{"abstract":"The retry admission operation is admitted even though a retry ignores the server requested wait period.","category":"Reliability","checks":9,"contract":"Return a Boolean admission decision for admit a remote operation retry. The record r must satisfy all of: r['retryable_result'] in [408,429,500,502,503,504]; r['attempt_budget'][0] < r['attempt_budget'][1]; r['remaining_deadline'][0]+r['remaining_deadline'][1] <= r['remaining_deadline'][2]; r['idempotency_safe'][0] or bool(r['idempotency_safe'][1]); r['retry_after'][0] >= r['retry_after'][1]. Extra tracing fields are ignored; validation does not mutate the record.","evaluation_group":"xd-retry-admission","failed_approach":"Adding the retry after check repairs the reported defect, but replacing the adjacent retryable result check loses that independent invariant.","family":"xd-retry-admission-retry_after","id":"FA-946","implementations":{"attempt":{"sha256":"1b314f89b84568b8299fb39722e1b28477b0db9ae8a5f759e98f900f73a9ab62","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(r):\n    return (r['attempt_budget'][0] < r['attempt_budget'][1]) and (r['remaining_deadline'][0]+r['remaining_deadline'][1] <= r['remaining_deadline'][2]) and (r['idempotency_safe'][0] or bool(r['idempotency_safe'][1])) and (r['retry_after'][0] >= r['retry_after'][1])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nr = {'retryable_result': 503, 'attempt_budget': [2, 3], 'remaining_deadline': [5, 3, 8], 'idempotency_safe': [False, 'op1'], 'retry_after': [10, 10]}\ncheck('valid operation', solve(r), True)\ncheck('A permanent rejection triggers another attempt', solve(dict(r, **{'retryable_result': 400})), False)\ncheck('An exhausted attempt budget permits one more request', solve(dict(r, **{'attempt_budget': [3, 3]})), False)\ncheck('A retry cannot finish within its remaining request deadline', solve(dict(r, **{'remaining_deadline': [5, 4, 8]})), False)\ncheck('A non-idempotent write is retried without an identity key', solve(dict(r, **{'idempotency_safe': [False, '']})), False)\ncheck('A retry ignores the server requested wait period', solve(dict(r, **{'retry_after': [9, 10]})), False)\ncheck('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)\ncheck('repeat validation is pure', solve(r), True)\ninvalid = {'retryable_result': 400, 'attempt_budget': [3, 3], 'remaining_deadline': [5, 4, 8], 'idempotency_safe': [False, ''], 'retry_after': [9, 10]}\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":"e03da17ab9b72aa8ae61fbbc67859020ca8f3cacab81e1df9715026fa2c17008","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(r):\n    return (r['retryable_result'] in [408,429,500,502,503,504]) and (r['attempt_budget'][0] < r['attempt_budget'][1]) and (r['remaining_deadline'][0]+r['remaining_deadline'][1] <= r['remaining_deadline'][2]) and (r['idempotency_safe'][0] or bool(r['idempotency_safe'][1]))\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nr = {'retryable_result': 503, 'attempt_budget': [2, 3], 'remaining_deadline': [5, 3, 8], 'idempotency_safe': [False, 'op1'], 'retry_after': [10, 10]}\ncheck('valid operation', solve(r), True)\ncheck('A permanent rejection triggers another attempt', solve(dict(r, **{'retryable_result': 400})), False)\ncheck('An exhausted attempt budget permits one more request', solve(dict(r, **{'attempt_budget': [3, 3]})), False)\ncheck('A retry cannot finish within its remaining request deadline', solve(dict(r, **{'remaining_deadline': [5, 4, 8]})), False)\ncheck('A non-idempotent write is retried without an identity key', solve(dict(r, **{'idempotency_safe': [False, '']})), False)\ncheck('A retry ignores the server requested wait period', solve(dict(r, **{'retry_after': [9, 10]})), False)\ncheck('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)\ncheck('repeat validation is pure', solve(r), True)\ninvalid = {'retryable_result': 400, 'attempt_budget': [3, 3], 'remaining_deadline': [5, 4, 8], 'idempotency_safe': [False, ''], 'retry_after': [9, 10]}\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":"f2ff00253088600ac6088376dfcc31413d4d31d641e245e0f84d9f8a1f28dcb3","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(r):\n    return (r['retryable_result'] in [408,429,500,502,503,504]) and (r['attempt_budget'][0] < r['attempt_budget'][1]) and (r['remaining_deadline'][0]+r['remaining_deadline'][1] <= r['remaining_deadline'][2]) and (r['idempotency_safe'][0] or bool(r['idempotency_safe'][1])) and (r['retry_after'][0] >= r['retry_after'][1])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nr = {'retryable_result': 503, 'attempt_budget': [2, 3], 'remaining_deadline': [5, 3, 8], 'idempotency_safe': [False, 'op1'], 'retry_after': [10, 10]}\ncheck('valid operation', solve(r), True)\ncheck('A permanent rejection triggers another attempt', solve(dict(r, **{'retryable_result': 400})), False)\ncheck('An exhausted attempt budget permits one more request', solve(dict(r, **{'attempt_budget': [3, 3]})), False)\ncheck('A retry cannot finish