[#4291] feat(eventsourcing): EventStoreTransaction - allow overriding AppendCondition calculated from sourcing#4295
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EventStoreTransaction - allow overriding AppendCondition calculated from sourcingEventStoreTransaction - allow overriding AppendCondition calculated from sourcing
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EventStoreTransaction - allow overriding AppendCondition calculated from sourcingEventStoreTransaction - allow overriding AppendCondition calculated from sourcing
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Mar 18, 2026
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…ng `AppendCondition` calculated from sourcing Allow users to control the AppendCondition used at commit time, beyond what automatic sourcing provides. This enables two primary use cases: 1. Appending without sourcing — enforcing uniqueness constraints without first sourcing events (e.g., ensuring a course name is unique by checking that no matching event exists since ORIGIN). 2. Narrowing (or broadening) the append condition — sourcing broad criteria for state but restricting which events are considered conflicting at commit time. Production changes: - AppendCondition: add replacingCriteria(EventCriteria) abstract method that preserves the consistency marker while replacing the criteria. Named "replacingCriteria" rather than "withCriteria" (as originally planned) because the interface already has a static factory method withCriteria(EventCriteria) and Java prohibits a static and abstract instance method with the same signature on a sealed interface. - NoAppendCondition: both wither methods (withMarker, replacingCriteria) now return DefaultAppendCondition instead of throwing. withMarker previously threw UnsupportedOperationException, but havingAnyTag() with a real marker is a valid, useful condition meaning "any event after this marker is a conflict." This makes NoAppendCondition composable (e.g., AppendCondition.none().withMarker(m) works). - DefaultAppendCondition: implement replacingCriteria mirroring the existing withMarker pattern (returns this if criteria unchanged). - EventStoreTransaction: add overrideAppendCondition(UnaryOperator) interface method. Input is AppendCondition.none() when no sourcing happened; returning none() bypasses conflict detection. Multiple calls compose (each receives the previous call's output). - DefaultEventStoreTransaction: implement override using a ResourceKey stored in ProcessingContext (consistent with appendConditionKey, eventQueueKey, appendPositionKey). Uses updateResource for atomic composition. Override applied in attachAppendEventsStep after marker resolution but before appendEvents, with DEBUG logging. - InterceptingEventStore: delegate overrideAppendCondition through InterceptingEventStoreTransaction. Test coverage: - DefaultAppendConditionTest: 2 tests for replacingCriteria - NoAppendConditionTest: 3 tests replacing the old throwing test, verifying composability of withMarker and replacingCriteria - DefaultEventStoreTransactionTest: 7 unit tests covering override without sourcing, after sourcing, chaining, criteria replacement, bypass, normal flow, and null rejection - StorageEngineBackedEventStoreTestSuite: 3 integration tests covering append-without-sourcing with conflict detection, narrowed criteria avoiding false conflicts, and bypass via none()
…ltEventStoreTransaction`
…veAppendCriteria method
… integration tests Replace generic CourseUpdated with CourseCreated, StudentSubscribedToCourse, and StudentUnsubscribedFromCourse event types to better illustrate real-world use cases: - shouldAppendWithOverriddenConditionWithoutSourcing: course name uniqueness - narrowedCriteriaShouldAvoidFalseConflict: subscription/unsubscription narrowing - overrideReturningNoneShouldBypassConflictDetection: duplicate course name bypass Add sourceCount() helper to avoid CourseUpdated-specific payload conversion.
… vs Aggregate hierarchy
The OverrideAppendCondition integration tests use DCB-specific patterns
(ORIGIN-based uniqueness, criteria narrowing by event type, conflict bypass)
that are not supported by aggregate-based storage engines. The aggregate-based
JPA engine uses sequence-number conflict detection via unique constraints,
ignoring AppendCondition criteria entirely.
Introduce a test suite hierarchy:
StorageEngineBackedEventStoreTestSuite (common: sourcing, streaming, tokens, conflicts)
├── DcbBasedStorageEngineBackedEventStoreTestSuite (DCB: overrideAppendCondition tests)
│ ├── InMemoryStorageEngineBackedEventStoreTest
│ └── AxonServerStorageEngineBackedEventStoreIT
└── AggregateBasedStorageEngineBackedEventStoreTestSuite (aggregate: placeholder)
└── AggregateBasedJpaStorageEngineBackedEventStoreIT
The 3 OverrideAppendCondition tests and DCB event records (CourseCreated,
StudentSubscribedToCourse, StudentUnsubscribedFromCourse) move from the base
suite to DcbBasedStorageEngineBackedEventStoreTestSuite. The base suite
exposes eventStore, awaitLatch, and RESOLVER as protected for subclass access.
…efault method and improve `NoAppendCondition` composability - Updated `replacingCriteria` in `AppendCondition` to a default implementation returning `DefaultAppendCondition`. - Modified `NoAppendCondition` to support composable operations like `withMarker` and `replacingCriteria`. - Adjusted documentation and method references for consistency and clarity.
…` in `InterceptingEventStoreTransaction`
…e() and improve test coverage Production: resolveAppendCondition now treats a null return from the override operator as AppendCondition.none(), bypassing conflict detection rather than propagating a NullPointerException to appendEvents. Test fixes: - Remove isInstanceOf(DefaultAppendCondition.class) assertions from NoAppendConditionTest — tests behavior via API (marker/criteria), not internal implementation types - Pre-populate events in overrideAfterSourcingReceivesDerivedCondition and overrideReplacingCriteriaPreservesMarker so sourcing produces a non-ORIGIN marker, making the marker assertions meaningful - Add overrideReturningNullIsTreatedAsNone test verifying the null handling
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MateuszNaKodach
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May 1, 2026
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Bunch of detail arguments to cover before we merge. Perhaps most importantly, I think this change would be important for #4388 as well. I stated we should change where this is merged in...but we can also simply port this entire PR once it's merged. I'll leave that choice up to you, @MateuszNaKodach.
| /** | ||
| * Bypassing conflict detection — creating two courses with the same name. | ||
| * <p> | ||
| * Demonstrates that returning {@link AppendCondition#none()} from the override completely |
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This test isn't unique to DCB, right? If you'd have an aggregate-based store, you can also have AppendCondition#none.
Use non-sentence style per standard #4291
Rename to replaceCriteria. It is a request to replace, not the fact replacing is already taking place #4291
Implement as default and throw Unsupported exception. Chances are slim users have implemented this, but they should if they want to use it. So, throw #4291
Not reuse criteria(). We'd want this method not to change because criteria() gets altered #4291
Move override tests to base test suite. Tests that are DCB-specific should have an assumption to cover them. #4291
Remove redundant import #4291
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My concerns have been addressed, hence I'm approving this pull request.
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This pull request resolves #4291.