{"abstract":"Stale if error window measures time after expiration.","category":"HTTP caching","checks":4,"contract":"Bounded offline decision model: stale if error window measures time after expiration. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.","evaluation_group":"xh-stale-if-error-window-measures-time-after-expiration","failed_approach":"The attempted repair uses `age < lifetime+window` and still violates a separate fixture.","family":"xh-stale-if-error-window-measures-time-after-expiration","id":"FA-6756","implementations":{"attempt":{"sha256":"f0af037002182edcf89d76a8c8049dc039e74e669c953f7bf7dbbe84803b414b","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(age, lifetime, window):\n    return age < lifetime+window\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(14, 10, 5), True)\", \"check('fixture 2', solve(16, 10, 5), False)\", \"check('fixture 3', solve(15, 10, 5), True)\", \"check('fixture 4', solve(5, 10, 5), False)\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\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":"db04567f0831b64dab41b6f241017605adcb267b42513cbdbfcf68eec2aa8079","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(age, lifetime, window):\n    return age <= window\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(14, 10, 5), True)\", \"check('fixture 2', solve(16, 10, 5), False)\", \"check('fixture 3', solve(15, 10, 5), True)\", \"check('fixture 4', solve(5, 10, 5), False)\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\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":"442f0df967b20cadc2b1b8da3e13bc1affe6aafa8406da7c80e78c42fc018882","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(age, lifetime, window):\n    return lifetime <= age <= lifetime+window\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(14, 10, 5), True)\", \"check('fixture 2', solve(16, 10, 5), False)\", \"check('fixture 3', solve(15, 10, 5), True)\", \"check('fixture 4', solve(5, 10, 5), False)\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\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":"Bounded deterministic policy model over validated inputs; not a complete protocol stack or an interoperability claim. The five variants rotate the same explicit fixture set. 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":"xh-stale-if-error-window-measures-time-after-expiration","generated_at":"2026-09-29T14:38:04.927655+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic http caching model isolates the stale-if-error-window-measures-time-after-expiration policy at a network component boundary.","repair":"Apply the explicit stale-if-error-window-measures-time-after-expiration contract, including the tested boundary and negative cases.","root_cause":"The faulty implementation uses `age <= window` for the stale-if-error-window-measures-time-after-expiration decision.","sha256":"ff6ac00a24ad7ff3017b50d13d3649eb08fa15f94485474cb98e549a58e72fe7","title":"Stale if error window measures time after expiration · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":37.465,"exit_code":1,"observations":[{"actual":false,"check":"fixture 2","expected":false,"passed":true},{"actual":false,"check":"fixture 3","expected":true,"passed":false},{"actual":true,"check":"fixture 4","expected":false,"passed":false},{"actual":true,"check":"fixture 1","expected":true,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": false, \"expected\": true, \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": true, \"expected\": false, \"passed\": false}, {\"check\": \"fixture 1\", \"actual\": true, \"expected\": true, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":36.178,"exit_code":1,"observations":[{"actual":false,"check":"fixture 2","expected":false,"passed":true},{"actual":false,"check":"fixture 3","expected":true,"passed":false},{"actual":true,"check":"fixture 4","expected":false,"passed":false},{"actual":false,"check":"fixture 1","expected":true,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": false, \"expected\": true, \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": true, \"expected\": false, \"passed\": false}, {\"check\": \"fixture 1\", \"actual\": false, \"expected\": true, \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":35.035,"exit_code":0,"observations":[{"actual":false,"check":"fixture 2","expected":false,"passed":true},{"actual":true,"check":"fixture 3","expected":true,"passed":true},{"actual":false,"check":"fixture 4","expected":false,"passed":true},{"actual":true,"check":"fixture 1","expected":true,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": true, \"expected\": true, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}