{"abstract":"Begin state violates retry transition semantics","category":"HTTP retries","checks":8,"contract":"begin(version,desired) creates a pending conditional write. sent records that it may have reached the server; lost means response absent. inspect(version,value) after loss reconciles: desired value at version+1 is committed, unchanged original version permits retry, any other state conflicts. retry only from retry state retains original precondition and desired body. ack(value) succeeds only for an active sent request. Return decisions and outgoing retry preconditions.","evaluation_group":"s3-http_retries-conditional-mutation","failed_approach":"The attempted repair changes the faulty site to desired=e[2]; state='idle' but still violates a regression oracle.","family":"s3-http_retries-conditional-mutation-begin-state","id":"FA-30236","implementations":{"attempt":{"sha256":"0a5b28b4499c68a3d7f71c5e01e5b01dcd4b9bc729b8a7b49cf4a27b802a22d8","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(events):\n    version=0; desired=None; state='idle'; out=[]\n    for e in events:\n        if e[0]=='begin':\n            version=e[1]; desired=e[2]; state='idle'\n        elif e[0]=='sent':\n            if state=='ready': state='sent'\n        elif e[0]=='lost':\n            if state=='sent': state='uncertain'\n        elif e[0]=='inspect':\n            if state!='uncertain': out.append('ignored'); continue\n            if e[1]==version+1 and e[2]==desired:\n                state='done'; out.append('committed')\n            elif e[1]==version:\n                state='retry'; out.append('retryable')\n            else: state='conflict'; out.append('conflict')\n        elif e[0]=='retry':\n            if state!='retry': out.append('denied'); continue\n            out.append(['send',version,desired]); state='ready'\n        elif e[0]=='ack':\n            if state=='sent': state='done'; out.append(['success',e[1]])\n            else: out.append('ignored')\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([('begin',N,N+9),('sent',),('lost',),('inspect',N,N+1),('retry',),('retry',),('sent',),('ack',N+9)]), ['retryable',['send',N,N+9],'denied',['success',N+9]])\ncheck('2', solve([('begin',N,N+9),('sent',),('lost',),('inspect',N+1,N+9),('retry',),('inspect',N,N)]), ['committed','denied','ignored'])\ncheck('3', solve([('begin',N,N+9),('sent',),('lost',),('inspect',N+1,N+8),('retry',),('inspect',N,N)]), ['conflict','denied','ignored'])\ncheck('4', solve([('begin',N,N+9),('sent',),('lost',),('inspect',N+2,N+9),('retry',)]), ['conflict','denied'])\ncheck('5', solve([('begin',N,N+9),('lost',),('inspect',N,N),('ack',N)]), ['ignored','ignored'])\ncheck('6', solve([('begin',N,N+9),('sent',),('lost',),('ack',N),('inspect',N-1,N),('retry',)]), ['ignored','conflict','denied'])\ncheck('7', solve([('begin',N,N+9),('sent',),('lost',),('inspect',N,N),('retry',),('ack',N)]), ['retryable',['send',N,N+9],'ignored'])\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":"2b7f03e728d4a3daa0607f06a44f0f2c7fe5d63cad218ccd81c45b33959660e2","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(events):\n    version=0; desired=None; state='idle'; out=[]\n    for e in events:\n        if e[0]=='begin':\n            version=e[1]; desired=e[2]; state='sent'\n        elif e[0]=='sent':\n            if state=='ready': state='sent'\n        elif e[0]=='lost':\n            if state=='sent': state='uncertain'\n        elif e[0]=='inspect':\n            if state!='uncertain': out.append('ignored'); continue\n            if e[1]==version+1 and e[2]==desired:\n                state='done'; out.append('committed')\n            elif e[1]==version:\n                state='retry'; out.append('retryable')\n            else: state='conflict'; out.append('conflict')\n        elif e[0]=='retry':\n            if state!='retry': out.append('denied'); continue\n            out.append(['send',version,desired]); state='ready'\n        elif e[0]=='ack':\n            if state=='sent': state='done'; out.append(['success',e[1]])\n            else: