FA-1589 / Reliability / Member archive
Cut traffic to a replacement region: Application traffic arrives before regional dependencies are ready · case 04
The regional cutover operation is admitted even though application traffic arrives before regional dependencies are ready.
Case contract
Return a Boolean admission decision for cut traffic to a replacement region. The record r must satisfy all of: r['replication_caught_up'][0] >= r['replication_caught_up'][1]; r['source_writes_stopped'] is True; all(r['dependency_ready']); r['capacity_headroom'][0]+r['capacity_headroom'][1] <= r['capacity_headroom'][2]; r['cutover_generation'][0] > r['cutover_generation'][1]. Extra tracing fields are ignored; validation does not mutate the record.
Why this case matters
A deterministic local contract for reliability. Each negative fixture violates exactly one invariant. No transport timing, persistence, cryptographic verification, or full protocol implementation is claimed.
One recorded failure
Sample boundary fixtureThis sample comes from the broken implementation of a controlled reproducer.
| Boundary fixture | Actual | Expected | Outcome |
|---|---|---|---|
| Application traffic arrives before regional dependencies are ready | true | false | Failed |
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