{"abstract":"Missing cached bytes remain unavailable instead of becoming zero bytes.","category":"HTTP ranges","checks":6,"contract":"cells maps integer offsets to one-character strings. Return the requested bytes only if every requested offset exists, else None; empty request returns empty.","evaluation_group":"s3-http_ranges-cache-assembly","failed_approach":"The partial repair uses return \"\".join(cells[i] for i in offsets if i in cells), which still violates the stated contract.","family":"s3-http_ranges-cache-holes-not-zero-filled","id":"FA-26501","implementations":{"attempt":{"sha256":"cf6b4e7754eaf10106f94368d08aaae4826c7bd26fddf3710497a6235b2eb68b","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(cells, offsets):\n    return \"\".join(cells[i] for i in offsets if i in cells)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('cache-holes-not-zero-filled fixture 0', solve( {N:\"a\"},[N,N+1]), None)\ncheck('cache-holes-not-zero-filled fixture 1', solve({},[N]), None)\ncheck('cache-holes-not-zero-filled fixture 2', solve({N:\"a\"},[N]), \"a\")\ncheck('cache-holes-not-zero-filled fixture 3', solve({},[]), \"\")\ncheck('cache-holes-not-zero-filled fixture 4', solve({0:\"\\x00\"},[0]), \"\\x00\")\ncheck('cache-holes-not-zero-filled fixture 5', solve({0:\"a\",1:\"b\"},[1,0]), \"ba\")\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":"a603738a5299e68647a9b4fdfced5d9ddeb0b318acb415d4ed518225eaee81f2","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(cells, offsets):\n    return \"\".join(cells.get(i,\"\\x00\") for i in offsets)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('cache-holes-not-zero-filled fixture 0', solve( {N:\"a\"},[N,N+1]), None)\ncheck('cache-holes-not-zero-filled fixture 1', solve({},[N]), None)\ncheck('cache-holes-not-zero-filled fixture 2', solve({N:\"a\"},[N]), \"a\")\ncheck('cache-holes-not-zero-filled fixture 3', solve({},[]), \"\")\ncheck('cache-holes-not-zero-filled fixture 4', solve({0:\"\\x00\"},[0]), \"\\x00\")\ncheck('cache-holes-not-zero-filled fixture 5', solve({0:\"a\",1:\"b\"},[1,0]), \"ba\")\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":"f17e80453e211a552ad0b171a54cd4b8cc1504c917a0fa8598c077932398ca2d","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(cells, offsets):\n    return \"\".join(cells[i] for i in offsets) if all(i in cells for i in offsets) else None\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('cache-holes-not-zero-filled fixture 0', solve( {N:\"a\"},[N,N+1]), None)\ncheck('cache-holes-not-zero-filled fixture 1', solve({},[N]), None)\ncheck('cache-holes-not-zero-filled fixture 2', solve({N:\"a\"},[N]), \"a\")\ncheck('cache-holes-not-zero-filled fixture 3', solve({},[]), \"\")\ncheck('cache-holes-not-zero-filled fixture 4', solve({0:\"\\x00\"},[0]), \"\\x00\")\ncheck('cache-holes-not-zero-filled fixture 5', solve({0:\"a\",1:\"b\"},[1,0]), \"ba\")\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-cache-holes-not-zero-filled","generated_at":"2026-09-29T14:41:16.557200+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: return \"\".join(cells[i] for i in offsets) if all(i in cells for i in offsets) else None","root_cause":"The cache-holes-not-zero-filled decision uses return \"\".join(cells.get(i,\"\\x00\") for i in offsets).","sha256":"5f993e3e5373d7da4e92058450572af048875c6e29d28f99086205393c412c4b","title":"Missing cached bytes remain unavailable instead of becoming zero bytes · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":38.799,"exit_code":1,"observations":[{"actual":"a","check":"cache-holes-not-zero-filled fixture 0","expected":null,"passed":false},{"actual":"","check":"cache-holes-not-zero-filled fixture 1","expected":null,"passed":false},{"actual":"a","check":"cache-holes-not-zero-filled