{"abstract":"Expose redirect events in request order without false completion: the last observed target branch emits an incorrect decision.","category":"HTTP redirects","checks":6,"contract":"Expose redirect events in request order without false completion. The explicit fixture inputs and outputs define a bounded offline policy; request identity must accompany the decision.","evaluation_group":"s3-http-redirects-redirect-observer","failed_approach":"The partial repair uses 'target' and still fails an explicit boundary or control.","family":"s3-http-redirects-redirect-observer-last-observed-target","id":"FA-28131","implementations":{"attempt":{"sha256":"59d984435c8f3cd83b1881ccc9edd27b5f571d440b55e083b1299a352629fea3","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, events, accepted, target, done, canceled):\n    return {'request': request, 'decision': [events + ([target] if accepted else []), done and not canceled, len(events), target, 'canceled' if canceled else ('redirect' if accepted else 'blocked')]} \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', '/b', '/a'], False, '/c', True, True), {'request': '/requests/' + str(N) + '/0', 'decision': [['/a', '/b', '/a'], False, 3, '/a', 'canceled']})\ncheck('fixture 2', solve('/requests/' + str(N) + '/1', ['/a', '/b'], True, '/c', False, False), {'request': '/requests/' + str(N) + '/1', 'decision': [['/a', '/b', '/c'], False, 2, '/b', 'redirect']})\ncheck('fixture 3', solve('/requests/' + str(N) + '/2', [], False, '/a', True, False), {'request': '/requests/' + str(N) + '/2', 'decision': [[], True, 0, None, 'blocked']})\ncheck('fixture 4', solve('/requests/' + str(N) + '/3', [], True, '/a', False, False), {'request': '/requests/' + str(N) + '/3', 'decision': [['/a'], False, 0, None, 'redirect']})\ncheck('fixture 5', solve('/requests/' + str(N) + '/4', ['/b'], True, '/c', True, True), {'request': '/requests/' + str(N) + '/4', 'decision': [['/b', '/c'], False, 1, '/b', 'canceled']})\ncheck('fixture 6', solve('/requests/' + str(N) + '/5', ['/a', '/b'], False, '/c', False, False), {'request': '/requests/' + str(N) + '/5', 'decision': [['/a', '/b'], False, 2, '/b', 'blocked']})\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":"84ee8110e2c80dd90fc77e5b23f77689dee2e9d587870fe656cd6e3b999dd436","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, events, accepted, target, done, canceled):\n    return {'request': request, 'decision': [events + ([target] if accepted else []), done and not canceled, len(events), events[0] if events else None, 'canceled' if canceled else ('redirect' if accepted else 'blocked')]} \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', '/b', '/a'], False, '/c', True, True), {'request': '/requests/' + str(N) + '/0', 'decision': [['/a', '/b', '/a'], False, 3, '/a', 'canceled']})\ncheck('fixture 2', solve('/requests/' + str(N) + '/1', ['/a', '/b'], True, '/c', False, False), {'request': '/requests/' + str(N) + '/1', 'decision': [['/a', '/b', '/c'], False, 2, '/b', 'redirect']})\ncheck('fixture 3', solve('/requests/' + str(N) + '/2', [], False, '/a', True, False), {'request': '/requests/' + str(N) + '/2', 'decision': [[], True, 0, None, 'blocked']})\ncheck('fixture 4', solve('/requests/' + str(N) + '/3', [], True, '/a', False, False), {'request': '/requests/' + str(N) + '/3', 'decision': [['/a'], False, 0, None, 'redirect']})\ncheck('fixture 5', solve('/requests/' + str(N) + '/4', ['/b'], True, '/c', True, True), {'request': '/requests/' + str(N) + '/4', 'decision': [['/b', '/c'], False, 1, '/b', 'canceled']})\ncheck('fixture 6', solve('/requests/' + str(N) + '/5', ['/a', '/b'], False, '/c', False, False), {'request': '/requests/' + str(N) + '/5', 'decision': [['/a', '/b'], False, 