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FA-67121 / Railway interlocking logic / Open access

Two-out-of-three occupancy voting: isolation policy · case 01

A persistently dissenting channel keeps voting one cycle too long or is never isolated.

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

ROOT CAUSE

Isolation needs one more discrepancy than isolate_after.

THE FAILURE

Isolation needs one more discrepancy than isolate_after.

Unsuccessful approach: Allowing only one isolation keeps a second faulty channel in the vote.

Case contract

Three channels report occupancy (True/False) or None when failed. A channel isolated earlier counts as None. With fewer than two healthy channels the vote is occupied. Otherwise the vote is occupied when occupied reports are at least as many as clear ones (ties are occupied). A healthy channel that disagrees with the vote increments its discrepancy count, otherwise (agreeing or None) the count resets; a channel is isolated for good when its count reaches isolate_after. Return all votes and isolated channel indices.

Why this case matters

Interlocking logic decides whether trains may be given authority; a wrong decision at this point either grants unsafe movements or strands traffic.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    k = x['isolate_after']
    bad = [0, 0, 0]
    iso = [False, False, False]
    votes = []
    for cyc in x['cycles']:
        vals = [None if iso[i] else cyc[i] for i in range(3)]
        healthy = [v for v in vals if v is not None]
        if len(healthy) < 2:
            vote = True
        else:
            t = sum(1 for v in healthy if v)
            f = len(healthy) - t
            vote = t >= f
        votes.append(vote)
        for i in range(3):
            if vals[i] is not None and vals[i] != vote:
                bad[i] += 1
                if bad[i] > k:
                    iso[i] = True
            else:
                bad[i] = 0
    return {'votes': votes, 'isolated': [i for i in range(3) if iso[i]]}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: persistent dissenter', {'isolate_after': 2, 'cycles': [[True, False, False], [True, False, False], [False, False, False]]}, {'votes': [False, False, False], 'isolated': [0]}), ('regression: two dissenters in turn', {'isolate_after': 2, 'cycles': [[True, False, False], [True, False, False], [False, True, False], [False, True, False], [False, False, False]]}, {'votes': [False, False, True, True, True], 'isolated': [0, 2]}), ('sampled regression 6', {'isolate_after': 2, 'cycles': [[None, False, True], [False, True, False], [True, False, False], [False, True, False], [False, False, False], [False, False, False], [None, False, True]]}, {'votes': [True, False, True, False, False, False, True], 'isolated': [1]}), ('regression: isolated channel keeps reporting', {'isolate_after': 1, 'cycles': [[True, False, False], [True, True, False]]}, {'votes': [False, True], 'isolated': [0, 2]}), ('boundary: two healthy channels disagree', {'isolate_after': 3, 'cycles': [[True, False, None]]}, {'votes': [True], 'isolated': []}), ('control 1', {'isolate_after': 2, 'cycles': [[False, False, False], [True, None, True], [True, True, True], [None, False, False]]}, {'votes': [False, True, True, False], 'isolated': []}), ('control 4', {'isolate_after': 2, 'cycles': [[False, True, True], [False, False, False], [False, False, False], [True, True, False], [True, True, True], [True, False, True], [False, False, False], [False, False, None], [True, True, True]]}, {'votes': [True, False, False, True, True, True, False, False, True], 'isolated': []}), ('control 7', {'isolate_after': 3, 'cycles': [[False, False, True], [False, False, False], [True, True, True], [False, True, True], [True, True, None], [False, False, False], [True, True, True], [False, False, False]]}, {'votes': [False, False, True, True, True, False, True, False], 'isolated': []})], [('regression: two dissenters in turn', {'isolate_after': 2, 'cycles': [[True, False, False], [True, False, False], [False, True, False], [False, True, False], [False, False, False]]}, {'votes': [False, False, True, True, True], 'isolated': [0, 2]}), ('regression: isolated