fixture 2","expected":"a","passed":true},{"actual":"","check":"cache-holes-not-zero-filled fixture 3","expected":"","passed":true},{"actual":"\u0000","check":"cache-holes-not-zero-filled fixture 4","expected":"\u0000","passed":true},{"actual":"ba","check":"cache-holes-not-zero-filled fixture 5","expected":"ba","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"cache-holes-not-zero-filled fixture 0\", \"actual\": \"a\", \"expected\": null, \"passed\": false}, {\"check\": \"cache-holes-not-zero-filled fixture 1\", \"actual\": \"\", \"expected\": null, \"passed\": false}, {\"check\": \"cache-holes-not-zero-filled fixture 2\", \"actual\": \"a\", \"expected\": \"a\", \"passed\": true}, {\"check\": \"cache-holes-not-zero-filled fixture 3\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}, {\"check\": \"cache-holes-not-zero-filled fixture 4\", \"actual\": \"\\u0000\", \"expected\": \"\\u0000\", \"passed\": true}, {\"check\": \"cache-holes-not-zero-filled fixture 5\", \"actual\": \"ba\", \"expected\": \"ba\", \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.734,"exit_code":1,"observations":[{"actual":"a\u0000","check":"cache-holes-not-zero-filled fixture 0","expected":null,"passed":false},{"actual":"\u0000","check":"cache-holes-not-zero-filled fixture 1","expected":null,"passed":false},{"actual":"a","check":"cache-holes-not-zero-filled fixture 2","expected":"a","passed":true},{"actual":"","check":"cache-holes-not-zero-filled fixture 3","expected":"","passed":true},{"actual":"\u0000","check":"cache-holes-not-zero-filled fixture 4","expected":"\u0000","passed":true},{"actual":"ba","check":"cache-holes-not-zero-filled fixture 5","expected":"ba","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"cache-holes-not-zero-filled fixture 0\", \"actual\": \"a\\u0000\", \"expected\": null, \"passed\": false}, {\"check\": \"cache-holes-not-zero-filled fixture 1\", \"actual\": \"\\u0000\", \"expected\": null, \"passed\": false}, {\"check\": \"cache-holes-not-zero-filled fixture 2\", \"actual\": \"a\", \"expected\": \"a\", \"passed\": true}, {\"check\": \"cache-holes-not-zero-filled fixture 3\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}, {\"check\": \"cache-holes-not-zero-filled fixture 4\", \"actual\": \"\\u0000\", \"expected\": \"\\u0000\", \"passed\": true}, {\"check\": \"cache-holes-not-zero-filled fixture 5\", \"actual\": \"ba\", \"expected\": \"ba\", \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":38.587,"exit_code":0,"observations":[{"actual":null,"check":"cache-holes-not-zero-filled fixture 0","expected":null,"passed":true},{"actual":null,"check":"cache-holes-not-zero-filled fixture 1","expected":null,"passed":true},{"actual":"a","check":"cache-holes-not-zero-filled fixture 2","expected":"a","passed":true},{"actual":"","check":"cache-holes-not-zero-filled fixture 3","expected":"","passed":true},{"actual":"\u0000","check":"cache-holes-not-zero-filled fixture 4","expected":"\u0000","passed":true},{"actual":"ba","check":"cache-holes-not-zero-filled fixture 5","expected":"ba","passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"cache-holes-not-zero-filled fixture 0\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"cache-holes-not-zero-filled fixture 1\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"cache-holes-not-zero-filled fixture 2\", \"actual\": \"a\", \"expected\": \"a\", \"passed\": true}, {\"check\": \"cache-holes-not-zero-filled fixture 3\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}, {\"check\": \"cache-holes-not-zero-filled fixture 4\", \"actual\": \"\\u0000\", \"expected\": \"\\u0000\", \"passed\": true}, {\"check\": \"cache-holes-not-zero-filled fixture 5\", \"actual\": \"ba\", \"expected\": \"ba\", \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}