FA-93311 / EV charging session scheduling / Open access
Staggered start after tariff switch: latest start derivation · case 01
Charging is pulled forward even when the staggered start would still finish in time.
ROOT CAUSE
The latest start subtracts the stagger delay a second time.
THE FAILURE
The latest start subtracts the stagger delay a second time.
Unsuccessful approach: Using depart as the latest start lets sessions finish after departure.
Case contract
To avoid a demand spike at a tariff switch each charger delays its start by delay = sum((i+1)*ord(c) for i, c in enumerate(cid)) % (max_delay+1) minutes after max(tariff_start, now). If that start is later than depart - dur it is pulled back to max(depart - dur, now). Status is 'ok' when start + dur <= depart else 'late'. Return [start, delay, status].
Why this case matters
Depot, workplace and public EV chargers schedule sessions against prices, circuit limits and departure deadlines; a wrong decision silently strands a driver or overloads a feeder.
1 / The failure
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(cid, tariff_start, now, depart, dur, max_delay):
delay = sum((i + 1) * ord(c) for i, c in enumerate(cid)) % (max_delay + 1)
start = max(tariff_start, now) + delay
latest = depart - dur - delay
if start > latest:
start = max(latest, now)
status = 'ok' if start + dur <= depart else 'late'
return [start, delay, status]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['boundary: no stagger configured', ['CP7', 100, 50, 400, 60, 0], [100, 0, 'ok']],
['boundary: deadline forces immediate start', ['CP12', 100, 50, 120, 70, 30], [50, 16, 'ok']],
['boundary: tariff already active', ['CP3', 10, 50, 400, 60, 10], [56, 6, 'ok']],
['regression: latest start derivation', ['CP929', 258, 12, 235, 31, 30], [204, 15, 'ok']],
['regression: latest start derivation (partial repair)', ['CP495', 117, 47, 359, 266, 0],
[93, 0, 'ok']],
['control 1', ['CP310', 208, 18, 199, 159, 0], [40, 0, 'ok']],
['control 2', ['CP766', 294, 150, 208, 201, 30], [150, 10, 'late']]],
[['boundary: no stagger configured', ['CP7', 100, 50, 400, 60, 0], [100, 0, 'ok']],
['boundary: deadline forces immediate start', ['CP12', 100, 50, 120, 70, 30], [50, 16, 'ok']],
['boundary: tariff already active', ['CP3', 10, 50, 400, 60, 10], [56, 6, 'ok']],
['regression: latest start derivation', ['CP990', 237, 16, 437, 299, 30], [138, 29, 'ok']],
['regression: latest start derivation (partial repair)', ['CP272', 217, 184, 482, 298, 15],
[184, 15, 'ok']],
['control 1', ['CP883', 235, 120, 211, 80, 5], [131, 4, 'ok']],
['control 2', ['CP742', 19, 177, 199, 247, 10], [177, 3, 'late']]],
[['boundary: no stagger configured', ['CP7', 100, 50, 400, 60, 0], [100, 0, 'ok']],
['boundary: deadline forces immediate start', ['CP12', 100, 50, 120, 70, 30], [50, 16, 'ok']],
['boundary: tariff already active', ['CP3', 10, 50, 400, 60, 10], [56, 6, 'ok']],
['regression: latest start derivation', ['CP466', 247, 123, 302, 127, 5], [175, 5, 'ok']],
['regression: latest start derivation (partial repair)', ['CP803', 164, 112, 215, 145, 5],
[112, 2, 'late']],
['control 1', ['CP783', 204, 99, 341, 202, 5], [139, 1, 'ok']],
['control 2', ['CP490', 211, 107, 512, 167, 10], [215, 4, 'ok']]],
