{"abstract":"Overflowing centered lines hang off both edges.","category":"Bidirectional text layout","checks":8,"contract":"Input [line width, content width, align, rtl]. justify (last line) behaves as start. start = left for LTR, right for RTL; end is the opposite. Overflowing centered content aligns to start. center offset is floor(slack/2) for LTR and ceil(slack/2) for RTL. Return the x offset of the content.","contract_signature":"x","evaluation_group":"w2-bidirectional-text-layout-direction-alignment","failed_approach":"Falling back to left regardless of direction clips RTL starts.","family":"w2-bidirectional-text-layout-direction-alignment-overflowing-center-fallback","id":"FA-80741","implementations":{"attempt":{"sha256":"cbdf15ef52cc6c2018415dc68c60389111ebaa5ac81e3aa6a0b688fe0aa26ec1","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    lw, cw, align, rtl = x\n    if align == 'justify':\n        align = 'start'\n    if align == 'start':\n        align = 'right' if rtl else 'left'\n    elif align == 'end':\n        align = 'left' if rtl else 'right'\n    if cw > lw and align == 'center':\n        align = 'left'\n    if align == 'left':\n        return 0\n    if align == 'right':\n        return lw - cw\n    slack = lw - cw\n    return (slack + 1) // 2 if rtl else slack // 2\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('overflowing center RTL', [10, 15, 'center', True], -5), ('regression: overflowing center fallback', [17, 50, 'center', False], 0), ('regression: overflowing center fallback', [17, 45, 'center', True], -28), ('regression: overflowing center fallback', [29, 32, 'center', True], -3), ('RTL end is left', [20, 5, 'end', True], 0), ('odd slack RTL center', [20, 5, 'center', True], 8), ('control layout', [37, 42, 'start', False], 0), ('control layout', [36, 39, 'right', False], -3)], [('regression: overflowing center fallback', [13, 20, 'center', False], 0), ('regression: overflowing center fallback', [26, 42, 'center', False], 0), ('regression: overflowing center fallback', [37, 38, 'center', True], -1), ('regression: overflowing center fallback', [12, 13, 'center', True], -1), ('RTL end is left', [20, 5, 'end', True], 0), ('overflowing center RTL', [10, 15, 'center', True], -5), ('control layout', [29, 31, 'left', False], 0), ('control layout', [37, 29, 'left', True], 0)], [('regression: overflowing center fallback', [10, 49, 'center', True], -39), ('overflowing center RTL', [10, 15, 'center', True], -5), ('regression: overflowing center fallback', [19, 31, 'center', True], -12), ('regression: overflowing center fallback', [24, 25, 'center', True], -1), ('odd slack RTL center', [20, 5, 'center', True], 8), ('RTL end is left', [20, 5, 'end', True], 0), ('control layout', [26, 13, 'left', True], 0), ('control layout', [36, 2, 'left', False], 0)], [('regression: overflowing center fallback', [37, 38, 'center', True], -1), ('regression: overflowing center fallback', [13, 28, 'center', False], 0), ('regression: overflowing center fallback', [32, 42, 'center', True], -10), ('regression: overflowing center fallback', [21, 22, 'center', True], -1), ('RTL end is left', [20, 5, 'end', True], 0), ('odd slack RTL center', [20, 5, 'center', True], 8), ('control layout', [22, 27, 'justify', True], -5), ('control layout', [10, 19, 'left', False], 0)], [('regression: overflowing center fallback', [24, 33, 'center', False], 0), ('regression: overflowing center fallback', [15, 28, 'center', False], 0), ('regression: overflowing center fallback', [17, 28, 'center', True], -11), ('regression: overflowing center fallback', [19, 25, 'center', True], -6), ('overflowing center RTL', [10, 15, 'center', True], -5), ('RTL end is left', [20, 5, 'end', True], 0), ('control layout', [17, 26, 'end', True], 0), ('control layout', [23, 9, 'start', True], 14)]]\nfor label, args, expected in fixtures[N - 1]:\n    check(label, solve(args), expected)\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":"1420902b80b0fe20f5abd3cd4fa212b8ca2bd1b0b0cb3e43f63a9659eebd27d2","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    lw, cw, align, rtl = x\n    if align == 'justify':\n        align = 'start'\n    if align == 'start':\n        align = 'right' if rtl else 'left'\n    elif align == 'end':\n        align = 'left' if rtl else 'right'\n    if cw > lw and align == 'start':\n        align = 'left' if not rtl else 'right'\n    if align == 'left':\n        return 0\n    if align == 'right':\n        return lw - cw\n    slack = lw - cw\n    return (slack + 1) // 2 if rtl else slack // 2\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('overflowing center RTL', [10, 15, 'center', True], -5), ('regression: overflowing center fallback', [17, 50, 'center', False], 0), ('regression: overflowing center fallback', [17, 45, 'center', True], -28), ('regression: overflowing center fallback', [29, 32, 'center', True], -3), ('RTL end is left', [20, 5, 'end', True], 0), ('odd slack RTL center', [20, 5, 'center', True], 8), ('control layout', [37, 42, 'start', False], 0), ('control layout', [36, 39, 'right', False], -3)], [('regression: overflowing center fallback', [13, 20, 'center', False], 0), ('regression: overflowing center fallback', [26, 42, 'center', False], 0), ('regression: overflowing center fallback', [37, 38, 'center', True], -1), ('regression: overflowing center fallback', [12, 13, 'center', True], -1), ('RTL end is left', [20, 5, 'end', True], 0), ('overflowing center