FA-79611 / Barcode symbology encoding / Open access

A separator after a fixed-length field is reported as an unknown AI · case 01

Labels from printers that add FNC1 after every field fail to parse.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Redundant GS characters are not skipped, so the parser tries to read an AI starting with GS.

VERIFIED REPAIR

Skip any GS found where an AI is expected.

Unsuccessful approach: Skipping only a GS right after the identifier misses separators between fields.

Case contract

Parse scanner output of a GS1-128 symbol: it must start with the symbology identifier "]C1"; FNC1 separators arrive as GS (0x1D) and redundant separators are skipped. AIs are recognised by the shortest matching prefix among the predefined fixed-length AIs (00:18, 01/02:14, 11/13/15/17:6, 3103:6) and variable AIs (10/21 max 20, 30/37 max 8, 400 max 30). A fixed field must be complete and contain no GS; a variable field runs to the next GS or the end and must have 1..max characters. Return [[ai, value], ...] or an error.

Why this case matters

Retail, logistics, pharmacy and document workflows depend on encoders that produce exactly the module pattern, code-set switches, separators and quiet zones scanners expect; one misplaced module or separator makes a label unreadable or, worse, scan as different data.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(s):
    fixed_len = {'00': 18, '01': 14, '02': 14, '11': 6, '13': 6, '15': 6, '17': 6, '3103': 6}
    var_max = {'10': 20, '21': 20, '30': 8, '37': 8, '400': 30}
    if not s.startswith(']C1'):
        return {'error': 'not-gs1'}
    i = 3
    out = []
    while i < len(s):
    
