{"abstract":"The bulkhead admission operation is admitted even though normal traffic consumes capacity reserved for recovery.","category":"Reliability","checks":9,"contract":"Return a Boolean admission decision for enter a dependency bulkhead. The record r must satisfy all of: r['active_capacity'][0] < r['active_capacity'][1]; r['queue_capacity'][0] < r['queue_capacity'][1]; r['queue_deadline'][0] < r['queue_deadline'][1]; r['priority_reservation'][0] or r['priority_reservation'][1] < r['priority_reservation'][2]-r['priority_reservation'][3]; r['isolation_key'][0] == r['isolation_key'][1]. Extra tracing fields are ignored; validation does not mutate the record.","evaluation_group":"xd-bulkhead-admission","failed_approach":"Adding the priority reservation check repairs the reported defect, but replacing the adjacent isolation key check loses that independent invariant.","family":"xd-bulkhead-admission-priority_reservation","id":"FA-1016","implementations":{"attempt":{"sha256":"b2b11c606efbc284cf57c10965e8df567b433931d6055b8d3896f300a58bd329","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(r):\n    return (r['active_capacity'][0] < r['active_capacity'][1]) and (r['queue_capacity'][0] < r['queue_capacity'][1]) and (r['queue_deadline'][0] < r['queue_deadline'][1]) and (r['priority_reservation'][0] or r['priority_reservation'][1] < r['priority_reservation'][2]-r['priority_reservation'][3])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nr = {'active_capacity': [2, 3], 'queue_capacity': [4, 5], 'queue_deadline': [8, 9], 'priority_reservation': [False, 2, 5, 2], 'isolation_key': ['db1', 'db1']}\ncheck('valid operation', solve(r), True)\ncheck('Concurrent calls exceed the dependency execution limit', solve(dict(r, **{'active_capacity': [3, 3]})), False)\ncheck('Waiting callers exceed the bounded waiting queue', solve(dict(r, **{'queue_capacity': [5, 5]})), False)\ncheck('A waiting call starts after its queue deadline', solve(dict(r, **{'queue_deadline': [9, 9]})), False)\ncheck('Normal traffic consumes capacity reserved for recovery', solve(dict(r, **{'priority_reservation': [False, 3, 5, 2]})), False)\ncheck('Unrelated dependencies share a bulkhead accounting key', solve(dict(r, **{'isolation_key': ['db2', 'db1']})), False)\ncheck('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)\ncheck('repeat validation is pure', solve(r), True)\ninvalid = {'active_capacity': [3, 3], 'queue_capacity': [5, 5], 'queue_deadline': [9, 9], 'priority_reservation': [False, 3, 5, 2], 'isolation_key': ['db2', 'db1']}\nkeys = list(invalid)\npair = {keys[N % len(keys)]: invalid[keys[N % len(keys)]], keys[(N+1) % len(keys)]: invalid[keys[(N+1) % len(keys)]]}\ncheck('two independent violations in variant', solve(dict(r, **pair)), False)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"ded5c83e07785d5f258331f22c70c1ec5067d53ea2667675e091ef992353b420","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(r):\n    return (r['active_capacity'][0] < r['active_capacity'][1]) and (r['queue_capacity'][0] < r['queue_capacity'][1]) and (r['queue_deadline'][0] < r['queue_deadline'][1]) and (r['isolation_key'][0] == r['isolation_key'][1])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nr = {'active_capacity': [2, 3], 'queue_capacity': [4, 5], 'queue_deadline': [8, 9], 'priority_reservation': [False, 2, 5, 2], 'isolation_key': ['db1', 'db1']}\ncheck('valid operation', solve(r), True)\ncheck('Concurrent calls exceed the dependency execution limit', solve(dict(r, **{'active_capacity': [3, 3]})), False)\ncheck('Waiting callers exceed the bounded waiting queue', solve(dict(r, **{'queue_capacity': [5, 5]})), False)\ncheck('A waiting call starts after its queue deadline', solve(dict(r, **{'queue_deadline': [9, 9]})), False)\ncheck('Normal traffic consumes capacity reserved for recovery', solve(dict(r, **{'priority_reservation': [False, 3, 5, 2]})), False)\ncheck('Unrelated dependencies share a bulkhead accounting key', solve(dict(r, **{'isolation_key': ['db2', 'db1']})), False)\ncheck('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)\ncheck('repeat validation is pure', solve(r), True)\ninvalid = {'active_capacity': [3, 3], 'queue_capacity': [5, 5], 'queue_deadline': [9, 9], 'priority_reservation': [False, 3, 5, 2], 'isolation_key': ['db2', 'db1']}\nkeys = list(invalid)\npair = {keys[N % len(keys)]: invalid[keys[N % len(keys)]], keys[(N+1) % len(keys)]: invalid[keys[(N+1) % len(keys)]]}\ncheck('two independent violations in variant', solve(dict(r, **pair)), False)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"fixed":{"sha256":"0cf65c3d6575d37617a023ceddabd36d71d06a67a402f5c55a7c961ee3b82e77","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(r):\n    return (r['active_capacity'][0] < r['active_capacity'][1]) and (r['queue_capacity'][0] < r['queue_capacity'][1]) and (r['queue_deadline'][0] < r['queue_deadline'][1]) and (r['priority_reservation'][0] or r['priority_reservation'][1] < r['priority_reservation'][2]-r['priority_reservation'][3]) and (r['isolation_key'][0] == r['isolation_key'][1])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nr = {'active_capacity': [2, 3], 'queue_capacity': [4, 5], 'queue_deadline': [8, 9], 'priority_reservation': [False, 2, 5, 2], 'isolation_key': ['db1', 'db1']}\ncheck('valid operation', solve(r), True)\ncheck('Concurrent calls exceed the dependency execution limit', solve(dict(r, **{'active_capacity': [3, 3]})), False)\ncheck('Waiting callers exceed the bounded waiting queue', solve(dict(r, **{'queue_capacity': [5, 5]})), False)\ncheck('A waiting call starts after its queue deadline', solve(dict(r, **{'queue_deadline': [9, 9]})), False)\ncheck('Normal traffic consumes capacity reserved for recovery', solve(dict(r, **{'priority_reservation': [False, 3, 5, 2]})), False)\ncheck('Unrelated dependencies share a bulkhead accounting key', solve(dict(r, **{'isolation_key': ['db2', 'db1']})), False)\ncheck('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)\ncheck('repeat validation is pure', solve(r), True)\ninvalid = {'active_capacity': [3, 3], 'queue_capacity': [5, 5], 'queue_deadline': [9, 9], 'priority_reservation': [False, 3, 5, 2], 'isolation_key': ['db2', 'db1']}\nkeys = list(invalid)\npair = {keys[N % len(keys)]: invalid[keys[N % len(keys)]], keys[(N+1) % len(keys)]: invalid[keys[(N+1) % len(keys)]]}\ncheck('two independent violations in