Implemented Stream tombstones

CHANGELOG.md

@@ -7,6 +7,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Added `deleteAsync(StreamId)` to `Session` for marking aggregates for deletion within a unit of work. No prior load is required — the stream ID alone is sufficient.
+- Added `deleteAsync(StreamId)` to `TargetPersistenceAdapter` for physical entity deletion in state-based persistence.
+- Added `softDeleteStreamAsync(StreamId)` to `EventStore` for tombstone-based stream deletion in event sourcing.
+- `StateBasedSession.saveChangesAsync` now processes deletion-marked entities by calling `adapter.deleteAsync` and removing them from the identity map.
+- Event sourcing `SessionImpl.saveChangesAsync` now soft-deletes marked streams via `EventStore.softDeleteStreamAsync`, writing a tombstone flag instead of rejecting deletion.
+- `InMemoryEventStore`, `HiveEventStore`, and `SembastEventStore` implement `softDeleteStreamAsync` — soft-deleted streams are excluded from `loadStreamAsync` and `getStreamIdsByAggregateTypeAsync` but their events are retained for auditability.
+- `InMemoryPersistenceAdapter`, `HivePersistenceAdapter`, and `SembastPersistenceAdapter` now implement `deleteAsync`.
+
 
 ## [5.2.0] - 2026-02-20
 

packages/continuum/example/lib/store_state_based.dart

@@ -77,6 +77,15 @@ class FakeUserApiAdapter implements TargetPersistenceAdapter<User> {
       '(${pendingOperations.length} event(s)) → 200 OK',
     );
   }
+
+  @override
+  Future<void> deleteAsync(StreamId streamId) async {
+    // Simulate network latency.
+    await Future<void>.delayed(const Duration(milliseconds: 50));
+
+    _backendDb.remove(streamId.value);
+    print('    [Backend] DELETE /users/${streamId.value} → 200 OK');
+  }
 }
 
 /// Simple record representing server-side user state.

packages/continuum/example/lib/store_state_based_local_db.dart

@@ -135,6 +135,12 @@ final class UserLocalDbAdapter implements TargetPersistenceAdapter<User> {
       'deactivatedAt': target.deactivatedAt?.toIso8601String(),
     });
   }
+
+  @override
+  Future<void> deleteAsync(StreamId streamId) async {
+    // Remove the target from the local database.
+    await _db.delete(streamId.value);
+  }
 }
 
 // ── Example ─────────────────────────────────────────────────────────────────

packages/continuum/example/lib/store_state_based_transactional.dart

@@ -91,6 +91,14 @@ final class FakeBackendApi {
 
     print('    [Backend] PATCH /users/$id → 200 OK');
   }
+
+  /// Simulates `DELETE /users/:id` — removes a user from the backend.
+  Future<void> deleteUserAsync(String id) async {
+    await Future<void>.delayed(const Duration(milliseconds: 30));
+
+    _database.remove(id);
+    print('    [Backend] DELETE /users/$id → 200 OK');
+  }
 }
 
 /// Simple record representing server-side user state.
@@ -183,6 +191,12 @@ final class UserApiAdapter implements TargetPersistenceAdapter<User> {
       }
     }
   }
+
+  @override
+  Future<void> deleteAsync(StreamId streamId) async {
+    // Delete the user from the backend.
+    await _api.deleteUserAsync(streamId.value);
+  }
 }
 
 // ── Example ─────────────────────────────────────────────────────────────────

packages/continuum_event_sourcing/lib/src/persistence/event_store.dart

@@ -42,8 +42,20 @@ abstract interface class EventStore {
   /// passed to [appendEventsAsync] or [AtomicEventStore.appendEventsToStreamsAsync]
   /// when events were first persisted for a stream.
   ///
-  /// Returns an empty list if no streams match.
+  /// Returns an empty list if no streams match. Streams that have been
+  /// soft-deleted via [softDeleteStreamAsync] are excluded.
   Future<List<StreamId>> getStreamIdsByAggregateTypeAsync(
     String aggregateType,
   );
+
+  /// Marks a stream as deleted using a tombstone flag in stream
+  /// metadata.
+  ///
+  /// The events remain in the store but the stream is treated as
+  /// non-existent: [loadStreamAsync] returns an empty list and
+  /// [getStreamIdsByAggregateTypeAsync] excludes it.
+  ///
+  /// Must be idempotent — soft-deleting a non-existent or already
+  /// deleted stream is a no-op.
+  Future<void> softDeleteStreamAsync(StreamId streamId);
 }

packages/continuum_event_sourcing/lib/src/persistence/session_impl.dart

@@ -267,6 +267,12 @@ final class SessionImpl extends SessionBase {
     for (var attempt = 0; attempt <= maxRetries; attempt++) {
       try {
         final batch = await _persistPendingEventsAsync();
+
+        // Soft-delete streams marked for deletion via tombstone metadata.
+        // This happens after successful event persistence so pending
+        // operations on the same stream are not lost.
+        await _softDeleteMarkedStreamsAsync();
+
         return batch;
       } on ConcurrencyException {
         final isLastAttempt = attempt == maxRetries;
@@ -281,6 +287,20 @@ final class SessionImpl extends SessionBase {
     return CommitBatch.empty;
   }
 
