{"abstract":"A packed-object origin maps logical byte requests to immutable backing objects: a hole cannot be silently dropped from a requested payload.","category":"HTTP ranges","checks":12,"contract":"x has pack strings keyed by handle, extent rows [logical-start,handle,physical-start,count], and explicit requested logical offsets. Extents may arrive unordered. Empty extents ignored. Reject negative mapping coordinates, missing handles, out-of-pack spans, or overlapping logical ownership. Return requested characters in request order, retaining repeated requested offsets; unavailable requested offsets yield None. This is a bounded storage adapter underlying HTTP range delivery, not interval normalization.","contract_signature":"x","evaluation_group":"s3-http_ranges-packed-origin-map","failed_approach":"The partial repair uses cells={}\nfor logical,handle,physical,count in x['extents']:\n    if count==0: continue\n    if logical<0 or physical<0 or count<0: return None\n    if handle not in x['packs']: return None\n    pack=x['packs'][handle]\n    if physical+count>len(pack): return None\n    for i in range(count):\n        at=logical+i\n        if at in cells: return None\n        cells[at]=pack[physical+i]\nreturn ''.join(cells.get(at,'?') for at in x['requested']), which still violates the stated contract.","family":"s3-http_ranges-packed-origin-map-missing-byte","id":"FA-26906","implementations":{"attempt":{"sha256":"fc47176d750f54c3be7b80eb4d514a397b153e22220ec72772621cde468641e2","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    cells={}\n    for logical,handle,physical,count in x['extents']:\n        if count==0: continue\n        if logical<0 or physical<0 or count<0: return None\n        if handle not in x['packs']: return None\n        pack=x['packs'][handle]\n        if physical+count>len(pack): return None\n        for i in range(count):\n            at=logical+i\n            if at in cells: return None\n            cells[at]=pack[physical+i]\n    return ''.join(cells.get(at,'?') for at in x['requested'])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('missing-byte fixture 0', json.loads(json.dumps(solve({'packs':{'a':'QabcZ','b':'RxyzS'},'extents':[[3,'b',1,3],[0,'a',1,3]],'requested':[0,3,1,4,2,5]}))), json.loads(json.dumps('axbycz')))\ncheck('missing-byte fixture 1', json.loads(json.dumps(solve({'packs':{'a':'QabcZ'},'extents':[[0,'a',1,3]],'requested':[2,0,2]}))), json.loads(json.dumps('cac')))\ncheck('missing-byte fixture 2', json.loads(json.dumps(solve({'packs':{'a':'abc'},'extents':[[0,'a',0,3]],'requested':[0,3]}))), json.loads(json.dumps(None)))\ncheck('missing-byte fixture 3', json.loads(json.dumps(solve({'packs':{'a':'abc'},'extents':[[0,'a',0,3],[1,'a',1,1]],'requested':[1]}))), json.loads(json.dumps(None)))\ncheck('missing-byte fixture 4', json.loads(json.dumps(solve({'packs':{'a':'abc'},'extents':[[0,'missing',0,0],[0,'a',0,3]],'requested':[0]}))), json.loads(json.dumps('a')))\ncheck('missing-byte fixture 5', json.loads(json.dumps(solve({'packs':{'a':'abc'},'extents':[[-1,'a',0,1]],'requested':[]}))), json.loads(json.dumps(None)))\ncheck('missing-byte fixture 6', json.loads(json.dumps(solve({'packs':{'a':'abc'},'extents':[[0,'a',-1,1]],'requested':[0]}))), json.loads(json.dumps(None)))\ncheck('missing-byte fixture 7', json.loads(json.dumps(solve({'packs':{'a':'abc'},'extents':[[0,'a',0,-1]],'requested':[]}))), json.loads(json.dumps(None)))\ncheck('missing-byte fixture 8', json.loads(json.dumps(solve({'packs':{},'extents':[[0,'a',0,1]],'requested':[]}))), json.loads(json.dumps(None)))\ncheck('missing-byte fixture 9', json.loads(json.dumps(solve({'packs':{'a':'abc'},'extents':[[0,'a',2,2]],'requested':[0]}))), json.loads(json.dumps(None)))\ncheck('missing-byte fixture 10', json.loads(json.dumps(solve({'packs':{},'extents':[],'requested':[]}))), json.loads(json.dumps('')))\ncheck('missing-byte fixture 