{"abstract":"Connection backpressure does not drop queued request order.","category":"Connection lifecycle","checks":4,"contract":"Bounded offline decision model: connection backpressure does not drop queued request order. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.","contract_signature":"queued, ready","evaluation_group":"xh-connection-backpressure-does-not-drop-queued-request-order","failed_approach":"The attempted repair uses `(queued[0],queued[1:]) if queued else (None,queued)` and still violates a separate fixture.","family":"xh-connection-backpressure-does-not-drop-queued-request-order","id":"FA-7826","implementations":{"attempt":{"sha256":"4c27a15175c3f4d054cab514454a47a528774b29fffe0dc1d6af095db46370c8","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(queued, ready):\n    return (queued[0],queued[1:]) if queued else (None,queued)\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'], True), ('a', ['b']))\", \"check('fixture 2', solve(['a'], False), (None, ['a']))\", \"check('fixture 3', solve([], True), (None, []))\", \"check('fixture 4', solve(['a'], True), ('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":"f721c49c437689aa3fb46e48df4e3d51270154121e7cf8521949f85fbfcb6c4b","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(queued, ready):\n    return (queued[-1],queued[:-1]) if ready and queued else (None,queued)\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'], True), ('a', ['b']))\", \"check('fixture 2', solve(['a'], False), (None, ['a']))\", \"check('fixture 3', solve([], True), (None, []))\", \"check('fixture 4', solve(['a'], True), ('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-connection-backpressure-does-not-drop-queued-request-order","generated_at":"2026-09-29T14:38:15.574270+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic connection lifecycle model isolates the connection-backpressure-does-not-drop-queued-request-order policy at a network component boundary.","root_cause":"The faulty implementation uses `(queued[-1],queued[:-1]) if ready and queued else (None,queued)` for the connection-backpressure-does-not-drop-queued-request-order decision.","sha256":"eb5f3a7afc7b40a543c754f7566a614248449d27aa7dee3ae8613869ea4fca99","title":"Connection backpressure does not drop queued request order · 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":43.69,"exit_code":1,"observations":[{"actual":["a",[]],"check":"fixture 2","expected":[null,["a"]],"passed":false},{"actual":[null,[]],"check":"fixture 3","expected":[null,[]],"passed":true},{"actual":["a",[]],"check":"fixture 4","expected":["a",[]],"passed":true},{"actual":["a",["b"]],"check":"fixture 1","expected":["a",["b"]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": [\"a\", []], \"expected\": [null, [\"a\"]], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [null, []], \"expected\": [null, []], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [\"a\", []], \"expected\": [\"a\", []], \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": [\"a\", [\"b\"]], \"expected\": [\"a\", [\"b\"]], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.563,"exit_code":1,"observations":[{"actual":[null,["a"]],"check":"fixture 2","expected":[null,["a"]],"passed":true},{"actual":[null,[]],"check":"fixture 3","expected":[null,[]],"passed":true},{"actual":["a",[]],"check":"fixture 4","expected":["a",[]],"passed":true},{"actual":["b",["a"]],"check":"fixture 1","expected":["a",["b"]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": [null, [\"a\"]], \"expected\": [null, [\"a\"]], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [null, []], \"expected\": [null, []], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [\"a\", []], \"expected\": [\"a\", []], \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": [\"b\", [\"a\"]], \"expected\": [\"a\", [\"b\"]], \"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."}}