out.append('ignored')\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([('begin',N,N+9),('sent',),('lost',),('inspect',N,N+1),('retry',),('retry',),('sent',),('ack',N+9)]), ['retryable',['send',N,N+9],'denied',['success',N+9]])\ncheck('2', solve([('begin',N,N+9),('sent',),('lost',),('inspect',N+1,N+9),('retry',),('inspect',N,N)]), ['committed','denied','ignored'])\ncheck('3', solve([('begin',N,N+9),('sent',),('lost',),('inspect',N+1,N+8),('retry',),('inspect',N,N)]), ['conflict','denied','ignored'])\ncheck('4', solve([('begin',N,N+9),('sent',),('lost',),('inspect',N+2,N+9),('retry',)]), ['conflict','denied'])\ncheck('5', solve([('begin',N,N+9),('lost',),('inspect',N,N),('ack',N)]), ['ignored','ignored'])\ncheck('6', solve([('begin',N,N+9),('sent',),('lost',),('ack',N),('inspect',N-1,N),('retry',)]), ['ignored','conflict','denied'])\ncheck('7', solve([('begin',N,N+9),('sent',),('lost',),('inspect',N,N),('retry',),('ack',N)]), ['retryable',['send',N,N+9],'ignored'])\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":"e4da5bf408a2ab2e3676f3b11d7ca79438c4fd559672f4aad786e2abd9cefe00","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(events):\n    version=0; desired=None; state='idle'; out=[]\n    for e in events:\n        if e[0]=='begin':\n            version=e[1]; desired=e[2]; state='ready'\n        elif e[0]=='sent':\n            if state=='ready': state='sent'\n        elif e[0]=='lost':\n            if state=='sent': state='uncertain'\n        elif e[0]=='inspect':\n            if state!='uncertain': out.append('ignored'); continue\n            if e[1]==version+1 and e[2]==desired:\n                state='done'; out.append('committed')\n            elif e[1]==version:\n                state='retry'; out.append('retryable')\n            else: state='conflict'; out.append('conflict')\n        elif e[0]=='retry':\n            if state!='retry': out.append('denied'); continue\n            out.append(['send',version,desired]); state='ready'\n        elif e[0]=='ack':\n            if state=='sent': state='done'; out.append(['success',e[1]])\n            else: out.append('ignored')\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([('begin',N,N+9),('sent',),('lost',),('inspect',N,N+1),('retry',),('retry',),('sent',),('ack',N+9)]), ['retryable',['send',N,N+9],'denied',['success',N+9]])\ncheck('2', solve([('begin',N,N+9),('sent',),('lost',),('inspect',N+1,N+9),('retry',),('inspect',N,N)]), ['committed','denied','ignored'])\ncheck('3', solve([('begin',N,N+9),('sent',),('lost',),('inspect',N+1,N+8),('retry',),('inspect',N,N)]), ['conflict','denied','ignored'])\ncheck('4', solve([('begin',N,N+9),('sent',),('lost',),('inspect',N+2,N+9),('retry',)]), ['conflict','denied'])\ncheck('5', solve([('begin',N,N+9),('lost',),('inspect',N,N),('ack',N)]), ['ignored','ignored'])\ncheck('6', solve([('begin',N,N+9),('sent',),('lost',),('ack',N),('inspect',N-1,N),('retry',)]), ['ignored','conflict','denied'])\ncheck('7', solve([('begin',N,N+9),('sent',),('lost',),('inspect',N,N),('retry',),('ack',N)]), ['retryable',['send',N,N+9],'ignored'])\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-conditional-mutation-begin-state","generated_at":"2026-09-29T14:41:50.979190+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Offline deterministic model of HTTP request retries.","repair":"Restore the specified transition desired=e[2]; state='ready'.","root_cause":"Begin state violates retry transition semantics","sha256":"5ed4579a056b3e02a872067deb8353f60dcad1e47a56abd7cfb670db641f5be9","title":"Conditional mutation retry reconciliation: Begin state violates retry transition semantics · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":40.092,"exit_code":1,"observations":[{"actual":[],"check":"0","expected":[],"passed":true},{"actual":["ignored","denied","denied","ignored"],"check":"1","expected":["retryable",["send",1,10],"denied",["success",10]],"passed":false},{"actual":["ignored","denied","ignored"],"check":"2","expected":["committed","denied","ignored"],"passed":false},{"actual":["ignored","denied","ignored"],"check":"3","expected":["conflict","denied","ignored"],"passed":false},{"actual":["ignored","denied"],"check":"4","expected":["conflict","denied"],"passed":false},{"actual":["ignored","ignored"],"check":"5","expected":["ignored","ignored"],"passed":true},{"actual":["ignored","ignored","denied"],"check":"6","expected":["ignored","conflict","denied"],"passed":false},{"actual":["ignored","denied","ignored"],"check":"7","expected":["retryable",["send",1,10],"ignored"],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"0\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"1\", \"actual\": [\"ignored\", \"denied\", \"denied\", \"ignored\"], \"expected\": [\"retryable\", [\"send\", 1, 10], \"denied\", [\"success\", 