{"abstract":"Preserve query-field structure while preparing a redirect target: the duplicate key preservation branch emits an incorrect decision.","category":"HTTP redirects","checks":6,"contract":"Preserve query-field structure while preparing a redirect target. The explicit fixture inputs and outputs define a bounded offline policy; request identity must accompany the decision.","contract_signature":"request, query","evaluation_group":"s3-http-redirects-query-field-routing","failed_approach":"The partial repair uses \"sorted(set(query.split('&'))) if query else []\" and still fails an explicit boundary or control.","family":"s3-http-redirects-query-field-routing-duplicate-key-preservation","id":"FA-28066","implementations":{"attempt":{"sha256":"fc956d2f387e6e13d09c294d5745f465bec58f59e7a7ac290bac3bc0ac57fdf2","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom urllib.parse import urlsplit, unquote, quote\nimport posixpath\nimport re\nN = 1\nobservations = []\ndef solve(request, query):\n    return {'request': request, 'decision': [sorted(set(query.split('&'))) if query else [], [('bare' if '=' not in p else 'value') for p in query.split('&')] if query else [], [p.partition('=')[2] for p in query.split('&')] if query else [], query.count('&')+1 if query else 0, query.split('&') if query else []]} \ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve('/requests/' + str(N) + '/0', 'a=1&a=1&b'), {'request': '/requests/' + str(N) + '/0', 'decision': [['a=1', 'a=1', 'b'], ['value', 'value', 'bare'], ['1', '1', ''], 3, ['a=1', 'a=1', 'b']]})\ncheck('fixture 2', solve('/requests/' + str(N) + '/1', 'a=&b=x=y=z'), {'request': '/requests/' + str(N) + '/1', 'decision': [['a=', 'b=x=y=z'], ['value', 'value'], ['', 'x=y=z'], 2, ['a=', 'b=x=y=z']]})\ncheck('fixture 3', solve('/requests/' + str(N) + '/2', 'a=x;y=z'), {'request': '/requests/' + str(N) + '/2', 'decision': [['a=x;y=z'], ['value'], ['x;y=z'], 1, ['a=x;y=z']]})\ncheck('fixture 4', solve('/requests/' + str(N) + '/3', 'a=x%26b=y'), {'request': '/requests/' + str(N) + '/3', 'decision': [['a=x%26b=y'], ['value'], ['x%26b=y'], 1, ['a=x%26b=y']]})\ncheck('fixture 5', solve('/requests/' + str(N) + '/4', 'flag'), {'request': '/requests/' + str(N) + '/4', 'decision': [['flag'], ['bare'], [''], 1, ['flag']]})\ncheck('fixture 6', solve('/requests/' + str(N) + '/5', ''), {'request': '/requests/' + str(N) + '/5', 'decision': [[], [], [], 0, []]})\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":"40de0f969552a35b95ebb42bc00b8cfe9eb4816673f027242cab864d4c02b5fb","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom urllib.parse import urlsplit, unquote, quote\nimport posixpath\nimport re\nN = 1\nobservations = []\ndef solve(request, query):\n    return {'request': request, 'decision': [list(dict.fromkeys(query.split('&'))) if query else [], [('bare' if '=' not in p else 'value') for p in query.split('&')] if query else [], [p.partition('=')[2] for p in query.split('&')] if query else [], query.count('&')+1 if query else 0, query.split('&') if query else []]} \ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve('/requests/' + str(N) + '/0', 'a=1&a=1&b'), {'request': '/requests/' + str(N) + '/0', 'decision': [['a=1', 'a=1', 'b'], ['value', 'value', 'bare'], ['1', '1', ''], 3, ['a=1', 'a=1', 'b']]})\ncheck('fixture 2', solve('/requests/' + str(N) + '/1', 'a=&b=x=y=z'), {'request': '/requests/' + str(N) + '/1', 'decision': [['a=', 'b=x=y=z'], ['value', 'value'], ['', 'x=y=z'], 2, ['a=', 'b=x=y=z']]})\ncheck('fixture 3', solve('/requests/' + str(N) + '/2', 'a=x;y=z'), {'request': '/requests/' + str(N) + '/2', 'decision': [['a=x;y=z'], ['value'], ['x;y=z'], 1, ['a=x;y=z']]})\ncheck('fixture 4', solve('/requests/' + str(N) + '/3', 'a=x%26b=y'), {'request': '/requests/' + str(N) + '/3', 'decision': [['a=x%26b=y'], ['value'], ['x%26b=y'], 1, ['a=x%26b=y']]})\ncheck('fixture 5', solve('/requests/' + str(N) + '/4', 'flag'), {'request': '/requests/' + str(N) + '/4', 'decision': [['flag'], ['bare'], [''], 1, ['flag']]})\ncheck('fixture 6', solve('/requests/' + str(N) + '/5', ''), {'request': '/requests/' + str(N) + '/5', 'decision': [[], [], [], 0, []]})\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":"Stipulated offline redirect policy, not a complete HTTP, browser, URL, cache, or security implementation. Numbered variants vary request correlation identity. 