FA-77996 / Subtitle cue timing / Open access

Minimum cue duration extension: neighbour gap limit · case 01

Extended cues butt directly against the following cue.

Verified by executionVariant 1 · 9 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The neighbour limit ignores the required minimum gap.

VERIFIED REPAIR

Limit the extension to neighbour_start - min_gap.

Unsuccessful approach: The off-by-one limit still leaves the gap one millisecond short.

Case contract

Cues [start,end] may be unsorted; the neighbour of a cue is the next cue in (start, input index) order. A cue shorter than min_dur has its end extended to start+min_dur, limited to neighbour_start - min_gap; an end is never shortened. Output keeps input order.

Why this case matters

Subtitle timing defects shift, hide or overlap captions that viewers depend on for comprehension and accessibility.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(cues, min_dur, min_gap):
    out=[list(c) for c in cues]
    order=sorted(range(len(out)),key=lambda k:(out[k][0],k))
    for pos,i in enumerate(order):
        c=out[i]
        if c[1]-c[0]>=min_dur:
            continue
        target=c[0]+min_dur
        if pos+1<len(order):
            target=min(target,out[order[pos+1]][0])
        c[1]=max(c[1],target)
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: neighbour gap limit', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('regression variant: neighbour gap limit', [[[0, 100], [200, 1400]], 1200, 40], [[0, 160], [200, 1400]]), ('partial repair probe: neighbour gap limit', [[[0, 1], [200, 900], [2000, 4000]], 700, 0], [[0, 200], [200, 900], [2000, 4000]]), ('partial repair variant: neighbour gap limit', [[[500, 1701], [200, 201], [1000, 1001]], 1200, 0], [[500, 1701], [200, 500], [1000, 2200]]), ('boundary control', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[1000, 2120], [200, 1400]], 1200, 80], [[1000, 2200], [200, 1400]]), ('normal control', [[[2000, 2001], [800, 1100]], 1000, 80], [[2000, 3000], [800, 1800]]), ('normal control', [[[1500, 2700], [1500, 2700]], 1200, 0], [[1500, 2700], [1500, 2700]])], [('regression: neighbour gap limit', [[[500, 600], [0, 100]], 700, 40], [[500, 1200], [0, 460]]), ('regression variant: neighbour gap limit', [[[200, 300], [800, 801]], 1000, 80], [[200, 720], [800, 1800]]), ('partial repair probe: neighbour gap limit', [[[1000, 1960], [2000, 2300], [3000, 3999], [3000, 3001]], 1000, 40], [[1000, 1960], [2000, 2960], [3000, 3999], [3000, 4000]]), ('partial repair variant: neighbour gap limit', [[[0, 100], [200, 1400]], 1200, 40], [[0, 160], [200, 1400]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('boundary control', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('normal control', [[[479, 2479], [2000, 2300], [1000, 2120], [800, 2001]], 1200, 80], [[479, 2479], [2000, 3200], [1000, 2120], [800, 2001]]), ('normal control', [[[2000, 2999], [500, 1501]], 1000, 80], [[2000, 3000], [500, 1501]]), ('normal control', [[[200, 500], [496, 1497], [800, 1799], [3000, 3999]], 1000, 40], [[200, 500], [496, 1497], [800, 1800], [3000, 4000]])], [('regression: neighbour gap limit', [[[1000, 1960], [2000, 2300], [3000, 3999], [3000, 3001]], 1000, 40], [[1000, 1960], [2000, 2960], [3000, 3999], [3000, 4000]]), ('regression variant: neighbour gap limit', [[[200, 500], [1394, 2593], [3000, 3300]], 1200, 80], [[200, 1314], [1394, 2594], [3000, 4200]]), ('partial repair probe: neighbour gap limit', [[[200, 500], [500, 800], [1500, 3500], [1500, 2699], [2000, 2001]], 1200, 40], [[200, 500], [500, 1460], [1500, 3500], [1500, 2699], [2000, 3200]]), ('partial repair variant: neighbour gap limit', [[[1500, 1600], [1500, 1600], [2000, 3200], [3000, 5000]], 1200, 0], [[1500, 1600], [1500, 2000], [2000, 3200], [3000, 5000]]), ('boundary control', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[2000, 2100], [3000, 3001]], 700, 0], [[2000, 2700], [3000, 3700]]), ('normal control', [[[200, 1201], [2000, 3001], [1000, 2000], [800, 1800]], 1000, 0], [[200, 1201], [2000, 3001], [1000, 2000], [800, 1800]]), ('normal control', [[[500, 501]], 1200, 40], [[500, 1700]])], [('regression: neighbour gap limit', [[[200, 500], [500, 800], [1500, 3500], [1500, 2699], [2000, 2001]], 1200, 40], [[200, 500], [500, 1460], [1500, 3500], [1500, 2699], [2000, 3200]]), ('regression variant: neighbour gap limit', [[[1500, 2501], [800, 1801], [1000, 2000], [200, 300], [200, 201]], 1000, 40], [[1500, 2501], [800, 1801], [1000, 2000], [200, 300], [200, 760]]), ('partial repair probe: neighbour gap limit', [[[0, 1001], [1500, 2500], [3000, 3999], [800, 2800], [0, 1]], 1000, 0], [[0, 1001], [1500, 2500], [3000, 4000], [800, 2800], [0, 800]]), ('partial repair variant: neighbour gap limit', [[[800, 1100], [1500, 2500], [2000, 2100], [2000, 2999]], 1000, 0], [[800, 1500], [1500, 2500], [2000, 2100], [2000, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('boundary control', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('normal control', [[[200, 900], [3000, 3701]], 700, 40], [[200, 900], [3000, 3701]]), ('normal control', [[[200, 900], [0, 699], [800, 2800]], 700, 0], [[200, 900], [0, 699], [800, 2800]]), ('normal control', [[[0, 1000], [1000, 2001], [1000, 2000], [3000, 4001], [3000, 3300]], 1000, 80], [[0, 1000], [1000, 2001], [1000, 2000], [3000, 4001], [3000, 4000]])], [('regression: neighbour gap limit', [[[500, 501], [200, 1160], [0, 1], [500, 1460]], 1000, 40], [[500, 501], [200, 1160], [0, 160], [500, 1500]]), ('regression variant: neighbour gap limit', [[[0, 300], [500, 1501], [800, 1720], [1500, 2499], [2000, 2920]], 1000, 80], [[0, 420], [500, 1501], [800, 1720], [1500, 2499], [2000, 3000]]), ('partial repair probe: neighbour gap limit', [[[800, 2800], [800, 900], [1500, 1501], [1000, 1700], [3000, 3300]], 700, 0], [[800, 2800], [800, 1000], [1500, 2200], [1000, 1700], [3000, 3700]]), ('partial repair variant: neighbour gap limit', [[[200, 300], [800, 801]], 1000, 80], [[200, 720], [800, 1800]]), ('boundary control', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[1500, 2701], [2000, 2300]], 1200, 40], [[1500, 2701], [2000, 3200]]), ('normal control', [[[0, 100], [1000, 1001]], 700, 80], [[0, 700], [1000, 1700]]), ('normal control', [[[655, 1655], [1000, 2000], [1500, 2500], [2000, 2300], [3000, 3300]], 1000, 0], [[655, 1655], [1000, 2000], [1500, 2500], [2000, 3000], [3000, 4000]])]]
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
regression: neighbour gap limit	`[[0, 500], [500, 3000]]`	`[[0, 420], [500, 3000]]`	Failed
regression variant: neighbour gap limit	`[[0, 200], [200, 1400]]`	`[[0, 160], [200, 1400]]`	Failed
partial repair probe: neighbour gap limit	`[[0, 200], [200, 900], [2000, 4000]]`	`[[0, 200], [200, 900], [2000, 4000]]`	Passed
partial repair variant: neighbour gap limit	`[[500, 1701], [200, 500], [1000, 2200]]`	`[[500, 1701], [200, 500], [1000, 2200]]`	Passed
boundary control	`[[0, 1000], [2000, 3000]]`	`[[0, 1000], [2000, 3000]]`	Passed
boundary control	`[[0, 1000]]`	`[[0, 1000]]`	Passed
normal control	`[[1000, 2200], [200, 1400]]`	`[[1000, 2200], [200, 1400]]`	Passed
normal control	`[[2000, 3000], [800, 1800]]`	`[[2000, 3000], [800, 1800]]`	Passed
normal control	`[[1500, 2700], [1500, 2700]]`	`[[1500, 2700], [1500, 2700]]`	Passed