        ai = None
        for L in (2, 3, 4):
            if s[i:i + L] in fixed_len or s[i:i + L] in var_max:
                ai = s[i:i + L]
                break
        if ai is None:
            return {'error': 'unknown-ai', 'at': i}
        i += len(ai)
        if ai in fixed_len:
            n = fixed_len[ai]
            val = s[i:i + n]
            if len(val) != n or '\x1d' in val:
                return {'error': 'short', 'ai': ai}
            i += n
        else:
            j = s.find('\x1d', i)
            if j == -1:
                j = len(s)
            val = s[i:j]
            if not 1 <= len(val) <= var_max[ai]:
                return {'error': 'length', 'ai': ai}
            i = j
        out.append([ai, val])
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[']C117140648306\x1d0141294680397442\x1d', [['17', '140648'], ['30', '6'], ['01', '41294680397442']]], [']C10031628106322192486810-B-1C99//CXB\x1d400991XX/BC9-9/C/B-BA\x1d10-/-X-X1//BB/19-A-1A', [['00', '316281063221924868'], ['10', '-B-1C99//CXB'], ['400', '991XX/BC9-9/C/B-BA'], ['10', '-/-X-X1//BB/19-A-1A']]], [']C011400783', {'error': 'not-gs1'}], [']C03019\x1d10B9', {'error': 'not-gs1'}], [']d221B-1BA9-B\x1d219X91//1X9-/1A-C\x1d10BBCB1-9/-/9//-/BC1-A-X\x1d21/ABXAX9C-CC/-\x1d', {'error': 'not-gs1'}], [']C0\x1d3028612956', {'error': 'not-gs1'}], [']d24009-X-1X1B/XAB/-9-9/X\x1d11103161400-A119BBXX-AX--1XB-C\x1d', {'error': 'not-gs1'}], [']C1306\x1d21ABB1A-1/-C/91X', [['30', '6'], ['21', 'ABB1A-1/-C/91X']]]], [[']C1310361473240011XBBC-1-CX1B-\x1d371255\x1d219X9B-C/', [['3103', '614732'], ['400', '11XBBC-1-CX1B-'], ['37', '1255'], ['21', '9X9B-C/']]], [']C1373238\x1d', [['37', '3238']]], [']C10044603095506351280311060380310300579483495402726338', {'error': 'unknown-ai', 'at': 41}], [']d211029205\x1d01139908024073283027281846\x1d10-X9C\x1d', {'error': 'not-gs1'}], [']C030473952263\x1d375323374', {'error': 'not-gs1'}], [']d23103386456', {'error': 'not-gs1'}], [']C030072\x1d303326538', {'error': 'not-gs1'}], [']C117074388\x1d10ABCAA///BCA/B\x1d30850\x1d400CA1//9', [['17', '074388'], ['10', 'ABCAA///BCA/B'], ['30', '850'], ['400', 'CA1//9']]]], [[']C117595764400A//-X1BCCBA9AX/-/99\x1d21CABB119BX1/19111XX\x1d3703\x1d', [['17', '595764'], ['400', 'A//-X1BCCBA9AX/-/99'], ['21', 'CABB119BX1/19111XX'], ['37', '03']]], [']C121-1CB9--/1-9X-B9X1\x1d00264947902548943503', [['21', '-1CB9--/1-9X-B9X1'], ['00', '264947902548943503']]], [']C111362276', [['11', '362276']]], [']C111990558117862\x1d10X-11\x1d0141668383672539', {'error': 'short', 'ai': '11'}], [']d2002942508545382808993103171446', {'error': 'not-gs1'}], [']C1006692098233759925', {'error': 'short', 'ai': '00'}], [']C0013259255554289421A1C9/9--C1\x1d0109002354118510B1B', {'error': 'not-gs1'}], [']C121-/1-X-9B\x1d17420369015026678280984317842704\x1d', [['21', '-/1-X-9B'], ['17', '420369'], ['01', '50266782809843'], ['17', '842704']]]], [[']C1211\x1d37789365790\x1d30311652\x1d', {'error': 'length', 'ai': '37'}], [']C1109--A9-C9CAA-X1\x1d3103048301', [['10', '9--A9-C9CAA-X1'], ['3103', '048301']]], [']C1308705431', [['30', '8705431']]], [']C010/ACC1C1C/9\x1d109\x1d00997634519263772689', {'error': 'not-gs1'}], [']C03103992498', {'error': 'not-gs1'}], [']C037551517779\x1d37107398', {'error': 'not-gs1'}], [']C037882', {'error': 'not-gs1'}], [']C11100096530067\x1d17348048', [['11', '000965'], ['30', '067'], ['17', '348048']]]], [[']C1219A9\x1d17625625\x1d', [['21', '9A9'], ['17', '625625']]], [']C13103235106211A-/B1\x1d', [['3103', '235106'], ['21', '1A-/B1']]], [']C01109918000653062932206451941', {'error': 'not-gs1'}], [']C017335622\x1d10/A/1X9\x1d1019911-1X/1B1/C-B\x1d400AX/C', {'error': 'not-gs1'}], [']C121BCAB-C9CCX1/9X/CCX/1-A\x1d3103050801250114151498', {'error': 'length', 'ai': '21'}], [']C13722241627', [['37', '22241627']]], [']d21722165221XXBCCX-C/B/C11X/AC\x1d00214639110761933483', {'error': 'not-gs1'}], [']C10109147699409412219X9/BACAA-C1/9X19-B\x1d21/\x1d17759960', [['01', '09147699409412'], ['21', '9X9/BACAA-C1/9X19-B'], ['21', '/'], ['17', '759960']]]]]
labels = ["regression: redundant GS skipping", "repair trap", "combined fault", "control", "control", "boundary", "boundary", "control"]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (labels[i % len(labels)], i), solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression: redundant GS skipping 0	`{'at': 14, 'error': 'unknown-ai'}`	`[['17', '140648'], ['30', '6'], ['01', '41294680397442']]`	Failed
repair trap 1	`{'at': 37, 'error': 'unknown-ai'}`	`[['00', '316281063221924868'], ['10', '-B-1C99//CXB'], ['400', '991XX/BC9-9/C/B-BA'], ['10', '-/-X-X1//BB/19-A-1A']]`	Failed
combined fault 2	`{'error': 'not-gs1'}`	`{'error': 'not-gs1'}`	Passed
control 3	`{'error': 'not-gs1'}`	`{'error': 'not-gs1'}`	Passed
control 4	`{'error': 'not-gs1'}`	`{'error': 'not-gs1'}`	Passed
boundary 5	`{'error': 'not-gs1'}`	`{'error': 'not-gs1'}`	Passed
boundary 6	`{'error': 'not-gs1'}`	`{'error': 'not-gs1'}`	Passed
control 7	`{'at': 6, 'error': 'unknown-ai'}`	`[['30', '6'], ['21', 'ABB1A-1/-C/91X']]`	Failed

