{"abstract":"Failure tried violates retry transition semantics","category":"HTTP retries","checks":7,"contract":"pool(endpoint IDs) sets ordered available endpoints. begin(request,affinity bool) resets attempted endpoint set and pin. pick selects first healthy untried endpoint; an affinity request must reuse its first endpoint on subsequent retries while healthy. down/up alter health. fail marks current endpoint attempted and clears active route. success finalizes. No route changes are HTTP redirects. Return chosen endpoint or exhausted/terminal/active.","contract_signature":"events","evaluation_group":"s3-http_retries-endpoint-retry-routing","failed_approach":"The attempted repair changes the faulty site to if active is not None: tried.add(pool[-1]) but still violates a regression oracle.","family":"s3-http_retries-endpoint-retry-routing-failure-tried","id":"FA-30506","implementations":{"attempt":{"sha256":"308a85bdbee18446cf2e506a44ee3e04ad9243957a9a585e1d4d173abfbf5181","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(events):\n    pool=[]; down=set(); tried=set(); pin=None; active=None; affinity=False; terminal=True; out=[]\n    for e in events:\n        if e[0]=='pool': pool=list(e[1]); down=set()\n        elif e[0]=='begin': tried=set(); pin=None; active=None; affinity=e[2]; terminal=False\n        elif e[0]=='down': down.add(e[1])\n        elif e[0]=='up': down.discard(e[1])\n        elif e[0]=='pick':\n            if terminal: out.append('terminal'); continue\n            if active is not None: out.append('active'); continue\n            if affinity and pin is not None:\n                options=[pin] if pin not in down and pin in pool else []\n            else: options=[p for p in pool if p not in down and p not in tried]\n            if not options: out.append('exhausted'); continue\n            active=options[0]\n            if pin is None: pin=active\n            out.append(active)\n        elif e[0]=='fail':\n            if active is not None: tried.add(pool[-1])\n            active=None\n        elif e[0]=='success': terminal=True; active=None\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('0', solve([]), [])\ncheck('1', solve([('pool',['b','a','c']),('begin','r',False),('pick',),('pick',),('fail',),('pick',),('fail',),('pick',),('fail',),('pick',)]), ['b','active','a','c','exhausted'])\ncheck('2', solve([('pool',['a','b']),('begin','r',True),('pick',),('fail',),('pick',),('fail',),('down','a'),('pick',)]), ['a','a','exhausted'])\ncheck('3', solve([('pool',['a','b','c']),('down','a'),('down','b'),('up','a'),('begin','r',False),('pick',),('fail',),('pick',)]), ['a','c'])\ncheck('4', solve([('pool',['a','b']),('begin','r',True),('pick',),('fail',),('pool',['b']),('pick',),('begin','s',True),('pick',)]), ['a','exhausted','b'])\ncheck('5', solve([('pool',[N,N+1]),('begin','r',False),('pick',),('success',),('pick',),('begin','s',False),('pick',)]), [N,'terminal',N])\ncheck('6', solve([('pool',['a']),('down','a'),('pool',['a']),('begin','r',False),('pick',)]), ['a'])\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":"04605cef2613ea50ac066937eb45c6d8fdd4a3baa9b0fe83a88f9b915b739ce5","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(events):\n    pool=[]; down=set(); tried=set(); pin=None; active=None; affinity=False; terminal=True; out=[]\n    for e in events:\n        if e[0]=='pool': pool=list(e[1]); down=set()\n        elif e[0]=='begin': tried=set(); pin=None; active=None; affinity=e[2]; terminal=False\n        elif e[0]=='down': down.add(e[1])\n        elif e[0]=='up': down.discard(e[1])\n        elif e[0]=='pick':\n            if terminal: out.append('terminal'); continue\n            if active is not None: out.append('active'); continue\n            if affinity and pin is not None:\n                options=[pin] if pin not in down and pin in pool else []\n            else: options=[p for p in pool if p not in down and p not in tried]\n            if not options: out.append('exhausted'); continue\n            active=options[0]\n            if pin is None: pin=active\n            out.append(active)\n        elif e[0]=='fail':\n            if active is not None: tried.discard(active)\n            active=None\n        elif