SHA-256 / af11d7b4f58e89e5418820d8978f029a2f77cf268c9f28c8d8c149d7b523552a

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(cues, min_dur, min_gap):
    out=[list(c) for c in cues]
    order=sorted(range(len(out)),key=lambda k:(out[k][0],k))
    for pos,i in enumerate(order):
        c=out[i]
        if c[1]-c[0]>=min_dur:
            continue
        target=c[0]+min_dur
        if pos+1<len(order):
            target=min(target,out[order[pos+1]][0]-min_gap+1)
        c[1]=max(c[1],target)
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: neighbour gap limit', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('regression variant: neighbour gap limit', [[[0, 100], [200, 1400]], 1200, 40], [[0, 160], [200, 1400]]), ('partial repair probe: neighbour gap limit', [[[0, 1], [200, 900], [2000, 4000]], 700, 0], [[0, 200], [200, 900], [2000, 4000]]), ('partial repair variant: neighbour gap limit', [[[500, 1701], [200, 201], [1000, 1001]], 1200, 0], [[500, 1701], [200, 500], [1000, 2200]]), ('boundary control', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[1000, 2120], [200, 1400]], 1200, 80], [[1000, 2200], [200, 1400]]), ('normal control', [[[2000, 2001], [800, 1100]], 1000, 80], [[2000, 3000], [800, 1800]]), ('normal control', [[[1500, 2700], [1500, 2700]], 1200, 0], [[1500, 2700], [1500, 2700]])], [('regression: neighbour gap limit', [[[500, 600], [0, 100]], 700, 40], [[500, 1200], [0, 460]]), ('regression variant: neighbour gap limit', [[[200, 300], [800, 801]], 1000, 80], [[200, 720], [800, 1800]]), ('partial repair probe: neighbour gap limit', [[[1000, 1960], [2000, 2300], [3000, 3999], [3000, 3001]], 1000, 40], [[1000, 1960], [2000, 2960], [3000, 3999], [3000, 4000]]), ('partial repair variant: neighbour gap limit', [[[0, 100], [200, 1400]], 1200, 40], [[0, 160], [200, 1400]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('boundary control', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('normal control', [[[479, 2479], [2000, 2300], [1000, 2120], [800, 2001]], 1200, 80], [[479, 2479], [2000, 3200], [1000, 2120], [800, 2001]]), ('normal control', [[[2000, 2999], [500, 1501]], 1000, 80], [[2000, 3000], [500, 1501]]), ('normal control', [[[200, 500], [496, 1497], [800, 1799], [3000, 3999]], 1000, 40], [[200, 500], [496, 1497], [800, 1800], [3000, 4000]])], [('regression: neighbour gap limit', [[[1000, 1960], [2000, 2300], [3000, 3999], [3000, 3001]], 1000, 40], [[1000, 1960], [2000, 2960], [3000, 3999], [3000, 4000]]), ('regression variant: neighbour gap limit', [[[200, 500], [1394, 2593], [3000, 3300]], 1200, 80], [[200, 1314], [1394, 2594], [3000, 4200]]), ('partial repair probe: neighbour gap limit', [[[200, 500], [500, 800], [1500, 3500], [1500, 2699], [2000, 2001]], 1200, 40], [[200, 500], [500, 1460], [1500, 3500], [1500, 2699], [2000, 3200]]), ('partial repair variant: neighbour gap limit', [[[1500, 1600], [1500, 1600], [2000, 3200], [3000, 5000]], 1200, 0], [[1500, 1600], [1500, 2000], [2000, 3200], [3000, 5000]]), ('boundary control', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[2000, 2100], [3000, 3001]], 700, 0], [[2000, 2700], [3000, 3700]]), ('normal control', [[[200, 1201], [2000, 3001], [1000, 2000], [800, 1800]], 1000, 0], [[200, 1201], [2000, 