{"abstract":"A matching cache validator suppresses range unsatisfiability.","category":"HTTP ranges","checks":6,"contract":"A matching GET cache validator produces [304,empty]; only stale requests evaluate ranges, yielding 206 or 416.","evaluation_group":"s3-http_ranges-conditional","failed_approach":"The partial repair uses return [304, \"\"] if fresh and satisfiable else ([206,body] if satisfiable else [416,\"\"]), which still violates the stated contract.","family":"s3-http_ranges-not-modified-before-unsatisfied","id":"FA-26346","implementations":{"attempt":{"sha256":"c54d033981cd874c41ca9a7e5474ea7c3ee43d6f5edbd85cf7f8d98fa3b41e3b","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(fresh, satisfiable, body):\n    return [304, \"\"] if fresh and satisfiable else ([206,body] if satisfiable else [416,\"\"])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('not-modified-before-unsatisfied fixture 0', solve(True,False,\"x\"*N), [304,\"\"])\ncheck('not-modified-before-unsatisfied fixture 1', solve(True,True,\"x\"*N), [304,\"\"])\ncheck('not-modified-before-unsatisfied fixture 2', solve(False,False,\"x\"*N), [416,\"\"])\ncheck('not-modified-before-unsatisfied fixture 3', solve(False,True,\"x\"*N), [206,\"x\"*N])\ncheck('not-modified-before-unsatisfied fixture 4', solve(True,False,\"\"), [304,\"\"])\ncheck('not-modified-before-unsatisfied fixture 5', solve(False,True,\"\"), [206,\"\"])\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":"04c6c364116b1e2fea4e08ce33fba61cb5d2615201c999508193987d09cae30b","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(fresh, satisfiable, body):\n    return [416, \"\"] if not satisfiable else ([304,\"\"] if fresh else [206,body])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('not-modified-before-unsatisfied fixture 0', solve(True,False,\"x\"*N), [304,\"\"])\ncheck('not-modified-before-unsatisfied fixture 1', solve(True,True,\"x\"*N), [304,\"\"])\ncheck('not-modified-before-unsatisfied fixture 2', solve(False,False,\"x\"*N), [416,\"\"])\ncheck('not-modified-before-unsatisfied fixture 3', solve(False,True,\"x\"*N), [206,\"x\"*N])\ncheck('not-modified-before-unsatisfied fixture 4', solve(True,False,\"\"), [304,\"\"])\ncheck('not-modified-before-unsatisfied fixture 5', solve(False,True,\"\"), [206,\"\"])\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":"b65442e72ead69ad5293182178dee2bfa944a0f1ae7daad97f3b79d9054837bc","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(fresh, satisfiable, body):\n    return [304, \"\"] if fresh else ([206,body] if satisfiable else [416,\"\"])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('not-modified-before-unsatisfied fixture 0', solve(True,False,\"x\"*N), [304,\"\"])\ncheck('not-modified-before-unsatisfied fixture 1', solve(True,True,\"x\"*N), [304,\"\"])\ncheck('not-modified-before-unsatisfied fixture 2', solve(False,False,\"x\"*N), [416,\"\"])\ncheck('not-modified-before-unsatisfied fixture 3', solve(False,True,\"x\"*N), [206,\"x\"*N])\ncheck('not-modified-before-unsatisfied fixture 4', solve(True,False,\"\"), [304,\"\"])\ncheck('not-modified-before-unsatisfied fixture 5', solve(False,True,\"\"), [206,\"\"])\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-not-modified-before-unsatisfied","generated_at":"2026-09-29T14:41:15.155234+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 [304, \"\"] if fresh else ([206,body] if satisfiable else [416,\"\"])","root_cause":"The not-modified-before-unsatisfied decision uses return [416, \"\"] if not satisfiable else ([304,\"\"] if fresh else [206,body]).","sha256":"667ebcf89d20ca13291d578095d4718a88d320d91051d788db1d9b88703e61fa","title":"A matching cache validator suppresses range unsatisfiability · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":39.317,"exit_code":1,"observations":[{"actual":[416,""],"check":"not-modified-before-unsatisfied fixture 0","expected":[304,""],"passed":false},{"actual":[304,""],"check":"not-modified-before-unsatisfied fixture 1","expected":[304,""],"passed":true},{"actual":[416,""],"check":"not-modified-before-unsatisfied fixture 2","expected":[416,""],"passed":true},{"actual":[206,"x"],"check":"not-modified-before-unsatisfied