e[0]=='success': terminal=True; active=None\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('0', solve([]), [])\ncheck('1', solve([('pool',['b','a','c']),('begin','r',False),('pick',),('pick',),('fail',),('pick',),('fail',),('pick',),('fail',),('pick',)]), ['b','active','a','c','exhausted'])\ncheck('2', solve([('pool',['a','b']),('begin','r',True),('pick',),('fail',),('pick',),('fail',),('down','a'),('pick',)]), ['a','a','exhausted'])\ncheck('3', solve([('pool',['a','b','c']),('down','a'),('down','b'),('up','a'),('begin','r',False),('pick',),('fail',),('pick',)]), ['a','c'])\ncheck('4', solve([('pool',['a','b']),('begin','r',True),('pick',),('fail',),('pool',['b']),('pick',),('begin','s',True),('pick',)]), ['a','exhausted','b'])\ncheck('5', solve([('pool',[N,N+1]),('begin','r',False),('pick',),('success',),('pick',),('begin','s',False),('pick',)]), [N,'terminal',N])\ncheck('6', solve([('pool',['a']),('down','a'),('pool',['a']),('begin','r',False),('pick',)]), ['a'])\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":"Stipulated bounded simulator, not a complete HTTP implementation or a standards conformance claim. 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":"s3-http_retries-endpoint-retry-routing-failure-tried","generated_at":"2026-09-29T14:41:53.677299+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Offline deterministic model of HTTP request retries.","root_cause":"Failure tried violates retry transition semantics","sha256":"a0cee99232b761cc3224de39e2039ece479ff64fea3edc9adf5d10eb7e51c1b6","title":"Retry routing with origin affinity: Failure tried violates retry transition semantics · 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":40.177,"exit_code":1,"observations":[{"actual":[],"check":"0","expected":[],"passed":true},{"actual":["b","active","b","b","b"],"check":"1","expected":["b","active","a","c","exhausted"],"passed":false},{"actual":["a","a","exhausted"],"check":"2","expected":["a","a","exhausted"],"passed":true},{"actual":["a","a"],"check":"3","expected":["a","c"],"passed":false},{"actual":["a","exhausted","b"],"check":"4","expected":["a","exhausted","b"],"passed":true},{"actual":[1,"terminal",1],"check":"5","expected":[1,"terminal",1],"passed":true},{"actual":["a"],"check":"6","expected":["a"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"0\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"1\", \"actual\": [\"b\", \"active\", \"b\", \"b\", \"b\"], \"expected\": [\"b\", \"active\", \"a\", \"c\", \"exhausted\"], \"passed\": false}, {\"check\": \"2\", \"actual\": [\"a\", \"a\", \"exhausted\"], \"expected\": [\"a\", \"a\", \"exhausted\"], \"passed\": true}, {\"check\": \"3\", \"actual\": [\"a\", \"a\"], \"expected\": [\"a\", \"c\"], \"passed\": false}, {\"check\": \"4\", \"actual\": [\"a\", \"exhausted\", \"b\"], \"expected\": [\"a\", \"exhausted\", \"b\"], \"passed\": true}, {\"check\": \"5\", \"actual\": [1, \"terminal\", 1], \"expected\": [1, \"terminal\", 1], \"passed\": true}, {\"check\": \"6\", \"actual\": [\"a\"], \"expected\": [\"a\"], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":43.257,"exit_code":1,"observations":[{"actual":[],"check":"0","expected":[],"passed":true},{"actual":["b","active","b","b","b"],"check":"1","expected":["b","active","a","c","exhausted"],"passed":false},{"actual":["a","a","exhausted"],"check":"2","expected":["a","a","exhausted"],"passed":true},{"actual":["a","a"],"check":"3","expected":["a","c"],"passed":false},{"actual":["a","exhausted","b"],"check":"4","expected":["a","exhausted","b"],"passed":true},{"actual":[1,"terminal",1],"check":"5","expected":[1,"terminal",1],"passed":true},{"actual":["a"],"check":"6","expected":["a"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"0\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"1\", \"actual\": [\"b\", \"active\", \"b\", \"b\", \"b\"], \"expected\": [\"b\", \"active\", \"a\", \"c\", \"exhausted\"], \"passed\": false}, {\"check\": \"2\", \"actual\": [\"a\", \"a\", \"exhausted\"], \"expected\": [\"a\", \"a\", \"exhausted\"], \"passed\": true}, {\"check\": \"3\", \"actual\": [\"a\", \"a\"], \"expected\": [\"a\", \"c\"], \"passed\": false}, {\"check\": \"4\", \"actual\": [\"a\", \"exhausted\", \"b\"], \"expected\": [\"a\", \"exhausted\", \"b\"], \"passed\": true}, {\"check\": \"5\", \"actual\": [1, \"terminal\", 1], \"expected\": [1, \"terminal\", 1], \"passed\": true}, {\"check\": \"6\", \"actual\": [\"a\"], \"expected\": [\"a\"], \"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."}}