{"abstract":"Only if cached miss returns gateway timeout.","category":"HTTP caching","checks":4,"contract":"Bounded offline decision model: only if cached miss returns gateway timeout. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.","contract_signature":"only, hit","evaluation_group":"xh-only-if-cached-miss-returns-gateway-timeout","failed_approach":"The attempted repair uses `'504' if only else 'fetch'` and still violates a separate fixture.","family":"xh-only-if-cached-miss-returns-gateway-timeout","id":"FA-6781","implementations":{"attempt":{"sha256":"dcba446a659571c6875a4c848b56a5f33400b90639e2fd8ad6263a1d74b45622","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(only, hit):\n    return '504' if only else 'fetch'\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(True, False), '504')\", \"check('fixture 2', solve(True, True), 'serve')\", \"check('fixture 3', solve(False, False), 'fetch')\", \"check('fixture 4', solve(False, True), 'serve')\"]\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":"9efa78a937ed1abe54fa18c447899987ddc73a212e2f9d2f700795c08aa5eee0","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(only, hit):\n    return 'serve' if hit else 'fetch'\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(True, False), '504')\", \"check('fixture 2', solve(True, True), 'serve')\", \"check('fixture 3', solve(False, False), 'fetch')\", \"check('fixture 4', solve(False, True), 'serve')\"]\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-only-if-cached-miss-returns-gateway-timeout","generated_at":"2026-09-29T14:38:05.061202+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic http caching model isolates the only-if-cached-miss-returns-gateway-timeout policy at a network component boundary.","root_cause":"The faulty implementation uses `'serve' if hit else 'fetch'` for the only-if-cached-miss-returns-gateway-timeout decision.","sha256":"55e660b11a0d9b40740fd5bcc822b79259dffe74eb1f53482e3547b74ba02435","title":"Only if cached miss returns gateway timeout · 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":35.782,"exit_code":1,"observations":[{"actual":"504","check":"fixture 2","expected":"serve","passed":false},{"actual":"fetch","check":"fixture 3","expected":"fetch","passed":true},{"actual":"fetch","check":"fixture 4","expected":"serve","passed":false},{"actual":"504","check":"fixture 1","expected":"504","passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": \"504\", \"expected\": \"serve\", \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": \"fetch\", \"expected\": \"fetch\", \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": \"fetch\", \"expected\": \"serve\", \"passed\": false}, {\"check\": \"fixture 1\", \"actual\": \"504\", \"expected\": \"504\", \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":36.672,"exit_code":1,"observations":[{"actual":"serve","check":"fixture 2","expected":"serve","passed":true},{"actual":"fetch","check":"fixture 3","expected":"fetch","passed":true},{"actual":"serve","check":"fixture 4","expected":"serve","passed":true},{"actual":"fetch","check":"fixture 1","expected":"504","passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": \"serve\", \"expected\": \"serve\", \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": \"fetch\", \"expected\": \"fetch\", \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": \"serve\", \"expected\": \"serve\", \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": \"fetch\", \"expected\": \"504\", \"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."}}