Solution: Event Log, Checkpoints, Memory and Deterministic Replay

Выбранный подход#

Use the existing shared vertical-slice public ports rather than creating a second event model. Events remain authoritative; live state and checkpoints are derived. The owned study supplies adversarial acceptance tests and records uncovered contract gaps.

Архитектура и поток данных#

validated command
-> authoritative engine transition
-> immutable event clone appended with sequence/state versions/visibility
-> live materialized GameState

recovery
-> replayEvents(genesis, allEvents)
-> verifyCheckpoint(genesis, allEvents, checkpoint)
-> replayFromCheckpoint(genesis, allEvents, checkpoint)
   -> reject verification mismatch
   -> replay suffix from verified checkpoint state
-> projectState(actor) using preserved visibility

replayFromCheckpoint owns verification, so a caller cannot accidentally use a tampered checkpoint through the public replay path. Summaries and retrieved memories remain outside the authority boundary.

Структура прототипа#

• prototype/event-log.verification.test.ts imports:
  • shared engine and seeded RNG;
  • InMemoryEventLog, checkpoint and replay functions;
  • canonical stateHash;
  • projectState;
  • runLongSessionReplay.
• prototype/README.md lists exact coverage and gaps.

No duplicate event/reducer/hash implementation is owned by this study.

Требования#

• Verified environment: macOS 26.4 (25E246), arm64.
• Runtime: Node.js v24.14.0 with built-in TypeScript stripping.
• Root dependencies installed according to the shared repository lockfile.
• External services: none.

Установка#

From repository root:

npm install
node --version

This study adds no dependency.

Запуск#

From repository root:

node --test RnD/technical/2026-07-25-event-log-memory-replay/prototype/event-log.verification.test.ts

The AC-05 test emits the full JSON replay report as a test diagnostic.

Тестирование#

node --test RnD/technical/2026-07-25-event-log-memory-replay/prototype/event-log.verification.test.ts
npm run typecheck

Fresh scoped result: 5 pass, 0 fail, 0 TODO. Fresh root TypeScript result: exit 0.

Конфигурация#

No environment variables or services are used. The shared long fixture has seed 20260725; the owned short fixture uses the same seed and checkpoints at half.

Ограничения и безопасность#

• InMemoryEventLog is not a durability proof.
• A checkpoint contains a full state clone and hash; storage authentication and encryption are out of scope.
• The event union lacks correction metadata.
• The long fixture lacks primary-event-reference and branch-chronology models.
• Synthetic fixtures contain no real player data.

Условия переноса в production#

• Preserve verification inside the checkpoint-replay authority boundary.
• Add an immutable correction event with authorized author, reason and corrected event reference.
• Add persistent append atomicity, authorization, backup/restore and migration tests.
• Establish cross-runtime canonical-hash vectors.
• Extend the fixed long fixture with branch chronology and primary-event references before marking the campaign gate fully passed.