{"abstract":"Success before observer violates retry transition semantics","category":"HTTP retries","checks":8,"contract":"begin(cap) starts pending request. fail(eligible,before-hook-ok) calls retry hook only for eligible failures with remaining cap; a failing hook terminally records hook-error without spending retry budget. Otherwise admit consumes one cap and enters waiting. wake starts it. success(observer-ok) stores success before observer invocation; observer failure is diagnostic only and never creates a retry. cancel is terminal. Return lifecycle decisions and remaining cap.","contract_signature":"events","evaluation_group":"s3-http_retries-retry-hook-failures","failed_approach":"The attempted repair changes the faulty site to state='failed'; out.append('success') but still violates a regression oracle.","family":"s3-http_retries-retry-hook-failures-success-before-observer","id":"FA-30821","implementations":{"attempt":{"sha256":"6d1924e41f88fbd378612807bec0eca5a04b60ceae5157e7ec90d454148eaa58","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(events):\n    cap=0; state='idle'; out=[]\n    for e in events:\n        if e[0]=='begin': cap=e[1]; state='running'\n        elif e[0]=='fail':\n            if state!='running': out.append('ignored'); continue\n            if not e[1]: state='failed'; out.append('fatal'); continue\n            if cap==0: state='failed'; out.append('exhausted'); continue\n            if not e[2]: state='failed'; out.append('hook-error'); continue\n            cap-=1; state='waiting'; out.append('scheduled')\n        elif e[0]=='wake':\n            if state=='waiting': state='running'; out.append('started')\n        elif e[0]=='success':\n            if state!='running': out.append('ignored'); continue\n            state='failed'; out.append('success')\n            if not e[1]: out.append('observer-error')\n        elif e[0]=='cancel': state='cancelled'\n    return [out,cap,state]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('0', solve([]), [[],0,'idle'])\ncheck('1', solve([('begin',2),('fail',True,True),('fail',True,True),('wake',),('success',False),('fail',True,True)]), [['scheduled','ignored','started','success','observer-error','ignored'],1,'done'])\ncheck('2', solve([('begin',N),('fail',True,False),('wake',)]), [['hook-error'],N,'failed'])\ncheck('3', solve([('begin',N),('fail',False,False)]), [['fatal'],N,'failed'])\ncheck('4', solve([('begin',0),('fail',True,False)]), [['exhausted'],0,'failed'])\ncheck('5', solve([('begin',N),('success',True),('success',False)]), [['success','ignored'],N,'done'])\ncheck('6', solve([('begin',N),('fail',True,True),('cancel',),('wake',),('success',False)]), [['scheduled','ignored'],N-1,'cancelled'])\ncheck('7', solve([('begin',N),('fail',False,True)]), [['fatal'],N,'failed'])\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":"c4e46f49cd56932e50b3c03a29ef20eb1a1d10f115b86f89c7d82ed2d588b90e","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(events):\n    cap=0; state='idle'; out=[]\n    for e in events:\n        if e[0]=='begin': cap=e[1]; state='running'\n        elif e[0]=='fail':\n            if state!='running': out.append('ignored'); continue\n            if not e[1]: state='failed'; out.append('fatal'); continue\n            if cap==0: state='failed'; out.append('exhausted'); continue\n            if not e[2]: state='failed'; out.append('hook-error'); continue\n            cap-=1; state='waiting'; out.append('scheduled')\n        elif e[0]=='wake':\n            if state=='waiting': state='running'; out.append('started')\n        elif e[0]=='success':\n            if state!='running': out.append('ignored'); continue\n            state='running'; out.append('success')\n            if not e[1]: out.append('observer-error')\n        elif e[0]=='cancel': state='cancelled'\n    return [out,cap,state]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('0', solve([]), [[],0,'idle'])\ncheck('1', solve([('begin',2),('fail',True,True),('fail',True,True),('wake',),('success',False),('fail',True,True)]), [['scheduled','ignored','started','success','observer-error','ignored'],1,'done'])\ncheck('2', solve([('begin',N),('fail',True,False),('wake',)]), [['hook-error'],N,'failed'])\ncheck('3', solve([('begin',N),('fail',False,False)]), [['fatal'],N,'failed'])\ncheck('4', solve([('begin',0),('fail',True,False)]), [['exhausted'],0,'failed'])\ncheck('5', solve([('begin',N),('success',True),('success',False)]), [['success','ignored'],N,'done'])\ncheck('6', solve([('begin',N),('fail',True,True),('cancel',),('wake',),('success',False)]), [['scheduled','ignored'],N-1,'cancelled'])\ncheck('7', solve([('begin',N),('fail',False,True)]), [['fatal'],N,'failed'])\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-retry-hook-failures-success-before-observer","generated_at":"2026-09-29T14:41:56.511971+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":"Success