channel keeps reporting', {'isolate_after': 1, 'cycles': [[True, False, False], [True, True, False]]}, {'votes': [False, True], 'isolated': [0, 2]}), ('sampled regression 45', {'isolate_after': 2, 'cycles': [[True, True, True], [False, False, False], [False, False, False], [False, True, False], [None, True, False], [None, True, False], [True, False, False]]}, {'votes': [True, False, False, False, True, True, True], 'isolated': [2]}), ('boundary: single healthy channel says clear', {'isolate_after': 3, 'cycles': [[False, None, None]]}, {'votes': [True], 'isolated': []}), ('regression: persistent dissenter', {'isolate_after': 2, 'cycles': [[True, False, False], [True, False, False], [False, False, False]]}, {'votes': [False, False, False], 'isolated': [0]}), ('sampled regression 12', {'isolate_after': 3, 'cycles': [[False, False, False], [False, True, False], [True, False, True], [True, False, True], [False, False, True], [False, False, False], [True, False, True], [True, True, True]]}, {'votes': [False, False, True, True, True, False, True, True], 'isolated': [1]}), ('control 15', {'isolate_after': 3, 'cycles': [[False, False, False], [False, None, False], [True, False, False], [True, None, False]]}, {'votes': [False, False, False, True], 'isolated': []}), ('control 18', {'isolate_after': 2, 'cycles': [[False, False, False], [None, False, True], [False, False, True], [True, False, False], [True, False, True], [False, False, False], [False, True, None], [False, False, False], [False, False, False]]}, {'votes': [False, True, False, False, True, False, True, False, False], 'isolated': []})], [('regression: isolated channel keeps reporting', {'isolate_after': 1, 'cycles': [[True, False, False], [True, True, False]]}, {'votes': [False, True], 'isolated': [0, 2]}), ('regression: two dissenters in turn', {'isolate_after': 2, 'cycles': [[True, False, False], [True, False, False], [False, True, False], [False, True, False], [False, False, False]]}, {'votes': [False, False, True, True, True], 'isolated': [0, 2]}), ('sampled regression 12', {'isolate_after': 3, 'cycles': [[False, False, False], [False, True, False], [True, False, True], [True, False, True], [False, False, True], [False, False, False], [True, False, True], [True, True, True]]}, {'votes': [False, False, True, True, True, False, True, True], 'isolated': [1]}), ('sampled regression 40', {'isolate_after': 2, 'cycles': [[True, None, True], [False, False, None], [False, True, False], [False, True, False], [True, True, True], [True, None, False], [None, False, False], [True, True, True]]}, {'votes': [True, False, False, False, True, True, True, True], 'isolated': [1, 2]}), ('boundary: dissent interrupted by failure', {'isolate_after': 2, 'cycles': [[True, False, False], [None, False, False], [True, False, False]]}, {'votes': [False, False, False], 'isolated': []}), ('control 23', {'isolate_after': 2, 'cycles': [[True, False, True], [None, False, False], [False, False, False], [False, False, False], [False, False, None], [False, False, False], [True, None, True]]}, {'votes': [True, False, False, False, False, False, True], 'isolated': []}), ('control 26', {'isolate_after': 2, 'cycles': [[True, True, True], [False, False, False], [False, False, True], [False, False, None]]}, {'votes': [True, False, False, False], 'isolated': []}), ('control 29', {'isolate_after': 2, 'cycles': [[False, False, True], [False, False, False], [False, False, True], [False, True, False], [False, True, True]]}, {'votes': [False, False, False, False, True], 'isolated': []})], [('regression: persistent dissenter', {'isolate_after': 2, 'cycles': [[True, False, False], [True, False, False], [False, False, False]]}, {'votes': [False, False, False], 'isolated': [0]}), ('regression: isolated channel keeps reporting', {'isolate_after': 1, 'cycles': [[True, False, False], [True, True, False]]}, {'votes': [False, True], 'isolated': [0, 2]}), ('boundary: two healthy channels disagree', {'isolate_after': 3, 'cycles': [[True, False, None]]}, {'votes': [True], 'isolated': []}), ('boundary: two healthy channels agree clear', {'isolate_after': 3, 'cycles': [[False, False, None]]}, {'votes': [False], 'isolated': []}), ('boundary: