{"abstract":"The barrier release operation is admitted even though arrivals from another barrier round count toward this round.","category":"Concurrency","checks":9,"contract":"Return a Boolean admission decision for release a distributed generation barrier. The record r must satisfy all of: len(set(r['participant_count'][0])) >= r['participant_count'][1]; all(x == r['generation_match'][0] for x in r['generation_match'][1]); set(r['registered_members'][0]) <= set(r['registered_members'][1]); r['barrier_not_broken'] is False; r['release_persisted'] is True. Extra tracing fields are ignored; validation does not mutate the record.","evaluation_group":"xd-barrier-release","failed_approach":"Adding the generation match check repairs the reported defect, but replacing the adjacent registered members check loses that independent invariant.","family":"xd-barrier-release-generation_match","id":"FA-1406","implementations":{"attempt":{"sha256":"fd9f9f59cf04267f0a9b1917344667b3288fd56e5f08619f89a29c8e8e944dcc","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(r):\n    return (len(set(r['participant_count'][0])) >= r['participant_count'][1]) and (all(x == r['generation_match'][0] for x in r['generation_match'][1])) and (r['barrier_not_broken'] is False) and (r['release_persisted'] is True)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nr = {'participant_count': [['a', 'b'], 2], 'generation_match': [3, [3, 3]], 'registered_members': [['a', 'b'], ['a', 'b', 'c']], 'barrier_not_broken': False, 'release_persisted': True}\ncheck('valid operation', solve(r), True)\ncheck('A barrier opens before enough distinct participants arrive', solve(dict(r, **{'participant_count': [['a', 'a'], 2]})), False)\ncheck('Arrivals from another barrier round count toward this round', solve(dict(r, **{'generation_match': [3, [2, 3]]})), False)\ncheck('Unregistered arrivals manufacture barrier completion', solve(dict(r, **{'registered_members': [['a', 'x'], ['a', 'b', 'c']]})), False)\ncheck('A failed barrier round is released as successful', solve(dict(r, **{'barrier_not_broken': True})), False)\ncheck('Waiters proceed before the generation release is durable', solve(dict(r, **{'release_persisted': False})), False)\ncheck('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)\ncheck('repeat validation is pure', solve(r), True)\ninvalid = {'participant_count': [['a', 'a'], 2], 'generation_match': [3, [2, 3]], 'registered_members': [['a', 'x'], ['a', 'b', 'c']], 'barrier_not_broken': True, 'release_persisted': False}\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":"b75451676d0dc9bcdc5b71a9533b6cfa8b508139fd24e8f76ca910a1f2d03653","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(r):\n    return (len(set(r['participant_count'][0])) >= r['participant_count'][1]) and (set(r['registered_members'][0]) <= set(r['registered_members'][1])) and (r['barrier_not_broken'] is False) and (r['release_persisted'] is True)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nr = {'participant_count': [['a', 'b'], 2], 'generation_match': [3, [3, 3]], 'registered_members': [['a', 'b'], ['a', 'b', 'c']], 'barrier_not_broken': False, 'release_persisted': True}\ncheck('valid operation', solve(r), True)\ncheck('A barrier opens before enough distinct participants arrive', solve(dict(r, **{'participant_count': [['a', 'a'], 2]})), False)\ncheck('Arrivals from another barrier round count toward this round', solve(dict(r, **{'generation_match': [3, [2, 3]]})), False)\ncheck('Unregistered arrivals manufacture barrier completion', solve(dict(r, **{'registered_members': [['a', 'x'], ['a', 'b', 'c']]})), False)\ncheck('A failed barrier round is released as successful', solve(dict(r, **{'barrier_not_broken': True})), False)\ncheck('Waiters proceed before the generation release is durable', solve(dict(r, **{'release_persisted': False})), False)\ncheck('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)\ncheck('repeat validation is pure', solve(r), True)\ninvalid = {'participant_count': [['a', 'a'], 2], 'generation_match': [3, [2, 3]], 'registered_members': [['a', 'x'], ['a', 'b', 'c']], 'barrier_not_broken': True, 'release_persisted': False}\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":"ec2f5589925fcf90ce901282dc6b368cd1f22af30a3e988b8b9c2d3bd9e8c311","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(r):\n    return (len(set(r['participant_count'][0])) >= r['participant_count'][1]) and (all(x == r['generation_match'][0] for x in r['generation_match'][1])) and (set(r['registered_members'][0]) <= set(r['registered_members'][1])) and (r['barrier_not_broken'] is False) and (r['release_persisted'] is True)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nr = {'participant_count': [['a', 'b'], 2], 'generation_match': [3, [3, 3]], 'registered_members': [['a', 'b'], ['a', 'b', 'c']], 'barrier_not_broken': False, 'release_persisted': True}\ncheck('valid operation', solve(r), True)\ncheck('A barrier opens before enough distinct participants arrive', solve(dict(r, **{'participant_count': [['a', 'a'], 2]})), False)\ncheck('Arrivals from another barrier round count toward this round', solve(dict(r, **{'generation_match': [3, [2, 3]]})), False)\ncheck('Unregistered arrivals manufacture barrier completion', solve(dict(r, **{'registered_members': [['a', 'x'], ['a', 