{"abstract":"The queue purge operation is admitted even though purge ignores an explicit retention hold.","category":"Queues","checks":9,"contract":"Return a Boolean admission decision for purge messages through a selected boundary. The record r must satisfy all of: r['boundary_fixed'][0] <= r['boundary_fixed'][1]; r['reserved_protected'] is False; r['namespace_match'][0] == r['namespace_match'][1]; r['queue_incarnation'][0] == r['queue_incarnation'][1]; r['retention_hold'] is False. Extra tracing fields are ignored; validation does not mutate the record.","contract_signature":"r","evaluation_group":"xd-queue-purge","failed_approach":"Adding the retention hold check repairs the reported defect, but replacing the adjacent boundary fixed check loses that independent invariant.","family":"xd-queue-purge-retention_hold","id":"FA-921","implementations":{"attempt":{"sha256":"1a8dff3dd470afad163591a65ece35219a4fa202ffb17920bee1f9f839634228","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(r):\n    return (r['reserved_protected'] is False) and (r['namespace_match'][0] == r['namespace_match'][1]) and (r['queue_incarnation'][0] == r['queue_incarnation'][1]) and (r['retention_hold'] is False)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nr = {'boundary_fixed': [100, 100], 'reserved_protected': False, 'namespace_match': ['t1', 't1'], 'queue_incarnation': ['g2', 'g2'], 'retention_hold': False}\ncheck('valid operation', solve(r), True)\ncheck('A moving purge boundary consumes messages published after purge began', solve(dict(r, **{'boundary_fixed': [101, 100]})), False)\ncheck('Purge deletes an actively reserved delivery', solve(dict(r, **{'reserved_protected': True})), False)\ncheck('Purge crosses into another tenant queue', solve(dict(r, **{'namespace_match': ['t2', 't1']})), False)\ncheck('A delayed purge targets a recreated queue with the same name', solve(dict(r, **{'queue_incarnation': ['g1', 'g2']})), False)\ncheck('Purge ignores an explicit retention hold', solve(dict(r, **{'retention_hold': True})), False)\ncheck('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)\ncheck('repeat validation is pure', solve(r), True)\ninvalid = {'boundary_fixed': [101, 100], 'reserved_protected': True, 'namespace_match': ['t2', 't1'], 'queue_incarnation': ['g1', 'g2'], 'retention_hold': True}\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":"cd9649acf503d362623b0bd543a45aff968180ed16ca3ed31cd956f094f36f2b","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(r):\n    return (r['boundary_fixed'][0] <= r['boundary_fixed'][1]) and (r['reserved_protected'] is False) and (r['namespace_match'][0] == r['namespace_match'][1]) and (r['queue_incarnation'][0] == r['queue_incarnation'][1])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nr = {'boundary_fixed': [100, 100], 'reserved_protected': False, 'namespace_match': ['t1', 't1'], 'queue_incarnation': ['g2', 'g2'], 'retention_hold': False}\ncheck('valid operation', solve(r), True)\ncheck('A moving purge boundary consumes messages published after purge began', solve(dict(r, **{'boundary_fixed': [101, 100]})), False)\ncheck('Purge deletes an actively reserved delivery', solve(dict(r, **{'reserved_protected': True})), False)\ncheck('Purge crosses into another tenant queue', solve(dict(r, **{'namespace_match': ['t2', 't1']})), False)\ncheck('A delayed purge targets a recreated queue with the same name', solve(dict(r, **{'queue_incarnation': ['g1', 'g2']})), False)\ncheck('Purge ignores an explicit retention hold', solve(dict(r, **{'retention_hold': True})), False)\ncheck('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)\ncheck('repeat validation is pure', solve(r), True)\ninvalid = {'boundary_fixed': [101, 100], 'reserved_protected': True, 'namespace_match': ['t2', 't1'], 'queue_incarnation': ['g1', 'g2'], 'retention_hold': True}\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-queue-purge-retention_hold","generated_at":"2026-09-29T14:36:57.204496+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic local contract for queues. Each negative fixture violates exactly one invariant. No transport timing, persistence, cryptographic verification, or full protocol implementation is claimed.","root_cause":"The admission path omits the retention hold invariant while validating the other operation preconditions.","sha256":"1cfc4cb45d6b8fa03125f1ceea46991118632fe8e665258dff36a1aac6c7c27e","title":"Purge messages through a selected boundary: Purge ignores an explicit retention hold · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":119.538,"exit_code":1,"observations":[{"actual":true,"check":"valid operation","expected":true,"passed":true},{"actual":true,"check":"A moving purge boundary consumes messages published after purge began","expected":false,"passed":false},{"actual":false,"check":"Purge deletes an actively reserved delivery","expected":false,"passed":true},{"actual":false,"check":"Purge crosses into another tenant queue","expected":false,"passed":true},{"actual":false,"check":"A delayed purge targets a recreated queue with the same name","expected":false,"passed":true},{"actual":false,"check":"Purge ignores an explicit retention hold","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 moving purge boundary consumes messages published after purge began\", \"actual\": true, \"expected\": false, \"passed\": false}, {\"check\": \"Purge deletes an actively reserved delivery\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Purge crosses into another tenant queue\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"A delayed purge targets a recreated queue with the same name\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Purge ignores an explicit retention hold\", \"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":37.59,"exit_code":1,"observations":[{"actual":true,"check":"valid operation","expected":true,"passed":true},{"actual":false,"check":"A moving purge boundary consumes messages published after purge began","expected":false,"passed":true},{"actual":false,"check":"Purge deletes an actively reserved delivery","expected":false,"passed":true},{"actual":false,"check":"Purge crosses into another tenant queue","expected":false,"passed":true},{"actual":false,"check":"A delayed purge targets a recreated queue with the same name","expected":false,"passed":true},{"actual":true,"check":"Purge ignores an explicit retention hold","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\": \"A moving purge boundary consumes messages published after purge began\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Purge deletes an actively reserved delivery\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Purge crosses into another tenant queue\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"A delayed purge targets a recreated queue with the same name\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Purge ignores an explicit retention hold\", \"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"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}