3001], [1000, 2000], [800, 1800]]), ('normal control', [[[500, 501]], 1200, 40], [[500, 1700]])], [('regression: neighbour gap limit', [[[200, 500], [500, 800], [1500, 3500], [1500, 2699], [2000, 2001]], 1200, 40], [[200, 500], [500, 1460], [1500, 3500], [1500, 2699], [2000, 3200]]), ('regression variant: neighbour gap limit', [[[1500, 2501], [800, 1801], [1000, 2000], [200, 300], [200, 201]], 1000, 40], [[1500, 2501], [800, 1801], [1000, 2000], [200, 300], [200, 760]]), ('partial repair probe: neighbour gap limit', [[[0, 1001], [1500, 2500], [3000, 3999], [800, 2800], [0, 1]], 1000, 0], [[0, 1001], [1500, 2500], [3000, 4000], [800, 2800], [0, 800]]), ('partial repair variant: neighbour gap limit', [[[800, 1100], [1500, 2500], [2000, 2100], [2000, 2999]], 1000, 0], [[800, 1500], [1500, 2500], [2000, 2100], [2000, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('boundary control', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('normal control', [[[200, 900], [3000, 3701]], 700, 40], [[200, 900], [3000, 3701]]), ('normal control', [[[200, 900], [0, 699], [800, 2800]], 700, 0], [[200, 900], [0, 699], [800, 2800]]), ('normal control', [[[0, 1000], [1000, 2001], [1000, 2000], [3000, 4001], [3000, 3300]], 1000, 80], [[0, 1000], [1000, 2001], [1000, 2000], [3000, 4001], [3000, 4000]])], [('regression: neighbour gap limit', [[[500, 501], [200, 1160], [0, 1], [500, 1460]], 1000, 40], [[500, 501], [200, 1160], [0, 160], [500, 1500]]), ('regression variant: neighbour gap limit', [[[0, 300], [500, 1501], [800, 1720], [1500, 2499], [2000, 2920]], 1000, 80], [[0, 420], [500, 1501], [800, 1720], [1500, 2499], [2000, 3000]]), ('partial repair probe: neighbour gap limit', [[[800, 2800], [800, 900], [1500, 1501], [1000, 1700], [3000, 3300]], 700, 0], [[800, 2800], [800, 1000], [1500, 2200], [1000, 1700], [3000, 3700]]), ('partial repair variant: neighbour gap limit', [[[200, 300], [800, 801]], 1000, 80], [[200, 720], [800, 1800]]), ('boundary control', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[1500, 2701], [2000, 2300]], 1200, 40], [[1500, 2701], [2000, 3200]]), ('normal control', [[[0, 100], [1000, 1001]], 700, 80], [[0, 700], [1000, 1700]]), ('normal control', [[[655, 1655], [1000, 2000], [1500, 2500], [2000, 2300], [3000, 3300]], 1000, 0], [[655, 1655], [1000, 2000], [1500, 2500], [2000, 3000], [3000, 4000]])]]
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
regression: neighbour gap limit	`[[0, 421], [500, 3000]]`	`[[0, 420], [500, 3000]]`	Failed
regression variant: neighbour gap limit	`[[0, 161], [200, 1400]]`	`[[0, 160], [200, 1400]]`	Failed
partial repair probe: neighbour gap limit	`[[0, 201], [200, 900], [2000, 4000]]`	`[[0, 200], [200, 900], [2000, 4000]]`	Failed
partial repair variant: neighbour gap limit	`[[500, 1701], [200, 501], [1000, 2200]]`	`[[500, 1701], [200, 500], [1000, 2200]]`	Failed
boundary control	`[[0, 1000], [2000, 3000]]`	`[[0, 1000], [2000, 3000]]`	Passed
boundary control	`[[0, 1000]]`	`[[0, 1000]]`	Passed
normal control	`[[1000, 2200], [200, 1400]]`	`[[1000, 2200], [200, 1400]]`	Passed
normal control	`[[2000, 3000], [800, 1800]]`	`[[2000, 3000], [800, 1800]]`	Passed
normal control	`[[1500, 2700], [1500, 2700]]`	`[[1500, 2700], [1500, 2700]]`	Passed

