{"abstract":"Any passage containing a double flat such as Gbb4 or Bbb4 is rejected as invalid.","category":"Music interval and transposition theory","checks":8,"contract":"Input [fifths, tokens]. fifths -7..7 gives signature sharps on F C G D A E B or flats on B E A D G C F. Tokens are \"|\" (barline) or letter + optional sign (# b x bb n) + single-digit octave. An explicit sign sets the alteration for that letter in that octave until the next barline (n = 0 cancels the signature); otherwise the signature applies. Return the MIDI numbers (C4 = 60) or None if any token or the signature is invalid.","contract_signature":"x","evaluation_group":"w2-music-interval-measure-accidentals","failed_approach":"Whitelisting a triple flat instead of the double flat still rejects bb tokens.","family":"w2-music-interval-measure-accidentals-double-flat-token","id":"FA-81001","implementations":{"attempt":{"sha256":"6e2cfbea63d5f7367b15234360df1402df788911a2efafa886086ac919036f0f","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    if not isinstance(x, list) or len(x) != 2:\n        return None\n    fifths, tokens = x\n    if not isinstance(fifths, int) or fifths < -7 or fifths > 7:\n        return None\n    base = {'C': 0, 'D': 2, 'E': 4, 'F': 5, 'G': 7, 'A': 9, 'B': 11}\n    keysig = {}\n    if fifths > 0:\n        for letter in 'FCGDAEB'[:fifths]:\n            keysig[letter] = 1\n    else:\n        for letter in 'BEADGCF'[:-fifths]:\n            keysig[letter] = -1\n    marks = {}\n    out = []\n    for tok in tokens:\n        if tok == '|':\n            marks = {}\n            continue\n        letter, sign, octave = tok[0], tok[1:-1], tok[-1]\n        if letter not in base or not octave.isdigit() or sign not in ('', '#', 'b', 'n', 'x', 'bbb'):\n            return None\n        slot = letter + octave\n        if sign:\n            marks[slot] = {'#': 1, 'b': -1, 'n': 0, 'x': 2, 'bb': -2}[sign]\n        alter = marks[slot] if slot in marks else keysig.get(letter, 0)\n        out.append(12 * (int(octave) + 1) + base[letter] + alter)\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[([1, ['F4', 'Fn4', 'F4', '|', 'F4']], [66, 65, 65, 66]), ([0, ['C#4', 'C4', '|', 'C4']], [61, 61, 60]), ([0, ['C#4', 'C5', 'C4']], [61, 72, 61]), ([-1, ['B4', 'Bn4', 'B4', '|', 'B4']], [70, 71, 71, 70]), ([-3, ['E4', 'A4', 'B4', 'D4']], [63, 68, 70, 62]), ([2, ['F4', 'C5', 'G4']], [66, 73, 67]), ([0, ['Gbb4', 'G4', '|', 'G4']], [65, 65, 67]), ([-1, ['Bbb4', 'B4', '|', 'B4']], [69, 69, 70])], [([-1, ['B4', 'Bn4', 'B4', '|', 'B4']], [70, 71, 71, 70]), ([-3, ['E4', 'A4', 'B4', 'D4']], [63, 68, 70, 62]), ([2, ['F4', 'C5', 'G4']], [66, 73, 67]), ([-2, ['Eb4', 'E4', 'En4', 'E4']], [63, 63, 64, 64]), ([0, ['Gbb4', 'G4', '|', 'G4']], [65, 65, 67]), ([3, ['Fx4', 'F4', '|', 'F4', 'G4']], [67, 67, 66, 68]), ([-7, ['F4', 'C4', 'B3']], [64, 59, 58]), ([-1, ['Bbb4', 'B4', '|', 'B4']], [69, 69, 70])], [([-2, ['Eb4', 'E4', 'En4', 'E4']], [63, 63, 64, 64]), ([0, ['Gbb4', 'G4', '|', 'G4']], [65, 65, 67]), ([3, ['Fx4', 'F4', '|', 'F4', 'G4']], [67, 67, 66, 68]), ([-7, ['F4', 'C4', 'B3']], [64, 59, 58]), ([7, ['B3', 'E4', 'C4']], [60, 65, 61]), ([8, ['C4']], None), ([0, ['H4']], None), ([-1, ['Bbb4', 'B4', '|', 'B4']], [69, 69, 70])], [([0, ['Gbb4', 'G4', '|', 'G4']], [65, 65, 67]), ([7, ['B3', 'E4', 'C4']], [60, 65, 61]), ([8, ['C4']], None), ([0, ['H4']], None), ([0, ['C#44']], None), ([4, ['D4', 'Dn4', 'D5', 'D4']], [63, 62, 75, 62]), ([-4, ['D4', 'Db4', 'D4', '|', 'D4']], [61, 61, 61, 61]), ([-1, ['Bbb4', 'B4', '|', 'B4']], [69, 69, 70])], [([0, ['Gbb4', 'G4', '|', 'G4']], [65, 65, 67]), ([0, ['C#44']], None), ([4, ['D4', 'Dn4', 'D5', 'D4']], [63, 62, 75, 