{"abstract":"Resident time advances cache age.","category":"HTTP caching","checks":4,"contract":"Bounded offline decision model: resident time advances cache age. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.","contract_signature":"initial, now, received","evaluation_group":"xh-resident-time-advances-cache-age","failed_approach":"The attempted repair uses `max(initial,now-received)` and still violates a separate fixture.","family":"xh-resident-time-advances-cache-age","id":"FA-6731","implementations":{"attempt":{"sha256":"7aea7da381eaa439d6c533da8c4125fdc016b6e3f11d17b031c96aade99b0d27","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(initial, now, received):\n    return max(initial,now-received)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(5, 20, 10), 15)\", \"check('fixture 2', solve(5, 8, 10), 5)\", \"check('fixture 3', solve(0, 10, 10), 0)\", \"check('fixture 4', solve(2, 12, 10), 4)\"]\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":"005d7cca8b36c312d6218c55ba4c8152e7e2a960b0031c4c3d51680279aca91f","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(initial, now, received):\n    return initial\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(5, 20, 10), 15)\", \"check('fixture 2', solve(5, 8, 10), 5)\", \"check('fixture 3', solve(0, 10, 10), 0)\", \"check('fixture 4', solve(2, 12, 10), 4)\"]\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-resident-time-advances-cache-age","generated_at":"2026-09-29T14:38:04.705513+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic http caching model isolates the resident-time-advances-cache-age policy at a network component boundary.","root_cause":"The faulty implementation uses `initial` for the resident-time-advances-cache-age decision.","sha256":"edc8ad63de2ceaf332304f998a360d3b06d1342e67ffdec05b236a7daec0a187","title":"Resident time advances cache age · 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":38.581,"exit_code":1,"observations":[{"actual":5,"check":"fixture 2","expected":5,"passed":true},{"actual":0,"check":"fixture 3","expected":0,"passed":true},{"actual":2,"check":"fixture 4","expected":4,"passed":false},{"actual":10,"check":"fixture 1","expected":15,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": 5, \"expected\": 5, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 2, \"expected\": 4, \"passed\": false}, {\"check\": \"fixture 1\", \"actual\": 10, \"expected\": 15, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.041,"exit_code":1,"observations":[{"actual":5,"check":"fixture 2","expected":5,"passed":true},{"actual":0,"check":"fixture 3","expected":0,"passed":true},{"actual":2,"check":"fixture 4","expected":4,"passed":false},{"actual":5,"check":"fixture 1","expected":15,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": 5, \"expected\": 5, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": 2, \"expected\": 4, \"passed\": false}, {\"check\": \"fixture 1\", \"actual\": 5, \"expected\": 15, \"passed\": false}], \"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."}}