FAILURE MAP
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FA-77991 / Subtitle cue timing / Open access

Minimum cue duration extension: extension base · case 01

Short cues become much longer than the minimum duration.

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

ROOT CAUSE

The extension target is measured from the current end rather than the start.

VERIFIED REPAIR

Extend to start + min_dur.

Unsuccessful approach: Subtracting the gap from the target shortens every isolated extended cue below the minimum.

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[1]+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: extension base', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('regression variant: extension base', [[[200, 500], [500, 800], [1500, 3500], [1500, 2699], [2000, 2001]], 1200, 40], [[200, 500], [500, 1460], [1500, 3500], [1500, 2699], [2000, 3200]]), ('partial repair probe: extension base', [[[1000, 2120], [200, 1400]], 1200, 80], [[1000, 2200], [200, 1400]]), ('partial repair variant: extension base', [[[0, 700], [1000, 1001], [2000, 2699]], 700, 80], [[0, 700], [1000, 1700], [2000, 2700]]), ('boundary control', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[0, 1], [200, 900], [2000, 4000]], 700, 0], [[0, 200], [200, 900], [2000, 4000]]), ('normal control', [[[1000, 3000]], 1200, 0], [[1000, 3000]]), ('normal control', [[[500, 800], [500, 2500], [800, 1799], [1000, 1001], [1000, 3000]], 1000, 40], [[500, 800], [500, 2500], [800, 1799], [1000, 1001], [1000, 3000]])], [('regression: extension base', [[[500, 600], [0, 100]], 700, 40], [[500, 1200], [0, 460]]), ('regression variant: extension base', [[[0, 1001], [1500, 2500], [3000, 3999], [800, 2800], [0, 1]], 1000, 0], [[0, 1001], [1500, 2500], [3000, 4000], [800, 2800], [0, 800]]), ('partial repair probe: extension base', [[[2000, 2001], [800, 1100]], 1000, 80], [[2000, 3000], [800, 1800]]), ('partial repair variant: extension base', [[[200, 500], [496, 1497], [800, 1799], [3000, 3999]], 1000, 40], [[200, 500], [496, 1497], [800, 1800], [3000, 4000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('boundary control', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('normal control', [[[2000, 4000], [1500, 1600], [1500, 2699]], 1200, 80], [[2000, 4000], [1500, 1600], [1500, 2699]]), ('normal control', [[[1500, 3500]], 700, 0], [[1500, 3500]]), ('normal control', [[[1500, 1600], [1500, 1600], [2000, 3200], [3000, 5000]], 1200, 0], [[1500, 1600], [1500, 2000], [2000, 3200], [3000, 5000]])], [('regression: extension base', [[[1000, 2120], [200, 1400]], 1200, 80], [[1000, 2200], [200, 1400]]), ('regression variant: extension base', [[[479, 2479], [2000, 2300], [1000, 2120], [800, 2001]], 1200, 80], [[479, 2479], [2000, 3200], [1000, 2120], [800, 2001]]), ('partial repair probe: extension base', [[[1000, 1960], [2000, 2300], [3000, 3999], [3000, 3001]], 1000, 40], [[1000, 1960], [2000, 2960], [3000, 3999], [3000, 4000]]), ('partial repair variant: extension base', [[[0, 1]], 1200, 40], [[0, 1200]]), ('boundary control', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[1000, 1999], [1000, 3000]], 1000, 80], [[1000, 1999], [1000, 3000]]), ('normal control', [[[2000, 3000], [2000, 3000], [1000, 1100], [4355, 6355]], 1000, 0], [[2000, 3000], [2000, 3000], [1000, 2000], [4355, 6355]]), ('normal control', [[[500, 1500]], 1000, 0], [[500, 1500]])], [('regression: extension base', [[[2000, 2001], [800, 1100]], 1000, 80], [[2000, 3000], [800, 1800]]), ('regression variant: extension base', [[[0, 2000], [200, 500]], 700, 80], [[0, 2000], [200, 900]]), ('partial repair probe: extension base', [[[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: extension base', [[[0, 2000], [200, 1160], [500, 1499], [1186, 1187], [2429, 3430]], 1000, 40], [[0, 2000], [200, 1160], [500, 1499], [1186, 2186], [2429, 3430]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('boundary control', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('normal control', [[[200, 901], [1000, 1100], [1000, 1701], [1000, 1701]], 700, 40], [[200, 901], [1000, 1100], [1000, 1701], [1000, 1701]]), ('normal control', [[[0, 300], [1000, 3000]], 1200, 0], [[0, 1000], [1000, 3000]]), ('normal control', [[[200, 2200], [1000, 2199], [2000, 2300], [3000, 3300], [3000, 4200]], 1200, 40], [[200, 2200], [1000, 2199], [2000, 2960], [3000, 3300], [3000, 4200]])], [('regression: extension base', [[[1000, 1960], [2000, 2300], [3000, 3999], [3000, 3001]], 1000, 40], [[1000, 1960], [2000, 2960], [3000, 3999], [3000, 4000]]), ('regression variant: extension base', [[[3000, 3700], [500, 501]], 700, 0], [[3000, 3700], [500, 1200]]), ('partial repair probe: extension base', [[[479, 2479], [2000, 2300], [1000, 2120], [800, 2001]], 1200, 80], [[479, 2479], [2000, 3200], [1000, 2120], [800, 2001]]), ('partial repair variant: extension base', [[[800, 1999]], 1200, 40], [[800, 2000]]), ('boundary control', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[200, 2200], [500, 1701], [500, 2500]], 1200, 80], [[200, 2200], [500, 1701], [500, 2500]]), ('normal control', [[[800, 2800], [1500, 2700], [3000, 4201]], 1200, 0], [[800, 2800], [1500, 2700], [3000, 4201]]), ('normal control', [[[500, 1700], [1422, 3422], [1500, 1800], [2000, 3160], [3000, 4200]], 1200, 40], [[500, 1700], [1422, 3422], [1500, 1960], [2000, 3160], [3000, 4200]])]]
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: extension base[[0, 1300], [2000, 3000]][[0, 1000], [2000, 3000]]Failed
regression variant: extension base[[200, 500], [500, 1460], [1500, 3500], [1500, 2699], [2000, 3201]][[200, 500], [500, 1460], [1500, 3500], [1500, 2699], [2000, 3200]]Failed
partial repair probe: extension base[[1000, 3320], [200, 1400]][[1000, 2200], [200, 1400]]Failed
partial repair variant: extension base[[0, 700], [1000, 1701], [2000, 3399]][[0, 700], [1000, 1700], [2000, 2700]]Failed
boundary control[[0, 420], [500, 3000]][[0, 420], [500, 3000]]Passed
boundary control[[0, 1000]][[0, 1000]]Passed
normal control[[0, 200], [200, 900], [2000, 4000]][[0, 200], [200, 900], [2000, 4000]]Passed
normal control[[1000, 3000]][[1000, 3000]]Passed
normal control[[500, 800], [500, 2500], [800, 1799], [1000, 1001], [1000, 3000]][[500, 800], [500, 2500], [800, 1799], [1000, 1001], [1000, 3000]]Passed