62]), ([-4, ['D4', 'Db4', 'D4', '|', 'D4']], [61, 61, 61, 61]), ([5, ['A4', 'An4', '|', 'A4']], [70, 69, 70]), ([0, ['B#3', 'C4', 'B3', '|', 'B3']], [60, 60, 60, 59]), ([-5, ['G4', 'Gn4', 'G4', 'G5']], [66, 67, 67, 78]), ([-1, ['Bbb4', 'B4', '|', 'B4']], [69, 69, 70])]]\nfor i, (args, expected) in enumerate(fixtures[N-1]):\n    check(\"oracle %d\" % i, 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":"1a1cdee0d02f0f2f4da5453f2aecbfdba3bd0e4fd070d7d7a52e6a947e916605","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    if not isinstance(x, list) or len(x) != 2:\n        return None\n    fifths, tokens = x\n    if not isinstance(fifths, int) or fifths < -7 or fifths > 7:\n        return None\n    base = {'C': 0, 'D': 2, 'E': 4, 'F': 5, 'G': 7, 'A': 9, 'B': 11}\n    keysig = {}\n    if fifths > 0:\n        for letter in 'FCGDAEB'[:fifths]:\n            keysig[letter] = 1\n    else:\n        for letter in 'BEADGCF'[:-fifths]:\n            keysig[letter] = -1\n    marks = {}\n    out = []\n    for tok in tokens:\n        if tok == '|':\n            marks = {}\n            continue\n        letter, sign, octave = tok[0], tok[1:-1], tok[-1]\n        if letter not in base or not octave.isdigit() or sign not in ('', '#', 'b', 'n', 'x'):\n            return None\n        slot = letter + octave\n        if sign:\n            marks[slot] = {'#': 1, 'b': -1, 'n': 0, 'x': 2, 'bb': -2}[sign]\n        alter = marks[slot] if slot in marks else keysig.get(letter, 0)\n        out.append(12 * (int(octave) + 1) + base[letter] + alter)\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[([1, ['F4', 'Fn4', 'F4', '|', 'F4']], [66, 65, 65, 66]), ([0, ['C#4', 'C4', '|', 'C4']], [61, 61, 60]), ([0, ['C#4', 'C5', 'C4']], [61, 72, 61]), ([-1, ['B4', 'Bn4', 'B4', '|', 'B4']], [70, 71, 71, 70]), ([-3, ['E4', 'A4', 'B4', 'D4']], [63, 68, 70, 62]), ([2, ['F4', 'C5', 'G4']], [66, 73, 67]), ([0, ['Gbb4', 'G4', '|', 'G4']], [65, 65, 67]), ([-1, ['Bbb4', 'B4', '|', 'B4']], [69, 69, 70])], [([-1, ['B4', 'Bn4', 'B4', '|', 'B4']], [70, 71, 71, 70]), ([-3, ['E4', 'A4', 'B4', 'D4']], [63, 68, 70, 62]), ([2, ['F4', 'C5', 'G4']], [66, 73, 67]), ([-2, ['Eb4', 'E4', 'En4', 'E4']], [63, 63, 64, 64]), ([0, ['Gbb4', 'G4', '|', 'G4']], [65, 65, 67]), ([3, ['Fx4', 'F4', '|', 'F4', 'G4']], [67, 67, 66, 68]), ([-7, ['F4', 'C4', 'B3']], [64, 59, 58]), ([-1, ['Bbb4', 'B4', '|', 'B4']], [69, 69, 70])], [([-2, ['Eb4', 'E4', 'En4', 'E4']], [63, 63, 64, 64]), ([0, ['Gbb4', 'G4', '|', 'G4']], [65, 65, 67]), ([3, ['Fx4', 'F4', '|', 'F4', 'G4']], [67, 67, 66, 68]), ([-7, ['F4', 'C4', 'B3']], [64, 59, 58]), ([7, ['B3', 'E4', 'C4']], [60, 65, 61]), ([8, ['C4']], None), ([0, ['H4']], None), ([-1, ['Bbb4', 'B4', '|', 'B4']], [69, 69, 70])], [([0, ['Gbb4', 'G4', '|', 'G4']], [65, 65, 67]), ([7, ['B3', 'E4', 'C4']], [60, 65, 61]), ([8, ['C4']], None), ([0, ['H4']], None), ([0, ['C#44']], None), ([4, ['D4', 'Dn4', 'D5', 'D4']], [63, 62, 75, 62]), ([-4, ['D4', 'Db4', 'D4', '|', 'D4']], [61, 61, 61, 61]), ([-1, ['Bbb4', 'B4', '|', 'B4']], [69, 69, 70])], [([0, ['Gbb4', 'G4', '|', 'G4']], [65, 65, 67]), ([0, ['C#44']], None), ([4, ['D4', 'Dn4', 'D5', 'D4']], [63, 62, 75, 62]), ([-4, ['D4', 'Db4', 'D4', '|', 'D4']], [61, 61, 61, 61]), ([5, ['A4', 'An4', '|', 'A4']], [70, 69, 70]), ([0, ['B#3', 'C4', 'B3', '|', 'B3']], [60, 60, 60, 59]), ([-5, ['G4', 'Gn4', 'G4', 'G5']], [66, 67, 67, 78]), ([-1, ['Bbb4', 'B4', '|', 'B4']], [69, 69, 70])]]\nfor i, (args, expected) in enumerate(fixtures[N-1]):\n    check(\"oracle %d\" % i, 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 bounded teaching model with a stipulated toy contract; it is not a complete music notation or theory engine. 