{"abstract":"An upload status endpoint reports committed byte coverage: arrival order cannot split or reverse acknowledged byte runs.","category":"HTTP ranges","checks":9,"contract":"x has a nonnegative complete length and committed byte offsets, which may repeat or arrive unordered. Reject offsets outside the representation. Return [complete|partial,acknowledged-range-field-or-null,next-missing-prefix-offset]. The local acknowledged field uses bytes= followed by comma-separated inclusive runs. Empty coverage has null header; an empty representation is complete. next-missing is the end of the committed contiguous prefix, not the highest written offset.","evaluation_group":"s3-http_ranges-upload-coverage-probe","failed_approach":"The partial repair uses positions=sorted(set(x['committed']),reverse=True)\nif any(p<0 or p>=x['total'] for p in positions): return None\nruns=[]\nfor p in positions:\n    if runs and p==runs[-1][1]+1:\n        runs[-1][1]=p\n    else:\n        runs.append([p,p])\nfield='bytes='+','.join(str(a)+'-'+str(b) for a,b in runs) if runs else None\nprefix=0\nfor p in positions:\n    if p!=prefix: break\n    prefix+=1\nstate='complete' if len(positions)==x['total'] else 'partial'\nreturn [state,field,prefix], which still violates the stated contract.","family":"s3-http_ranges-upload-coverage-probe-coverage-sort","id":"FA-27391","implementations":{"attempt":{"sha256":"0120c3b6f83973cd3546b811cca4f32d5d5173f67f11432af4b264f2bee45ffa","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    positions=sorted(set(x['committed']),reverse=True)\n    if any(p<0 or p>=x['total'] for p in positions): return None\n    runs=[]\n    for p in positions:\n        if runs and p==runs[-1][1]+1:\n            runs[-1][1]=p\n        else:\n            runs.append([p,p])\n    field='bytes='+','.join(str(a)+'-'+str(b) for a,b in runs) if runs else None\n    prefix=0\n    for p in positions:\n        if p!=prefix: break\n        prefix+=1\n    state='complete' if len(positions)==x['total'] else 'partial'\n    return [state,field,prefix]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('coverage-sort fixture 0', json.loads(json.dumps(solve({'total':7,'committed':[4,0,1,5,1]}))), json.loads(json.dumps(['partial','bytes=0-1,4-5',2])))\ncheck('coverage-sort fixture 1', json.loads(json.dumps(solve({'total':3,'committed':[2,0,1]}))), json.loads(json.dumps(['complete','bytes=0-2',3])))\ncheck('coverage-sort fixture 2', json.loads(json.dumps(solve({'total':0,'committed':[]}))), json.loads(json.dumps(['complete',None,0])))\ncheck('coverage-sort fixture 3', json.loads(json.dumps(solve({'total':4,'committed':[2,3]}))), json.loads(json.dumps(['partial','bytes=2-3',0])))\ncheck('coverage-sort fixture 4', json.loads(json.dumps(solve({'total':4,'committed':[0,2]}))), json.loads(json.dumps(['partial','bytes=0-0,2-2',1])))\ncheck('coverage-sort fixture 5', json.loads(json.dumps(solve({'total':N+1,'committed':list(range(N))}))), json.loads(json.dumps(['partial',\"bytes=0-\"+str(N-1),N])))\ncheck('coverage-sort fixture 6', json.loads(json.dumps(solve({'total':3,'committed':[3]}))), json.loads(json.dumps(None)))\ncheck('coverage-sort fixture 7', json.loads(json.dumps(solve({'total':3,'committed':[-1]}))), json.loads(json.dumps(None)))\ncheck('coverage-sort fixture 8', json.loads(json.dumps(solve({'total':3,'committed':[]}))), json.loads(json.dumps(['partial',None,0])))\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":"017a078b2b2a5da12858288748e72574b23d6c1be134b5ee317d8bb771808209","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    positions=list(dict.fromkeys(x['committed']))\n    if any(p<0 or p>=x['total'] for p in positions): return None\n    runs=[]\n    for p in positions:\n        if runs and p==runs[-1][1]+1:\n            runs[-1][1]=p\n        else:\n            runs.append([p,p])\n    field='bytes='+','.join(str(a)+'-'+str(b) for a,b in runs) if runs else None\n    prefix=0\n    for p in positions:\n        if p!