{"abstract":"Left arrows wrap into the previous grid edge.","category":"Keyboard accessibility","checks":11,"contract":"Arrow keys move one cell and clamp without wrapping; Home/End target row edges; Control additionally targets the first/last row.","contract_signature":"rows, columns, row, column, key, ctrl","evaluation_group":"xi-grid-navigation","failed_approach":"Moving by two skips adjacent cells.","family":"xi-grid-navigation-left-clamp","id":"FA-8356","implementations":{"attempt":{"sha256":"1194df07e482378eee612081188d4e0f894572e5886859aad09c93a7c38acf12","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(rows, columns, row, column, key, ctrl):\n    if key == 'Left': column = max(0, column-2)\n    elif key == 'Right': column = min(columns-1, column+1)\n    elif key == 'Up': row = max(0, row-1)\n    elif key == 'Down': row = min(rows-1, row+1)\n    elif key == 'Home': column = 0; row = 0 if ctrl else row\n    elif key == 'End': column = columns-1; row = rows-1 if ctrl else row\n    return (row, column)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('left boundary', solve(3, 5, 1, 0, 'Left', False), (1, 0))\ncheck('left step', solve(3, 5, 1, 3, 'Left', False), (1, 2))\ncheck('right boundary', solve(3, 5, 1, 4, 'Right', False), (1, 4))\ncheck('right step', solve(3, 5, 1, 3, 'Right', False), (1, 4))\ncheck('up', solve(3, 5, 1, 3, 'Up', False), (0, 3))\ncheck('home', solve(3, 5, 1, 3, 'Home', False), (1, 0))\ncheck('ctrl home', solve(3, 5, 1, 3, 'Home', True), (0, 0))\ncheck('end', solve(3, 5, 1, 3, 'End', False), (1, 4))\ncheck('ctrl end', solve(3, 5, 1, 3, 'End', True), (2, 4))\ncheck('parameterized grid shape', solve(N+2,N+3,N,N,'Right',False), (N,N+1))\nfor repetition in range(N):\n    check('repeat ctrl end', solve(3, 5, 1, 3, 'End', True), (2, 4))\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":"1f9b733c97899060567c33b508d99474acb94234d48d8f50fb11e4f55dab6bdd","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(rows, columns, row, column, key, ctrl):\n    if key == 'Left': column = (column-1) % columns\n    elif key == 'Right': column = min(columns-1, column+1)\n    elif key == 'Up': row = max(0, row-1)\n    elif key == 'Down': row = min(rows-1, row+1)\n    elif key == 'Home': column = 0; row = 0 if ctrl else row\n    elif key == 'End': column = columns-1; row = rows-1 if ctrl else row\n    return (row, column)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('left boundary', solve(3, 5, 1, 0, 'Left', False), (1, 0))\ncheck('left step', solve(3, 5, 1, 3, 'Left', False), (1, 2))\ncheck('right boundary', solve(3, 5, 1, 4, 'Right', False), (1, 4))\ncheck('right step', solve(3, 5, 1, 3, 'Right', False), (1, 4))\ncheck('up', solve(3, 5, 1, 3, 'Up', False), (0, 3))\ncheck('home', solve(3, 5, 1, 3, 'Home', False), (1, 0))\ncheck('ctrl home', solve(3, 5, 1, 3, 'Home', True), (0, 0))\ncheck('end', solve(3, 5, 1, 3, 'End', False), (1, 4))\ncheck('ctrl end', solve(3, 5, 1, 3, 'End', True), (2, 4))\ncheck('parameterized grid shape', solve(N+2,N+3,N,N,'Right',False), (N,N+1))\nfor repetition in range(N):\n    check('repeat ctrl end', solve(3, 5, 1, 3, 'End', True), (2, 4))\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":" 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":"xi-grid-navigation-left-clamp","generated_at":"2026-09-29T14:38:20.783411+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic model of grid-cell keyboard movement; this isolates one interface invariant without requiring a browser.","root_cause":"The left clamp operation uses `(column-1) % columns` where the contract requires `max(0, column-1)`.","sha256":"af046650a4e6f5f7494c143ba8aa5b53219df726840ebc89af159623f4d75e42","title":"Grid-cell keyboard movement: Left arrows wrap into the