SHA-256 / 9802e69cd9f0576219a9a80d615fe33c89e6cd84cf7b89f63e1f8d4676dfc09a

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(s):
    fixed_len = {'00': 18, '01': 14, '02': 14, '11': 6, '13': 6, '15': 6, '17': 6, '3103': 6}
    var_max = {'10': 20, '21': 20, '30': 8, '37': 8, '400': 30}
    if not s.startswith(']C1'):
        return {'error': 'not-gs1'}
    i = 3
    out = []
    while i < len(s):
        if s[i] == '\x1d' and i == 3:
            i += 1
            continue
        ai = None
        for L in (2, 3, 4):
            if s[i:i + L] in fixed_len or s[i:i + L] in var_max:
                ai = s[i:i + L]
                break
        if ai is None:
            return {'error': 'unknown-ai', 'at': i}
        i += len(ai)
        if ai in fixed_len:
            n = fixed_len[ai]
            val = s[i:i + n]
            if len(val) != n or '\x1d' in val:
                return {'error': 'short', 'ai': ai}
            i += n
        else:
            j = s.find('\x1d', i)
            if j == -1:
                j = len(s)
            val = s[i:j]
            if not 1 <= len(val) <= var_max[ai]:
                return {'error': 'length', 'ai': ai}
            i = j
        out.append([ai, val])
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[']C117140648306\x1d0141294680397442\x1d', [['17', '140648'], ['30', '6'], ['01', '41294680397442']]], [']C10031628106322192486810-B-1C99//CXB\x1d400991XX/BC9-9/C/B-BA\x1d10-/-X-X1//BB/19-A-1A', [['00', '316281063221924868'], ['10', '-B-1C99//CXB'], ['400', '991XX/BC9-9/C/B-BA'], ['10', '-/-X-X1//BB/19-A-1A']]], [']C011400783', {'error': 'not-gs1'}], [']C03019\x1d10B9', {'error': 'not-gs1'}], [']d221B-1BA9-B\x1d219X91//1X9-/1A-C\x1d10BBCB1-9/-/9//-/BC1-A-X\x1d21/ABXAX9C-CC/-\x1d', {'error': 'not-gs1'}], [']C0\x1d3028612956', {'error': 'not-gs1'}], [']d24009-X-1X1B/XAB/-9-9/X\x1d11103161400-A119BBXX-AX--1XB-C\x1d', {'error': 'not-gs1'}], [']C1306\x1d21ABB1A-1/-C/91X', [['30', '6'], ['21', 'ABB1A-1/-C/91X']]]], [[']C1310361473240011XBBC-1-CX1B-\x1d371255\x1d219X9B-C/', [['3103', '614732'], ['400', '11XBBC-1-CX1B-'], ['37', '1255'], ['21', '9X9B-C/']]], [']C1373238\x1d', [['37', '3238']]], [']C10044603095506351280311060380310300579483495402726338', {'error': 'unknown-ai', 'at': 41}], [']d211029205\x1d01139908024073283027281846\x1d10-X9C\x1d', {'error': 'not-gs1'}], [']C030473952263\x1d375323374', {'error': 'not-gs1'}], [']d23103386456', {'error': 'not-gs1'}], [']C030072\x1d303326538', {'error': 'not-gs1'}], [']C117074388\x1d10ABCAA///BCA/B\x1d30850\x1d400CA1//9', [['17', '074388'], ['10', 'ABCAA///BCA/B'], ['30', '850'], ['400', 'CA1//9']]]], [[']C117595764400A//-X1BCCBA9AX/-/99\x1d21CABB119BX1/19111XX\x1d3703\x1d', [['17', '595764'], ['400', 'A//-X1BCCBA9AX/-/99'], ['21', 