{"abstract":"Late duplicate commits overwrite the first durable result","category":"HTTP retries","checks":6,"contract":"submit(key,body) returns new for absent key, pending for matching in-flight key, conflict for a changed body, and cached(value) for a completed matching key. commit(key,value) commits only existing pending entries. forget removes a receipt. Return decisions and receipt table.","evaluation_group":"s3-http_retries-receipt-reconciliation","failed_approach":"The attempted repair changes the faulty site to receipts[e[1]][1]!='missing' but still violates a regression oracle.","family":"s3-http_retries-receipt-reconciliation-commit-only-pending","id":"FA-29611","implementations":{"attempt":{"sha256":"7f74da96cb6e88de928705edb265d3d52f392f73d854e8274840a817eaaf7ec0","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(events):\n    receipts={}; out=[]\n    for e in events:\n        if e[0]=='submit':\n            key,body=e[1],e[2]\n            if key not in receipts:\n                receipts[key]=[body,'pending',None]\n                out.append('new')\n            elif receipts[key][0]!=body:\n                out.append('conflict')\n            elif receipts[key][1]=='pending':\n                out.append('pending')\n            else:\n                out.append(['cached',receipts[key][2]])\n        elif e[0]=='commit':\n            if e[1] in receipts and receipts[e[1]][1]!='missing':\n                receipts[e[1]][1]='done'\n                receipts[e[1]][2]=e[2]\n        elif e[0]=='forget':\n            receipts.pop(e[1],None)\n    return [out,receipts]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('0', solve([]), [[],{}])\ncheck('1', solve([('submit','a',N),('submit','a',N)]), [['new','pending'],{'a':[N,'pending',None]}])\ncheck('2', solve([('submit','a',N),('submit','b',N),('submit','a',N+1)]), [['new','new','conflict'],{'a':[N,'pending',None],'b':[N,'pending',None]}])\ncheck('3', solve([('submit','a',N),('commit','a',N+5),('commit','a',99),('submit','a',N),('submit','a',N+1)]), [['new',['cached',N+5],'conflict'],{'a':[N,'done',N+5]}])\ncheck('4', solve([('commit','absent',N),('forget','absent')]), [[],{}])\ncheck('5', solve([('submit','a',N),('submit','b',N+1),('forget','a'),('submit','a',N+2)]), [['new','new','new'],{'b':[N+1,'pending',None],'a':[N+2,'pending',None]}])\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":"79adeb692351a514392b0bc0a7bb45152e30fd5b8ead1617d26fa7f118d7de24","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(events):\n    receipts={}; out=[]\n    for e in events:\n        if e[0]=='submit':\n            key,body=e[1],e[2]\n            if key not in receipts:\n                receipts[key]=[body,'pending',None]\n                out.append('new')\n            elif receipts[key][0]!=body:\n                out.append('conflict')\n            elif receipts[key][1]=='pending':\n                out.append('pending')\n            else:\n                out.append(['cached',receipts[key][2]])\n        elif e[0]=='commit':\n            if e[1] in receipts and True:\n                receipts[e[1]][1]='done'\n                receipts[e[1]][2]=e[2]\n        elif e[0]=='forget':\n            receipts.pop(e[1],None)\n    return [out,receipts]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('0', solve([]), [[],{}])\ncheck('1', solve([('submit','a',N),('submit','a',N)]), [['new','pending'],{'a':[N,'pending',None]}])\ncheck('2', solve([('submit','a',N),('submit','b',N),('submit','a',N+1)]), [['new','new','conflict'],{'a':[N,'pending',None],'b':[N,'pending',None]}])\ncheck('3', solve([('submit','a',N),('commit','a',N+5),('commit','a',99),('submit','a',N),('submit','a',N+1)]), [['new',['cached',N+5],'conflict'],{'a':[N,'done',N+5]}])\ncheck('4', solve([('commit','absent',N),('forget','absent')]), [[],{}])\ncheck('5', solve([('submit','a',N),('submit','b',N+1),('forget','a'),('submit','a',N+2)]), [['new','new','new'],{'b':[N+1,'pending',None],'a':[N+2,'pending',None]}])\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":"d954eef688bc7ddbed441b3968ffe7e8f2aca46edfd6335bbe8676104a62e2cb","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(events):\n    receipts={}; out=[]\n    for e in events:\n        if e[0]=='submit':\n            key,body=e[1],e[2]\n            if key not in receipts:\n                receipts[key]=[body,'pending',None]\n                out.append('new')\n            elif receipts[key][0]!