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":"s3-http-redirects-query-field-routing-duplicate-key-preservation","generated_at":"2026-09-29T14:41:30.812183+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Models a redirect controller decision before following a target or exposing a redirect result.","root_cause":"The duplicate-key-preservation decision uses \"list(dict.fromkeys(query.split('&'))) if query else []\"; this violates the stipulated controller policy.","sha256":"4a6865ec3f602611fc49a97ad3b1e59605310526e742e47f0581979ddeed20ec","title":"Preserve query-field structure while preparing a redirect target: duplicate key preservation · case 01","variant":1,"variant_policy":"N changes request correlation identity. Policy boundary fixtures are reused; numbered variants are not independent examples.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":39.257,"exit_code":1,"observations":[{"actual":{"decision":[["a=1","b"],["value","value","bare"],["1","1",""],3,["a=1","a=1","b"]],"request":"/requests/1/0"},"check":"fixture 1","expected":{"decision":[["a=1","a=1","b"],["value","value","bare"],["1","1",""],3,["a=1","a=1","b"]],"request":"/requests/1/0"},"passed":false},{"actual":{"decision":[["a=","b=x=y=z"],["value","value"],["","x=y=z"],2,["a=","b=x=y=z"]],"request":"/requests/1/1"},"check":"fixture 2","expected":{"decision":[["a=","b=x=y=z"],["value","value"],["","x=y=z"],2,["a=","b=x=y=z"]],"request":"/requests/1/1"},"passed":true},{"actual":{"decision":[["a=x;y=z"],["value"],["x;y=z"],1,["a=x;y=z"]],"request":"/requests/1/2"},"check":"fixture 3","expected":{"decision":[["a=x;y=z"],["value"],["x;y=z"],1,["a=x;y=z"]],"request":"/requests/1/2"},"passed":true},{"actual":{"decision":[["a=x%26b=y"],["value"],["x%26b=y"],1,["a=x%26b=y"]],"request":"/requests/1/3"},"check":"fixture 4","expected":{"decision":[["a=x%26b=y"],["value"],["x%26b=y"],1,["a=x%26b=y"]],"request":"/requests/1/3"},"passed":true},{"actual":{"decision":[["flag"],["bare"],[""],1,["flag"]],"request":"/requests/1/4"},"check":"fixture 5","expected":{"decision":[["flag"],["bare"],[""],1,["flag"]],"request":"/requests/1/4"},"passed":true},{"actual":{"decision":[[],[],[],0,[]],"request":"/requests/1/5"},"check":"fixture 6","expected":{"decision":[[],[],[],0,[]],"request":"/requests/1/5"},"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": {\"request\": \"/requests/1/0\", \"decision\": [[\"a=1\", \"b\"], [\"value\", \"value\", \"bare\"], [\"1\", \"1\", \"\"], 3, [\"a=1\", \"a=1\", \"b\"]]}, \"expected\": {\"request\": \"/requests/1/0\", \"decision\": [[\"a=1\", \"a=1\", \"b\"], [\"value\", \"value\", \"bare\"], [\"1\", \"1\", \"\"], 3, [\"a=1\", \"a=1\", \"b\"]]}, \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": {\"request\": \"/requests/1/1\", \"decision\": [[\"a=\", \"b=x=y=z\"], [\"value\", \"value\"], [\"\", \"x=y=z\"], 2, [\"a=\", \"b=x=y=z\"]]}, \"expected\": {\"request\": \"/requests/1/1\", \"decision\": [[\"a=\", \"b=x=y=z\"], [\"value\", \"value\"], [\"\", \"x=y=z\"], 2, [\"a=\", \"b=x=y=z\"]]}, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": {\"request\": \"/requests/1/2\", \"decision\": [[\"a=x;y=z\"], [\"value\"], [\"x;y=z\"], 1, [\"a=x;y=z\"]]}, \"expected\": {\"request\": \"/requests/1/2\", \"decision\": [[\"a=x;y=z\"], [\"value\"], [\"x;y=z\"], 1, [\"a=x;y=z\"]]}, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": {\"request\": \"/requests/1/3\", \"decision\": [[\"a=x%26b=y\"], [\"value\"], [\"x%26b=y\"], 