'CABB119BX1/19111XX'], ['37', '03']]], [']C121-1CB9--/1-9X-B9X1\x1d00264947902548943503', [['21', '-1CB9--/1-9X-B9X1'], ['00', '264947902548943503']]], [']C111362276', [['11', '362276']]], [']C111990558117862\x1d10X-11\x1d0141668383672539', {'error': 'short', 'ai': '11'}], [']d2002942508545382808993103171446', {'error': 'not-gs1'}], [']C1006692098233759925', {'error': 'short', 'ai': '00'}], [']C0013259255554289421A1C9/9--C1\x1d0109002354118510B1B', {'error': 'not-gs1'}], [']C121-/1-X-9B\x1d17420369015026678280984317842704\x1d', [['21', '-/1-X-9B'], ['17', '420369'], ['01', '50266782809843'], ['17', '842704']]]], [[']C1211\x1d37789365790\x1d30311652\x1d', {'error': 'length', 'ai': '37'}], [']C1109--A9-C9CAA-X1\x1d3103048301', [['10', '9--A9-C9CAA-X1'], ['3103', '048301']]], [']C1308705431', [['30', '8705431']]], [']C010/ACC1C1C/9\x1d109\x1d00997634519263772689', {'error': 'not-gs1'}], [']C03103992498', {'error': 'not-gs1'}], [']C037551517779\x1d37107398', {'error': 'not-gs1'}], [']C037882', {'error': 'not-gs1'}], [']C11100096530067\x1d17348048', [['11', '000965'], ['30', '067'], ['17', '348048']]]], [[']C1219A9\x1d17625625\x1d', [['21', '9A9'], ['17', '625625']]], [']C13103235106211A-/B1\x1d', [['3103', '235106'], ['21', '1A-/B1']]], [']C01109918000653062932206451941', {'error': 'not-gs1'}], [']C017335622\x1d10/A/1X9\x1d1019911-1X/1B1/C-B\x1d400AX/C', {'error': 'not-gs1'}], [']C121BCAB-C9CCX1/9X/CCX/1-A\x1d3103050801250114151498', {'error': 'length', 'ai': '21'}], [']C13722241627', [['37', '22241627']]], [']d21722165221XXBCCX-C/B/C11X/AC\x1d00214639110761933483', {'error': 'not-gs1'}], [']C10109147699409412219X9/BACAA-C1/9X19-B\x1d21/\x1d17759960', [['01', '09147699409412'], ['21', '9X9/BACAA-C1/9X19-B'], ['21', '/'], ['17', '759960']]]]]
labels = ["regression: redundant GS skipping", "repair trap", "combined fault", "control", "control", "boundary", "boundary", "control"]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (labels[i % len(labels)], i), solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression: redundant GS skipping 0	`{'at': 14, 'error': 'unknown-ai'}`	`[['17', '140648'], ['30', '6'], ['01', '41294680397442']]`	Failed
repair trap 1	`{'at': 37, 'error': 'unknown-ai'}`	`[['00', '316281063221924868'], ['10', '-B-1C99//CXB'], ['400', '991XX/BC9-9/C/B-BA'], ['10', '-/-X-X1//BB/19-A-1A']]`	Failed
combined fault 2	`{'error': 'not-gs1'}`	`{'error': 'not-gs1'}`	Passed
control 3	`{'error': 'not-gs1'}`	`{'error': 'not-gs1'}`	Passed
control 4	`{'error': 'not-gs1'}`	`{'error': 'not-gs1'}`	Passed
boundary 5	`{'error': 'not-gs1'}`	`{'error': 'not-gs1'}`	Passed
boundary 6	`{'error': 'not-gs1'}`	`{'error': 'not-gs1'}`	Passed
control 7	`{'at': 6, 'error': 'unknown-ai'}`	`[['30', '6'], ['21', 'ABB1A-1/-C/91X']]`	Failed