single healthy channel says clear', {'isolate_after': 3, 'cycles': [[False, None, None]]}, {'votes': [True], 'isolated': []}), ('control 34', {'isolate_after': 2, 'cycles': [[True, True, False], [False, True, False], [True, True, True], [True, True, True], [True, False, True], [False, False, False], [True, False, True]]}, {'votes': [True, False, True, True, True, False, True], 'isolated': []}), ('control 37', {'isolate_after': 3, 'cycles': [[True, True, True], [False, False, False], [False, False, False], [False, True, False], [True, False, False], [False, False, False]]}, {'votes': [True, False, False, False, False, False], 'isolated': []}), ('sampled regression 40', {'isolate_after': 2, 'cycles': [[True, None, True], [False, False, None], [False, True, False], [False, True, False], [True, True, True], [True, None, False], [None, False, False], [True, True, True]]}, {'votes': [True, False, False, False, True, True, True, True], 'isolated': [1, 2]})], [('regression: two dissenters in turn', {'isolate_after': 2, 'cycles': [[True, False, False], [True, False, False], [False, True, False], [False, True, False], [False, False, False]]}, {'votes': [False, False, True, True, True], 'isolated': [0, 2]}), ('sampled regression 39', {'isolate_after': 2, 'cycles': [[True, False, True], [False, True, None], [True, False, False], [True, True, False], [False, False, False], [True, False, True], [True, True, True]]}, {'votes': [True, True, False, True, False, True, True], 'isolated': [0]}), ('boundary: two healthy channels agree clear', {'isolate_after': 3, 'cycles': [[False, False, None]]}, {'votes': [False], 'isolated': []}), ('boundary: single healthy channel says clear', {'isolate_after': 3, 'cycles': [[False, None, None]]}, {'votes': [True], 'isolated': []}), ('regression: persistent dissenter', {'isolate_after': 2, 'cycles': [[True, False, False], [True, False, False], [False, False, False]]}, {'votes': [False, False, False], 'isolated': [0]}), ('sampled regression 45', {'isolate_after': 2, 'cycles': [[True, True, True], [False, False, False], [False, False, False], [False, True, False], [None, True, False], [None, True, False], [True, False, False]]}, {'votes': [True, False, False, False, True, True, True], 'isolated': [2]}), ('control 48', {'isolate_after': 2, 'cycles': [[False, False, False], [False, False, False], [False, True, True], [True, True, None], [False, True, False], [True, True, True], [False, False, False], [False, False, False], [False, True, False]]}, {'votes': [False, False, True, True, False, True, False, False, False], 'isolated': []}), ('control 51', {'isolate_after': 3, 'cycles': [[False, False, False], [True, False, False], [True, True, True], [True, True, True], [True, True, True], [True, True, True], [True, False, True], [True, False, False], [True, True, True]]}, {'votes': [False, False, True, True, True, True, True, False, True], 'isolated': []})]]
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 fixtureActualExpectedOutcome
regression: persistent dissenter{'isolated': [], 'votes': [False, False, False]}{'isolated': [0], 'votes': [False, False, False]}Failed
regression: two dissenters in turn{'isolated': [], 'votes': [False, False, False, False, False]}{'isolated': [0, 2], 'votes': [False, False, True, True, True]}Failed
sampled regression 6{'isolated': [], 'votes': [True, False, False, False, False, False, True]}{'isolated': [1], 'votes': [True, False, True, False, False, False, True]}Failed
regression: isolated channel keeps reporting{'isolated': [], 'votes': [False, True]}{'isolated': [0, 2], 'votes': [False, True]}Failed
boundary: two healthy channels disagree{'isolated': [], 'votes': [True]}{'isolated': [], 'votes': [True]}Passed
control 1{'isolated': [], 'votes': [False, True, True, False]}{'isolated': [], 'votes': [False, True, True, False]}Passed
control 4{'isolated': [], 'votes': [True, False, False, True, True, True, False, False, True]}{'isolated': [], 'votes': [True, False, False, True, True, True, False, False, True]}Passed
control 7{'isolated': [], 'votes': [False, False, True, True, True, False, True, False]}{'isolated': [], 'votes': [False, False, True, True, True, False, True, False]}Passed

