{"abstract":"Carets attached to RTL characters appear on the wrong side.","category":"Bidirectional text layout","checks":8,"contract":"Input [levels, logical caret offset k, affinity]. Characters are one unit wide and visually ordered by level reversal. Affinity \"after\" attaches the caret to the leading edge of character k (if k < n), otherwise to the trailing edge of character k-1; offset 0 always uses the leading edge of character 0. The leading edge of an LTR character is its left side, of an RTL (odd) character its right side. Return the visual x.","contract_signature":"x","evaluation_group":"w2-bidirectional-text-layout-caret-position","failed_approach":"Always using the right side breaks LTR characters.","family":"w2-bidirectional-text-layout-caret-position-leading-edge-side","id":"FA-80631","implementations":{"attempt":{"sha256":"717a454435d2c99d2f43f336c70c6c591bbe94ffdefbe4b87370bf773f57ab4c","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    def reorder(lv):\n        vis = list(range(len(lv)))\n        odd = [l for l in lv if l % 2 == 1]\n        if not odd:\n            return vis\n        for lev in range(max(lv), min(odd) - 1, -1):\n            i = 0\n            while i < len(vis):\n                if lv[vis[i]] >= lev:\n                    j = i\n                    while j < len(vis) and lv[vis[j]] >= lev:\n                        j += 1\n                    vis[i:j] = vis[i:j][::-1]\n                    i = j\n                else:\n                    i += 1\n        return vis\n    \n    levels, k, affinity = x\n    n = len(levels)\n    if n == 0:\n        return 0\n    vis = reorder(levels)\n    pos = [0] * n\n    for v, i in enumerate(vis):\n        pos[i] = v\n    if affinity == 'after' and k < n or k == 0:\n        j = k\n        leading = True\n    else:\n        j = k - 1\n        leading = False\n    rtl = levels[j] % 2 == 1\n    if leading:\n        return pos[j] + 1\n    return pos[j] if rtl else pos[j] + 1\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('same boundary after', [[0, 0, 1, 1], 2, 'after'], 4), ('regression: leading edge side', [[1, 1, 1, 0], 0, 'after'], 3), ('regression: leading edge side', [[2, 0], 0, 'after'], 0), ('regression: leading edge side', [[2, 2, 2, 2, 2, 3, 3, 2, 1], 0, 'before'], 1), ('line end', [[1, 1, 1], 3, 'after'], 0), ('caret at direction boundary', [[0, 0, 1, 1], 2, 'before'], 2), ('control layout', [[3, 3, 3, 2, 2, 3, 3, 3, 3, 2], 9, 'before'], 5), ('control layout', [[2, 2, 2, 2, 1, 1, 3], 3, 'before'], 6)], [('regression: leading edge side', [[1, 1, 1, 1, 0, 1, 1, 1], 4, 'after'], 4), ('regression: leading edge side', [[4, 3, 3, 3], 3, 'after'], 1), ('regression: leading edge side', [[2, 2, 2, 2, 2, 2, 2], 2, 'after'], 2), ('regression: leading edge side', [[4], 0, 'after'], 0), ('line start before', [[1, 1, 0], 0, 'before'], 2), ('same boundary after', [[0, 0, 1, 1], 2, 'after'], 4), ('control layout', [[1, 1, 1, 1, 3, 3, 1, 1], 1, 'before'], 7), ('control layout', [[0, 0, 1, 1, 2, 2, 2, 0, 0], 6, 'before'], 4)], [('regression: leading edge side', [[2, 2, 2, 2, 2, 2, 2, 1, 1], 1, 'after'], 3), ('regression: leading edge side', [[2, 2, 2, 2, 1], 4, 'after'], 1), ('regression: leading edge side', [[3, 0, 0, 0, 2, 2, 2], 3, 'after'], 3), ('regression: leading edge side', [[3, 2, 2, 2, 1, 1, 3, 3, 3], 1, 'after'], 6), ('same boundary after', [[0, 0, 1, 1], 2, 'after'], 4), ('line end', [[1, 1, 1], 3, 'after'], 0), ('control layout', [[1, 1, 1, 1, 3, 3, 3], 4, 'before'], 3), ('control layout', [[0, 0, 0, 1, 3, 3, 3, 3], 6, 'before'], 5)], [('regression: leading edge side', [[3, 3, 3, 3, 1, 1, 1], 6, 'after'], 1), ('regression: leading edge side', [[1, 1], 1, 'after'], 1), ('regression: leading edge side', [[2, 2, 3, 3, 3, 1, 1, 3], 0, 'after'], 3), ('regression: leading edge side', [[4, 4, 4, 4, 2], 1, 'after'], 1), ('caret at direction boundary', [[0, 0, 1, 1], 2, 