+  /// Soft-deletes all streams in [streamsMarkedForDeletion] via
+  /// [EventStore.softDeleteStreamAsync] and removes them from the
+  /// identity map.
+  Future<void> _softDeleteMarkedStreamsAsync() async {
+    // Copy to avoid concurrent modification during iteration.
+    final streamIds = Set<StreamId>.of(streamsMarkedForDeletion);
+
+    for (final streamId in streamIds) {
+      await _eventStore.softDeleteStreamAsync(streamId);
+      trackedEntities.remove(streamId);
+      streamsMarkedForDeletion.remove(streamId);
+    }
+  }
+
   /// Core persistence logic extracted so [saveChangesAsync] can retry it.
   Future<CommitBatch> _persistPendingEventsAsync() async {
     final pendingEntries = <MapEntry<StreamId, TrackedEntity>>[];

packages/continuum_event_sourcing/test/persistence/event_application_mode_test.mocks.dart

@@ -78,4 +78,13 @@ class MockEventStore extends _i1.Mock implements _i2.EventStore {
             ),
           )
           as _i3.Future<List<_i5.StreamId>>);
+
+  @override
+  _i3.Future<void> softDeleteStreamAsync(_i5.StreamId? streamId) =>
+      (super.noSuchMethod(
+            Invocation.method(#softDeleteStreamAsync, [streamId]),
+            returnValue: _i3.Future<void>.value(),
+            returnValueForMissingStub: _i3.Future<void>.value(),
+          )
+          as _i3.Future<void>);
 }

packages/continuum_event_sourcing/test/persistence/session_apply_async_test.mocks.dart

@@ -78,4 +78,13 @@ class MockEventStore extends _i1.Mock implements _i2.EventStore {
             ),
           )
           as _i3.Future<List<_i5.StreamId>>);
+
+  @override
+  _i3.Future<void> softDeleteStreamAsync(_i5.StreamId? streamId) =>
+      (super.noSuchMethod(
+            Invocation.method(#softDeleteStreamAsync, [streamId]),
+            returnValue: _i3.Future<void>.value(),
+            returnValueForMissingStub: _i3.Future<void>.value(),
+          )
+          as _i3.Future<void>);
 }

packages/continuum_event_sourcing/test/persistence/session_concurrency_retry_test.mocks.dart

@@ -80,6 +80,15 @@ class MockEventStore extends _i1.Mock implements _i2.EventStore {
             ),
           )
           as _i3.Future<List<_i5.StreamId>>);
+
+  @override
+  _i3.Future<void> softDeleteStreamAsync(_i5.StreamId? streamId) =>
+      (super.noSuchMethod(
+            Invocation.method(#softDeleteStreamAsync, [streamId]),
+            returnValue: _i3.Future<void>.value(),
+            returnValueForMissingStub: _i3.Future<void>.value(),
+          )
+          as _i3.Future<void>);
 }
 
 /// A class which mocks [AtomicEventStore].
@@ -142,4 +151,13 @@ class MockAtomicEventStore extends _i1.Mock implements _i7.AtomicEventStore {
             ),
           )
           as _i3.Future<List<_i5.StreamId>>);
+
+  @override
+  _i3.Future<void> softDeleteStreamAsync(_i5.StreamId? streamId) =>
+      (super.noSuchMethod(
+            Invocation.method(#softDeleteStreamAsync, [streamId]),
+            returnValue: _i3.Future<void>.value(),
+            returnValueForMissingStub: _i3.Future<void>.value(),
+          )
+          as _i3.Future<void>);
 }

packages/continuum_event_sourcing/test/persistence/session_load_all_async_test.mocks.dart

@@ -80,6 +80,15 @@ class MockEventStore extends _i1.Mock implements _i2.EventStore {
             ),
           )
           as _i3.Future<List<_i5.StreamId>>);
+
+  @override
+  _i3.Future<void> softDeleteStreamAsync(_i5.StreamId? streamId) =>
+      (super.noSuchMethod(
+            Invocation.method(#softDeleteStreamAsync, [streamId]),
+            returnValue: _i3.Future<void>.value(),
+            returnValueForMissingStub: _i3.Future<void>.value(),
+          )
+          as _i3.Future<void>);
 }
 