2, '/b', 'blocked']})\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":"e8ee6c261d6c7a8f0f134377aa251974d311a013423f4c0df3ec6afd3cf9a18f","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, events, accepted, target, done, canceled):\n    return {'request': request, 'decision': [events + ([target] if accepted else []), done and not canceled, len(events), events[-1] if events else None, 'canceled' if canceled else ('redirect' if accepted else 'blocked')]} \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', '/b', '/a'], False, '/c', True, True), {'request': '/requests/' + str(N) + '/0', 'decision': [['/a', '/b', '/a'], False, 3, '/a', 'canceled']})\ncheck('fixture 2', solve('/requests/' + str(N) + '/1', ['/a', '/b'], True, '/c', False, False), {'request': '/requests/' + str(N) + '/1', 'decision': [['/a', '/b', '/c'], False, 2, '/b', 'redirect']})\ncheck('fixture 3', solve('/requests/' + str(N) + '/2', [], False, '/a', True, False), {'request': '/requests/' + str(N) + '/2', 'decision': [[], True, 0, None, 'blocked']})\ncheck('fixture 4', solve('/requests/' + str(N) + '/3', [], True, '/a', False, False), {'request': '/requests/' + str(N) + '/3', 'decision': [['/a'], False, 0, None, 'redirect']})\ncheck('fixture 5', solve('/requests/' + str(N) + '/4', ['/b'], True, '/c', True, True), {'request': '/requests/' + str(N) + '/4', 'decision': [['/b', '/c'], False, 1, '/b', 'canceled']})\ncheck('fixture 6', solve('/requests/' + str(N) + '/5', ['/a', '/b'], False, '/c', False, False), {'request': '/requests/' + str(N) + '/5', 'decision': [['/a', '/b'], False, 2, '/b', 'blocked']})\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-redirect-observer-last-observed-target","generated_at":"2026-09-29T14:41:31.299162+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.","repair":"At this decision use 'events[-1] if events else None', preserving the other controller outputs.","root_cause":"The last-observed-target decision uses 'events[0] if events else None'; this violates the stipulated controller policy.","sha256":"8864f690beb2ea89d6490c501cf58a0b9285595d8ffc9ba7068026a2d3308b6f","title":"Expose redirect events in request order without false completion: last observed target · case 01","variant":1,"variant_policy":"N changes request correlation identity. Policy boundary fixtures are reused; numbered variants are not independent examples.","verification":{"attempt":{"elapsed_ms":39.492,"exit_code":1,"observations":[{"actual":{"decision":[["/a","/b","/a"],false,3,"/c","canceled"],"request":"/requests/1/0"},"check":"fixture 1","expected":{"decision":[["/a","/b","/a"],false,3,"/a","canceled"],"request":"/requests/1/0"},"passed":false},{"actual":{"decision":[["/a","/b","/c"],false,2,"/c","redirect"],"request":"/requests/1/1"},"check":"fixture 2","expected":{"decision":[["/a","/b","/c"],false,2,"/b","redirect"],"request":"/requests/1/1"},"passed":false},{"actual":{"decision":[[],true,0,"/a","blocked"],"request":"/requests/1/2"},"check":"fixture 3","expected":{"decision":[[],true,0,null,"blocked"],"request":"/requests/1/2"},"passed":false},{"actual":{"decision":[["/a"],false,0,"/a","redirect"],"request":"/requests/1/3"},"check":"fixture 4","expected":{"decision":[["/a"],false,0,null,"redirect"],"request":"/requests/1/3"},"passed":false},{"actual":{"decision":[["/b","/c"],false,1,"/c","canceled"],"request":"/requests/1/4"},"check":"fixture 5","expected":{"decision":[["/b","/c"],false,1,"/b","canceled"],"request":"/requests/1/4"},"passed":false},{"actual":{"decision":[["/a","/b"],false,2,"/c","blocked"],"request":"/requests/1/5"},"check":"fixture 6","expected":{"decision":[["/a","/b"],false,2,"/b","blocked"],"request":"/requests/1/5"},"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": {\"request\": \"/requests/1/0\", \"decision\": [[\"/a\", \"/b\", \"/a\"], false, 