FA-80786 / Bidirectional text layout / Open access

Isolating run sequences: eos level comparison · case 01

Sequence end types follow the next character only.

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

ROOT CAUSE

eos takes the parity of the following level instead of the higher of the two.

VERIFIED REPAIR

Take the parity of the higher of the last and following levels.

Unsuccessful approach: Using only the last character level ignores the following context.

Case contract

Input [classes, levels, paragraph level]. Split into maximal level runs; chain a run ending in a matched isolate initiator (LRI/RLI/FSI) with the run starting at its matching PDI (stack matching; unmatched PDI ignored). For each sequence sos = parity of max(level of first char, level of preceding char or paragraph level); eos = parity of max(level of last char, level of following char or paragraph level), using the paragraph level when the last char is an isolate initiator. Return [[indices, sos, eos]].

Why this case matters

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.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(x):
    classes, levels, para = x
    n = len(classes)
    match = {}
    stack = []
    for i, c in enumerate(classes):
        if c in ('LRI', 'RLI', 'FSI'):
            stack.append(i)
        elif c == 'PDI' and stack:
            match[stack.pop()] = i
    runs = []
    for i in range(n):
        if runs and levels[i] == levels[runs[-1][-1]]:
            runs[-1].append(i)
        else:
            runs.append([i])
    start_of = {r[0]: r for r in runs}
    seqs = []
    used = set()
    for r in runs:
        if r[0] in used:
            continue
        seq = list(r)
        used.add(r[0])
        while True:
            tail = seq[-1]
            if classes[tail] not in ('LRI', 'RLI', 'FSI') or tail not in match:
                break
            nxt = start_of.get(match[tail])
            if nxt is None:
                break
            seq.extend(nxt)
            used.add(nxt[0])
        seqs.append(seq)
    out = []
    for seq in seqs:
        first, last = seq[0], seq[-1]
        lv = levels[first]
        prev = levels[first - 1] if first > 0 else para
        sos = 'R' if max(lv, prev) % 2 else 'L'
        if classes[last] in ('LRI', 'RLI', 'FSI'):
            nxt_lv = para
        else:
            nxt_lv = levels[last + 1] if last + 1 < n else para
        eos = 'R' if nxt_lv % 2 else 'L'
        out.append([seq, sos, eos])
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('isolate joins outer run', [['L', 'RLI', 'R', 'PDI', 'L'], [0, 0, 1, 0, 0], 0], [[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'R']]), ('regression: eos level comparison', [['L', 'L', 'EN'], [2, 2, 2], 1], [[[0, 1, 2], 'L', 'L']]), ('regression: eos level comparison', [['EN', 'L', 'EN', 'PDI', 'EN'], [1, 2, 1, 1, 1], 1], [[[0], 'R', 'L'], [[1], 'L', 'L'], [[2, 3, 4], 'L', 'R']]), ('regression: eos level comparison', [['R', 'EN', 'PDI', 'R', 'ON', 'R'], [0, 0, 0, 1, 0, 1], 0], [[[0, 1, 2], 'L', 'R'], [[3], 'R', 'R'], [[4], 'R', 'R'], [[5], 'R', 'R']]), ('unmatched initiator at end', [['L', 'R', 'RLI'], [0, 1, 1], 0], [[[0], 'L', 'R'], [[1, 2], 'R', 'R']]), ('nested isolates', [['R', 'LRI', 'L', 'RLI', 'R', 'PDI', 'PDI', 'R'], [1, 1, 2, 2, 3, 2, 1, 1], 1], [[[0, 1, 6, 7], 'R', 'R'], [[2, 3, 5], 'L', 'L'], [[4], 'R', 'R']]), ('control layout', [['EN', 'PDI', 'L', 'LRI', 'LRI', 'EN', 'EN', 'L'], [0, 0, 0, 0, 2, 4, 4, 4], 0], [[[0, 1, 2, 3], 'L', 'L'], [[4], 'L', 'L'], [[5, 6, 7], 'L', 'L']]), ('control layout', [['EN', 'EN', 'RLI', 'PDI', 'R', 'EN', 'PDI', 'ON', 