SHA-256 / 50bf6f2d7f60d25fc0703a3a137eb8f1d261f8496029d445bbddf35ffe97edaf

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    k = x['isolate_after']
    bad = [0, 0, 0]
    iso = [False, False, False]
    votes = []
    for cyc in x['cycles']:
        vals = [None if iso[i] else cyc[i] for i in range(3)]
        healthy = [v for v in vals if v is not None]
        if len(healthy) < 2:
            vote = True
        else:
            t = sum(1 for v in healthy if v)
            f = len(healthy) - t
            vote = t >= f
        votes.append(vote)
        for i in range(3):
            if vals[i] is not None and vals[i] != vote:
                bad[i] += 1
                if bad[i] >= k and not any(iso):
                    iso[i] = True
            else:
                bad[i] = 0
    return {'votes': votes, 'isolated': [i for i in range(3) if iso[i]]}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: persistent dissenter', {'isolate_after': 2, 'cycles': [[True, False, False], [True, False, False], [False, False, False]]}, {'votes': [False, False, False], 'isolated': [0]}), ('regression: two dissenters in turn', {'isolate_after': 2, 'cycles': [[True, False, False], [True, False, False], [False, True, False], [False, True, False], [False, False, False]]}, {'votes': [False, False, True, True, True], 'isolated': [0, 2]}), ('sampled regression 6', {'isolate_after': 2, 'cycles': [[None, False, True], [False, True, False], [True, False, False], [False, True, False], [False, False, False], [False, False, False], [None, False, True]]}, {'votes': [True, False, True, False, False, False, True], 'isolated': [1]}), ('regression: isolated channel keeps reporting', {'isolate_after': 1, 'cycles': [[True, False, False], [True, True, False]]}, {'votes': [False, True], 'isolated': [0, 2]}), ('boundary: two healthy channels disagree', {'isolate_after': 3, 'cycles': [[True, False, None]]}, {'votes': [True], 'isolated': []}), ('control 1', {'isolate_after': 2, 'cycles': [[False, False, False], [True, None, True], [True, True, True], [None, False, False]]}, {'votes': [False, True, True, False], 'isolated': []}), ('control 4', {'isolate_after': 2, 'cycles': [[False, True, True], [False, False, False], [False, False, False], [True, True, False], [True, True, True], [True, False, True], [False, False, False], [False, False, None], [True, True, True]]}, {'votes': [True, False, False, True, True, True, False, False, True], 'isolated': []}), ('control 7', {'isolate_after': 3, 'cycles': [[False, False, True], [False, False, False], [True, True, True], [False, True, True], [True, True, None], [False, False, False], [True, True, True], [False, False, False]]}, {'votes': [False, False, True, True, True, False, True, False], 'isolated': []})], [('regression: two dissenters in turn', {'isolate_after': 2, 'cycles': [[True, False, False], [True, False, False], [False, True, False], [False, True, False], [False, False, False]]}, {'votes': [False, False, True, True, True], 'isolated': [0, 2]}), ('regression: isolated channel keeps reporting', {'isolate_after': 1, 'cycles': [[True, False, False], [True, True, False]]}, {'votes': [False, True], 'isolated': [0, 2]}), ('sampled regression 45', {'isolate_after': 2, 'cycles': [[True, True, True], [False, False, False], [False, False, False], [False, True, False], [None, True, False], [None, True, False], [True, False, False]]}, {'votes': [True, False, False, False, True, True, True], 'isolated': [2]}), ('boundary: single healthy channel says clear', {'isolate_after': 3, 'cycles': [[False, None, None]]}, {'votes': [True], 'isolated': []}), ('regression: persistent dissenter', {'isolate_after': 2, 'cycles': [[True, False, False], [True, False, False], [False, False, False]]}, {'votes': [False, False, False], 'isolated': [0]}), ('sampled regression 12', {'isolate_after': 3, 'cycles': [[False, False, False], [False, True, False], [True, False, True], [True, False, True], [False, False, True], [False, False, False], [True, False, True], [True, True, True]]}, {'votes': [False, False, True, True, True, False, True, True], 