previous grid edge · 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":40.366,"exit_code":1,"observations":[{"actual":[1,0],"check":"left boundary","expected":[1,0],"passed":true},{"actual":[1,1],"check":"left step","expected":[1,2],"passed":false},{"actual":[1,4],"check":"right boundary","expected":[1,4],"passed":true},{"actual":[1,4],"check":"right step","expected":[1,4],"passed":true},{"actual":[0,3],"check":"up","expected":[0,3],"passed":true},{"actual":[1,0],"check":"home","expected":[1,0],"passed":true},{"actual":[0,0],"check":"ctrl home","expected":[0,0],"passed":true},{"actual":[1,4],"check":"end","expected":[1,4],"passed":true},{"actual":[2,4],"check":"ctrl end","expected":[2,4],"passed":true},{"actual":[1,2],"check":"parameterized grid shape","expected":[1,2],"passed":true},{"actual":[2,4],"check":"repeat ctrl end","expected":[2,4],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"left boundary\", \"actual\": [1, 0], \"expected\": [1, 0], \"passed\": true}, {\"check\": \"left step\", \"actual\": [1, 1], \"expected\": [1, 2], \"passed\": false}, {\"check\": \"right boundary\", \"actual\": [1, 4], \"expected\": [1, 4], \"passed\": true}, {\"check\": \"right step\", \"actual\": [1, 4], \"expected\": [1, 4], \"passed\": true}, {\"check\": \"up\", \"actual\": [0, 3], \"expected\": [0, 3], \"passed\": true}, {\"check\": \"home\", \"actual\": [1, 0], \"expected\": [1, 0], \"passed\": true}, {\"check\": \"ctrl home\", \"actual\": [0, 0], \"expected\": [0, 0], \"passed\": true}, {\"check\": \"end\", \"actual\": [1, 4], \"expected\": [1, 4], \"passed\": true}, {\"check\": \"ctrl end\", \"actual\": [2, 4], \"expected\": [2, 4], \"passed\": true}, {\"check\": \"parameterized grid shape\", \"actual\": [1, 2], \"expected\": [1, 2], \"passed\": true}, {\"check\": \"repeat ctrl end\", \"actual\": [2, 4], \"expected\": [2, 4], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.362,"exit_code":1,"observations":[{"actual":[1,4],"check":"left boundary","expected":[1,0],"passed":false},{"actual":[1,2],"check":"left step","expected":[1,2],"passed":true},{"actual":[1,4],"check":"right boundary","expected":[1,4],"passed":true},{"actual":[1,4],"check":"right step","expected":[1,4],"passed":true},{"actual":[0,3],"check":"up","expected":[0,3],"passed":true},{"actual":[1,0],"check":"home","expected":[1,0],"passed":true},{"actual":[0,0],"check":"ctrl home","expected":[0,0],"passed":true},{"actual":[1,4],"check":"end","expected":[1,4],"passed":true},{"actual":[2,4],"check":"ctrl end","expected":[2,4],"passed":true},{"actual":[1,2],"check":"parameterized grid shape","expected":[1,2],"passed":true},{"actual":[2,4],"check":"repeat ctrl end","expected":[2,4],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"left boundary\", \"actual\": [1, 4], \"expected\": [1, 0], \"passed\": false}, {\"check\": \"left step\", \"actual\": [1, 2], \"expected\": [1, 2], \"passed\": true}, {\"check\": \"right boundary\", \"actual\": [1, 4], \"expected\": [1, 4], \"passed\": true}, {\"check\": \"right step\", \"actual\": [1, 4], \"expected\": [1, 4], \"passed\": true}, {\"check\": \"up\", \"actual\": [0, 3], \"expected\": [0, 3], \"passed\": true}, {\"check\": \"home\", \"actual\": [1, 0], \"expected\": [1, 0], \"passed\": true}, {\"check\": \"ctrl home\", \"actual\": [0, 0], \"expected\": [0, 0], \"passed\": true}, {\"check\": \"end\", \"actual\": [1, 4], \"expected\": [1, 4], \"passed\": true}, {\"check\": \"ctrl end\", \"actual\": [2, 4], \"expected\": [2, 4], \"passed\": true}, {\"check\": \"parameterized grid shape\", \"actual\": [1, 2], \"expected\": [1, 2], \"passed\": true}, {\"check\": \"repeat ctrl end\", \"actual\": [2, 4], \"expected\": [2, 4], \"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."}}