'EN', 'ON', 'L', 'ON'], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], 0], [[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11], 'L', 'L']])], [('regression: eos level comparison', [['R', 'R', 'RLI', 'L', 'PDI', 'ON', 'L', 'EN', 'L', 'EN', 'L'], [0, 1, 0, 2, 0, 0, 0, 0, 0, 0, 0], 0], [[[0], 'L', 'R'], [[1], 'R', 'R'], [[2, 4, 5, 6, 7, 8, 9, 10], 'R', 'L'], [[3], 'L', 'L']]), ('regression: eos level comparison', [['FSI', 'ON', 'EN', 'R', 'PDI', 'L', 'L', 'EN'], [0, 2, 2, 3, 0, 0, 0, 0], 0], [[[0, 4, 5, 6, 7], 'L', 'L'], [[1, 2], 'L', 'R'], [[3], 'R', 'R']]), ('regression: eos level comparison', [['LRI', 'R', 'PDI', 'EN', 'L', 'EN', 'EN', 'L', 'LRI', 'PDI', 'ON', 'R', 'L'], [1, 3, 1, 2, 1, 1, 2, 2, 1, 1, 1, 1, 1], 1], [[[0, 2], 'R', 'L'], [[1], 'R', 'R'], [[3], 'L', 'L'], [[4, 5], 'L', 'L'], [[6, 7], 'L', 'L'], [[8, 9, 10, 11, 12], 'L', 'R']]), ('regression: eos level comparison', [['L', 'ON', 'PDI', 'L', 'R', 'PDI', 'EN', 'ON', 'ON', 'LRI', 'L', 'ON', 'PDI', 'FSI'], [2, 1, 1, 2, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1], 1], [[[0], 'L', 'L'], [[1, 2], 'L', 'L'], [[3], 'L', 'L'], [[4, 5], 'L', 'L'], [[6], 'L', 'L'], [[7, 8, 9, 12, 13], 'L', 'R'], [[10, 11], 'L', 'L']]), ('unmatched initiator at end', [['L', 'R', 'RLI'], [0, 1, 1], 0], [[[0], 'L', 'R'], [[1, 2], 'R', 'R']]), ('isolate joins outer run', [['L', 'RLI', 'R', 'PDI', 'L'], [0, 0, 1, 0, 0], 0], [[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'R']]), ('control layout', [['PDI', 'PDI', 'L', 'ON', 'ON', 'L', 'ON', 'ON', 'EN', 'PDI'], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], 0], [[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9], 'L', 'L']]), ('control layout', [['R', 'L', 'PDI'], [1, 1, 1], 1], [[[0, 1, 2], 'R', 'R']])], [('regression: eos level comparison', [['LRI', 'LRI', 'EN', 'PDI', 'EN', 'R', 'R', 'R', 'L', 'PDI', 'EN'], [1, 2, 4, 2, 2, 2, 3, 3, 2, 1, 2], 1], [[[0, 9], 'R', 'L'], [[1, 3, 4, 5], 'L', 'R'], [[2], 'L', 'L'], [[6, 7], 'R', 'R'], [[8], 'R', 'L'], [[10], 'L', 'L']]), ('regression: eos level comparison', [['RLI', 'RLI', 'R', 'PDI', 'EN', 'R', 'ON', 'PDI', 'L', 'L', 'EN', 'L', 'L'], [0, 1, 3, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0], 0], [[[0, 7, 8, 9, 10, 11, 12], 'L', 'L'], [[1, 3, 4, 5, 6], 'R', 'R'], [[2], 'R', 'R']]), ('regression: eos level comparison', [['EN', 'EN', 'PDI', 'R', 'PDI'], [0, 0, 0, 1, 0], 0], [[[0, 1, 2], 'L', 'R'], [[3], 'R', 'R'], [[4], 'R', 'L']]), ('regression: eos level comparison', [['R', 'EN', 'R', 'FSI', 'ON', 'R', 'PDI', 'PDI', 'PDI', 'ON', 'RLI', 'ON', 'EN', 'R'], [1, 0, 1, 0, 2, 2, 0, 0, 0, 0, 0, 1, 1, 1], 0], [[[0], 'R', 'R'], [[1], 'R', 'R'], [[2], 'R', 'R'], [[3, 6, 7, 8, 9, 10], 'R', 'L'], [[4, 5], 'L', 'L'], [[11, 12, 13], 'R', 'R']]), ('unmatched initiator at end', [['L', 'R', 'RLI'], [0, 1, 1], 0], [[[0], 'L', 'R'], [[1, 2], 'R', 'R']]), ('nested isolates', [['R', 'LRI', 'L', 'RLI', 'R', 'PDI', 'PDI', 'R'], [1, 1, 2, 2, 3, 2, 1, 1], 1], [[[0, 1, 6, 7], 'R', 'R'], [[2, 3, 5], 'L', 'L'], [[4], 'R', 'R']]), ('control layout', [['EN', 'L', 'EN', 'R', 'ON', 'R', 'ON', 'L', 'EN', 'L', 'PDI'], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], 0], [[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 'L', 'L']]), ('control layout', [['EN', 'PDI', 'EN', 'PDI'], [1, 1, 1, 1], 1], [[[0, 1, 2, 3], 'R', 'R']])], [('regression: eos level comparison', [['EN', 'L', 'ON', 'PDI', 'R', 'R', 'LRI'], [1, 2, 1, 1, 1, 1, 1], 1], [[[0], 'R', 'L'], [[1], 'L', 'L'], [[2, 3, 4, 5, 6], 'L', 'R']]), ('regression: eos level comparison', [['PDI', 'EN', 'ON', 'EN', 'ON', 'ON', 'RLI', 'R', 'ON', 'EN', 'PDI', 'L'], [1, 2, 1, 