'isolated': [1]}), ('control 15', {'isolate_after': 3, 'cycles': [[False, False, False], [False, None, False], [True, False, False], [True, None, False]]}, {'votes': [False, False, False, True], 'isolated': []}), ('control 18', {'isolate_after': 2, 'cycles': [[False, False, False], [None, False, True], [False, False, True], [True, False, False], [True, False, True], [False, False, False], [False, True, None], [False, False, False], [False, False, False]]}, {'votes': [False, True, False, False, True, False, True, False, False], 'isolated': []})], [('regression: isolated channel keeps reporting', {'isolate_after': 1, 'cycles': [[True, False, False], [True, True, False]]}, {'votes': [False, True], 'isolated': [0, 2]}), ('regression: two dissenters in turn', {'isolate_after': 2, 'cycles': [[True, False, False], [True, False, False], [False, True, False], [False, True, False], [False, False, False]]}, {'votes': [False, False, True, True, True], 'isolated': [0, 2]}), ('sampled regression 12', {'isolate_after': 3, 'cycles': [[False, False, False], [False, True, False], [True, False, True], [True, False, True], [False, False, True], [False, False, False], [True, False, True], [True, True, True]]}, {'votes': [False, False, True, True, True, False, True, True], 'isolated': [1]}), ('sampled regression 40', {'isolate_after': 2, 'cycles': [[True, None, True], [False, False, None], [False, True, False], [False, True, False], [True, True, True], [True, None, False], [None, False, False], [True, True, True]]}, {'votes': [True, False, False, False, True, True, True, True], 'isolated': [1, 2]}), ('boundary: dissent interrupted by failure', {'isolate_after': 2, 'cycles': [[True, False, False], [None, False, False], [True, False, False]]}, {'votes': [False, False, False], 'isolated': []}), ('control 23', {'isolate_after': 2, 'cycles': [[True, False, True], [None, False, False], [False, False, False], [False, False, False], [False, False, None], [False, False, False], [True, None, True]]}, {'votes': [True, False, False, False, False, False, True], 'isolated': []}), ('control 26', {'isolate_after': 2, 'cycles': [[True, True, True], [False, False, False], [False, False, True], [False, False, None]]}, {'votes': [True, False, False, False], 'isolated': []}), ('control 29', {'isolate_after': 2, 'cycles': [[False, False, True], [False, False, False], [False, False, True], [False, True, False], [False, True, True]]}, {'votes': [False, False, False, False, True], 'isolated': []})], [('regression: persistent dissenter', {'isolate_after': 2, 'cycles': [[True, False, False], [True, False, False], [False, False, False]]}, {'votes': [False, False, False], 'isolated': [0]}), ('regression: isolated channel keeps reporting', {'isolate_after': 1, 'cycles': [[True, False, False], [True, True, False]]}, {'votes': [False, True], 'isolated': [0, 2]}), ('boundary: two healthy channels disagree', {'isolate_after': 3, 'cycles': [[True, False, None]]}, {'votes': [True], 'isolated': []}), ('boundary: two healthy channels agree clear', {'isolate_after': 3, 'cycles': [[False, False, None]]}, {'votes': [False], 'isolated': []}), ('boundary: single healthy channel says clear', {'isolate_after': 3, 'cycles': [[False, None, None]]}, {'votes': [True], 'isolated': []}), ('control 34', {'isolate_after': 2, 'cycles': [[True, True, False], [False, True, False], [True, True, True], [True, True, True], [True, False, True], [False, False, False], [True, False, True]]}, {'votes': [True, False, True, True, True, False, True], 'isolated': []}), ('control 37', {'isolate_after': 3, 'cycles': [[True, True, True], [False, False, False], [False, False, False], [False, True, False], [True, False, False], [False, False, False]]}, {'votes': [True, False, False, False, False, False], 'isolated': []}), ('sampled regression 40', {'isolate_after': 2, 