11', json.loads(json.dumps(solve({'packs':{'a':\"p\"*N},'extents':[[0,'a',0,N]],'requested':[0]}))), json.loads(json.dumps('p')))\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":"d1abbc20118257dce9d27f9f00b2955e30d3d7673f2e45c29cc601f4831d2015","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    cells={}\n    for logical,handle,physical,count in x['extents']:\n        if count==0: continue\n        if logical<0 or physical<0 or count<0: return None\n        if handle not in x['packs']: return None\n        pack=x['packs'][handle]\n        if physical+count>len(pack): return None\n        for i in range(count):\n            at=logical+i\n            if at in cells: return None\n            cells[at]=pack[physical+i]\n    return ''.join(cells.get(at,'') for at in x['requested'])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('missing-byte fixture 0', json.loads(json.dumps(solve({'packs':{'a':'QabcZ','b':'RxyzS'},'extents':[[3,'b',1,3],[0,'a',1,3]],'requested':[0,3,1,4,2,5]}))), json.loads(json.dumps('axbycz')))\ncheck('missing-byte fixture 1', json.loads(json.dumps(solve({'packs':{'a':'QabcZ'},'extents':[[0,'a',1,3]],'requested':[2,0,2]}))), json.loads(json.dumps('cac')))\ncheck('missing-byte fixture 2', json.loads(json.dumps(solve({'packs':{'a':'abc'},'extents':[[0,'a',0,3]],'requested':[0,3]}))), json.loads(json.dumps(None)))\ncheck('missing-byte fixture 3', json.loads(json.dumps(solve({'packs':{'a':'abc'},'extents':[[0,'a',0,3],[1,'a',1,1]],'requested':[1]}))), json.loads(json.dumps(None)))\ncheck('missing-byte fixture 4', json.loads(json.dumps(solve({'packs':{'a':'abc'},'extents':[[0,'missing',0,0],[0,'a',0,3]],'requested':[0]}))), json.loads(json.dumps('a')))\ncheck('missing-byte fixture 5', json.loads(json.dumps(solve({'packs':{'a':'abc'},'extents':[[-1,'a',0,1]],'requested':[]}))), json.loads(json.dumps(None)))\ncheck('missing-byte fixture 6', json.loads(json.dumps(solve({'packs':{'a':'abc'},'extents':[[0,'a',-1,1]],'requested':[0]}))), json.loads(json.dumps(None)))\ncheck('missing-byte fixture 7', json.loads(json.dumps(solve({'packs':{'a':'abc'},'extents':[[0,'a',0,-1]],'requested':[]}))), json.loads(json.dumps(None)))\ncheck('missing-byte fixture 8', json.loads(json.dumps(solve({'packs':{},'extents':[[0,'a',0,1]],'requested':[]}))), json.loads(json.dumps(None)))\ncheck('missing-byte fixture 9', json.loads(json.dumps(solve({'packs':{'a':'abc'},'extents':[[0,'a',2,2]],'requested':[0]}))), json.loads(json.dumps(None)))\ncheck('missing-byte fixture 10', json.loads(json.dumps(solve({'packs':{},'extents':[],'requested':[]}))), json.loads(json.dumps('')))\ncheck('missing-byte fixture 11', json.loads(json.dumps(solve({'packs':{'a':\"p\"*N},'extents':[[0,'a',0,N]],'requested':[0]}))), json.loads(json.dumps('p')))\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-packed-origin-map-missing-byte","generated_at":"2026-09-29T14:41:20.096991+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.","root_cause":"The packed-origin-map-missing-byte decision uses cells={}\nfor logical,handle,physical,count in x['extents']:\n    if count==0: continue\n    if logical<0 or physical<0 or count<0: return None\n    if handle not in x['packs']: return None\n    pack=x['packs'][handle]\n    if physical+count>len(pack): return None\n    for i in range(count):\n        at=logical+i\n        if at in cells: return None\n        cells[at]=pack[physical+i]\nreturn ''.join(cells.get(at,'') for at in x['requested']).","sha256":"0e8a5d60c2529c4cb80beacc69a2ac816962eab65847b458b21e17b913049546","title":"A packed-object origin maps logical byte requests to immutable backing objects: a hole cannot be silently dropped from a requested payload · 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":38.712,"exit_code":1,"observations":[{"actual":"axbycz","check":"missing-byte fixture 0","expected":"axbycz","passed":true},{"actual":"cac","check":"missing-byte fixture 1","expected":"cac","passed":true},{"actual":"a?","check":"missing-byte fixture 