2, 1, 1, 1, 3, 3, 4, 1, 2], 1], [[[0], 'R', 'L'], [[1], 'L', 'L'], [[2], 'L', 'L'], [[3], 'L', 'L'], [[4, 5, 6, 10], 'L', 'L'], [[7, 8], 'R', 'L'], [[9], 'L', 'L'], [[11], 'L', 'L']]), ('regression: eos level comparison', [['FSI', 'EN', 'PDI', 'L', 'R', 'ON', 'ON', 'LRI'], [1, 2, 1, 2, 1, 1, 1, 1], 1], [[[0, 2], 'R', 'L'], [[1], 'L', 'L'], [[3], 'L', 'L'], [[4, 5, 6, 7], 'L', 'R']]), ('regression: eos level comparison', [['R', 'R', 'L', 'L', 'ON'], [1, 1, 2, 1, 1], 1], [[[0, 1], 'R', 'L'], [[2], 'L', 'L'], [[3, 4], 'L', 'R']]), ('isolate joins outer run', [['L', 'RLI', 'R', 'PDI', 'L'], [0, 0, 1, 0, 0], 0], [[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'R']]), ('unmatched initiator at end', [['L', 'R', 'RLI'], [0, 1, 1], 0], [[[0], 'L', 'R'], [[1, 2], 'R', 'R']]), ('control layout', [['R', 'R', 'EN', 'L', 'ON', 'ON', 'RLI', 'PDI', 'RLI'], [1, 1, 1, 1, 1, 1, 1, 1, 1], 1], [[[0, 1, 2, 3, 4, 5, 6, 7, 8], 'R', 'R']]), ('control layout', [['RLI', 'RLI', 'ON', 'RLI', 'L', 'PDI', 'R'], [1, 3, 5, 5, 7, 5, 5], 1], [[[0], 'R', 'R'], [[1], 'R', 'R'], [[2, 3, 5, 6], 'R', 'R'], [[4], 'R', 'R']])], [('regression: eos level comparison', [['L', 'ON', 'EN', 'R'], [0, 0, 0, 1], 0], [[[0, 1, 2], 'L', 'R'], [[3], 'R', 'R']]), ('regression: eos level comparison', [['ON', 'ON', 'ON', 'RLI', 'EN', 'L'], [1, 1, 1, 1, 4, 3], 1], [[[0, 1, 2, 3], 'R', 'R'], [[4], 'L', 'L'], [[5], 'L', 'R']]), ('regression: eos level comparison', [['ON', 'LRI', 'RLI', 'R', 'L', 'RLI', 'ON', 'EN'], [1, 1, 2, 3, 3, 3, 5, 6], 1], [[[0, 1], 'R', 'R'], [[2], 'L', 'L'], [[3, 4, 5], 'R', 'R'], [[6], 'R', 'L'], [[7], 'L', 'L']]), ('regression: eos level comparison', [['RLI', 'RLI', 'L', 'L'], [0, 1, 3, 4], 0], [[[0], 'L', 'L'], [[1], 'R', 'R'], [[2], 'R', 'L'], [[3], 'L', 'L']]), ('isolate joins outer run', [['L', 'RLI', 'R', 'PDI', 'L'], [0, 0, 1, 0, 0], 0], [[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'R']]), ('nested isolates', [['R', 'LRI', 'L', 'RLI', 'R', 'PDI', 'PDI', 'R'], [1, 1, 2, 2, 3, 2, 1, 1], 1], [[[0, 1, 6, 7], 'R', 'R'], [[2, 3, 5], 'L', 'L'], [[4], 'R', 'R']]), ('control layout', [['L', 'ON', 'EN', 'R', 'EN', 'L', 'FSI'], [0, 0, 0, 0, 0, 0, 0], 0], [[[0, 1, 2, 3, 4, 5, 6], 'L', 'L']]), ('control layout', [['PDI', 'PDI', 'ON', 'L', 'FSI'], [0, 0, 0, 0, 0], 0], [[[0, 1, 2, 3, 4], 'L', 'L']])]]
for label, args, expected in fixtures[N - 1]:
    check(label, 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
isolate joins outer run	`[[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'L']]`	`[[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'R']]`	Failed
regression: eos level comparison	`[[[0, 1, 2], 'L', 'R']]`	`[[[0, 1, 2], 'L', 'L']]`	Failed
regression: eos level comparison	`[[[0], 'R', 'L'], [[1], 'L', 'R'], [[2, 3, 4], 'L', 'R']]`	`[[[0], 'R', 'L'], [[1], 'L', 'L'], [[2, 3, 4], 'L', 'R']]`	Failed
regression: eos level comparison	`[[[0, 1, 2], 'L', 'R'], [[3], 'R', 'L'], [[4], 'R', 'R'], [[5], 'R', 'L']]`	`[[[0, 1, 2], 'L', 'R'], [[3], 'R', 'R'], [[4], 'R', 'R'], [[5], 'R', 'R']]`	Failed
unmatched initiator at end	`[[[0], 'L', 'R'], [[1, 2], 'R', 'L']]`	`[[[0], 'L', 'R'], [[1, 2], 'R', 'R']]`	Failed
nested isolates	`[[[0, 1, 6, 7], 'R', 'R'], [[2, 3, 5], 'L', 'R'], [[4], 'R', 'L']]`	`[[[0, 1, 6, 7], 'R', 'R'], [[2, 3, 5], 'L', 'L'], [[4], 'R', 'R']]`	Failed
control layout	`[[[0, 1, 2, 3], 'L', 'L'], [[4], 'L', 'L'], [[5, 6, 7], 'L', 'L']]`	`[[[0, 1, 2, 3], 'L', 'L'], [[4], 'L', 'L'], [[5, 6, 7], 'L', 'L']]`	Passed
control layout	`[[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11], 'L', 'L']]`	`[[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11], 'L', 'L']]`	Passed