[['boundary: no stagger configured', ['CP7', 100, 50, 400, 60, 0], [100, 0, 'ok']],
['boundary: deadline forces immediate start', ['CP12', 100, 50, 120, 70, 30], [50, 16, 'ok']],
['boundary: tariff already active', ['CP3', 10, 50, 400, 60, 10], [56, 6, 'ok']],
['regression: latest start derivation', ['CP873', 194, 7, 146, 117, 15], [29, 6, 'ok']],
['regression: latest start derivation (partial repair)', ['CP174', 226, 53, 139, 171, 5],
[53, 2, 'late']],
['control 1', ['CP137', 10, 19, 66, 6, 15], [24, 5, 'ok']],
['control 2', ['CP783', 210, 193, 350, 267, 30], [193, 3, 'late']]],
[['boundary: no stagger configured', ['CP7', 100, 50, 400, 60, 0], [100, 0, 'ok']],
['boundary: deadline forces immediate start', ['CP12', 100, 50, 120, 70, 30], [50, 16, 'ok']],
['boundary: tariff already active', ['CP3', 10, 50, 400, 60, 10], [56, 6, 'ok']],
['regression: latest start derivation', ['CP353', 241, 118, 320, 150, 5], [170, 1, 'ok']],
['regression: latest start derivation (partial repair)', ['CP776', 104, 179, 210, 259, 30],
[179, 14, 'late']],
['control 1', ['CP873', 194, 7, 146, 117, 15], [29, 6, 'ok']],
['control 2', ['CP733', 56, 136, 418, 4, 0], [136, 0, 'ok']]]]
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 |
|---|---|---|---|
| boundary: no stagger configured | [100, 0, 'ok'] | [100, 0, 'ok'] | Passed |
| boundary: deadline forces immediate start | [50, 16, 'ok'] | [50, 16, 'ok'] | Passed |
| boundary: tariff already active | [56, 6, 'ok'] | [56, 6, 'ok'] | Passed |
| regression: latest start derivation | [189, 15, 'ok'] | [204, 15, 'ok'] | Failed |
| regression: latest start derivation (partial repair) | [93, 0, 'ok'] | [93, 0, 'ok'] | Passed |
| control 1 | [40, 0, 'ok'] | [40, 0, 'ok'] | Passed |
| control 2 | [150, 10, 'late'] | [150, 10, 'late'] | Passed |
SHA-256 / 0a55184984bc27f18437f57b8fddc8a2ba3bb8c69ced805fd61c0578e372d2d7
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
N = 1
observations = []
def solve(cid, tariff_start, now, depart, dur, max_delay):
delay = sum((i + 1) * ord(c) for i, c in enumerate(cid)) % (max_delay + 1)
start = max(tariff_start, now) + delay
latest = depart
if start > latest:
start = max(latest, now)
status = 'ok' if start + dur <= depart else 'late'
return [start, delay, status]
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['boundary: no stagger configured', ['CP7', 100, 50, 400, 60, 0], [100, 0, 'ok']],
['boundary: deadline forces immediate start', ['CP12', 100, 50, 120, 70, 30], [50, 16, 'ok']],
['boundary: tariff already active', ['CP3', 10, 50, 400, 60, 10], [56, 6, 'ok']],
['regression: latest start derivation', ['CP929', 258, 12, 235, 31, 30], [204, 15, 'ok']],
['regression: latest start derivation (partial repair)', ['CP495', 117, 47, 359, 266, 0],
[93, 0, 'ok']],
['control 1', ['CP310', 208, 18, 199, 159, 0], [40, 0, 'ok']],
['control 2', ['CP766', 294, 150, 208, 201, 30], [150, 10, 'late']]],
[['boundary: no stagger configured', ['CP7', 100, 50, 400, 60, 0], [100, 0, 'ok']],
['boundary: deadline forces immediate start', ['CP12', 100, 50, 120, 70, 30], [50, 16, 'ok']],
['boundary: tariff already active', ['CP3', 10, 50, 400, 60, 10], [56, 6, 'ok']],
['regression: latest start derivation', ['CP990', 237, 16, 437, 299, 30], [138, 29, 'ok']],
['regression: latest start derivation (partial repair)', ['CP272', 217, 184, 482, 298, 15],