variant', solve(dict(r, **pair)), False)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":" This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"xd-bulkhead-admission-priority_reservation","generated_at":"2026-09-29T14:36:57.929457+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"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.","repair":"Require r['priority_reservation'][0] or r['priority_reservation'][1] < r['priority_reservation'][2]-r['priority_reservation'][3] together with every other stated precondition before accepting the operation.","root_cause":"The admission path omits the priority reservation invariant while validating the other operation preconditions.","sha256":"8716cf817130b2704f5c104bbda8eb76bf0792c5b472e9a9d12611e2f404933d","title":"Enter a dependency bulkhead: Normal traffic consumes capacity reserved for recovery · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":34.75,"exit_code":1,"observations":[{"actual":true,"check":"valid operation","expected":true,"passed":true},{"actual":false,"check":"Concurrent calls exceed the dependency execution limit","expected":false,"passed":true},{"actual":false,"check":"Waiting callers exceed the bounded waiting queue","expected":false,"passed":true},{"actual":false,"check":"A waiting call starts after its queue deadline","expected":false,"passed":true},{"actual":false,"check":"Normal traffic consumes capacity reserved for recovery","expected":false,"passed":true},{"actual":true,"check":"Unrelated dependencies share a bulkhead accounting key","expected":false,"passed":false},{"actual":true,"check":"unrelated tracing metadata","expected":true,"passed":true},{"actual":true,"check":"repeat validation is pure","expected":true,"passed":true},{"actual":false,"check":"two independent violations in variant","expected":false,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"valid operation\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"Concurrent calls exceed the dependency execution limit\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Waiting callers exceed the bounded waiting queue\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"A waiting call starts after its queue deadline\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Normal traffic consumes capacity reserved for recovery\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Unrelated dependencies share a bulkhead accounting key\", \"actual\": true, \"expected\": false, \"passed\": false}, {\"check\": \"unrelated tracing metadata\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"repeat validation is pure\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"two independent violations in variant\", \"actual\": false, \"expected\": false, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":55.854,"exit_code":1,"observations":[{"actual":true,"check":"valid operation","expected":true,"passed":true},{"actual":false,"check":"Concurrent calls exceed the dependency execution limit","expected":false,"passed":true},{"actual":false,"check":"Waiting callers exceed the bounded waiting queue","expected":false,"passed":true},{"actual":false,"check":"A waiting call starts after its queue deadline","expected":false,"passed":true},{"actual":true,"check":"Normal traffic consumes capacity reserved for recovery","expected":false,"passed":false},{"actual":false,"check":"Unrelated dependencies share a bulkhead accounting key","expected":false,"passed":true},{"actual":true,"check":"unrelated tracing metadata","expected":true,"passed":true},{"actual":true,"check":"repeat validation is pure","expected":true,"passed":true},{"actual":false,"check":"two independent violations in variant","expected":false,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"valid operation\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"Concurrent calls exceed the dependency execution limit\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Waiting callers exceed the bounded waiting queue\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"A waiting call starts after its queue deadline\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Normal traffic consumes capacity reserved for recovery\", \"actual\": true, \"expected\": false, \"passed\": false}, {\"check\": \"Unrelated dependencies share a bulkhead accounting key\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"unrelated tracing metadata\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"repeat validation is pure\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"two independent violations in variant\", \"actual\": false, \"expected\": false, \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":37.491,"exit_code":0,"observations":[{"actual":true,"check":"valid operation","expected":true,"passed":true},{"actual":false,"check":"Concurrent calls exceed the dependency execution limit","expected":false,"passed":true},{"actual":false,"check":"Waiting callers exceed the bounded waiting queue","expected":false,"passed":true},{"actual":false,"check":"A waiting call starts after its queue deadline","expected":false,"passed":true},{"actual":false,"check":"Normal traffic consumes capacity reserved for recovery","expected":false,"passed":true},{"actual":false,"check":"Unrelated dependencies share a bulkhead accounting key","expected":false,"passed":true},{"actual":true,"check":"unrelated tracing metadata","expected":true,"passed":true},{"actual":true,"check":"repeat validation is pure","expected":true,"passed":true},{"actual":false,"check":"two independent violations in variant","expected":false,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"valid operation\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"Concurrent calls exceed the dependency execution limit\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Waiting callers exceed the bounded waiting queue\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"A waiting call starts after its queue deadline\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Normal traffic consumes capacity reserved for recovery\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Unrelated dependencies share a bulkhead accounting key\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"unrelated tracing metadata\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"repeat validation is pure\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"two independent violations in variant\", \"actual\": false, \"expected\": false, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}