SHA-256 / 83d2cb781e6715ad96ec58a1a2448f465cb03f1967799035dcfe2e15e3504694

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(x):
    classes, levels, para = x
    n = len(classes)
    match = {}
    stack = []
    for i, c in enumerate(classes):
        if c in ('LRI', 'RLI', 'FSI'):
            stack.append(i)
        elif c == 'PDI' and stack:
            match[stack.pop()] = i
    runs = []
    for i in range(n):
        if runs and levels[i] == levels[runs[-1][-1]]:
            runs[-1].append(i)
        else:
            runs.append([i])
    start_of = {r[0]: r for r in runs}
    seqs = []
    used = set()
    for r in runs:
        if r[0] in used:
            continue
        seq = list(r)
        used.add(r[0])
        while True:
            tail = seq[-1]
            if classes[tail] not in ('LRI', 'RLI', 'FSI') or tail not in match:
                break
            nxt = start_of.get(match[tail])
            if nxt is None:
                break
            seq.extend(nxt)
            used.add(nxt[0])
        seqs.append(seq)
    out = []
    for seq in seqs:
        first, last = seq[0], seq[-1]
        lv = levels[first]
        prev = levels[first - 1] if first > 0 else para
        sos = 'R' if max(lv, prev) % 2 else 'L'
        if classes[last] in ('LRI', 'RLI', 'FSI'):
            nxt_lv = para
        else:
            nxt_lv = levels[last + 1] if last + 1 < n else para
        eos = 'R' if levels[last] % 2 else 'L'
        out.append([seq, sos, eos])
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('isolate joins outer run', [['L', 'RLI', 'R', 'PDI', 'L'], [0, 0, 1, 0, 0], 0], [[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'R']]), ('regression: eos level comparison', [['L', 'L', 'EN'], [2, 2, 2], 1], [[[0, 1, 2], 'L', 'L']]), ('regression: eos level comparison', [['EN', 'L', 'EN', 'PDI', 'EN'], [1, 2, 1, 1, 1], 1], [[[0], 'R', 'L'], [[1], 'L', 'L'], [[2, 3, 4], 'L', 'R']]), ('regression: eos level comparison', [['R', 'EN', 'PDI', 'R', 'ON', 'R'], [0, 0, 0, 1, 0, 1], 0], [[[0, 1, 2], 'L', 'R'], [[3], 'R', 'R'], [[4], 'R', 'R'], [[5], 'R', 'R']]), ('unmatched initiator at end', [['L', 'R', 'RLI'], [0, 1, 1], 0], [[[0], 'L', 'R'], [[1, 2], 'R', 'R']]), ('nested isolates', [['R', 'LRI', 'L', 'RLI', 'R', 'PDI', 'PDI', 'R'], [1, 1, 2, 2, 3, 2, 1, 1], 1], [[[0, 1, 6, 7], 'R', 'R'], [[2, 3, 5], 'L', 'L'], [[4], 'R', 'R']]), ('control layout', [['EN', 'PDI', 'L', 'LRI', 'LRI', 'EN', 'EN', 'L'], [0, 0, 0, 0, 2, 4, 4, 4], 0], [[[0, 1, 2, 3], 'L', 'L'], [[4], 'L', 'L'], [[5, 6, 7], 'L', 'L']]), ('control layout', [['EN', 'EN', 'RLI', 'PDI', 'R', 'EN', 'PDI', 'ON', 'EN', 'ON', 'L', 'ON'], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], 0], [[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11], 'L', 'L']])], [('regression: eos level comparison', [['R', 'R', 'RLI', 'L', 'PDI', 'ON', 'L', 'EN', 'L', 'EN', 'L'], [0, 1, 0, 2, 0, 0, 0, 0, 0, 0, 0], 0], [[[0], 'L', 'R'], [[1], 'R', 'R'], [[2, 4, 5, 6, 7, 8, 9, 10], 'R', 'L'], [[3], 'L', 'L']]), ('regression: eos level comparison', [['FSI', 'ON', 'EN', 'R', 'PDI', 'L', 'L', 'EN'], [0, 2, 2, 3, 0, 0, 0, 0], 0], [[[0, 4, 5, 6, 7], 'L', 'L'], [[1, 2], 'L', 'R'], [[3], 'R', 'R']]), ('regression: eos level comparison', [['LRI', 'R', 'PDI', 'EN', 'L', 'EN', 'EN', 'L', 'LRI', 'PDI', 'ON', 'R', 'L'], [1, 3, 1, 2, 1, 1, 2, 2, 1, 1, 1, 1, 1], 1], [[[0, 2], 'R', 'L'], [[1], 'R', 'R'], [[3], 'L', 'L'], [[4, 5], 'L', 'L'], [[6, 7], 'L', 'L'], [[8, 9, 10, 11, 12], 'L', 'R']]), ('regression: eos level comparison', [['L', 'ON', 'PDI', 'L', 'R', 'PDI', 'EN', 'ON', 'ON', 'LRI', 'L', 'ON', 'PDI', 'FSI'], [2, 1, 1, 2, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1], 1], [[[0], 'L', 'L'], [[1, 2], 'L', 'L'], [[3], 'L', 'L'], [[4, 5], 'L', 'L'], [[6], 'L', 'L'], [[7, 8, 9, 12, 13], 'L', 'R'], [[10, 11], 'L', 'L']]), ('unmatched initiator at end', [['L', 'R', 'RLI'], [0, 1, 1], 0], [[[0], 'L', 'R'], [[1, 2], 'R', 'R']]), ('isolate joins outer run', [['L', 'RLI', 'R', 'PDI', 'L'], [0, 0, 1, 0, 0], 0], [[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'R']]), ('control layout', [['PDI', 'PDI', 'L', 'ON', 'ON', 'L', 'ON', 'ON', 'EN', 'PDI'], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], 0], [[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9], 'L', 'L']]), ('control layout', [['R', 'L', 'PDI'], [1, 1, 1], 1], [[[0, 1, 2], 'R', 'R']])], [('regression: eos level comparison', [['LRI', 'LRI', 'EN', 'PDI', 'EN', 'R', 'R', 'R', 'L', 'PDI', 'EN'], [1, 2, 4, 2, 2, 2, 3, 3, 2, 1, 2], 1], [[[0, 9], 'R', 'L'], [[1, 3, 4, 5], 'L', 'R'], [[2], 'L', 'L'], [[6, 7], 'R', 'R'], [[8], 'R', 'L'], [[10], 'L', 'L']]), ('regression: eos level comparison', [['RLI', 'RLI', 'R', 'PDI', 'EN', 'R', 'ON', 'PDI', 'L', 'L', 'EN', 'L', 'L'], [0, 1, 3, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0], 0], [[[0, 7, 8, 9, 10, 11, 12], 'L', 'L'], [[1, 3, 4, 5, 6], 'R', 'R'], [[2], 'R', 'R']]), ('regression: eos level