{"abstract":"Blackhole route terminates lookup instead of falling back.","category":"Network routing","checks":4,"contract":"Bounded offline decision model: blackhole route terminates lookup instead of falling back. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.","evaluation_group":"xh-blackhole-route-terminates-lookup-instead-of-falling-back","failed_approach":"The attempted repair uses `None if match is None else match` and still violates a separate fixture.","family":"xh-blackhole-route-terminates-lookup-instead-of-falling-back","id":"FA-7201","implementations":{"attempt":{"sha256":"0968b86c87d5927429d1babceb7fb5a8661f8d12c53499f132fa6dd44f09f63c","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(match, blackhole, fallback):\n    return None if match is None else match\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(None, True, 'default'), None)\", \"check('fixture 2', solve('a', False, 'default'), 'a')\", \"check('fixture 3', solve(None, False, 'default'), 'default')\", \"check('fixture 4', solve(None, False, None), None)\"]\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":"f83981aa4ee9307cbfa497df6e10a26f0ef91e8e75a949ddd8bec0178272e538","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(match, blackhole, fallback):\n    return match if match is not None else fallback\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(None, True, 'default'), None)\", \"check('fixture 2', solve('a', False, 'default'), 'a')\", \"check('fixture 3', solve(None, False, 'default'), 'default')\", \"check('fixture 4', solve(None, False, None), None)\"]\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":"71eb15d23e5c24858c65e1c87e33f4a39b16c5db624654da59251b329be0a15e","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(match, blackhole, fallback):\n    return None if blackhole else (match if match is not None else fallback)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(None, True, 'default'), None)\", \"check('fixture 2', solve('a', False, 'default'), 'a')\", \"check('fixture 3', solve(None, False, 'default'), 'default')\", \"check('fixture 4', solve(None, False, None), None)\"]\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-blackhole-route-terminates-lookup-instead-of-falling-back","generated_at":"2026-09-29T14:38:09.240847+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic network routing model isolates the blackhole-route-terminates-lookup-instead-of-falling-back policy at a network component boundary.","repair":"Apply the explicit blackhole-route-terminates-lookup-instead-of-falling-back contract, including the tested boundary and negative cases.","root_cause":"The faulty implementation uses `match if match is not None else fallback` for the blackhole-route-terminates-lookup-instead-of-falling-back decision.","sha256":"298b963975a16136a506461f9eb9db8721be1e68573fa015d6a7cdc9a5b53672","title":"Blackhole route terminates lookup instead of falling back · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":47.239,"exit_code":1,"observations":[{"actual":"a","check":"fixture 2","expected":"a","passed":true},{"actual":null,"check":"fixture 3","expected":"default","passed":false},{"actual":null,"check":"fixture 4","expected":null,"passed":true},{"actual":null,"check":"fixture 1","expected":null,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": \"a\", \"expected\": \"a\", \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": null, \"expected\": \"default\", \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": null, \"expected\": null, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":42.887,"exit_code":1,"observations":[{"actual":"a","check":"fixture 2","expected":"a","passed":true},{"actual":"default","check":"fixture 3","expected":"default","passed":true},{"actual":null,"check":"fixture 4","expected":null,"passed":true},{"actual":"default","check":"fixture 1","expected":null,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": \"a\", \"expected\": \"a\", \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": \"default\", \"expected\": \"default\", \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": \"default\", \"expected\": null, \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":43.303,"exit_code":0,"observations":[{"actual":"a","check":"fixture 2","expected":"a","passed":true},{"actual":"default","check":"fixture 3","expected":"default","passed":true},{"actual":null,"check":"fixture 4","expected":null,"passed":true},{"actual":null,"check":"fixture 1","expected":null,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": \"a\", \"expected\": \"a\", \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": \"default\", \"expected\": \"default\", \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": null, \"expected\": null, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}