=prefix: break\n        prefix+=1\n    state='complete' if len(positions)==x['total'] else 'partial'\n    return [state,field,prefix]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('coverage-sort fixture 0', json.loads(json.dumps(solve({'total':7,'committed':[4,0,1,5,1]}))), json.loads(json.dumps(['partial','bytes=0-1,4-5',2])))\ncheck('coverage-sort fixture 1', json.loads(json.dumps(solve({'total':3,'committed':[2,0,1]}))), json.loads(json.dumps(['complete','bytes=0-2',3])))\ncheck('coverage-sort fixture 2', json.loads(json.dumps(solve({'total':0,'committed':[]}))), json.loads(json.dumps(['complete',None,0])))\ncheck('coverage-sort fixture 3', json.loads(json.dumps(solve({'total':4,'committed':[2,3]}))), json.loads(json.dumps(['partial','bytes=2-3',0])))\ncheck('coverage-sort fixture 4', json.loads(json.dumps(solve({'total':4,'committed':[0,2]}))), json.loads(json.dumps(['partial','bytes=0-0,2-2',1])))\ncheck('coverage-sort fixture 5', json.loads(json.dumps(solve({'total':N+1,'committed':list(range(N))}))), json.loads(json.dumps(['partial',\"bytes=0-\"+str(N-1),N])))\ncheck('coverage-sort fixture 6', json.loads(json.dumps(solve({'total':3,'committed':[3]}))), json.loads(json.dumps(None)))\ncheck('coverage-sort fixture 7', json.loads(json.dumps(solve({'total':3,'committed':[-1]}))), json.loads(json.dumps(None)))\ncheck('coverage-sort fixture 8', json.loads(json.dumps(solve({'total':3,'committed':[]}))), json.loads(json.dumps(['partial',None,0])))\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":"3cfff964b22e89105269d171493c7b4993f200fa7bd792e758953ae39a12fd43","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    positions=sorted(set(x['committed']))\n    if any(p<0 or p>=x['total'] for p in positions): return None\n    runs=[]\n    for p in positions:\n        if runs and p==runs[-1][1]+1:\n            runs[-1][1]=p\n        else:\n            runs.append([p,p])\n    field='bytes='+','.join(str(a)+'-'+str(b) for a,b in runs) if runs else None\n    prefix=0\n    for p in positions:\n        if p!=prefix: break\n        prefix+=1\n    state='complete' if len(positions)==x['total'] else 'partial'\n    return [state,field,prefix]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('coverage-sort fixture 0', json.loads(json.dumps(solve({'total':7,'committed':[4,0,1,5,1]}))), json.loads(json.dumps(['partial','bytes=0-1,4-5',2])))\ncheck('coverage-sort fixture 1', json.loads(json.dumps(solve({'total':3,'committed':[2,0,1]}))), json.loads(json.dumps(['complete','bytes=0-2',3])))\ncheck('coverage-sort fixture 2', json.loads(json.dumps(solve({'total':0,'committed':[]}))), json.loads(json.dumps(['complete',None,0])))\ncheck('coverage-sort fixture 3', json.loads(json.dumps(solve({'total':4,'committed':[2,3]}))), json.loads(json.dumps(['partial','bytes=2-3',0])))\ncheck('coverage-sort fixture 4', json.loads(json.dumps(solve({'total':4,'committed':[0,2]}))), json.loads(json.dumps(['partial','bytes=0-0,2-2',1])))\ncheck('coverage-sort fixture 5', json.loads(json.dumps(solve({'total':N+1,'committed':list(range(N))}))), json.loads(json.dumps(['partial',\"bytes=0-\"+str(N-1),N])))\ncheck('coverage-sort fixture 6', json.loads(json.dumps(solve({'total':3,'committed':[3]}))), json.loads(json.dumps(None)))\ncheck('coverage-sort fixture 7', json.loads(json.dumps(solve({'total':3,'committed':[-1]}))), json.loads(json.dumps(None)))\ncheck('coverage-sort fixture 8', json.loads(json.dumps(solve({'total':3,'committed':[]}))), json.loads(json.dumps(['partial',None,0])))\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":"Deterministic simplified range service, with stipulated local policies and already parsed trusted inputs; not a complete HTTP implementation. 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_ranges-upload-coverage-probe-coverage-sort","generated_at":"2026-09-29T14:41:24.645164+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Range responses combine representation identity, conditional requests, framing, and partial-object state.","repair":"Apply the bounded decision exactly: positions=sorted(set(x['committed']))\nif any(p<0 or p>=x['total'] for p in positions): return None\nruns=[]\nfor p in positions:\n    if runs and p==runs[-1][1]+1:\n        runs[-1][1]=p\n    else:\n        runs.append([p,p])\nfield='bytes='+','.join(str(a)+'-'+str(b) for a,b in runs) if runs else None\nprefix=0\nfor p in positions:\n    if p!