javap on the published JAR:
public class JpaLedgerEntryRepository implements LedgerEntryRepository {
...
RuntimeVisibleAnnotations:
jakarta.enterprise.context.ApplicationScoped
jakarta.enterprise.inject.Alternative
@Alternative without @Priority. Never activated unless explicitly selected. The upstream library designed it as an opt-in implementation — the casehub-engine-ledger module was supposed to provide the active bean. Which it did, through inheritance. Until it didn’t.
The fix and the pattern
Four other modules — runtime, blackboard, resilience, work-adapter — already had NoOpLedgerEntryRepository stubs. They’d been added at various points when those modules hit the same classpath issue. The flow module never needed one because the inherited type chain had been silently satisfying the dependency.
The fix was mechanical: add the same NoOpLedgerEntryRepository stub to flow/src/test/java/, exclude the ledger capture beans per protocol PP-20260610-18a084. Twenty-four tests pass. CI green. PR merged.
The interesting part isn’t the fix — it’s the failure mode. @DefaultBean classes that implement an SPI via inheritance create invisible downstream coupling. The coupling doesn’t show up in import statements, dependency declarations, or any static analysis. It shows up when someone refactors the class for perfectly good reasons and a module three hops away in the dependency graph fails at CDI deployment time.