SHA-256 / 140a2205314ed71d30fe757a57dc67e0ffa7751587a1d940f0c19ac781b912a5

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(s):
    fixed_len = {'00': 18, '01': 14, '02': 14, '11': 6, '13': 6, '15': 6, '17': 6, '3103': 6}
    var_max = {'10': 20, '21': 20, '30': 8, '37': 8, '400': 30}
    if not s.startswith(']C1'):
        return {'error': 'not-gs1'}
    i = 3
    out = []
    while i < len(s):
        if s[i] == '\x1d':
            i += 1
            continue
        ai = None
        for L in (2, 3, 4):
            if s[i:i + L] in fixed_len or s[i:i + L] in var_max:
                ai = s[i:i + L]
                break
        if ai is None:
            return {'error': 'unknown-ai', 'at': i}
        i += len(ai)
        if ai in fixed_len:
            n = fixed_len[ai]
            val = s[i:i + n]
            if len(val) != n or '\x1d' in val:
                return {'error': 'short', 'ai': ai}
            i += n
        else:
            j = s.find('\x1d', i)
            if j == -1:
                j = len(s)
            val = s[i:j]
            if not 1 <= len(val) <= var_max[ai]:
                return {'error': 'length', 'ai': ai}
            i = j
        out.append([ai, val])
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[']C117140648306\x1d0141294680397442\x1d', [['17', '140648'], ['30', '6'], ['01', '41294680397442']]], [']C10031628106322192486810-B-1C99//CXB\x1d400991XX/BC9-9/C/B-BA\x1d10-/-X-X1//BB/19-A-1A', [['00', '316281063221924868'], ['10', '-B-1C99//CXB'], ['400', '991XX/BC9-9/C/B-BA'], ['10', '-/-X-X1//BB/19-A-1A']]], [']C011400783', {'error': 'not-gs1'}], [']C03019\x1d10B9', {'error': 'not-gs1'}], [']d221B-1BA9-B\x1d219X91//1X9-/1A-C\x1d10BBCB1-9/-/9//-/BC1-A-X\x1d21/ABXAX9C-CC/-\x1d', {'error': 'not-gs1'}], [']C0\x1d3028612956', {'error': 'not-gs1'}], [']d24009-X-1X1B/XAB/-9-9/X\x1d11103161400-A119BBXX-AX--1XB-C\x1d', {'error': 'not-gs1'}], [']C1306\x1d21ABB1A-1/-C/91X', [['30', '6'], ['21', 'ABB1A-1/-C/91X']]]], [[']C1310361473240011XBBC-1-CX1B-\x1d371255\x1d219X9B-C/', [['3103', '614732'], ['400', '11XBBC-1-CX1B-'], ['37', '1255'], ['21', '9X9B-C/']]], [']C1373238\x1d', [['37', '3238']]], [']C10044603095506351280311060380310300579483495402726338', {'error': 'unknown-ai', 'at': 41}], [']d211029205\x1d01139908024073283027281846\x1d10-X9C\x1d', {'error': 'not-gs1'}], [']C030473952263\x1d375323374', {'error': 'not-gs1'}], [']d23103386456', {'error': 'not-gs1'}], [']C030072\x1d303326538', {'error': 'not-gs1'}], [']C117074388\x1d10ABCAA///BCA/B\x1d30850\x1d400CA1//9', [['17', '074388'], ['10', 'ABCAA///BCA/B'], ['30', '850'], ['400', 'CA1//9']]]], [[']C117595764400A//-X1BCCBA9AX/-/99\x1d21CABB119BX1/19111XX\x1d3703\x1d', [['17', '595764'], ['400', 'A//-X1BCCBA9AX/-/99'], ['21', 'CABB119BX1/19111XX'], ['37', '03']]], [']C121-1CB9--/1-9X-B9X1\x1d00264947902548943503', [['21', '-1CB9--/1-9X-B9X1'], ['00', '264947902548943503']]], [']C111362276', [['11', '362276']]], [']C111990558117862\x1d10X-11\x1d0141668383672539', {'error': 'short', 