comparison', [['EN', 'EN', 'PDI', 'R', 'PDI'], [0, 0, 0, 1, 0], 0], [[[0, 1, 2], 'L', 'R'], [[3], 'R', 'R'], [[4], 'R', 'L']]), ('regression: eos level comparison', [['R', 'EN', 'R', 'FSI', 'ON', 'R', 'PDI', 'PDI', 'PDI', 'ON', 'RLI', 'ON', 'EN', 'R'], [1, 0, 1, 0, 2, 2, 0, 0, 0, 0, 0, 1, 1, 1], 0], [[[0], 'R', 'R'], [[1], 'R', 'R'], [[2], 'R', 'R'], [[3, 6, 7, 8, 9, 10], 'R', 'L'], [[4, 5], 'L', 'L'], [[11, 12, 13], 'R', 'R']]), ('unmatched initiator at end', [['L', 'R', 'RLI'], [0, 1, 1], 0], [[[0], 'L', 'R'], [[1, 2], 'R', 'R']]), ('nested isolates', [['R', 'LRI', 'L', 'RLI', 'R', 'PDI', 'PDI', 'R'], [1, 1, 2, 2, 3, 2, 1, 1], 1], [[[0, 1, 6, 7], 'R', 'R'], [[2, 3, 5], 'L', 'L'], [[4], 'R', 'R']]), ('control layout', [['EN', 'L', 'EN', 'R', 'ON', 'R', 'ON', 'L', 'EN', 'L', 'PDI'], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], 0], [[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 'L', 'L']]), ('control layout', [['EN', 'PDI', 'EN', 'PDI'], [1, 1, 1, 1], 1], [[[0, 1, 2, 3], 'R', 'R']])], [('regression: eos level comparison', [['EN', 'L', 'ON', 'PDI', 'R', 'R', 'LRI'], [1, 2, 1, 1, 1, 1, 1], 1], [[[0], 'R', 'L'], [[1], 'L', 'L'], [[2, 3, 4, 5, 6], 'L', 'R']]), ('regression: eos level comparison', [['PDI', 'EN', 'ON', 'EN', 'ON', 'ON', 'RLI', 'R', 'ON', 'EN', 'PDI', 'L'], [1, 2, 1, 2, 1, 1, 1, 3, 3, 4, 1, 2], 1], [[[0], 'R', 'L'], [[1], 'L', 'L'], [[2], 'L', 'L'], [[3], 'L', 'L'], [[4, 5, 6, 10], 'L', 'L'], [[7, 8], 'R', 'L'], [[9], 'L', 'L'], [[11], 'L', 'L']]), ('regression: eos level comparison', [['FSI', 'EN', 'PDI', 'L', 'R', 'ON', 'ON', 'LRI'], [1, 2, 1, 2, 1, 1, 1, 1], 1], [[[0, 2], 'R', 'L'], [[1], 'L', 'L'], [[3], 'L', 'L'], [[4, 5, 6, 7], 'L', 'R']]), ('regression: eos level comparison', [['R', 'R', 'L', 'L', 'ON'], [1, 1, 2, 1, 1], 1], [[[0, 1], 'R', 'L'], [[2], 'L', 'L'], [[3, 4], 'L', 'R']]), ('isolate joins outer run', [['L', 'RLI', 'R', 'PDI', 'L'], [0, 0, 1, 0, 0], 0], [[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'R']]), ('unmatched initiator at end', [['L', 'R', 'RLI'], [0, 1, 1], 0], [[[0], 'L', 'R'], [[1, 2], 'R', 'R']]), ('control layout', [['R', 'R', 'EN', 'L', 'ON', 'ON', 'RLI', 'PDI', 'RLI'], [1, 1, 1, 1, 1, 1, 1, 1, 1], 1], [[[0, 1, 2, 3, 4, 5, 6, 7, 8], 'R', 'R']]), ('control layout', [['RLI', 'RLI', 'ON', 'RLI', 'L', 'PDI', 'R'], [1, 3, 5, 5, 7, 5, 5], 1], [[[0], 'R', 'R'], [[1], 'R', 'R'], [[2, 3, 5, 6], 'R', 'R'], [[4], 'R', 'R']])], [('regression: eos level comparison', [['L', 'ON', 'EN', 'R'], [0, 0, 0, 1], 0], [[[0, 1, 2], 'L', 'R'], [[3], 'R', 'R']]), ('regression: eos level comparison', [['ON', 'ON', 'ON', 'RLI', 'EN', 'L'], [1, 1, 1, 1, 4, 3], 1], [[[0, 1, 2, 3], 'R', 'R'], [[4], 'L', 'L'], [[5], 'L', 'R']]), ('regression: eos level comparison', [['ON', 'LRI', 'RLI', 'R', 'L', 'RLI', 'ON', 'EN'], [1, 1, 2, 3, 3, 3, 5, 6], 1], [[[0, 1], 'R', 'R'], [[2], 'L', 'L'], [[3, 4, 5], 'R', 'R'], [[6], 'R', 'L'], [[7], 'L', 'L']]), ('regression: eos level comparison', [['RLI', 'RLI', 'L', 'L'], [0, 1, 3, 4], 0], [[[0], 'L', 'L'], [[1], 'R', 'R'], [[2], 'R', 'L'], [[3], 'L', 'L']]), ('isolate joins outer run', [['L', 'RLI', 'R', 'PDI', 'L'], [0, 0, 1, 0, 0], 0], [[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'R']]), ('nested isolates', [['R', 'LRI', 'L', 'RLI', 'R', 'PDI', 'PDI', 'R'], [1, 1, 2, 2, 3, 2, 1, 1], 1], [[[0, 1, 6, 7], 'R', 'R'], [[2, 3, 5], 'L', 'L'], [[4], 'R', 'R']]), ('control layout', [['L', 'ON', 'EN', 'R', 'EN', 'L', 'FSI'], [0, 0, 0, 0, 0, 0, 0], 0], [[[0, 1, 2, 3, 4, 5, 6], 'L', 'L']]), ('control layout', [['PDI', 'PDI', 'ON', 'L', 'FSI'], [0, 0, 0, 0, 0], 0], [[[0, 1, 2, 3, 4], 'L', 'L']])]]
for label, args, expected in fixtures[N - 1]:
    check(label, 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
isolate joins outer run	`[[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'R']]`	`[[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'R']]`	Passed
regression: eos level comparison	`[[[0, 1, 2], 'L', 'L']]`	`[[[0, 1, 2], 'L', 'L']]`	Passed
regression: eos level comparison	`[[[0], 'R', 'R'], [[1], 'L', 'L'], [[2, 3, 4], 'L', 'R']]`	`[[[0], 'R', 'L'], [[1], 'L', 'L'], [[2, 3, 4], 'L', 'R']]`	Failed
regression: eos level comparison	`[[[0, 1, 2], 'L', 'L'], [[3], 'R', 'R'], [[4], 'R', 'L'], [[5], 'R', 'R']]`	`[[[0, 1, 2], 'L', 'R'], [[3], 'R', 'R'], [[4], 'R', 'R'], [[5], 'R', 'R']]`	Failed
unmatched initiator at end	`[[[0], 'L', 'L'], [[1, 2], 'R', 'R']]`	`[[[0], 'L', 'R'], [[1, 2], 'R', 'R']]`	Failed
nested isolates	`[[[0, 1, 6, 7], 'R', 'R'], [[2, 3, 5], 'L', 'L'], [[4], 'R', 'R']]`	`[[[0, 1, 6, 7], 'R', 'R'], [[2, 3, 5], 'L', 'L'], [[4], 'R', 'R']]`	Passed
control layout	`[[[0, 1, 2, 3], 'L', 'L'], [[4], 'L', 'L'], [[5, 6, 7], 'L', 'L']]`	`[[[0, 1, 2, 3], 'L', 'L'], [[4], 'L', 'L'], [[5, 6, 7], 'L', 'L']]`	Passed
control layout	`[[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11], 'L', 'L']]`	`[[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11], 'L', 'L']]`	Passed