=body:\n                out.append('conflict')\n            elif receipts[key][1]=='pending':\n                out.append('pending')\n            else:\n                out.append(['cached',receipts[key][2]])\n        elif e[0]=='commit':\n            if e[1] in receipts and receipts[e[1]][1]=='pending':\n                receipts[e[1]][1]='done'\n                receipts[e[1]][2]=e[2]\n        elif e[0]=='forget':\n            receipts.pop(e[1],None)\n    return [out,receipts]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('0', solve([]), [[],{}])\ncheck('1', solve([('submit','a',N),('submit','a',N)]), [['new','pending'],{'a':[N,'pending',None]}])\ncheck('2', solve([('submit','a',N),('submit','b',N),('submit','a',N+1)]), [['new','new','conflict'],{'a':[N,'pending',None],'b':[N,'pending',None]}])\ncheck('3', solve([('submit','a',N),('commit','a',N+5),('commit','a',99),('submit','a',N),('submit','a',N+1)]), [['new',['cached',N+5],'conflict'],{'a':[N,'done',N+5]}])\ncheck('4', solve([('commit','absent',N),('forget','absent')]), [[],{}])\ncheck('5', solve([('submit','a',N),('submit','b',N+1),('forget','a'),('submit','a',N+2)]), [['new','new','new'],{'b':[N+1,'pending',None],'a':[N+2,'pending',None]}])\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-receipt-reconciliation-commit-only-pending","generated_at":"2026-09-29T14:41:44.874763+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 receipts[e[1]][1]=='pending'.","root_cause":"Late duplicate commits overwrite the first durable result","sha256":"810a8b7708bd2c713c3932d9aa9aca05f0a2db4bf538f5dcaa89ef8de297b28c","title":"Retry reconciliation with a server receipt: Late duplicate commits overwrite the first durable result · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":44.686,"exit_code":1,"observations":[{"actual":[[],{}],"check":"0","expected":[[],{}],"passed":true},{"actual":[["new","pending"],{"a":[1,"pending",null]}],"check":"1","expected":[["new","pending"],{"a":[1,"pending",null]}],"passed":true},{"actual":[["new","new","conflict"],{"a":[1,"pending",null],"b":[1,"pending",null]}],"check":"2","expected":[["new","new","conflict"],{"a":[1,"pending",null],"b":[1,"pending",null]}],"passed":true},{"actual":[["new",["cached",99],"conflict"],{"a":[1,"done",99]}],"check":"3","expected":[["new",["cached",6],"conflict"],{"a":[1,"done",6]}],"passed":false},{"actual":[[],{}],"check":"4","expected":[[],{}],"passed":true},{"actual":[["new","new","new"],{"a":[3,"pending",null],"b":[2,"pending",null]}],"check":"5","expected":[["new","new","new"],{"a":[3,"pending",null],"b":[2,"pending",null]}],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"0\", \"actual\": [[], {}], \"expected\": [[], {}], \"passed\": true}, {\"check\": \"1\", \"actual\": [[\"new\", \"pending\"], {\"a\": [1, \"pending\", null]}], \"expected\": [[\"new\", \"pending\"], {\"a\": [1, \"pending\", null]}], \"passed\": true}, {\"check\": \"2\", \"actual\": [[\"new\", \"new\", \"conflict\"], {\"a\": [1, \"pending\", null], \"b\": [1, \"pending\", null]}], \"expected\": [[\"new\", \"new\", \"conflict\"], {\"a\": [1, \"pending\", null], \"b\": [1, \"pending\", null]}], \"passed\": true}, {\"check\": \"3\", \"actual\": [[\"new\", [\"cached\", 99], \"conflict\"], {\"a\": [1, \"done\", 99]}], \"expected\": [[\"new\", [\"cached\", 6], \"conflict\"], {\"a\": [1, \"done\", 