{"abstract":"The queue redrive operation is admitted even though redrive races an updated dead-letter record.","category":"Queues","checks":9,"contract":"Return a Boolean admission decision for redrive a previously dead-lettered message. The record r must satisfy all of: r['redrive_budget'][0] < r['redrive_budget'][1]; r['source_version'][0] == r['source_version'][1]; r['destination_schema'][0] in r['destination_schema'][1]; r['retention_remaining'][0] < r['retention_remaining'][1]; r['rate_tokens'][0] >= r['rate_tokens'][1]. Extra tracing fields are ignored; validation does not mutate the record.","contract_signature":"r","evaluation_group":"xd-queue-redrive","failed_approach":"Adding the source version check repairs the reported defect, but replacing the adjacent destination schema check loses that independent invariant.","family":"xd-queue-redrive-source_version","id":"FA-831","implementations":{"attempt":{"sha256":"fa64b6790dcd7932d42a8bf7f1df909aa454faf1d6b96710e75892950e4b45bd","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(r):\n    return (r['redrive_budget'][0] < r['redrive_budget'][1]) and (r['source_version'][0] == r['source_version'][1]) and (r['retention_remaining'][0] < r['retention_remaining'][1]) and (r['rate_tokens'][0] >= r['rate_tokens'][1])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nr = {'redrive_budget': [2, 3], 'source_version': [7, 7], 'destination_schema': [2, [2, 3]], 'retention_remaining': [19, 20], 'rate_tokens': [3, 3]}\ncheck('valid operation', solve(r), True)\ncheck('Poison messages circulate past the redrive allowance', solve(dict(r, **{'redrive_budget': [3, 3]})), False)\ncheck('Redrive races an updated dead-letter record', solve(dict(r, **{'source_version': [6, 7]})), False)\ncheck('The target consumer cannot decode the original schema', solve(dict(r, **{'destination_schema': [1, [2, 3]]})), False)\ncheck('Redrive revives a message past its absolute retention', solve(dict(r, **{'retention_remaining': [20, 20]})), False)\ncheck('Redrive bypasses its recovery traffic budget', solve(dict(r, **{'rate_tokens': [2, 3]})), False)\ncheck('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)\ncheck('repeat validation is pure', solve(r), True)\ninvalid = {'redrive_budget': [3, 3], 'source_version': [6, 7], 'destination_schema': [1, [2, 3]], 'retention_remaining': [20, 20], 'rate_tokens': [2, 3]}\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":"0f36719aaa0b8108a1064ed59a21b1c56fc4f9aff201500a892f9932ddf2e49c","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(r):\n    return (r['redrive_budget'][0] < r['redrive_budget'][1]) and (r['destination_schema'][0] in r['destination_schema'][1]) and (r['retention_remaining'][0] < r['retention_remaining'][1]) and (r['rate_tokens'][0] >= r['rate_tokens'][1])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nr = {'redrive_budget': [2, 3], 'source_version': [7, 7], 'destination_schema': [2, [2, 3]], 'retention_remaining': [19, 20], 'rate_tokens': [3, 3]}\ncheck('valid operation', solve(r), True)\ncheck('Poison messages circulate past the redrive allowance', solve(dict(r, **{'redrive_budget': [3, 3]})), False)\ncheck('Redrive races an updated dead-letter record', solve(dict(r, **{'source_version': [6, 7]})), False)\ncheck('The target consumer cannot decode the original schema', solve(dict(r, **{'destination_schema': [1, [2, 3]]})), False)\ncheck('Redrive revives a message past its absolute retention', solve(dict(r, **{'retention_remaining': [20, 20]})), False)\ncheck('Redrive bypasses its recovery traffic budget', solve(dict(r, **{'rate_tokens': [2, 3]})), False)\ncheck('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)\ncheck('repeat validation is pure', solve(r), True)\ninvalid = {'redrive_budget': [3, 3], 'source_version': [6, 7], 'destination_schema': [1, [2, 3]], 'retention_remaining': [20, 20], 'rate_tokens': [2, 3]}\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-redrive-source_version","generated_at":"2026-09-29T14:36:56.528812+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 source version invariant while validating the other operation preconditions.","sha256":"38369ff12ff7e372a417d4310d21256e167318fdd6cf43fc3e2bb70470f5b948","title":"Redrive a previously dead-lettered message: Redrive races an updated dead-letter record · 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":33.6,"exit_code":1,"observations":[{"actual":true,"check":"valid operation","expected":true,"passed":true},{"actual":false,"check":"Poison messages circulate past the redrive allowance","expected":false,"passed":true},{"actual":false,"check":"Redrive races an updated dead-letter record","expected":false,"passed":true},{"actual":true,"check":"The target consumer cannot decode the original schema","expected":false,"passed":false},{"actual":false,"check":"Redrive revives a message past its absolute retention","expected":false,"passed":true},{"actual":false,"check":"Redrive bypasses its recovery traffic budget","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\": \"Poison messages circulate past the redrive allowance\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Redrive races an updated dead-letter record\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"The target consumer cannot decode the original schema\", \"actual\": true, \"expected\": false, \"passed\": false}, {\"check\": \"Redrive revives a message past its absolute retention\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Redrive bypasses its recovery traffic budget\", \"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":29.085,"exit_code":1,"observations":[{"actual":true,"check":"valid operation","expected":true,"passed":true},{"actual":false,"check":"Poison messages circulate past the redrive allowance","expected":false,"passed":true},{"actual":true,"check":"Redrive races an updated dead-letter record","expected":false,"passed":false},{"actual":false,"check":"The target consumer cannot decode the original schema","expected":false,"passed":true},{"actual":false,"check":"Redrive revives a message past its absolute retention","expected":false,"passed":true},{"actual":false,"check":"Redrive bypasses its recovery traffic budget","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\": \"Poison messages circulate past the redrive allowance\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Redrive races an updated dead-letter record\", \"actual\": true, \"expected\": false, \"passed\": false}, {\"check\": \"The target consumer cannot decode the original schema\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Redrive revives a message past its absolute retention\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"Redrive bypasses its recovery traffic budget\", \"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"}},"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."}}