SHA-256 / f1e1f1113909450808a71586ef0c36be3ed93024f879da16fb6f9b61352ae70e

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(cues, min_dur, min_gap):
    out=[list(c) for c in cues]
    order=sorted(range(len(out)),key=lambda k:(out[k][0],k))
    for pos,i in enumerate(order):
        c=out[i]
        if c[1]-c[0]>=min_dur:
            continue
        target=c[0]+min_dur
        if pos+1<len(order):
            target=min(target,out[order[pos+1]][0]-min_gap)
        c[1]=max(c[1],target)
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: neighbour gap limit', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('regression variant: neighbour gap limit', [[[0, 100], [200, 1400]], 1200, 40], [[0, 160], [200, 1400]]), ('partial repair probe: neighbour gap limit', [[[0, 1], [200, 900], [2000, 4000]], 700, 0], [[0, 200], [200, 900], [2000, 4000]]), ('partial repair variant: neighbour gap limit', [[[500, 1701], [200, 201], [1000, 1001]], 1200, 0], [[500, 1701], [200, 500], [1000, 2200]]), ('boundary control', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[1000, 2120], [200, 1400]], 1200, 80], [[1000, 2200], [200, 1400]]), ('normal control', [[[2000, 2001], [800, 1100]], 1000, 80], [[2000, 3000], [800, 1800]]), ('normal control', [[[1500, 2700], [1500, 2700]], 1200, 0], [[1500, 2700], [1500, 2700]])], [('regression: neighbour gap limit', [[[500, 600], [0, 100]], 700, 40], [[500, 1200], [0, 460]]), ('regression variant: neighbour gap limit', [[[200, 300], [800, 801]], 1000, 80], [[200, 720], [800, 1800]]), ('partial repair probe: neighbour gap limit', [[[1000, 1960], [2000, 2300], [3000, 3999], [3000, 3001]], 1000, 40], [[1000, 1960], [2000, 2960], [3000, 3999], [3000, 4000]]), ('partial repair variant: neighbour gap limit', [[[0, 100], [200, 1400]], 1200, 40], [[0, 160], [200, 1400]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('boundary control', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('normal control', [[[479, 2479], [2000, 2300], [1000, 2120], [800, 2001]], 1200, 80], [[479, 2479], [2000, 3200], [1000, 2120], [800, 2001]]), ('normal control', [[[2000, 2999], [500, 1501]], 1000, 80], [[2000, 3000], [500, 1501]]), ('normal control', [[[200, 500], [496, 1497], [800, 1799], [3000, 3999]], 1000, 40], [[200, 500], [496, 1497], [800, 1800], [3000, 4000]])], [('regression: neighbour gap limit', [[[1000, 1960], [2000, 2300], [3000, 3999], [3000, 3001]], 1000, 40], [[1000, 1960], [2000, 2960], [3000, 3999], [3000, 4000]]), ('regression variant: neighbour gap limit', [[[200, 500], [1394, 2593], [3000, 3300]], 1200, 80], [[200, 1314], [1394, 2594], [3000, 4200]]), ('partial repair probe: neighbour gap limit', [[[200, 500], [500, 800], [1500, 3500], [1500, 2699], [2000, 2001]], 1200, 40], [[200, 500], [500, 1460], [1500, 3500], [1500, 2699], [2000, 3200]]), ('partial repair variant: neighbour gap limit', [[[1500, 1600], [1500, 1600], [2000, 3200], [3000, 5000]], 1200, 0], [[1500, 1600], [1500, 2000], [2000, 3200], [3000, 5000]]), ('boundary control', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[2000, 2100], [3000, 3001]], 700, 0], [[2000, 2700], [3000, 3700]]), ('normal control', [[[200, 1201], [2000, 3001], [1000, 2000], [800, 1800]], 1000, 0], [[200, 1201], [2000, 3001], [1000, 2000], [800, 1800]]), ('normal control', [[[500, 501]], 1200, 40], [[500, 1700]])], [('regression: neighbour gap limit', [[[200, 500], [500, 800], [1500, 3500], [1500, 2699], [2000, 