SHA-256 / 92183b0c50e4d1050b4a8f790456d169c8e2a458fee9a69543a8975f78b0a86e

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(x):
    classes, levels, para = x
    n = len(classes)
    match = {}
    stack = []
    for i, c in enumerate(classes):
        if c in ('LRI', 'RLI', 'FSI'):
            stack.append(i)
        elif c == 'PDI' and stack:
            match[stack.pop()] = i
    runs = []
    for i in range(n):
        if runs and levels[i] == levels[runs[-1][-1]]:
            runs[-1].append(i)
        else:
            runs.append([i])
    start_of = {r[0]: r for r in runs}
    seqs = []
    used = set()
    for r in runs:
        if r[0] in used:
            continue
        seq = list(r)
        used.add(r[0])
        while True:
            tail = seq[-1]
            if classes[tail] not in ('LRI', 'RLI', 'FSI') or tail not in match:
                break
            nxt = start_of.get(match[tail])
            if nxt is None:
                break
            seq.extend(nxt)
            used.add(nxt[0])
        seqs.append(seq)
    out = []
    for seq in seqs:
        first, last = seq[0], seq[-1]
        lv = levels[first]
        prev = levels[first - 1] if first > 0 else para
        sos = 'R' if max(lv, prev) % 2 else 'L'
        if classes[last] in ('LRI', 'RLI', 'FSI'):
            nxt_lv = para
        else:
            nxt_lv = levels[last + 1] if last + 1 < n else para
        eos = 'R' if max(levels[last], nxt_lv) % 2 else 'L'
        out.append([seq, sos, eos])
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('isolate joins outer run', [['L', 'RLI', 'R', 'PDI', 'L'], [0, 0, 1, 0, 0], 0], [[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'R']]), ('regression: eos level comparison', [['L', 'L', 'EN'], [2, 2, 2], 1], [[[0, 1, 2], 'L', 'L']]), ('regression: eos level comparison', [['EN', 'L', 'EN', 'PDI', 'EN'], [1, 2, 1, 1, 1], 1], [[[0], 'R', 'L'], [[1], 'L', 'L'], [[2, 3, 4], 'L', 'R']]), ('regression: eos level comparison', [['R', 'EN', 'PDI', 'R', 'ON', 'R'], [0, 0, 0, 1, 0, 1], 0], [[[0, 1, 2], 'L', 'R'], [[3], 'R', 'R'], [[4], 'R', 'R'], [[5], 'R', 'R']]), ('unmatched initiator at end', [['L', 'R', 'RLI'], [0, 1, 1], 0], [[[0], 'L', 'R'], [[1, 2], 'R', 'R']]), ('nested isolates', [['R', 'LRI', 'L', 'RLI', 'R', 'PDI', 'PDI', 'R'], [1, 1, 2, 2, 3, 2, 1, 1], 1], [[[0, 1, 6, 7], 'R', 'R'], [[2, 3, 5], 'L', 'L'], [[4], 'R', 'R']]), ('control layout', [['EN', 'PDI', 'L', 'LRI', 'LRI', 'EN', 'EN', 'L'], [0, 0, 0, 0, 2, 4, 4, 4], 0], [[[0, 1, 2, 3], 'L', 'L'], [[4], 'L', 'L'], [[5, 6, 7], 'L', 'L']]), ('control layout', [['EN', 'EN', 'RLI', 'PDI', 'R', 'EN', 'PDI', 'ON', 'EN', 'ON', 'L', 'ON'], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], 0], [[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11], 'L', 'L']])], [('regression: eos level comparison', [['R', 'R', 'RLI', 'L', 'PDI', 'ON', 'L', 'EN', 'L', 'EN', 'L'], [0, 1, 0, 2, 0, 0, 0, 0, 0, 0, 0], 0], [[[0], 'L', 'R'], [[1], 'R', 'R'], [[2, 4, 5, 6, 7, 8, 9, 10], 'R', 'L'], [[3], 'L', 'L']]), ('regression: eos level comparison', [['FSI', 'ON', 'EN', 'R', 'PDI', 'L', 'L', 'EN'], [0, 2, 2, 3, 0, 0, 0, 0], 0], [[[0, 4, 5, 6, 7], 'L', 'L'], [[1, 2], 'L', 'R'], [[3], 'R', 'R']]), ('regression: eos level comparison', [['LRI', 'R', 'PDI', 'EN', 'L', 'EN', 'EN', 'L', 'LRI', 'PDI', 'ON', 'R', 'L'], [1, 3, 1, 2, 1, 1, 2, 2, 1, 1, 1, 1, 1], 1], [[[0, 2], 'R', 