=prefix: break\n    prefix+=1\nstate='complete' if len(positions)==x['total'] else 'partial'\nreturn [state,field,prefix]","root_cause":"The upload-coverage-probe-coverage-sort decision uses positions=list(dict.fromkeys(x['committed']))\nif any(p<0 or p>=x['total'] for p in positions): return None\nruns=[]\nfor p in positions:\n    if runs and p==runs[-1][1]+1:\n        runs[-1][1]=p\n    else:\n        runs.append([p,p])\nfield='bytes='+','.join(str(a)+'-'+str(b) for a,b in runs) if runs else None\nprefix=0\nfor p in positions:\n    if p!=prefix: break\n    prefix+=1\nstate='complete' if len(positions)==x['total'] else 'partial'\nreturn [state,field,prefix].","sha256":"0f01331dc4e916dbe310ffd4380326800f612aba7c02e96a0426fc76ce4a11ff","title":"An upload status endpoint reports committed byte coverage: arrival order cannot split or reverse acknowledged byte runs · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":37.274,"exit_code":1,"observations":[{"actual":["partial","bytes=5-5,4-4,1-1,0-0",0],"check":"coverage-sort fixture 0","expected":["partial","bytes=0-1,4-5",2],"passed":false},{"actual":["complete","bytes=2-2,1-1,0-0",0],"check":"coverage-sort fixture 1","expected":["complete","bytes=0-2",3],"passed":false},{"actual":["complete",null,0],"check":"coverage-sort fixture 2","expected":["complete",null,0],"passed":true},{"actual":["partial","bytes=3-3,2-2",0],"check":"coverage-sort fixture 3","expected":["partial","bytes=2-3",0],"passed":false},{"actual":["partial","bytes=2-2,0-0",0],"check":"coverage-sort fixture 4","expected":["partial","bytes=0-0,2-2",1],"passed":false},{"actual":["partial","bytes=0-0",1],"check":"coverage-sort fixture 5","expected":["partial","bytes=0-0",1],"passed":true},{"actual":null,"check":"coverage-sort fixture 6","expected":null,"passed":true},{"actual":null,"check":"coverage-sort fixture 7","expected":null,"passed":true},{"actual":["partial",null,0],"check":"coverage-sort fixture 8","expected":["partial",null,0],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"coverage-sort fixture 0\", \"actual\": [\"partial\", \"bytes=5-5,4-4,1-1,0-0\", 0], \"expected\": [\"partial\", \"bytes=0-1,4-5\", 2], \"passed\": false}, {\"check\": \"coverage-sort fixture 1\", \"actual\": [\"complete\", \"bytes=2-2,1-1,0-0\", 0], \"expected\": [\"complete\", \"bytes=0-2\", 3], \"passed\": false}, {\"check\": \"coverage-sort fixture 2\", \"actual\": [\"complete\", null, 0], \"expected\": [\"complete\", null, 0], \"passed\": true}, {\"check\": \"coverage-sort fixture 3\", \"actual\": [\"partial\", \"bytes=3-3,2-2\", 0], \"expected\": [\"partial\", \"bytes=2-3\", 0], \"passed\": false}, {\"check\": \"coverage-sort fixture 4\", \"actual\": [\"partial\", \"bytes=2-2,0-0\", 0], \"expected\": [\"partial\", \"bytes=0-0,2-2\", 1], \"passed\": false}, {\"check\": \"coverage-sort fixture 5\", \"actual\": [\"partial\", \"bytes=0-0\", 1], \"expected\": [\"partial\", \"bytes=0-0\", 1], \"passed\": true}, {\"check\": \"coverage-sort fixture 6\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"coverage-sort fixture 7\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"coverage-sort fixture 8\", \"actual\": [\"partial\", null, 0], \"expected\": [\"partial\", null, 0], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":35.577,"exit_code":1,"observations":[{"actual":["partial","bytes=4-4,0-1,5-5",0],"check":"coverage-sort fixture 0","expected":["partial","bytes=0-1,4-5",2],"passed":false},{"actual":["complete","bytes=2-2,0-1",0],"check":"coverage-sort fixture 1","expected":["complete","bytes=0-2",3],"passed":false},{"actual":["complete",null,0],"check":"coverage-sort fixture 2","expected":["complete",null,0],"passed":true},{"actual":["partial","bytes=2-3",0],"check":"coverage-sort fixture 3","expected":["partial","bytes=2-3",0],"passed":true},{"actual":["partial","bytes=0-0,2-2",1],"check":"coverage-sort