'before'], 2), ('same boundary after', [[0, 0, 1, 1], 2, 'after'], 4), ('control layout', [[2, 2, 2, 3, 3, 2, 2, 2, 3, 3], 10, 'after'], 8), ('control layout', [[1, 1, 1, 1, 1, 0, 2, 2], 4, 'before'], 1)], [('regression: leading edge side', [[2, 2, 2, 4, 4, 4, 4, 3, 3], 4, 'after'], 6), ('regression: leading edge side', [[1, 1, 1, 1, 1], 2, 'after'], 3), ('regression: leading edge side', [[2, 2, 1, 1], 0, 'after'], 2), ('regression: leading edge side', [[3, 3, 2, 2, 2, 2, 2, 2, 1, 1], 7, 'after'], 9), ('line end', [[1, 1, 1], 3, 'after'], 0), ('same boundary after', [[0, 0, 1, 1], 2, 'after'], 4), ('control layout', [[2, 3, 4, 1, 1, 1, 1, 2], 5, 'before'], 3), ('control layout', [[1, 1, 1, 3, 3, 3, 3, 1, 1, 1], 9, 'before'], 1)]]\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":"64ee8ca0dbca149ef312909664a23d78361f05eb194562ce41fa5e75fe44033f","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    def reorder(lv):\n        vis = list(range(len(lv)))\n        odd = [l for l in lv if l % 2 == 1]\n        if not odd:\n            return vis\n        for lev in range(max(lv), min(odd) - 1, -1):\n            i = 0\n            while i < len(vis):\n                if lv[vis[i]] >= lev:\n                    j = i\n                    while j < len(vis) and lv[vis[j]] >= lev:\n                        j += 1\n                    vis[i:j] = vis[i:j][::-1]\n                    i = j\n                else:\n                    i += 1\n        return vis\n    \n    levels, k, affinity = x\n    n = len(levels)\n    if n == 0:\n        return 0\n    vis = reorder(levels)\n    pos = [0] * n\n    for v, i in enumerate(vis):\n        pos[i] = v\n    if affinity == 'after' and k < n or k == 0:\n        j = k\n        leading = True\n    else:\n        j = k - 1\n        leading = False\n    rtl = levels[j] % 2 == 1\n    if leading:\n        return pos[j] if rtl else pos[j] + 1\n    return pos[j] if rtl else pos[j] + 1\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('same boundary after', [[0, 0, 1, 1], 2, 'after'], 4), ('regression: leading edge side', [[1, 1, 1, 0], 0, 'after'], 3), ('regression: leading edge side', [[2, 0], 0, 'after'], 0), ('regression: leading edge side', [[2, 2, 2, 2, 2, 3, 3, 2, 1], 0, 'before'], 1), ('line end', [[1, 1, 1], 3, 'after'], 0), ('caret at direction boundary', [[0, 0, 1, 1], 2, 'before'], 2), ('control layout', [[3, 3, 3, 2, 2, 3, 3, 3, 3, 2], 9, 'before'], 5), ('control layout', [[2, 2, 2, 2, 1, 1, 3], 3, 'before'], 6)], [('regression: leading edge side', [[1, 1, 1, 1, 0, 1, 1, 1], 4, 'after'], 4), ('regression: leading edge side', [[4, 3, 3, 3], 3, 'after'], 1), ('regression: leading edge side', [[2, 2, 2, 2, 2, 2, 2], 2, 'after'], 2), ('regression: leading edge side', [[4], 0, 'after'], 0), ('line start before', [[1, 1, 0], 0, 'before'], 2), ('same boundary after', [[0, 0, 1, 1], 2, 'after'], 4), ('control layout', [[1, 1, 1, 1, 3, 3, 1, 1], 1, 'before'], 7), ('control layout', [[0, 0, 1, 1, 2, 2, 2, 0, 0], 6, 'before'], 4)], [('regression: leading edge side', [[2, 2, 2, 2, 2, 2, 2, 1, 1], 1, 'after'], 3), ('regression: leading edge side', [[2, 2, 2, 2, 1], 4, 'after'], 1), ('regression: leading edge side', [[3, 0, 0, 0, 2, 2, 2], 3, 'after'], 3), ('regression: leading edge side', [[3, 2, 2, 2, 1, 1, 3, 3, 3], 1, 'after'], 6), ('same boundary after', [[0, 0, 1, 1], 2, 'after'], 4), ('line end', [[1, 1, 1], 3, 'after'], 0), ('control layout', [[1, 1, 1, 1, 3, 3, 3], 4, 'before'], 3), ('control layout', [[0, 0, 0, 1, 3, 3, 3, 3], 6, 'before'], 5)], [('regression: leading edge side', [[3, 3, 3, 3, 1, 1, 1], 6, 'after'], 1), ('regression: leading edge side', [[1, 1], 1, 'after'], 1), ('regression: leading edge side', [[2, 2, 3, 3, 3, 1, 1, 3], 0, 'after'], 3), ('regression: leading edge side', [[4, 4, 4, 4, 2], 1, 'after'], 1), ('caret at direction boundary', [[0, 0, 1, 1], 2, 'before'], 2), ('same boundary