'L'], [[1], 'R', 'R'], [[3], 'L', 'L'], [[4, 5], 'L', 'L'], [[6, 7], 'L', 'L'], [[8, 9, 10, 11, 12], 'L', 'R']]), ('regression: eos level comparison', [['L', 'ON', 'PDI', 'L', 'R', 'PDI', 'EN', 'ON', 'ON', 'LRI', 'L', 'ON', 'PDI', 'FSI'], [2, 1, 1, 2, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1], 1], [[[0], 'L', 'L'], [[1, 2], 'L', 'L'], [[3], 'L', 'L'], [[4, 5], 'L', 'L'], [[6], 'L', 'L'], [[7, 8, 9, 12, 13], 'L', 'R'], [[10, 11], 'L', 'L']]), ('unmatched initiator at end', [['L', 'R', 'RLI'], [0, 1, 1], 0], [[[0], 'L', 'R'], [[1, 2], 'R', 'R']]), ('isolate joins outer run', [['L', 'RLI', 'R', 'PDI', 'L'], [0, 0, 1, 0, 0], 0], [[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'R']]), ('control layout', [['PDI', 'PDI', 'L', 'ON', 'ON', 'L', 'ON', 'ON', 'EN', 'PDI'], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], 0], [[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9], 'L', 'L']]), ('control layout', [['R', 'L', 'PDI'], [1, 1, 1], 1], [[[0, 1, 2], 'R', 'R']])], [('regression: eos level comparison', [['LRI', 'LRI', 'EN', 'PDI', 'EN', 'R', 'R', 'R', 'L', 'PDI', 'EN'], [1, 2, 4, 2, 2, 2, 3, 3, 2, 1, 2], 1], [[[0, 9], 'R', 'L'], [[1, 3, 4, 5], 'L', 'R'], [[2], 'L', 'L'], [[6, 7], 'R', 'R'], [[8], 'R', 'L'], [[10], 'L', 'L']]), ('regression: eos level comparison', [['RLI', 'RLI', 'R', 'PDI', 'EN', 'R', 'ON', 'PDI', 'L', 'L', 'EN', 'L', 'L'], [0, 1, 3, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0], 0], [[[0, 7, 8, 9, 10, 11, 12], 'L', 'L'], [[1, 3, 4, 5, 6], 'R', 'R'], [[2], 'R', 'R']]), ('regression: eos level comparison', [['EN', 'EN', 'PDI', 'R', 'PDI'], [0, 0, 0, 1, 0], 0], [[[0, 1, 2], 'L', 'R'], [[3], 'R', 'R'], [[4], 'R', 'L']]), ('regression: eos level comparison', [['R', 'EN', 'R', 'FSI', 'ON', 'R', 'PDI', 'PDI', 'PDI', 'ON', 'RLI', 'ON', 'EN', 'R'], [1, 0, 1, 0, 2, 2, 0, 0, 0, 0, 0, 1, 1, 1], 0], [[[0], 'R', 'R'], [[1], 'R', 'R'], [[2], 'R', 'R'], [[3, 6, 7, 8, 9, 10], 'R', 'L'], [[4, 5], 'L', 'L'], [[11, 12, 13], 'R', 'R']]), ('unmatched initiator at end', [['L', 'R', 'RLI'], [0, 1, 1], 0], [[[0], 'L', 'R'], [[1, 2], 'R', 'R']]), ('nested isolates', [['R', 'LRI', 'L', 'RLI', 'R', 'PDI', 'PDI', 'R'], [1, 1, 2, 2, 3, 2, 1, 1], 1], [[[0, 1, 6, 7], 'R', 'R'], [[2, 3, 5], 'L', 'L'], [[4], 'R', 'R']]), ('control layout', [['EN', 'L', 'EN', 'R', 'ON', 'R', 'ON', 'L', 'EN', 'L', 'PDI'], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], 0], [[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 'L', 'L']]), ('control layout', [['EN', 'PDI', 'EN', 'PDI'], [1, 1, 1, 1], 1], [[[0, 1, 2, 3], 'R', 'R']])], [('regression: eos level comparison', [['EN', 'L', 'ON', 'PDI', 'R', 'R', 'LRI'], [1, 2, 1, 1, 1, 1, 1], 1], [[[0], 'R', 'L'], [[1], 'L', 'L'], [[2, 3, 4, 5, 6], 'L', 'R']]), ('regression: eos level comparison', [['PDI', 'EN', 'ON', 'EN', 'ON', 'ON', 'RLI', 'R', 'ON', 'EN', 'PDI', 'L'], [1, 2, 1, 2, 1, 1, 1, 3, 3, 4, 1, 2], 1], [[[0], 'R', 'L'], [[1], 'L', 'L'], [[2], 'L', 'L'], [[3], 'L', 'L'], [[4, 5, 6, 10], 'L', 'L'], [[7, 8], 'R', 'L'], [[9], 'L', 'L'], [[11], 'L', 'L']]), ('regression: eos level comparison', [['FSI', 'EN', 'PDI', 'L', 'R', 'ON', 'ON', 'LRI'], [1, 2, 1, 2, 1, 1, 1, 1], 1], [[[0, 2], 'R', 'L'], [[1], 'L', 'L'], [[3], 'L', 'L'], [[4, 5, 6, 7], 'L', 'R']]), ('regression: eos level comparison', [['R', 'R', 'L', 'L', 'ON'], [1, 1, 2, 1, 1], 1], [[[0, 1], 'R', 'L'], [[2], 'L', 'L'], [[3, 4], 'L', 