'ai': '11'}], [']d2002942508545382808993103171446', {'error': 'not-gs1'}], [']C1006692098233759925', {'error': 'short', 'ai': '00'}], [']C0013259255554289421A1C9/9--C1\x1d0109002354118510B1B', {'error': 'not-gs1'}], [']C121-/1-X-9B\x1d17420369015026678280984317842704\x1d', [['21', '-/1-X-9B'], ['17', '420369'], ['01', '50266782809843'], ['17', '842704']]]], [[']C1211\x1d37789365790\x1d30311652\x1d', {'error': 'length', 'ai': '37'}], [']C1109--A9-C9CAA-X1\x1d3103048301', [['10', '9--A9-C9CAA-X1'], ['3103', '048301']]], [']C1308705431', [['30', '8705431']]], [']C010/ACC1C1C/9\x1d109\x1d00997634519263772689', {'error': 'not-gs1'}], [']C03103992498', {'error': 'not-gs1'}], [']C037551517779\x1d37107398', {'error': 'not-gs1'}], [']C037882', {'error': 'not-gs1'}], [']C11100096530067\x1d17348048', [['11', '000965'], ['30', '067'], ['17', '348048']]]], [[']C1219A9\x1d17625625\x1d', [['21', '9A9'], ['17', '625625']]], [']C13103235106211A-/B1\x1d', [['3103', '235106'], ['21', '1A-/B1']]], [']C01109918000653062932206451941', {'error': 'not-gs1'}], [']C017335622\x1d10/A/1X9\x1d1019911-1X/1B1/C-B\x1d400AX/C', {'error': 'not-gs1'}], [']C121BCAB-C9CCX1/9X/CCX/1-A\x1d3103050801250114151498', {'error': 'length', 'ai': '21'}], [']C13722241627', [['37', '22241627']]], [']d21722165221XXBCCX-C/B/C11X/AC\x1d00214639110761933483', {'error': 'not-gs1'}], [']C10109147699409412219X9/BACAA-C1/9X19-B\x1d21/\x1d17759960', [['01', '09147699409412'], ['21', '9X9/BACAA-C1/9X19-B'], ['21', '/'], ['17', '759960']]]]]
labels = ["regression: redundant GS skipping", "repair trap", "combined fault", "control", "control", "boundary", "boundary", "control"]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (labels[i % len(labels)], i), solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression: redundant GS skipping 0	`[['17', '140648'], ['30', '6'], ['01', '41294680397442']]`	`[['17', '140648'], ['30', '6'], ['01', '41294680397442']]`	Passed
repair trap 1	`[['00', '316281063221924868'], ['10', '-B-1C99//CXB'], ['400', '991XX/BC9-9/C/B-BA'], ['10', '-/-X-X1//BB/19-A-1A']]`	`[['00', '316281063221924868'], ['10', '-B-1C99//CXB'], ['400', '991XX/BC9-9/C/B-BA'], ['10', '-/-X-X1//BB/19-A-1A']]`	Passed
combined fault 2	`{'error': 'not-gs1'}`	`{'error': 'not-gs1'}`	Passed
control 3	`{'error': 'not-gs1'}`	`{'error': 'not-gs1'}`	Passed
control 4	`{'error': 'not-gs1'}`	`{'error': 'not-gs1'}`	Passed
boundary 5	`{'error': 'not-gs1'}`	`{'error': 'not-gs1'}`	Passed
boundary 6	`{'error': 'not-gs1'}`	`{'error': 'not-gs1'}`	Passed
control 7	`[['30', '6'], ['21', 'ABB1A-1/-C/91X']]`	`[['30', '6'], ['21', 'ABB1A-1/-C/91X']]`	Passed

SHA-256 / 1e9479ebbfbf5e6d16d2bf6f487c3efa7bb28460b036c760391cb287791c80e1

Verification & scope

A deterministic bounded teaching model with a stipulated contract; it makes no claim of conformance to any published specification. 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.

Observations recorded using Python 3.12.14 at 2026-09-29T14:49:46.267883+00:00.

Case digest / 087be6b2afcd264e0767574dc77d944922e0c25ed7e7ddfb2ae7512c7734dfb9