fixture 3","expected":[206,"x"],"passed":true},{"actual":[416,""],"check":"not-modified-before-unsatisfied fixture 4","expected":[304,""],"passed":false},{"actual":[206,""],"check":"not-modified-before-unsatisfied fixture 5","expected":[206,""],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"not-modified-before-unsatisfied fixture 0\", \"actual\": [416, \"\"], \"expected\": [304, \"\"], \"passed\": false}, {\"check\": \"not-modified-before-unsatisfied fixture 1\", \"actual\": [304, \"\"], \"expected\": [304, \"\"], \"passed\": true}, {\"check\": \"not-modified-before-unsatisfied fixture 2\", \"actual\": [416, \"\"], \"expected\": [416, \"\"], \"passed\": true}, {\"check\": \"not-modified-before-unsatisfied fixture 3\", \"actual\": [206, \"x\"], \"expected\": [206, \"x\"], \"passed\": true}, {\"check\": \"not-modified-before-unsatisfied fixture 4\", \"actual\": [416, \"\"], \"expected\": [304, \"\"], \"passed\": false}, {\"check\": \"not-modified-before-unsatisfied fixture 5\", \"actual\": [206, \"\"], \"expected\": [206, \"\"], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.321,"exit_code":1,"observations":[{"actual":[416,""],"check":"not-modified-before-unsatisfied fixture 0","expected":[304,""],"passed":false},{"actual":[304,""],"check":"not-modified-before-unsatisfied fixture 1","expected":[304,""],"passed":true},{"actual":[416,""],"check":"not-modified-before-unsatisfied fixture 2","expected":[416,""],"passed":true},{"actual":[206,"x"],"check":"not-modified-before-unsatisfied fixture 3","expected":[206,"x"],"passed":true},{"actual":[416,""],"check":"not-modified-before-unsatisfied fixture 4","expected":[304,""],"passed":false},{"actual":[206,""],"check":"not-modified-before-unsatisfied fixture 5","expected":[206,""],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"not-modified-before-unsatisfied fixture 0\", \"actual\": [416, \"\"], \"expected\": [304, \"\"], \"passed\": false}, {\"check\": \"not-modified-before-unsatisfied fixture 1\", \"actual\": [304, \"\"], \"expected\": [304, \"\"], \"passed\": true}, {\"check\": \"not-modified-before-unsatisfied fixture 2\", \"actual\": [416, \"\"], \"expected\": [416, \"\"], \"passed\": true}, {\"check\": \"not-modified-before-unsatisfied fixture 3\", \"actual\": [206, \"x\"], \"expected\": [206, \"x\"], \"passed\": true}, {\"check\": \"not-modified-before-unsatisfied fixture 4\", \"actual\": [416, \"\"], \"expected\": [304, \"\"], \"passed\": false}, {\"check\": \"not-modified-before-unsatisfied fixture 5\", \"actual\": [206, \"\"], \"expected\": [206, \"\"], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":38.902,"exit_code":0,"observations":[{"actual":[304,""],"check":"not-modified-before-unsatisfied fixture 0","expected":[304,""],"passed":true},{"actual":[304,""],"check":"not-modified-before-unsatisfied fixture 1","expected":[304,""],"passed":true},{"actual":[416,""],"check":"not-modified-before-unsatisfied fixture 2","expected":[416,""],"passed":true},{"actual":[206,"x"],"check":"not-modified-before-unsatisfied fixture 3","expected":[206,"x"],"passed":true},{"actual":[304,""],"check":"not-modified-before-unsatisfied fixture 4","expected":[304,""],"passed":true},{"actual":[206,""],"check":"not-modified-before-unsatisfied fixture 5","expected":[206,""],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"not-modified-before-unsatisfied fixture 0\", \"actual\": [304, \"\"], \"expected\": [304, \"\"], \"passed\": true}, {\"check\": \"not-modified-before-unsatisfied fixture 1\", \"actual\": [304, \"\"], \"expected\": [304, \"\"], \"passed\": true}, {\"check\": \"not-modified-before-unsatisfied fixture 2\", \"actual\": [416, \"\"], \"expected\": [416, \"\"], \"passed\": true}, {\"check\": \"not-modified-before-unsatisfied fixture 3\", \"actual\": [206, \"x\"], \"expected\": [206, \"x\"], \"passed\": true}, {\"check\": \"not-modified-before-unsatisfied fixture 4\", \"actual\": [304, \"\"], \"expected\": [304, \"\"], \"passed\": true}, {\"check\": \"not-modified-before-unsatisfied fixture 5\", \"actual\": [206, \"\"], \"expected\": [206, \"\"], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}