'R']]), ('isolate joins outer run', [['L', 'RLI', 'R', 'PDI', 'L'], [0, 0, 1, 0, 0], 0], [[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'R']]), ('unmatched initiator at end', [['L', 'R', 'RLI'], [0, 1, 1], 0], [[[0], 'L', 'R'], [[1, 2], 'R', 'R']]), ('control layout', [['R', 'R', 'EN', 'L', 'ON', 'ON', 'RLI', 'PDI', 'RLI'], [1, 1, 1, 1, 1, 1, 1, 1, 1], 1], [[[0, 1, 2, 3, 4, 5, 6, 7, 8], 'R', 'R']]), ('control layout', [['RLI', 'RLI', 'ON', 'RLI', 'L', 'PDI', 'R'], [1, 3, 5, 5, 7, 5, 5], 1], [[[0], 'R', 'R'], [[1], 'R', 'R'], [[2, 3, 5, 6], 'R', 'R'], [[4], 'R', 'R']])], [('regression: eos level comparison', [['L', 'ON', 'EN', 'R'], [0, 0, 0, 1], 0], [[[0, 1, 2], 'L', 'R'], [[3], 'R', 'R']]), ('regression: eos level comparison', [['ON', 'ON', 'ON', 'RLI', 'EN', 'L'], [1, 1, 1, 1, 4, 3], 1], [[[0, 1, 2, 3], 'R', 'R'], [[4], 'L', 'L'], [[5], 'L', 'R']]), ('regression: eos level comparison', [['ON', 'LRI', 'RLI', 'R', 'L', 'RLI', 'ON', 'EN'], [1, 1, 2, 3, 3, 3, 5, 6], 1], [[[0, 1], 'R', 'R'], [[2], 'L', 'L'], [[3, 4, 5], 'R', 'R'], [[6], 'R', 'L'], [[7], 'L', 'L']]), ('regression: eos level comparison', [['RLI', 'RLI', 'L', 'L'], [0, 1, 3, 4], 0], [[[0], 'L', 'L'], [[1], 'R', 'R'], [[2], 'R', 'L'], [[3], 'L', 'L']]), ('isolate joins outer run', [['L', 'RLI', 'R', 'PDI', 'L'], [0, 0, 1, 0, 0], 0], [[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'R']]), ('nested isolates', [['R', 'LRI', 'L', 'RLI', 'R', 'PDI', 'PDI', 'R'], [1, 1, 2, 2, 3, 2, 1, 1], 1], [[[0, 1, 6, 7], 'R', 'R'], [[2, 3, 5], 'L', 'L'], [[4], 'R', 'R']]), ('control layout', [['L', 'ON', 'EN', 'R', 'EN', 'L', 'FSI'], [0, 0, 0, 0, 0, 0, 0], 0], [[[0, 1, 2, 3, 4, 5, 6], 'L', 'L']]), ('control layout', [['PDI', 'PDI', 'ON', 'L', 'FSI'], [0, 0, 0, 0, 0], 0], [[[0, 1, 2, 3, 4], 'L', 'L']])]]
for label, args, expected in fixtures[N - 1]:
    check(label, 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
isolate joins outer run	`[[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'R']]`	`[[[0, 1, 3, 4], 'L', 'L'], [[2], 'R', 'R']]`	Passed
regression: eos level comparison	`[[[0, 1, 2], 'L', 'L']]`	`[[[0, 1, 2], 'L', 'L']]`	Passed
regression: eos level comparison	`[[[0], 'R', 'L'], [[1], 'L', 'L'], [[2, 3, 4], 'L', 'R']]`	`[[[0], 'R', 'L'], [[1], 'L', 'L'], [[2, 3, 4], 'L', 'R']]`	Passed
regression: eos level comparison	`[[[0, 1, 2], 'L', 'R'], [[3], 'R', 'R'], [[4], 'R', 'R'], [[5], 'R', 'R']]`	`[[[0, 1, 2], 'L', 'R'], [[3], 'R', 'R'], [[4], 'R', 'R'], [[5], 'R', 'R']]`	Passed
unmatched initiator at end	`[[[0], 'L', 'R'], [[1, 2], 'R', 'R']]`	`[[[0], 'L', 'R'], [[1, 2], 'R', 'R']]`	Passed
nested isolates	`[[[0, 1, 6, 7], 'R', 'R'], [[2, 3, 5], 'L', 'L'], [[4], 'R', 'R']]`	`[[[0, 1, 6, 7], 'R', 'R'], [[2, 3, 5], 'L', 'L'], [[4], 'R', 'R']]`	Passed
control layout	`[[[0, 1, 2, 3], 'L', 'L'], [[4], 'L', 'L'], [[5, 6, 7], 'L', 'L']]`	`[[[0, 1, 2, 3], 'L', 'L'], [[4], 'L', 'L'], [[5, 6, 7], 'L', 'L']]`	Passed
control layout	`[[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11], 'L', 'L']]`	`[[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11], 'L', 'L']]`	Passed

SHA-256 / e138b5a5b2eeab3c2abdda24a695903f0cdc0545f064c90ec00b9f1b034e759b

Verification & scope

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.

Observations recorded using Python 3.12.14 at 2026-09-29T14:49:57.003775+00:00.

Case digest / 98ddb625bb122cc29cbbedc0a90c86354525350a60839e8d5eca45e84b191b44