{"id":"event-store-optimistic-concurrency","text":"`EventStore.append()` accepts an `expected_version` parameter and rejects appends when the stream's current version doesn't match, implementing optimistic concurrency control for event streams","truth_value":"IN","source":"entries/2026/05/29/topic-ddia-ch12-unbundling.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"event-store-optimistic-concurrency","truth_value":"IN","reason":"premise"}]}}