before observer violates retry transition semantics","sha256":"23757ce6d8b8365e9c77bdc20da6d6cd36be4422f3fa89069b81451134acfd3a","title":"Retry hook failure containment: Success before observer 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":39.654,"exit_code":1,"observations":[{"actual":[[],0,"idle"],"check":"0","expected":[[],0,"idle"],"passed":true},{"actual":[["scheduled","ignored","started","success","observer-error","ignored"],1,"failed"],"check":"1","expected":[["scheduled","ignored","started","success","observer-error","ignored"],1,"done"],"passed":false},{"actual":[["hook-error"],1,"failed"],"check":"2","expected":[["hook-error"],1,"failed"],"passed":true},{"actual":[["fatal"],1,"failed"],"check":"3","expected":[["fatal"],1,"failed"],"passed":true},{"actual":[["exhausted"],0,"failed"],"check":"4","expected":[["exhausted"],0,"failed"],"passed":true},{"actual":[["success","ignored"],1,"failed"],"check":"5","expected":[["success","ignored"],1,"done"],"passed":false},{"actual":[["scheduled","ignored"],0,"cancelled"],"check":"6","expected":[["scheduled","ignored"],0,"cancelled"],"passed":true},{"actual":[["fatal"],1,"failed"],"check":"7","expected":[["fatal"],1,"failed"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"0\", \"actual\": [[], 0, \"idle\"], \"expected\": [[], 0, \"idle\"], \"passed\": true}, {\"check\": \"1\", \"actual\": [[\"scheduled\", \"ignored\", \"started\", \"success\", \"observer-error\", \"ignored\"], 1, \"failed\"], \"expected\": [[\"scheduled\", \"ignored\", \"started\", \"success\", \"observer-error\", \"ignored\"], 1, \"done\"], \"passed\": false}, {\"check\": \"2\", \"actual\": [[\"hook-error\"], 1, \"failed\"], \"expected\": [[\"hook-error\"], 1, \"failed\"], \"passed\": true}, {\"check\": \"3\", \"actual\": [[\"fatal\"], 1, \"failed\"], \"expected\": [[\"fatal\"], 1, \"failed\"], \"passed\": true}, {\"check\": \"4\", \"actual\": [[\"exhausted\"], 0, \"failed\"], \"expected\": [[\"exhausted\"], 0, \"failed\"], \"passed\": true}, {\"check\": \"5\", \"actual\": [[\"success\", \"ignored\"], 1, \"failed\"], \"expected\": [[\"success\", \"ignored\"], 1, \"done\"], \"passed\": false}, {\"check\": \"6\", \"actual\": [[\"scheduled\", \"ignored\"], 0, \"cancelled\"], \"expected\": [[\"scheduled\", \"ignored\"], 0, \"cancelled\"], \"passed\": true}, {\"check\": \"7\", \"actual\": [[\"fatal\"], 1, \"failed\"], \"expected\": [[\"fatal\"], 1, \"failed\"], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.839,"exit_code":1,"observations":[{"actual":[[],0,"idle"],"check":"0","expected":[[],0,"idle"],"passed":true},{"actual":[["scheduled","ignored","started","success","observer-error","scheduled"],0,"waiting"],"check":"1","expected":[["scheduled","ignored","started","success","observer-error","ignored"],1,"done"],"passed":false},{"actual":[["hook-error"],1,"failed"],"check":"2","expected":[["hook-error"],1,"failed"],"passed":true},{"actual":[["fatal"],1,"failed"],"check":"3","expected":[["fatal"],1,"failed"],"passed":true},{"actual":[["exhausted"],0,"failed"],"check":"4","expected":[["exhausted"],0,"failed"],"passed":true},{"actual":[["success","success","observer-error"],1,"running"],"check":"5","expected":[["success","ignored"],1,"done"],"passed":false},{"actual":[["scheduled","ignored"],0,"cancelled"],"check":"6","expected":[["scheduled","ignored"],0,"cancelled"],"passed":true},{"actual":[["fatal"],1,"failed"],"check":"7","expected":[["fatal"],1,"failed"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"0\", \"actual\": [[], 0, \"idle\"], \"expected\": [[], 0, \"idle\"], \"passed\": true}, {\"check\": \"1\", \"actual\": [[\"scheduled\", \"ignored\", \"started\", \"success\", \"observer-error\", \"scheduled\"], 0, \"waiting\"], \"expected\": [[\"scheduled\", \"ignored\", \"started\", \"success\", \"observer-error\", \"ignored\"], 1, \"done\"], \"passed\": false}, {\"check\": \"2\", \"actual\": [[\"hook-error\"], 1, \"failed\"], \"expected\": [[\"hook-error\"], 1, \"failed\"], \"passed\": true}, {\"check\": \"3\", \"actual\": [[\"fatal\"], 1, \"failed\"], \"expected\": [[\"fatal\"], 1, \"failed\"], \"passed\": true}, {\"check\": \"4\", \"actual\": [[\"exhausted\"], 0, \"failed\"], \"expected\": [[\"exhausted\"], 0, \"failed\"], \"passed\": true}, {\"check\": \"5\", \"actual\": [[\"success\", \"success\", \"observer-error\"], 1, \"running\"], \"expected\": [[\"success\", \"ignored\"], 1, \"done\"], \"passed\": false}, {\"check\": \"6\", \"actual\": [[\"scheduled\", \"ignored\"], 0, \"cancelled\"], \"expected\": [[\"scheduled\", \"ignored\"], 0, \"cancelled\"], \"passed\": true}, {\"check\": \"7\", \"actual\": [[\"fatal\"], 1, \"failed\"], \"expected\": [[\"fatal\"], 1, \"failed\"], \"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."}}