[184, 15, 'ok']],
['control 1', ['CP883', 235, 120, 211, 80, 5], [131, 4, 'ok']],
['control 2', ['CP742', 19, 177, 199, 247, 10], [177, 3, 'late']]],
[['boundary: no stagger configured', ['CP7', 100, 50, 400, 60, 0], [100, 0, 'ok']],
['boundary: deadline forces immediate start', ['CP12', 100, 50, 120, 70, 30], [50, 16, 'ok']],
['boundary: tariff already active', ['CP3', 10, 50, 400, 60, 10], [56, 6, 'ok']],
['regression: latest start derivation', ['CP466', 247, 123, 302, 127, 5], [175, 5, 'ok']],
['regression: latest start derivation (partial repair)', ['CP803', 164, 112, 215, 145, 5],
[112, 2, 'late']],
['control 1', ['CP783', 204, 99, 341, 202, 5], [139, 1, 'ok']],
['control 2', ['CP490', 211, 107, 512, 167, 10], [215, 4, 'ok']]],
[['boundary: no stagger configured', ['CP7', 100, 50, 400, 60, 0], [100, 0, 'ok']],
['boundary: deadline forces immediate start', ['CP12', 100, 50, 120, 70, 30], [50, 16, 'ok']],
['boundary: tariff already active', ['CP3', 10, 50, 400, 60, 10], [56, 6, 'ok']],
['regression: latest start derivation', ['CP873', 194, 7, 146, 117, 15], [29, 6, 'ok']],
['regression: latest start derivation (partial repair)', ['CP174', 226, 53, 139, 171, 5],
[53, 2, 'late']],
['control 1', ['CP137', 10, 19, 66, 6, 15], [24, 5, 'ok']],
['control 2', ['CP783', 210, 193, 350, 267, 30], [193, 3, 'late']]],
[['boundary: no stagger configured', ['CP7', 100, 50, 400, 60, 0], [100, 0, 'ok']],
['boundary: deadline forces immediate start', ['CP12', 100, 50, 120, 70, 30], [50, 16, 'ok']],
['boundary: tariff already active', ['CP3', 10, 50, 400, 60, 10], [56, 6, 'ok']],
['regression: latest start derivation', ['CP353', 241, 118, 320, 150, 5], [170, 1, 'ok']],
['regression: latest start derivation (partial repair)', ['CP776', 104, 179, 210, 259, 30],
[179, 14, 'late']],
['control 1', ['CP873', 194, 7, 146, 117, 15], [29, 6, 'ok']],
['control 2', ['CP733', 56, 136, 418, 4, 0], [136, 0, 'ok']]]]
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 |
|---|---|---|---|
| boundary: no stagger configured | [100, 0, 'ok'] | [100, 0, 'ok'] | Passed |
| boundary: deadline forces immediate start | [116, 16, 'late'] | [50, 16, 'ok'] | Failed |
| boundary: tariff already active | [56, 6, 'ok'] | [56, 6, 'ok'] | Passed |
| regression: latest start derivation | [235, 15, 'late'] | [204, 15, 'ok'] | Failed |
| regression: latest start derivation (partial repair) | [117, 0, 'late'] | [93, 0, 'ok'] | Failed |
| control 1 | [199, 0, 'late'] | [40, 0, 'ok'] | Failed |
| control 2 | [208, 10, 'late'] | [150, 10, 'late'] | Failed |
SHA-256 / 5db70cc4095800c6fd517692e61f2fd88198c59516986ba939fff859bb808a92
HELD IN THE MEMBER ARCHIVE
The verified repair and its recorded checks are member-only.
This mechanism has 7 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.
Member access is invitation-based. Sign in with your invited account to inspect the repair.
Sign in to the archive ↗Verification & scope
Deterministic stipulated toy contract for teaching; no claim of conformance with any standard, vendor protocol or production controller. 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 2026-09-29T14:51:53.985328+00:00.
Case digest / 75629762df11bf30ba012f833870eef48e29601d8807d66868b14a015f2b34f7