after', [[0, 0, 1, 1], 2, 'after'], 4), ('control layout', [[2, 2, 2, 3, 3, 2, 2, 2, 3, 3], 10, 'after'], 8), ('control layout', [[1, 1, 1, 1, 1, 0, 2, 2], 4, 'before'], 1)], [('regression: leading edge side', [[2, 2, 2, 4, 4, 4, 4, 3, 3], 4, 'after'], 6), ('regression: leading edge side', [[1, 1, 1, 1, 1], 2, 'after'], 3), ('regression: leading edge side', [[2, 2, 1, 1], 0, 'after'], 2), ('regression: leading edge side', [[3, 3, 2, 2, 2, 2, 2, 2, 1, 1], 7, 'after'], 9), ('line end', [[1, 1, 1], 3, 'after'], 0), ('same boundary after', [[0, 0, 1, 1], 2, 'after'], 4), ('control layout', [[2, 3, 4, 1, 1, 1, 1, 2], 5, 'before'], 3), ('control layout', [[1, 1, 1, 3, 3, 3, 3, 1, 1, 1], 9, 'before'], 1)]]\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-caret-position-leading-edge-side","generated_at":"2026-09-29T14:49:55.538675+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 leading-edge formula uses the trailing-edge sides.","sha256":"2a83f34bec84899f9109f2962c7d1becde7d46420dd2f18836a8a4f14f31d8b4","title":"Caret visual position: leading edge side · 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":42.238,"exit_code":1,"observations":[{"actual":4,"check":"same boundary after","expected":4,"passed":true},{"actual":3,"check":"regression: leading edge side","expected":3,"passed":true},{"actual":1,"check":"regression: leading edge side","expected":0,"passed":false},{"actual":2,"check":"regression: leading edge side","expected":1,"passed":false},{"actual":0,"check":"line end","expected":0,"passed":true},{"actual":2,"check":"caret at direction boundary","expected":2,"passed":true},{"actual":5,"check":"control layout","expected":5,"passed":true},{"actual":6,"check":"control layout","expected":6,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"same boundary after\", \"actual\": 4, \"expected\": 4, \"passed\": true}, {\"check\": \"regression: leading edge side\", \"actual\": 3, \"expected\": 3, \"passed\": true}, {\"check\": \"regression: leading edge side\", \"actual\": 1, \"expected\": 0, \"passed\": false}, {\"check\": \"regression: leading edge side\", \"actual\": 2, \"expected\": 1, \"passed\": false}, {\"check\": \"line end\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"caret at direction boundary\", \"actual\": 2, \"expected\": 2, \"passed\": true}, {\"check\": \"control layout\", \"actual\": 5, \"expected\": 5, \"passed\": true}, {\"check\": \"control layout\", \"actual\": 6, \"expected\": 6, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.502,"exit_code":1,"observations":[{"actual":3,"check":"same boundary after","expected":4,"passed":false},{"actual":2,"check":"regression: leading edge side","expected":3,"passed":false},{"actual":1,"check":"regression: leading edge side","expected":0,"passed":false},{"actual":2,"check":"regression: leading edge side","expected":1,"passed":false},{"actual":0,"check":"line end","expected":0,"passed":true},{"actual":2,"check":"caret at direction boundary","expected":2,"passed":true},{"actual":5,"check":"control layout","expected":5,"passed":true},{"actual":6,"check":"control layout","expected":6,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"same boundary after\", \"actual\": 3, \"expected\": 4, \"passed\": false}, {\"check\": \"regression: leading edge side\", \"actual\": 2, \"expected\": 3, \"passed\": false}, {\"check\": \"regression: leading edge side\", \"actual\": 1, \"expected\": 0, \"passed\": false}, {\"check\": \"regression: leading edge side\", \"actual\": 2, \"expected\": 1, \"passed\": false}, {\"check\": \"line end\", \"actual\": 0, \"expected\": 0, \"passed\": true}, {\"check\": \"caret at direction boundary\", \"actual\": 2, \"expected\": 2, \"passed\": true}, {\"check\": \"control layout\", \"actual\": 5, \"expected\": 5, \"passed\": true}, {\"check\": \"control layout\", \"actual\": 6, \"expected\": 6, \"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."}}