2001]], 1200, 40], [[200, 500], [500, 1460], [1500, 3500], [1500, 2699], [2000, 3200]]), ('regression variant: neighbour gap limit', [[[1500, 2501], [800, 1801], [1000, 2000], [200, 300], [200, 201]], 1000, 40], [[1500, 2501], [800, 1801], [1000, 2000], [200, 300], [200, 760]]), ('partial repair probe: neighbour gap limit', [[[0, 1001], [1500, 2500], [3000, 3999], [800, 2800], [0, 1]], 1000, 0], [[0, 1001], [1500, 2500], [3000, 4000], [800, 2800], [0, 800]]), ('partial repair variant: neighbour gap limit', [[[800, 1100], [1500, 2500], [2000, 2100], [2000, 2999]], 1000, 0], [[800, 1500], [1500, 2500], [2000, 2100], [2000, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('boundary control', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('normal control', [[[200, 900], [3000, 3701]], 700, 40], [[200, 900], [3000, 3701]]), ('normal control', [[[200, 900], [0, 699], [800, 2800]], 700, 0], [[200, 900], [0, 699], [800, 2800]]), ('normal control', [[[0, 1000], [1000, 2001], [1000, 2000], [3000, 4001], [3000, 3300]], 1000, 80], [[0, 1000], [1000, 2001], [1000, 2000], [3000, 4001], [3000, 4000]])], [('regression: neighbour gap limit', [[[500, 501], [200, 1160], [0, 1], [500, 1460]], 1000, 40], [[500, 501], [200, 1160], [0, 160], [500, 1500]]), ('regression variant: neighbour gap limit', [[[0, 300], [500, 1501], [800, 1720], [1500, 2499], [2000, 2920]], 1000, 80], [[0, 420], [500, 1501], [800, 1720], [1500, 2499], [2000, 3000]]), ('partial repair probe: neighbour gap limit', [[[800, 2800], [800, 900], [1500, 1501], [1000, 1700], [3000, 3300]], 700, 0], [[800, 2800], [800, 1000], [1500, 2200], [1000, 1700], [3000, 3700]]), ('partial repair variant: neighbour gap limit', [[[200, 300], [800, 801]], 1000, 80], [[200, 720], [800, 1800]]), ('boundary control', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[1500, 2701], [2000, 2300]], 1200, 40], [[1500, 2701], [2000, 3200]]), ('normal control', [[[0, 100], [1000, 1001]], 700, 80], [[0, 700], [1000, 1700]]), ('normal control', [[[655, 1655], [1000, 2000], [1500, 2500], [2000, 2300], [3000, 3300]], 1000, 0], [[655, 1655], [1000, 2000], [1500, 2500], [2000, 3000], [3000, 4000]])]]
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
regression: neighbour gap limit	`[[0, 420], [500, 3000]]`	`[[0, 420], [500, 3000]]`	Passed
regression variant: neighbour gap limit	`[[0, 160], [200, 1400]]`	`[[0, 160], [200, 1400]]`	Passed
partial repair probe: neighbour gap limit	`[[0, 200], [200, 900], [2000, 4000]]`	`[[0, 200], [200, 900], [2000, 4000]]`	Passed
partial repair variant: neighbour gap limit	`[[500, 1701], [200, 500], [1000, 2200]]`	`[[500, 1701], [200, 500], [1000, 2200]]`	Passed
boundary control	`[[0, 1000], [2000, 3000]]`	`[[0, 1000], [2000, 3000]]`	Passed
boundary control	`[[0, 1000]]`	`[[0, 1000]]`	Passed
normal control	`[[1000, 2200], [200, 1400]]`	`[[1000, 2200], [200, 1400]]`	Passed
normal control	`[[2000, 3000], [800, 1800]]`	`[[2000, 3000], [800, 1800]]`	Passed
normal control	`[[1500, 2700], [1500, 2700]]`	`[[1500, 2700], [1500, 2700]]`	Passed

SHA-256 / 29c0535b7e861ebb4305b1d395750f0dff8be3cc6555fc8e2d0dc39f47c87b1d

Verification & scope

A deterministic bounded teaching model with a stipulated toy contract; it does not claim conformance to any subtitle standard. 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 2026-09-29T14:49:31.274452+00:00.

Case digest / 83613014618fd6d71726c703b3aae7ccecb9db4574bc78c89664732c9462c5d6