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-music-interval-measure-accidentals-double-flat-token","generated_at":"2026-09-29T14:49:59.007133+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Pitch spelling and interval arithmetic decide the notes that notation, transposition and analysis tools display or play.","root_cause":"The sign whitelist omits the bb double-flat token although the alteration table defines it.","sha256":"60698bd12d9cb62d8fc98e3946414a2fe9cf3dbeb098cc7009294613bbdf6d07","title":"Key signature and measure accidental resolution: double flat token rejected · 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":39.971,"exit_code":1,"observations":[{"actual":[66,65,65,66],"check":"oracle 0","expected":[66,65,65,66],"passed":true},{"actual":[61,61,60],"check":"oracle 1","expected":[61,61,60],"passed":true},{"actual":[61,72,61],"check":"oracle 2","expected":[61,72,61],"passed":true},{"actual":[70,71,71,70],"check":"oracle 3","expected":[70,71,71,70],"passed":true},{"actual":[63,68,70,62],"check":"oracle 4","expected":[63,68,70,62],"passed":true},{"actual":[66,73,67],"check":"oracle 5","expected":[66,73,67],"passed":true},{"actual":null,"check":"oracle 6","expected":[65,65,67],"passed":false},{"actual":null,"check":"oracle 7","expected":[69,69,70],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 0\", \"actual\": [66, 65, 65, 66], \"expected\": [66, 65, 65, 66], \"passed\": true}, {\"check\": \"oracle 1\", \"actual\": [61, 61, 60], \"expected\": [61, 61, 60], \"passed\": true}, {\"check\": \"oracle 2\", \"actual\": [61, 72, 61], \"expected\": [61, 72, 61], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [70, 71, 71, 70], \"expected\": [70, 71, 71, 70], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [63, 68, 70, 62], \"expected\": [63, 68, 70, 62], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [66, 73, 67], \"expected\": [66, 73, 67], \"passed\": true}, {\"check\": \"oracle 6\", \"actual\": null, \"expected\": [65, 65, 67], \"passed\": false}, {\"check\": \"oracle 7\", \"actual\": null, \"expected\": [69, 69, 70], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.909,"exit_code":1,"observations":[{"actual":[66,65,65,66],"check":"oracle 0","expected":[66,65,65,66],"passed":true},{"actual":[61,61,60],"check":"oracle 1","expected":[61,61,60],"passed":true},{"actual":[61,72,61],"check":"oracle 2","expected":[61,72,61],"passed":true},{"actual":[70,71,71,70],"check":"oracle 3","expected":[70,71,71,70],"passed":true},{"actual":[63,68,70,62],"check":"oracle 4","expected":[63,68,70,62],"passed":true},{"actual":[66,73,67],"check":"oracle 5","expected":[66,73,67],"passed":true},{"actual":null,"check":"oracle 6","expected":[65,65,67],"passed":false},{"actual":null,"check":"oracle 7","expected":[69,69,70],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 0\", \"actual\": [66, 65, 65, 66], \"expected\": [66, 65, 65, 66], \"passed\": true}, {\"check\": \"oracle 1\", \"actual\": [61, 61, 60], \"expected\": [61, 61, 60], \"passed\": true}, {\"check\": \"oracle 2\", \"actual\": [61, 72, 61], \"expected\": [61, 72, 61], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [70, 71, 71, 70], \"expected\": [70, 71, 71, 70], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [63, 68, 70, 62], \"expected\": [63, 68, 70, 62], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [66, 73, 67], \"expected\": [66, 73, 67], \"passed\": true}, {\"check\": \"oracle 6\", \"actual\": null, \"expected\": [65, 65, 67], \"passed\": false}, {\"check\": \"oracle 7\", \"actual\": null, \"expected\": [69, 69, 70], \"passed\": false}], \"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."}}