fixture 4","expected":["partial","bytes=0-0,2-2",1],"passed":true},{"actual":["partial","bytes=0-0",1],"check":"coverage-sort fixture 5","expected":["partial","bytes=0-0",1],"passed":true},{"actual":null,"check":"coverage-sort fixture 6","expected":null,"passed":true},{"actual":null,"check":"coverage-sort fixture 7","expected":null,"passed":true},{"actual":["partial",null,0],"check":"coverage-sort fixture 8","expected":["partial",null,0],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"coverage-sort fixture 0\", \"actual\": [\"partial\", \"bytes=4-4,0-1,5-5\", 0], \"expected\": [\"partial\", \"bytes=0-1,4-5\", 2], \"passed\": false}, {\"check\": \"coverage-sort fixture 1\", \"actual\": [\"complete\", \"bytes=2-2,0-1\", 0], \"expected\": [\"complete\", \"bytes=0-2\", 3], \"passed\": false}, {\"check\": \"coverage-sort fixture 2\", \"actual\": [\"complete\", null, 0], \"expected\": [\"complete\", null, 0], \"passed\": true}, {\"check\": \"coverage-sort fixture 3\", \"actual\": [\"partial\", \"bytes=2-3\", 0], \"expected\": [\"partial\", \"bytes=2-3\", 0], \"passed\": true}, {\"check\": \"coverage-sort fixture 4\", \"actual\": [\"partial\", \"bytes=0-0,2-2\", 1], \"expected\": [\"partial\", \"bytes=0-0,2-2\", 1], \"passed\": true}, {\"check\": \"coverage-sort fixture 5\", \"actual\": [\"partial\", \"bytes=0-0\", 1], \"expected\": [\"partial\", \"bytes=0-0\", 1], \"passed\": true}, {\"check\": \"coverage-sort fixture 6\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"coverage-sort fixture 7\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"coverage-sort fixture 8\", \"actual\": [\"partial\", null, 0], \"expected\": [\"partial\", null, 0], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":38.14,"exit_code":0,"observations":[{"actual":["partial","bytes=0-1,4-5",2],"check":"coverage-sort fixture 0","expected":["partial","bytes=0-1,4-5",2],"passed":true},{"actual":["complete","bytes=0-2",3],"check":"coverage-sort fixture 1","expected":["complete","bytes=0-2",3],"passed":true},{"actual":["complete",null,0],"check":"coverage-sort fixture 2","expected":["complete",null,0],"passed":true},{"actual":["partial","bytes=2-3",0],"check":"coverage-sort fixture 3","expected":["partial","bytes=2-3",0],"passed":true},{"actual":["partial","bytes=0-0,2-2",1],"check":"coverage-sort fixture 4","expected":["partial","bytes=0-0,2-2",1],"passed":true},{"actual":["partial","bytes=0-0",1],"check":"coverage-sort fixture 5","expected":["partial","bytes=0-0",1],"passed":true},{"actual":null,"check":"coverage-sort fixture 6","expected":null,"passed":true},{"actual":null,"check":"coverage-sort fixture 7","expected":null,"passed":true},{"actual":["partial",null,0],"check":"coverage-sort fixture 8","expected":["partial",null,0],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"coverage-sort fixture 0\", \"actual\": [\"partial\", \"bytes=0-1,4-5\", 2], \"expected\": [\"partial\", \"bytes=0-1,4-5\", 2], \"passed\": true}, {\"check\": \"coverage-sort fixture 1\", \"actual\": [\"complete\", \"bytes=0-2\", 3], \"expected\": [\"complete\", \"bytes=0-2\", 3], \"passed\": true}, {\"check\": \"coverage-sort fixture 2\", \"actual\": [\"complete\", null, 0], \"expected\": [\"complete\", null, 0], \"passed\": true}, {\"check\": \"coverage-sort fixture 3\", \"actual\": [\"partial\", \"bytes=2-3\", 0], \"expected\": [\"partial\", \"bytes=2-3\", 0], \"passed\": true}, {\"check\": \"coverage-sort fixture 4\", \"actual\": [\"partial\", \"bytes=0-0,2-2\", 1], \"expected\": [\"partial\", \"bytes=0-0,2-2\", 1], \"passed\": true}, {\"check\": \"coverage-sort fixture 5\", \"actual\": [\"partial\", \"bytes=0-0\", 1], \"expected\": [\"partial\", \"bytes=0-0\", 1], \"passed\": true}, {\"check\": \"coverage-sort fixture 6\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"coverage-sort fixture 7\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"coverage-sort fixture 8\", \"actual\": [\"partial\", null, 0], \"expected\": [\"partial\", null, 0], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}