10]], \"passed\": false}, {\"check\": \"2\", \"actual\": [\"ignored\", \"denied\", \"ignored\"], \"expected\": [\"committed\", \"denied\", \"ignored\"], \"passed\": false}, {\"check\": \"3\", \"actual\": [\"ignored\", \"denied\", \"ignored\"], \"expected\": [\"conflict\", \"denied\", \"ignored\"], \"passed\": false}, {\"check\": \"4\", \"actual\": [\"ignored\", \"denied\"], \"expected\": [\"conflict\", \"denied\"], \"passed\": false}, {\"check\": \"5\", \"actual\": [\"ignored\", \"ignored\"], \"expected\": [\"ignored\", \"ignored\"], \"passed\": true}, {\"check\": \"6\", \"actual\": [\"ignored\", \"ignored\", \"denied\"], \"expected\": [\"ignored\", \"conflict\", \"denied\"], \"passed\": false}, {\"check\": \"7\", \"actual\": [\"ignored\", \"denied\", \"ignored\"], \"expected\": [\"retryable\", [\"send\", 1, 10], \"ignored\"], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":43.568,"exit_code":1,"observations":[{"actual":[],"check":"0","expected":[],"passed":true},{"actual":["retryable",["send",1,10],"denied",["success",10]],"check":"1","expected":["retryable",["send",1,10],"denied",["success",10]],"passed":true},{"actual":["committed","denied","ignored"],"check":"2","expected":["committed","denied","ignored"],"passed":true},{"actual":["conflict","denied","ignored"],"check":"3","expected":["conflict","denied","ignored"],"passed":true},{"actual":["conflict","denied"],"check":"4","expected":["conflict","denied"],"passed":true},{"actual":["retryable","ignored"],"check":"5","expected":["ignored","ignored"],"passed":false},{"actual":["ignored","conflict","denied"],"check":"6","expected":["ignored","conflict","denied"],"passed":true},{"actual":["retryable",["send",1,10],"ignored"],"check":"7","expected":["retryable",["send",1,10],"ignored"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"0\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"1\", \"actual\": [\"retryable\", [\"send\", 1, 10], \"denied\", [\"success\", 10]], \"expected\": [\"retryable\", [\"send\", 1, 10], \"denied\", [\"success\", 10]], \"passed\": true}, {\"check\": \"2\", \"actual\": [\"committed\", \"denied\", \"ignored\"], \"expected\": [\"committed\", \"denied\", \"ignored\"], \"passed\": true}, {\"check\": \"3\", \"actual\": [\"conflict\", \"denied\", \"ignored\"], \"expected\": [\"conflict\", \"denied\", \"ignored\"], \"passed\": true}, {\"check\": \"4\", \"actual\": [\"conflict\", \"denied\"], \"expected\": [\"conflict\", \"denied\"], \"passed\": true}, {\"check\": \"5\", \"actual\": [\"retryable\", \"ignored\"], \"expected\": [\"ignored\", \"ignored\"], \"passed\": false}, {\"check\": \"6\", \"actual\": [\"ignored\", \"conflict\", \"denied\"], \"expected\": [\"ignored\", \"conflict\", \"denied\"], \"passed\": true}, {\"check\": \"7\", \"actual\": [\"retryable\", [\"send\", 1, 10], \"ignored\"], \"expected\": [\"retryable\", [\"send\", 1, 10], \"ignored\"], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":39.815,"exit_code":0,"observations":[{"actual":[],"check":"0","expected":[],"passed":true},{"actual":["retryable",["send",1,10],"denied",["success",10]],"check":"1","expected":["retryable",["send",1,10],"denied",["success",10]],"passed":true},{"actual":["committed","denied","ignored"],"check":"2","expected":["committed","denied","ignored"],"passed":true},{"actual":["conflict","denied","ignored"],"check":"3","expected":["conflict","denied","ignored"],"passed":true},{"actual":["conflict","denied"],"check":"4","expected":["conflict","denied"],"passed":true},{"actual":["ignored","ignored"],"check":"5","expected":["ignored","ignored"],"passed":true},{"actual":["ignored","conflict","denied"],"check":"6","expected":["ignored","conflict","denied"],"passed":true},{"actual":["retryable",["send",1,10],"ignored"],"check":"7","expected":["retryable",["send",1,10],"ignored"],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"0\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"1\", \"actual\": [\"retryable\", [\"send\", 1, 10], \"denied\", [\"success\", 10]], \"expected\": [\"retryable\", [\"send\", 1, 10], \"denied\", [\"success\", 10]], \"passed\": true}, {\"check\": \"2\", \"actual\": [\"committed\", \"denied\", \"ignored\"], \"expected\": [\"committed\", \"denied\", \"ignored\"], \"passed\": true}, {\"check\": \"3\", \"actual\": [\"conflict\", \"denied\", \"ignored\"], \"expected\": [\"conflict\", \"denied\", \"ignored\"], \"passed\": true}, {\"check\": \"4\", \"actual\": [\"conflict\", \"denied\"], \"expected\": [\"conflict\", \"denied\"], \"passed\": true}, {\"check\": \"5\", \"actual\": [\"ignored\", \"ignored\"], \"expected\": [\"ignored\", \"ignored\"], \"passed\": true}, {\"check\": \"6\", \"actual\": [\"ignored\", \"conflict\", \"denied\"], \"expected\": [\"ignored\", \"conflict\", \"denied\"], \"passed\": true}, {\"check\": \"7\", \"actual\": [\"retryable\", [\"send\", 1, 10], \"ignored\"], \"expected\": [\"retryable\", [\"send\", 1, 10], \"ignored\"], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}