'cycles': [[True, None, True], [False, False, None], [False, True, False], [False, True, False], [True, True, True], [True, None, False], [None, False, False], [True, True, True]]}, {'votes': [True, False, False, False, True, True, True, True], 'isolated': [1, 2]})], [('regression: two dissenters in turn', {'isolate_after': 2, 'cycles': [[True, False, False], [True, False, False], [False, True, False], [False, True, False], [False, False, False]]}, {'votes': [False, False, True, True, True], 'isolated': [0, 2]}), ('sampled regression 39', {'isolate_after': 2, 'cycles': [[True, False, True], [False, True, None], [True, False, False], [True, True, False], [False, False, False], [True, False, True], [True, True, True]]}, {'votes': [True, True, False, True, False, True, True], 'isolated': [0]}), ('boundary: two healthy channels agree clear', {'isolate_after': 3, 'cycles': [[False, False, None]]}, {'votes': [False], 'isolated': []}), ('boundary: single healthy channel says clear', {'isolate_after': 3, 'cycles': [[False, None, None]]}, {'votes': [True], 'isolated': []}), ('regression: persistent dissenter', {'isolate_after': 2, 'cycles': [[True, False, False], [True, False, False], [False, False, False]]}, {'votes': [False, False, False], 'isolated': [0]}), ('sampled regression 45', {'isolate_after': 2, 'cycles': [[True, True, True], [False, False, False], [False, False, False], [False, True, False], [None, True, False], [None, True, False], [True, False, False]]}, {'votes': [True, False, False, False, True, True, True], 'isolated': [2]}), ('control 48', {'isolate_after': 2, 'cycles': [[False, False, False], [False, False, False], [False, True, True], [True, True, None], [False, True, False], [True, True, True], [False, False, False], [False, False, False], [False, True, False]]}, {'votes': [False, False, True, True, False, True, False, False, False], 'isolated': []}), ('control 51', {'isolate_after': 3, 'cycles': [[False, False, False], [True, False, False], [True, True, True], [True, True, True], [True, True, True], [True, True, True], [True, False, True], [True, False, False], [True, True, True]]}, {'votes': [False, False, True, True, True, True, True, False, True], 'isolated': []})]]
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 fixtureActualExpectedOutcome
regression: persistent dissenter{'isolated': [0], 'votes': [False, False, False]}{'isolated': [0], 'votes': [False, False, False]}Passed
regression: two dissenters in turn{'isolated': [0], 'votes': [False, False, True, True, False]}{'isolated': [0, 2], 'votes': [False, False, True, True, True]}Failed
sampled regression 6{'isolated': [1], 'votes': [True, False, True, False, False, False, True]}{'isolated': [1], 'votes': [True, False, True, False, False, False, True]}Passed
regression: isolated channel keeps reporting{'isolated': [0], 'votes': [False, True]}{'isolated': [0, 2], 'votes': [False, True]}Failed
boundary: two healthy channels disagree{'isolated': [], 'votes': [True]}{'isolated': [], 'votes': [True]}Passed
control 1{'isolated': [], 'votes': [False, True, True, False]}{'isolated': [], 'votes': [False, True, True, False]}Passed
control 4{'isolated': [], 'votes': [True, False, False, True, True, True, False, False, True]}{'isolated': [], 'votes': [True, False, False, True, True, True, False, False, True]}Passed
control 7{'isolated': [], 'votes': [False, False, True, True, True, False, True, False]}{'isolated': [], 'votes': [False, False, True, True, True, False, True, False]}Passed

SHA-256 / b0ab3bf151c44fef5c903b58db44bc7590a0684272ecd6caf7c6d70f3a927b35

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 8 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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Verification & scope

Stipulated toy interlocking contract for a bounded teaching model; it makes no claim of conformance to any railway signalling standard and omits real safety cases. 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 2026-09-29T14:47:49.986192+00:00.

Case digest / 613db2c9cac122ba2eb30f251bc50a3c8c9bf5cb3472fe12714ccf48a61f2099