6]}], \"passed\": false}, {\"check\": \"4\", \"actual\": [[], {}], \"expected\": [[], {}], \"passed\": true}, {\"check\": \"5\", \"actual\": [[\"new\", \"new\", \"new\"], {\"b\": [2, \"pending\", null], \"a\": [3, \"pending\", null]}], \"expected\": [[\"new\", \"new\", \"new\"], {\"b\": [2, \"pending\", null], \"a\": [3, \"pending\", null]}], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":43.497,"exit_code":1,"observations":[{"actual":[[],{}],"check":"0","expected":[[],{}],"passed":true},{"actual":[["new","pending"],{"a":[1,"pending",null]}],"check":"1","expected":[["new","pending"],{"a":[1,"pending",null]}],"passed":true},{"actual":[["new","new","conflict"],{"a":[1,"pending",null],"b":[1,"pending",null]}],"check":"2","expected":[["new","new","conflict"],{"a":[1,"pending",null],"b":[1,"pending",null]}],"passed":true},{"actual":[["new",["cached",99],"conflict"],{"a":[1,"done",99]}],"check":"3","expected":[["new",["cached",6],"conflict"],{"a":[1,"done",6]}],"passed":false},{"actual":[[],{}],"check":"4","expected":[[],{}],"passed":true},{"actual":[["new","new","new"],{"a":[3,"pending",null],"b":[2,"pending",null]}],"check":"5","expected":[["new","new","new"],{"a":[3,"pending",null],"b":[2,"pending",null]}],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"0\", \"actual\": [[], {}], \"expected\": [[], {}], \"passed\": true}, {\"check\": \"1\", \"actual\": [[\"new\", \"pending\"], {\"a\": [1, \"pending\", null]}], \"expected\": [[\"new\", \"pending\"], {\"a\": [1, \"pending\", null]}], \"passed\": true}, {\"check\": \"2\", \"actual\": [[\"new\", \"new\", \"conflict\"], {\"a\": [1, \"pending\", null], \"b\": [1, \"pending\", null]}], \"expected\": [[\"new\", \"new\", \"conflict\"], {\"a\": [1, \"pending\", null], \"b\": [1, \"pending\", null]}], \"passed\": true}, {\"check\": \"3\", \"actual\": [[\"new\", [\"cached\", 99], \"conflict\"], {\"a\": [1, \"done\", 99]}], \"expected\": [[\"new\", [\"cached\", 6], \"conflict\"], {\"a\": [1, \"done\", 6]}], \"passed\": false}, {\"check\": \"4\", \"actual\": [[], {}], \"expected\": [[], {}], \"passed\": true}, {\"check\": \"5\", \"actual\": [[\"new\", \"new\", \"new\"], {\"b\": [2, \"pending\", null], \"a\": [3, \"pending\", null]}], \"expected\": [[\"new\", \"new\", \"new\"], {\"b\": [2, \"pending\", null], \"a\": [3, \"pending\", null]}], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":42.65,"exit_code":0,"observations":[{"actual":[[],{}],"check":"0","expected":[[],{}],"passed":true},{"actual":[["new","pending"],{"a":[1,"pending",null]}],"check":"1","expected":[["new","pending"],{"a":[1,"pending",null]}],"passed":true},{"actual":[["new","new","conflict"],{"a":[1,"pending",null],"b":[1,"pending",null]}],"check":"2","expected":[["new","new","conflict"],{"a":[1,"pending",null],"b":[1,"pending",null]}],"passed":true},{"actual":[["new",["cached",6],"conflict"],{"a":[1,"done",6]}],"check":"3","expected":[["new",["cached",6],"conflict"],{"a":[1,"done",6]}],"passed":true},{"actual":[[],{}],"check":"4","expected":[[],{}],"passed":true},{"actual":[["new","new","new"],{"a":[3,"pending",null],"b":[2,"pending",null]}],"check":"5","expected":[["new","new","new"],{"a":[3,"pending",null],"b":[2,"pending",null]}],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"0\", \"actual\": [[], {}], \"expected\": [[], {}], \"passed\": true}, {\"check\": \"1\", \"actual\": [[\"new\", \"pending\"], {\"a\": [1, \"pending\", null]}], \"expected\": [[\"new\", \"pending\"], {\"a\": [1, \"pending\", null]}], \"passed\": true}, {\"check\": \"2\", \"actual\": [[\"new\", \"new\", \"conflict\"], {\"a\": [1, \"pending\", null], \"b\": [1, \"pending\", null]}], \"expected\": [[\"new\", \"new\", \"conflict\"], {\"a\": [1, \"pending\", null], \"b\": [1, \"pending\", null]}], \"passed\": true}, {\"check\": \"3\", \"actual\": [[\"new\", [\"cached\", 6], \"conflict\"], {\"a\": [1, \"done\", 6]}], \"expected\": [[\"new\", [\"cached\", 6], \"conflict\"], {\"a\": [1, \"done\", 6]}], \"passed\": true}, {\"check\": \"4\", \"actual\": [[], {}], \"expected\": [[], {}], \"passed\": true}, {\"check\": \"5\", \"actual\": [[\"new\", \"new\", \"new\"], {\"b\": [2, \"pending\", null], \"a\": [3, \"pending\", null]}], \"expected\": [[\"new\", \"new\", \"new\"], {\"b\": [2, \"pending\", null], \"a\": [3, \"pending\", null]}], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}