3, \"/c\", \"canceled\"]}, \"expected\": {\"request\": \"/requests/1/0\", \"decision\": [[\"/a\", \"/b\", \"/a\"], false, 3, \"/a\", \"canceled\"]}, \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": {\"request\": \"/requests/1/1\", \"decision\": [[\"/a\", \"/b\", \"/c\"], false, 2, \"/c\", \"redirect\"]}, \"expected\": {\"request\": \"/requests/1/1\", \"decision\": [[\"/a\", \"/b\", \"/c\"], false, 2, \"/b\", \"redirect\"]}, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": {\"request\": \"/requests/1/2\", \"decision\": [[], true, 0, \"/a\", \"blocked\"]}, \"expected\": {\"request\": \"/requests/1/2\", \"decision\": [[], true, 0, null, \"blocked\"]}, \"passed\": false}, {\"check\": \"fixture 4\", \"actual\": {\"request\": \"/requests/1/3\", \"decision\": [[\"/a\"], false, 0, \"/a\", \"redirect\"]}, \"expected\": {\"request\": \"/requests/1/3\", \"decision\": [[\"/a\"], false, 0, null, \"redirect\"]}, \"passed\": false}, {\"check\": \"fixture 5\", \"actual\": {\"request\": \"/requests/1/4\", \"decision\": [[\"/b\", \"/c\"], false, 1, \"/c\", \"canceled\"]}, \"expected\": {\"request\": \"/requests/1/4\", \"decision\": [[\"/b\", \"/c\"], false, 1, \"/b\", \"canceled\"]}, \"passed\": false}, {\"check\": \"fixture 6\", \"actual\": {\"request\": \"/requests/1/5\", \"decision\": [[\"/a\", \"/b\"], false, 2, \"/c\", \"blocked\"]}, \"expected\": {\"request\": \"/requests/1/5\", \"decision\": [[\"/a\", \"/b\"], false, 2, \"/b\", \"blocked\"]}, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.862,"exit_code":1,"observations":[{"actual":{"decision":[["/a","/b","/a"],false,3,"/a","canceled"],"request":"/requests/1/0"},"check":"fixture 1","expected":{"decision":[["/a","/b","/a"],false,3,"/a","canceled"],"request":"/requests/1/0"},"passed":true},{"actual":{"decision":[["/a","/b","/c"],false,2,"/a","redirect"],"request":"/requests/1/1"},"check":"fixture 2","expected":{"decision":[["/a","/b","/c"],false,2,"/b","redirect"],"request":"/requests/1/1"},"passed":false},{"actual":{"decision":[[],true,0,null,"blocked"],"request":"/requests/1/2"},"check":"fixture 3","expected":{"decision":[[],true,0,null,"blocked"],"request":"/requests/1/2"},"passed":true},{"actual":{"decision":[["/a"],false,0,null,"redirect"],"request":"/requests/1/3"},"check":"fixture 4","expected":{"decision":[["/a"],false,0,null,"redirect"],"request":"/requests/1/3"},"passed":true},{"actual":{"decision":[["/b","/c"],false,1,"/b","canceled"],"request":"/requests/1/4"},"check":"fixture 5","expected":{"decision":[["/b","/c"],false,1,"/b","canceled"],"request":"/requests/1/4"},"passed":true},{"actual":{"decision":[["/a","/b"],false,2,"/a","blocked"],"request":"/requests/1/5"},"check":"fixture 6","expected":{"decision":[["/a","/b"],false,2,"/b","blocked"],"request":"/requests/1/5"},"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": {\"request\": \"/requests/1/0\", \"decision\": [[\"/a\", \"/b\", \"/a\"], false, 3, \"/a\", \"canceled\"]}, \"expected\": {\"request\": \"/requests/1/0\", \"decision\": [[\"/a\", \"/b\", \"/a\"], false, 3, \"/a\", \"canceled\"]}, \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": {\"request\": \"/requests/1/1\", \"decision\": [[\"/a\", \"/b\", \"/c\"], false, 2, \"/a\", \"redirect\"]}, \"expected\": {\"request\": \"/requests/1/1\", \"decision\": [[\"/a\", \"/b\", \"/c\"], false, 2, \"/b\", \"redirect\"]}, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": {\"request\": \"/requests/1/2\", \"decision\": [[], true, 0, null, \"blocked\"]}, \"expected\": {\"request\": \"/requests/1/2\", \"decision\": [[], true, 