2","expected":null,"passed":false},{"actual":null,"check":"missing-byte fixture 3","expected":null,"passed":true},{"actual":"a","check":"missing-byte fixture 4","expected":"a","passed":true},{"actual":null,"check":"missing-byte fixture 5","expected":null,"passed":true},{"actual":null,"check":"missing-byte fixture 6","expected":null,"passed":true},{"actual":null,"check":"missing-byte fixture 7","expected":null,"passed":true},{"actual":null,"check":"missing-byte fixture 8","expected":null,"passed":true},{"actual":null,"check":"missing-byte fixture 9","expected":null,"passed":true},{"actual":"","check":"missing-byte fixture 10","expected":"","passed":true},{"actual":"p","check":"missing-byte fixture 11","expected":"p","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"missing-byte fixture 0\", \"actual\": \"axbycz\", \"expected\": \"axbycz\", \"passed\": true}, {\"check\": \"missing-byte fixture 1\", \"actual\": \"cac\", \"expected\": \"cac\", \"passed\": true}, {\"check\": \"missing-byte fixture 2\", \"actual\": \"a?\", \"expected\": null, \"passed\": false}, {\"check\": \"missing-byte fixture 3\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"missing-byte fixture 4\", \"actual\": \"a\", \"expected\": \"a\", \"passed\": true}, {\"check\": \"missing-byte fixture 5\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"missing-byte fixture 6\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"missing-byte fixture 7\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"missing-byte fixture 8\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"missing-byte fixture 9\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"missing-byte fixture 10\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}, {\"check\": \"missing-byte fixture 11\", \"actual\": \"p\", \"expected\": \"p\", \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.166,"exit_code":1,"observations":[{"actual":"axbycz","check":"missing-byte fixture 0","expected":"axbycz","passed":true},{"actual":"cac","check":"missing-byte fixture 1","expected":"cac","passed":true},{"actual":"a","check":"missing-byte fixture 2","expected":null,"passed":false},{"actual":null,"check":"missing-byte fixture 3","expected":null,"passed":true},{"actual":"a","check":"missing-byte fixture 4","expected":"a","passed":true},{"actual":null,"check":"missing-byte fixture 5","expected":null,"passed":true},{"actual":null,"check":"missing-byte fixture 6","expected":null,"passed":true},{"actual":null,"check":"missing-byte fixture 7","expected":null,"passed":true},{"actual":null,"check":"missing-byte fixture 8","expected":null,"passed":true},{"actual":null,"check":"missing-byte fixture 9","expected":null,"passed":true},{"actual":"","check":"missing-byte fixture 10","expected":"","passed":true},{"actual":"p","check":"missing-byte fixture 11","expected":"p","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"missing-byte fixture 0\", \"actual\": \"axbycz\", \"expected\": \"axbycz\", \"passed\": true}, {\"check\": \"missing-byte fixture 1\", \"actual\": \"cac\", \"expected\": \"cac\", \"passed\": true}, {\"check\": \"missing-byte fixture 2\", \"actual\": \"a\", \"expected\": null, \"passed\": false}, {\"check\": \"missing-byte fixture 3\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"missing-byte fixture 4\", \"actual\": \"a\", \"expected\": \"a\", \"passed\": true}, {\"check\": \"missing-byte fixture 5\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"missing-byte fixture 6\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"missing-byte fixture 7\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"missing-byte fixture 8\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"missing-byte fixture 9\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"missing-byte fixture 10\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}, {\"check\": \"missing-byte fixture 11\", \"actual\": \"p\", \"expected\": \"p\", \"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."}}