1, [\"a=x%26b=y\"]]}, \"expected\": {\"request\": \"/requests/1/3\", \"decision\": [[\"a=x%26b=y\"], [\"value\"], [\"x%26b=y\"], 1, [\"a=x%26b=y\"]]}, \"passed\": true}, {\"check\": \"fixture 5\", \"actual\": {\"request\": \"/requests/1/4\", \"decision\": [[\"flag\"], [\"bare\"], [\"\"], 1, [\"flag\"]]}, \"expected\": {\"request\": \"/requests/1/4\", \"decision\": [[\"flag\"], [\"bare\"], [\"\"], 1, [\"flag\"]]}, \"passed\": true}, {\"check\": \"fixture 6\", \"actual\": {\"request\": \"/requests/1/5\", \"decision\": [[], [], [], 0, []]}, \"expected\": {\"request\": \"/requests/1/5\", \"decision\": [[], [], [], 0, []]}, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":37.511,"exit_code":1,"observations":[{"actual":{"decision":[["a=1","b"],["value","value","bare"],["1","1",""],3,["a=1","a=1","b"]],"request":"/requests/1/0"},"check":"fixture 1","expected":{"decision":[["a=1","a=1","b"],["value","value","bare"],["1","1",""],3,["a=1","a=1","b"]],"request":"/requests/1/0"},"passed":false},{"actual":{"decision":[["a=","b=x=y=z"],["value","value"],["","x=y=z"],2,["a=","b=x=y=z"]],"request":"/requests/1/1"},"check":"fixture 2","expected":{"decision":[["a=","b=x=y=z"],["value","value"],["","x=y=z"],2,["a=","b=x=y=z"]],"request":"/requests/1/1"},"passed":true},{"actual":{"decision":[["a=x;y=z"],["value"],["x;y=z"],1,["a=x;y=z"]],"request":"/requests/1/2"},"check":"fixture 3","expected":{"decision":[["a=x;y=z"],["value"],["x;y=z"],1,["a=x;y=z"]],"request":"/requests/1/2"},"passed":true},{"actual":{"decision":[["a=x%26b=y"],["value"],["x%26b=y"],1,["a=x%26b=y"]],"request":"/requests/1/3"},"check":"fixture 4","expected":{"decision":[["a=x%26b=y"],["value"],["x%26b=y"],1,["a=x%26b=y"]],"request":"/requests/1/3"},"passed":true},{"actual":{"decision":[["flag"],["bare"],[""],1,["flag"]],"request":"/requests/1/4"},"check":"fixture 5","expected":{"decision":[["flag"],["bare"],[""],1,["flag"]],"request":"/requests/1/4"},"passed":true},{"actual":{"decision":[[],[],[],0,[]],"request":"/requests/1/5"},"check":"fixture 6","expected":{"decision":[[],[],[],0,[]],"request":"/requests/1/5"},"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": {\"request\": \"/requests/1/0\", \"decision\": [[\"a=1\", \"b\"], [\"value\", \"value\", \"bare\"], [\"1\", \"1\", \"\"], 3, [\"a=1\", \"a=1\", \"b\"]]}, \"expected\": {\"request\": \"/requests/1/0\", \"decision\": [[\"a=1\", \"a=1\", \"b\"], [\"value\", \"value\", \"bare\"], [\"1\", \"1\", \"\"], 3, [\"a=1\", \"a=1\", \"b\"]]}, \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": {\"request\": \"/requests/1/1\", \"decision\": [[\"a=\", \"b=x=y=z\"], [\"value\", \"value\"], [\"\", \"x=y=z\"], 2, [\"a=\", \"b=x=y=z\"]]}, \"expected\": {\"request\": \"/requests/1/1\", \"decision\": [[\"a=\", \"b=x=y=z\"], [\"value\", \"value\"], [\"\", \"x=y=z\"], 2, [\"a=\", \"b=x=y=z\"]]}, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": {\"request\": \"/requests/1/2\", \"decision\": [[\"a=x;y=z\"], [\"value\"], [\"x;y=z\"], 1, [\"a=x;y=z\"]]}, \"expected\": {\"request\": \"/requests/1/2\", \"decision\": [[\"a=x;y=z\"], [\"value\"], [\"x;y=z\"], 1, [\"a=x;y=z\"]]}, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": {\"request\": \"/requests/1/3\", \"decision\": [[\"a=x%26b=y\"], [\"value\"], [\"x%26b=y\"], 1, [\"a=x%26b=y\"]]}, \"expected\": {\"request\": \"/requests/1/3\", \"decision\": [[\"a=x%26b=y\"], [\"value\"], [\"x%26b=y\"], 1, [\"a=x%26b=y\"]]}, \"passed\": true}, {\"check\": \"fixture 5\", \"actual\": {\"request\": \"/requests/1/4\", \"decision\": [[\"flag\"], [\"bare\"], [\"\"], 1, [\"flag\"]]}, \"expected\": {\"request\": \"/requests/1/4\", \"decision\": [[\"flag\"], [\"bare\"], [\"\"], 1, [\"flag\"]]}, \"passed\": true}, {\"check\": \"fixture 6\", \"actual\": {\"request\": \"/requests/1/5\", \"decision\": [[], [], [], 0, []]}, \"expected\": {\"request\": \"/requests/1/5\", \"decision\": [[], [], [], 0, []]}, \"passed\": true}], \"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."}}