0, null, \"blocked\"]}, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": {\"request\": \"/requests/1/3\", \"decision\": [[\"/a\"], false, 0, null, \"redirect\"]}, \"expected\": {\"request\": \"/requests/1/3\", \"decision\": [[\"/a\"], false, 0, null, \"redirect\"]}, \"passed\": true}, {\"check\": \"fixture 5\", \"actual\": {\"request\": \"/requests/1/4\", \"decision\": [[\"/b\", \"/c\"], false, 1, \"/b\", \"canceled\"]}, \"expected\": {\"request\": \"/requests/1/4\", \"decision\": [[\"/b\", \"/c\"], false, 1, \"/b\", \"canceled\"]}, \"passed\": true}, {\"check\": \"fixture 6\", \"actual\": {\"request\": \"/requests/1/5\", \"decision\": [[\"/a\", \"/b\"], false, 2, \"/a\", \"blocked\"]}, \"expected\": {\"request\": \"/requests/1/5\", \"decision\": [[\"/a\", \"/b\"], false, 2, \"/b\", \"blocked\"]}, \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":37.238,"exit_code":0,"observations":[{"actual":{"decision":[["/a","/b","/a"],false,3,"/a","canceled"],"request":"/requests/1/0"},"check":"fixture 1","expected":{"decision":[["/a","/b","/a"],false,3,"/a","canceled"],"request":"/requests/1/0"},"passed":true},{"actual":{"decision":[["/a","/b","/c"],false,2,"/b","redirect"],"request":"/requests/1/1"},"check":"fixture 2","expected":{"decision":[["/a","/b","/c"],false,2,"/b","redirect"],"request":"/requests/1/1"},"passed":true},{"actual":{"decision":[[],true,0,null,"blocked"],"request":"/requests/1/2"},"check":"fixture 3","expected":{"decision":[[],true,0,null,"blocked"],"request":"/requests/1/2"},"passed":true},{"actual":{"decision":[["/a"],false,0,null,"redirect"],"request":"/requests/1/3"},"check":"fixture 4","expected":{"decision":[["/a"],false,0,null,"redirect"],"request":"/requests/1/3"},"passed":true},{"actual":{"decision":[["/b","/c"],false,1,"/b","canceled"],"request":"/requests/1/4"},"check":"fixture 5","expected":{"decision":[["/b","/c"],false,1,"/b","canceled"],"request":"/requests/1/4"},"passed":true},{"actual":{"decision":[["/a","/b"],false,2,"/b","blocked"],"request":"/requests/1/5"},"check":"fixture 6","expected":{"decision":[["/a","/b"],false,2,"/b","blocked"],"request":"/requests/1/5"},"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": {\"request\": \"/requests/1/0\", \"decision\": [[\"/a\", \"/b\", \"/a\"], false, 3, \"/a\", \"canceled\"]}, \"expected\": {\"request\": \"/requests/1/0\", \"decision\": [[\"/a\", \"/b\", \"/a\"], false, 3, \"/a\", \"canceled\"]}, \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": {\"request\": \"/requests/1/1\", \"decision\": [[\"/a\", \"/b\", \"/c\"], false, 2, \"/b\", \"redirect\"]}, \"expected\": {\"request\": \"/requests/1/1\", \"decision\": [[\"/a\", \"/b\", \"/c\"], false, 2, \"/b\", \"redirect\"]}, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": {\"request\": \"/requests/1/2\", \"decision\": [[], true, 0, null, \"blocked\"]}, \"expected\": {\"request\": \"/requests/1/2\", \"decision\": [[], true, 0, null, \"blocked\"]}, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": {\"request\": \"/requests/1/3\", \"decision\": [[\"/a\"], false, 0, null, \"redirect\"]}, \"expected\": {\"request\": \"/requests/1/3\", \"decision\": [[\"/a\"], false, 0, null, \"redirect\"]}, \"passed\": true}, {\"check\": \"fixture 5\", \"actual\": {\"request\": \"/requests/1/4\", \"decision\": [[\"/b\", \"/c\"], false, 1, \"/b\", \"canceled\"]}, \"expected\": {\"request\": \"/requests/1/4\", \"decision\": [[\"/b\", \"/c\"], false, 1, \"/b\", \"canceled\"]}, \"passed\": true}, {\"check\": \"fixture 6\", \"actual\": {\"request\": \"/requests/1/5\", \"decision\": [[\"/a\", \"/b\"], false, 2, \"/b\", \"blocked\"]}, \"expected\": {\"request\": \"/requests/1/5\", \"decision\": [[\"/a\", \"/b\"], false, 2, \"/b\", \"blocked\"]}, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}