within its remaining request deadline', solve(dict(r, **{'remaining_deadline': [5, 4, 8]})), False)\ncheck('A non-idempotent write is retried without an identity key', solve(dict(r, **{'idempotency_safe': [False, '']})), False)\ncheck('A retry ignores the server requested wait period', solve(dict(r, **{'retry_after': [9, 10]})), False)\ncheck('unrelated tracing metadata', solve(dict(r, trace='run-'+str(N))), True)\ncheck('repeat validation is pure', solve(r), True)\ninvalid = {'retryable_result': 400, 'attempt_budget': [3, 3], 'remaining_deadline': [5, 4, 8], 'idempotency_safe': [False, ''], 'retry_after': [9, 10]}\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-retry-admission-retry_after","generated_at":"2026-09-29T14:36:57.233890+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['retry_after'][0] >= r['retry_after'][1] together with every other stated precondition before accepting the operation.","root_cause":"The admission path omits the retry after invariant while validating the other operation preconditions.","sha256":"27147242629851dd1d7dfd6dba871ae560682c703f54c1140e3c5b08945e544e","title":"Admit a remote operation retry: A retry ignores the server requested wait period · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":31.044,"exit_code":1,"observations":[{"actual":true,"check":"valid operation","expected":true,"passed":true},{"actual":true,"check":"A permanent rejection triggers another attempt","expected":false,"passed":false},{"actual":false,"check":"An exhausted attempt budget permits one more request","expected":false,"passed":true},{"actual":false,"check":"A retry cannot finish within its remaining request deadline","expected":false,"passed":true},{"actual":false,"check":"A non-idempotent write is retried without an identity key","expected":false,"passed":true},{"actual":false,"check":"A retry ignores the server requested wait period","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 permanent rejection triggers another attempt\", \"actual\": true, \"expected\": false, \"passed\": false}, {\"check\": \"An exhausted attempt budget permits one more request\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"A retry cannot finish within its remaining request deadline\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"A non-idempotent write is retried without an identity key\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"A retry ignores the server requested wait period\", \"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":120.782,"exit_code":1,"observations":[{"actual":true,"check":"valid operation","expected":true,"passed":true},{"actual":false,"check":"A permanent rejection triggers another attempt","expected":false,"passed":true},{"actual":false,"check":"An exhausted attempt budget permits one more request","expected":false,"passed":true},{"actual":false,"check":"A retry cannot finish within its remaining request deadline","expected":false,"passed":true},{"actual":false,"check":"A non-idempotent write is retried without an identity key","expected":false,"passed":true},{"actual":true,"check":"A retry ignores the server requested wait period","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 permanent rejection triggers another attempt\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"An exhausted attempt budget permits one more request\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"A retry cannot finish within its remaining request deadline\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"A non-idempotent write is retried without an identity key\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"A retry ignores the server requested wait period\", \"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"},"fixed":{"elapsed_ms":33.572,"exit_code":0,"observations":[{"actual":true,"check":"valid operation","expected":true,"passed":true},{"actual":false,"check":"A permanent rejection triggers another attempt","expected":false,"passed":true},{"actual":false,"check":"An exhausted attempt budget permits one more request","expected":false,"passed":true},{"actual":false,"check":"A retry cannot finish within its remaining request deadline","expected":false,"passed":true},{"actual":false,"check":"A non-idempotent write is retried without an identity key","expected":false,"passed":true},{"actual":false,"check":"A retry ignores the server requested wait period","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 permanent rejection triggers another attempt\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"An exhausted attempt budget permits one more request\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"A retry cannot finish within its remaining request deadline\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"A non-idempotent write is retried without an identity key\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"A retry ignores the server requested wait period\", \"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"}