 /// A class which mocks [AtomicEventStore].
@@ -142,4 +151,13 @@ class MockAtomicEventStore extends _i1.Mock implements _i7.AtomicEventStore {
             ),
           )
           as _i3.Future<List<_i5.StreamId>>);
+
+  @override
+  _i3.Future<void> softDeleteStreamAsync(_i5.StreamId? streamId) =>
+      (super.noSuchMethod(
+            Invocation.method(#softDeleteStreamAsync, [streamId]),
+            returnValue: _i3.Future<void>.value(),
+            returnValueForMissingStub: _i3.Future<void>.value(),
+          )
+          as _i3.Future<void>);
 }

packages/continuum_event_sourcing/test/persistence/session_test.mocks.dart

@@ -80,6 +80,15 @@ class MockEventStore extends _i1.Mock implements _i2.EventStore {
             ),
           )
           as _i3.Future<List<_i5.StreamId>>);
+
+  @override
+  _i3.Future<void> softDeleteStreamAsync(_i5.StreamId? streamId) =>
+      (super.noSuchMethod(
+            Invocation.method(#softDeleteStreamAsync, [streamId]),
+            returnValue: _i3.Future<void>.value(),
+            returnValueForMissingStub: _i3.Future<void>.value(),
+          )
+          as _i3.Future<void>);
 }
 
 /// A class which mocks [AtomicEventStore].
@@ -142,4 +151,13 @@ class MockAtomicEventStore extends _i1.Mock implements _i7.AtomicEventStore {
             ),
           )
           as _i3.Future<List<_i5.StreamId>>);
+
+  @override
+  _i3.Future<void> softDeleteStreamAsync(_i5.StreamId? streamId) =>
+      (super.noSuchMethod(
+            Invocation.method(#softDeleteStreamAsync, [streamId]),
+            returnValue: _i3.Future<void>.value(),
+            returnValueForMissingStub: _i3.Future<void>.value(),
+          )
+          as _i3.Future<void>);
 }

packages/continuum_generator/lib/src/combining_builder.dart

@@ -154,7 +154,10 @@ class CombiningBuilder implements Builder {
       buffer.writeln('/// Backward-compatible alias for [\$targetList].');
       buffer.writeln('///');
       buffer.writeln('/// This package historically exposed discovered targets as `\$aggregateList`.');
-      buffer.writeln("@Deprecated('Use \$targetList instead.')");
+      // Use a raw string literal so `$targetList` is not treated as string
+      // interpolation by the Dart compiler.
+      // Emit the `$` via `${'\$'}` so the generator does not try to interpolate.
+      buffer.writeln("@Deprecated(r'Use ${'\$'}targetList instead.')");
       buffer.writeln('final List<GeneratedAggregate> \$aggregateList = \$targetList;');
       buffer.writeln();
     }

packages/continuum_generator/test/combining_builder_test.dart

@@ -34,10 +34,10 @@ void main() {
   });
 
   group('CombiningBuilder', () {
-    test('generates lib/continuum.g.dart for aggregate roots', () async {
-      // Arrange: Provide a synthetic `$lib$` input and a single annotated
-      // aggregate. This verifies the happy path where at least one aggregate
-      // exists and a combining output should be produced.
+    test('generates lib/continuum.g.dart for operation targets', () async {
+      // Arrange: Provide a synthetic `$lib$` input and a single operation
+      // target. This verifies the happy path where at least one target exists
+      // and a combining output should be produced.
       final builder = continuumCombiningBuilder(const BuilderOptions({}));
 
       // Act + Assert: The output should exist and contain expected imports and
@@ -46,14 +46,17 @@ void main() {
         builder,
         {
           'continuum_generator|lib/user.dart': """
-import 'package:bounded/bounded.dart';
+import 'package:continuum/continuum.dart';
 
 final class UserId extends TypedIdentity<String> {
   const UserId(super.value);
 }
 
-class User extends AggregateRoot<UserId> {
-  User(super.id);
+@OperationTarget()
+class User {
+  User(this.id);
+
+  final UserId id;
 }
 """,
         },
@@ -67,7 +70,7 @@ class User extends AggregateRoot<UserId> {
               contains("import 'user.dart';"),
               contains(r'final List<GeneratedAggregate> $targetList = ['),
               contains(r'  $User,'),
-              contains(r"@Deprecated('Use $targetList instead.')"),
+              contains(r"@Deprecated(r'Use $targetList instead.')"),
               contains(r'final List<GeneratedAggregate> $aggregateList = $targetList;'),
             ),
           ),