'b', 'c']]})), False)\ncheck('A failed barrier round is released as successful', solve(dict(r, **{'barrier_not_broken': True})), False)\ncheck('Waiters proceed before the generation release is durable', solve(dict(r, **{'release_persisted': False})), False)\ncheck('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)\ncheck('repeat validation is pure', solve(r), True)\ninvalid = {'participant_count': [['a', 'a'], 2], 'generation_match': [3, [2, 3]], 'registered_members': [['a', 'x'], ['a', 'b', 'c']], 'barrier_not_broken': True, 'release_persisted': False}\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-barrier-release-generation_match","generated_at":"2026-09-29T14:37:02.209092+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic local contract for concurrency. Each negative fixture violates exactly one invariant. No transport timing, persistence, cryptographic verification, or full protocol implementation is claimed.","repair":"Require all(x == r['generation_match'][0] for x in r['generation_match'][1]) together with every other stated precondition before accepting the operation.","root_cause":"The admission path omits the generation match invariant while validating the other operation preconditions.","sha256":"9a1d5478b78ba4033f2a432eca4a3b9e8e3ae3a3d8d1dc44357077b289c792b1","title":"Release a distributed generation barrier: Arrivals from another barrier round count toward this round · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":40.846,"exit_code":1,"observations":[{"actual":true,"check":"valid operation","expected":true,"passed":true},{"actual":false,"check":"A barrier opens before enough distinct participants arrive","expected":false,"passed":true},{"actual":false,"check":"Arrivals from another barrier round count toward this round","expected":false,"passed":true},{"actual":true,"check":"Unregistered arrivals manufacture barrier completion","expected":false,"passed":false},{"actual":false,"check":"A failed barrier round is released as successful","expected":false,"passed":true},{"actual":false,"check":"Waiters proceed before the generation release is durable","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\": \"A barrier opens before enough distinct participants arrive\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Arrivals from another barrier round count toward this round\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Unregistered arrivals manufacture barrier completion\", \"actual\": true, \"expected\": false, \"passed\": false}, {\"check\": \"A failed barrier round is released as successful\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Waiters proceed before the generation release is durable\", \"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"},"broken":{"elapsed_ms":38.127,"exit_code":1,"observations":[{"actual":true,"check":"valid operation","expected":true,"passed":true},{"actual":false,"check":"A barrier opens before enough distinct participants arrive","expected":false,"passed":true},{"actual":true,"check":"Arrivals from another barrier round count toward this round","expected":false,"passed":false},{"actual":false,"check":"Unregistered arrivals manufacture barrier completion","expected":false,"passed":true},{"actual":false,"check":"A failed barrier round is released as successful","expected":false,"passed":true},{"actual":false,"check":"Waiters proceed before the generation release is durable","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\": \"A barrier opens before enough distinct participants arrive\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Arrivals from another barrier round count toward this round\", \"actual\": true, \"expected\": false, \"passed\": false}, {\"check\": \"Unregistered arrivals manufacture barrier completion\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"A failed barrier round is released as successful\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Waiters proceed before the generation release is durable\", \"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":39.78,"exit_code":0,"observations":[{"actual":true,"check":"valid operation","expected":true,"passed":true},{"actual":false,"check":"A barrier opens before enough distinct participants arrive","expected":false,"passed":true},{"actual":false,"check":"Arrivals from another barrier round count toward this round","expected":false,"passed":true},{"actual":false,"check":"Unregistered arrivals manufacture barrier completion","expected":false,"passed":true},{"actual":false,"check":"A failed barrier round is released as successful","expected":false,"passed":true},{"actual":false,"check":"Waiters proceed before the generation release is durable","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\": \"A barrier opens before enough distinct participants arrive\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Arrivals from another barrier round count toward this round\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Unregistered arrivals manufacture barrier completion\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"A failed barrier round is released as successful\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Waiters proceed before the generation release is durable\", \"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"}