{"abstract":"Sse data lines join with newlines not concatenation.","category":"WebSocket and browser transport policies","checks":4,"contract":"Bounded offline decision model: sse data lines join with newlines not concatenation. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.","evaluation_group":"xh-sse-data-lines-join-with-newlines-not-concatenation","failed_approach":"The attempted repair uses `\"\\n\".join(lines)+\"\\n\"` and still violates a separate fixture.","family":"xh-sse-data-lines-join-with-newlines-not-concatenation","id":"FA-7651","implementations":{"attempt":{"sha256":"afbebd5a05484145c9344eaac18ac03f9c2a140660d66aa43152bf13289ad21f","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(lines):\n    return \"\\n\".join(lines)+\"\\n\"\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(['a', 'b']), 'a\\\\nb')\", \"check('fixture 2', solve([]), '')\", \"check('fixture 3', solve(['']), '')\", \"check('fixture 4', solve(['a']), 'a')\"]\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":"498767c1bec8b657cd245d00c619314a9bf45a3c8b09cbf439bb4784fa24c8cd","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(lines):\n    return \"\".join(lines)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(['a', 'b']), 'a\\\\nb')\", \"check('fixture 2', solve([]), '')\", \"check('fixture 3', solve(['']), '')\", \"check('fixture 4', solve(['a']), 'a')\"]\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":"84b4f2554d2bce91de6ae53d2ebf164ef408b64610b4732da8b0e24cd5c1f1c1","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(lines):\n    return \"\\n\".join(lines)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve(['a', 'b']), 'a\\\\nb')\", \"check('fixture 2', solve([]), '')\", \"check('fixture 3', solve(['']), '')\", \"check('fixture 4', solve(['a']), 'a')\"]\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-sse-data-lines-join-with-newlines-not-concatenation","generated_at":"2026-09-29T14:38:14.036162+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic websocket and browser transport policies model isolates the sse-data-lines-join-with-newlines-not-concatenation policy at a network component boundary.","repair":"Apply the explicit sse-data-lines-join-with-newlines-not-concatenation contract, including the tested boundary and negative cases.","root_cause":"The faulty implementation uses `\"\".join(lines)` for the sse-data-lines-join-with-newlines-not-concatenation decision.","sha256":"a78227716f7bf63540891cf26c90846895f072603f46e792ce97d281488557e4","title":"Sse data lines join with newlines not concatenation · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":39.995,"exit_code":1,"observations":[{"actual":"\n","check":"fixture 2","expected":"","passed":false},{"actual":"\n","check":"fixture 3","expected":"","passed":false},{"actual":"a\n","check":"fixture 4","expected":"a","passed":false},{"actual":"a\nb\n","check":"fixture 1","expected":"a\nb","passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": \"\\n\", \"expected\": \"\", \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": \"\\n\", \"expected\": \"\", \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": \"a\\n\", \"expected\": \"a\", \"passed\": false}, {\"check\": \"fixture 1\", \"actual\": \"a\\nb\\n\", \"expected\": \"a\\nb\", \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":41.189,"exit_code":1,"observations":[{"actual":"","check":"fixture 2","expected":"","passed":true},{"actual":"","check":"fixture 3","expected":"","passed":true},{"actual":"a","check":"fixture 4","expected":"a","passed":true},{"actual":"ab","check":"fixture 1","expected":"a\nb","passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": \"a\", \"expected\": \"a\", \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": \"ab\", \"expected\": \"a\\nb\", \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":37.77,"exit_code":0,"observations":[{"actual":"","check":"fixture 2","expected":"","passed":true},{"actual":"","check":"fixture 3","expected":"","passed":true},{"actual":"a","check":"fixture 4","expected":"a","passed":true},{"actual":"a\nb","check":"fixture 1","expected":"a\nb","passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": \"\", \"expected\": \"\", \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": \"a\", \"expected\": \"a\", \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": \"a\\nb\", \"expected\": \"a\\nb\", \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}