RTL', [10, 15, 'center', True], -5), ('control layout', [29, 31, 'left', False], 0), ('control layout', [37, 29, 'left', True], 0)], [('regression: overflowing center fallback', [10, 49, 'center', True], -39), ('overflowing center RTL', [10, 15, 'center', True], -5), ('regression: overflowing center fallback', [19, 31, 'center', True], -12), ('regression: overflowing center fallback', [24, 25, 'center', True], -1), ('odd slack RTL center', [20, 5, 'center', True], 8), ('RTL end is left', [20, 5, 'end', True], 0), ('control layout', [26, 13, 'left', True], 0), ('control layout', [36, 2, 'left', False], 0)], [('regression: overflowing center fallback', [37, 38, 'center', True], -1), ('regression: overflowing center fallback', [13, 28, 'center', False], 0), ('regression: overflowing center fallback', [32, 42, 'center', True], -10), ('regression: overflowing center fallback', [21, 22, 'center', True], -1), ('RTL end is left', [20, 5, 'end', True], 0), ('odd slack RTL center', [20, 5, 'center', True], 8), ('control layout', [22, 27, 'justify', True], -5), ('control layout', [10, 19, 'left', False], 0)], [('regression: overflowing center fallback', [24, 33, 'center', False], 0), ('regression: overflowing center fallback', [15, 28, 'center', False], 0), ('regression: overflowing center fallback', [17, 28, 'center', True], -11), ('regression: overflowing center fallback', [19, 25, 'center', True], -6), ('overflowing center RTL', [10, 15, 'center', True], -5), ('RTL end is left', [20, 5, 'end', True], 0), ('control layout', [17, 26, 'end', True], 0), ('control layout', [23, 9, 'start', True], 14)]]\nfor label, args, expected in fixtures[N - 1]:\n    check(label, solve(args), expected)\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":"A deterministic toy bidi model over stipulated class labels and integer levels; it is inspired by, but does not claim conformance to, any published algorithm. 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":"w2-bidirectional-text-layout-direction-alignment-overflowing-center-fallback","generated_at":"2026-09-29T14:49:56.743373+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Mixed right-to-left and left-to-right text must resolve levels and visual order exactly, or words, numbers and carets land in the wrong place.","root_cause":"The overflow fallback checks the wrong alignment value.","sha256":"7272cea60170fd804d9c9361a88e128538a38999feae5f9ad7a84ea7722c46fe","title":"Direction-relative alignment: overflowing center fallback · 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":40.811,"exit_code":1,"observations":[{"actual":0,"check":"overflowing center RTL","expected":-5,"passed":false},{"actual":0,"check":"regression: overflowing center fallback","expected":0,"passed":true},{"actual":0,"check":"regression: overflowing center fallback","expected":-28,"passed":false},{"actual":0,"check":"regression: overflowing center fallback","expected":-3,"passed":false},{"actual":0,"check":"RTL end is left","expected":0,"passed":true},{"actual":8,"check":"odd slack RTL center","expected":8,"passed":true},{"actual":0,"check":"control layout","expected":0,"passed":true},{"actual":-3,"check":"control layout","expected":-3,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"overflowing center RTL\", \"actual\": 0, \"expected\": -5, \"passed\": false}, {\"check\": \"regression: overflowing center fallback\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"regression: overflowing center fallback\", \"actual\": 0, \"expected\": -28, \"passed\": false}, {\"check\": \"regression: overflowing center fallback\", \"actual\": 0, \"expected\": -3, \"passed\": false}, {\"check\": \"RTL end is left\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"odd slack RTL center\", \"actual\": 8, \"expected\": 8, \"passed\": true}, {\"check\": \"control layout\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"control layout\", \"actual\": -3, \"expected\": -3, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.549,"exit_code":1,"observations":[{"actual":-2,"check":"overflowing center RTL","expected":-5,"passed":false},{"actual":-17,"check":"regression: overflowing center fallback","expected":0,"passed":false},{"actual":-14,"check":"regression: overflowing center fallback","expected":-28,"passed":false},{"actual":-1,"check":"regression: overflowing center fallback","expected":-3,"passed":false},{"actual":0,"check":"RTL end is left","expected":0,"passed":true},{"actual":8,"check":"odd slack RTL center","expected":8,"passed":true},{"actual":0,"check":"control layout","expected":0,"passed":true},{"actual":-3,"check":"control layout","expected":-3,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"overflowing center RTL\", \"actual\": -2, \"expected\": -5, \"passed\": false}, {\"check\": \"regression: overflowing center fallback\", \"actual\": -17, \"expected\": 0, \"passed\": false}, {\"check\": \"regression: overflowing center fallback\", \"actual\": -14, \"expected\": -28, \"passed\": false}, {\"check\": \"regression: overflowing center fallback\", \"actual\": -1, \"expected\": -3, \"passed\": false}, {\"check\": \"RTL end is left\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"odd slack RTL center\", \"actual\": 8, \"expected\": 8, \"passed\": true}, {\"check\": \"control layout\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"control layout\", \"actual\": -3, \"expected\": -3, \"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."}}