SHA-256 / d315a07e3d4245b6e1e4a2665a91a60b1408ae54f50ad1bf701a3bab69503669

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-min_gap
        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: extension base', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('regression variant: extension base', [[[200, 500], [500, 800], [1500, 3500], [1500, 2699], [2000, 2001]], 1200, 40], [[200, 500], [500, 1460], [1500, 3500], [1500, 2699], [2000, 3200]]), ('partial repair probe: extension base', [[[1000, 2120], [200, 1400]], 1200, 80], [[1000, 2200], [200, 1400]]), ('partial repair variant: extension base', [[[0, 700], [1000, 1001], [2000, 2699]], 700, 80], [[0, 700], [1000, 1700], [2000, 2700]]), ('boundary control', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[0, 1], [200, 900], [2000, 4000]], 700, 0], [[0, 200], [200, 900], [2000, 4000]]), ('normal control', [[[1000, 3000]], 1200, 0], [[1000, 3000]]), ('normal control', [[[500, 800], [500, 2500], [800, 1799], [1000, 1001], [1000, 3000]], 1000, 40], [[500, 800], [500, 2500], [800, 1799], [1000, 1001], [1000, 3000]])], [('regression: extension base', [[[500, 600], [0, 100]], 700, 40], [[500, 1200], [0, 460]]), ('regression variant: extension base', [[[0, 1001], [1500, 2500], [3000, 3999], [800, 2800], [0, 1]], 1000, 0], [[0, 1001], [1500, 2500], [3000, 4000], [800, 2800], [0, 800]]), ('partial repair probe: extension base', [[[2000, 2001], [800, 1100]], 1000, 80], [[2000, 3000], [800, 1800]]), ('partial repair variant: extension base', [[[200, 500], [496, 1497], [800, 1799], [3000, 3999]], 1000, 40], [[200, 500], [496, 1497], [800, 1800], [3000, 4000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('boundary control', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('normal control', [[[2000, 4000], [1500, 1600], [1500, 2699]], 1200, 80], [[2000, 4000], [1500, 1600], [1500, 2699]]), ('normal control', [[[1500, 3500]], 700, 0], [[1500, 3500]]), ('normal control', [[[1500, 1600], [1500, 1600], [2000, 3200], [3000, 5000]], 1200, 0], [[1500, 1600], [1500, 2000], [2000, 3200], [3000, 5000]])], [('regression: extension base', [[[1000, 2120], [200, 1400]], 1200, 80], [[1000, 2200], [200, 1400]]), ('regression variant: extension base', [[[479, 2479], [2000, 2300], [1000, 2120], [800, 2001]], 1200, 80], [[479, 2479], [2000, 3200], [1000, 2120], [800, 2001]]), ('partial repair probe: extension base', [[[1000, 1960], [2000, 2300], [3000, 3999], [3000, 3001]], 1000, 40], [[1000, 1960], [2000, 2960], [3000, 3999], [3000, 4000]]), ('partial repair variant: extension base', [[[0, 1]], 1200, 40], [[0, 1200]]), ('boundary control', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[1000, 1999], [1000, 3000]], 1000, 80], [[1000, 1999], [1000, 3000]]), ('normal control', [[[2000, 3000], [2000, 3000], [1000, 1100], [4355, 6355]], 1000, 0], [[2000, 3000], [2000, 3000], [1000, 2000], [4355, 6355]]), ('normal control', [[[500, 1500]], 1000, 0], [[500, 1500]])], [('regression: extension base', [[[2000, 2001], [800, 1100]], 1000, 80], [[2000, 3000], [800, 1800]]), ('regression variant: extension base', [[[0, 2000], [200, 500]], 700, 80], [[0, 2000], [200, 900]]), ('partial repair probe: extension base', [[[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: extension base', [[[0, 2000], [200, 1160], [500, 1499], [1186, 1187], [2429, 3430]], 1000, 40], [[0, 2000], [200, 1160], [500, 1499], [1186, 2186], [2429, 3430]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('boundary control', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('normal control', [[[200, 901], [1000, 1100], [1000, 1701], [1000, 1701]], 700, 40], [[200, 901], [1000, 1100], [1000, 1701], [1000, 1701]]), ('normal control', [[[0, 300], [1000, 3000]], 1200, 0], [[0, 1000], [1000, 3000]]), ('normal control', [[[200, 2200], [1000, 2199], [2000, 2300], [3000, 3300], [3000, 4200]], 1200, 40], [[200, 2200], [1000, 2199], [2000, 2960], [3000, 3300], [3000, 4200]])], [('regression: extension base', [[[1000, 1960], [2000, 2300], [3000, 3999], [3000, 3001]], 1000, 40], [[1000, 1960], [2000, 2960], [3000, 3999], [3000, 4000]]), ('regression variant: extension base', [[[3000, 3700], [500, 501]], 700, 0], [[3000, 3700], [500, 1200]]), ('partial repair probe: extension base', [[[479, 2479], [2000, 2300], [1000, 2120], [800, 2001]], 1200, 80], [[479, 2479], [2000, 3200], [1000, 2120], [800, 2001]]), ('partial repair variant: extension base', [[[800, 1999]], 1200, 40], [[800, 2000]]), ('boundary control', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[200, 2200], [500, 1701], [500, 2500]], 1200, 80], [[200, 2200], [500, 1701], [500, 2500]]), ('normal control', [[[800, 2800], [1500, 2700], [3000, 4201]], 1200, 0], [[800, 2800], [1500, 2700], [3000, 4201]]), ('normal control', [[[500, 1700], [1422, 3422], [1500, 1800], [2000, 3160], [3000, 4200]], 1200, 40], [[500, 1700], [1422, 3422], [1500, 1960], [2000, 3160], [3000, 4200]])]]
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: extension base[[0, 920], [2000, 3000]][[0, 1000], [2000, 3000]]Failed
regression variant: extension base[[200, 500], [500, 1460], [1500, 3500], [1500, 2699], [2000, 3160]][[200, 500], [500, 1460], [1500, 3500], [1500, 2699], [2000, 3200]]Failed
partial repair probe: extension base[[1000, 2120], [200, 1400]][[1000, 2200], [200, 1400]]Failed
partial repair variant: extension base[[0, 700], [1000, 1620], [2000, 2699]][[0, 700], [1000, 1700], [2000, 2700]]Failed
boundary control[[0, 420], [500, 3000]][[0, 420], [500, 3000]]Passed
boundary control[[0, 1000]][[0, 1000]]Passed
normal control[[0, 200], [200, 900], [2000, 4000]][[0, 200], [200, 900], [2000, 4000]]Passed
normal control[[1000, 3000]][[1000, 3000]]Passed
normal control[[500, 800], [500, 2500], [800, 1799], [1000, 1001], [1000, 3000]][[500, 800], [500, 2500], [800, 1799], [1000, 1001], [1000, 3000]]Passed

SHA-256 / 0d5ba7b4e8b09cc1cb28801231619f4f2b92108a1b893a31bdc52ba8a686381e

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: extension base', [[[0, 300], [2000, 3000]], 1000, 80], [[0, 1000], [2000, 3000]]), ('regression variant: extension base', [[[200, 500], [500, 800], [1500, 3500], [1500, 2699], [2000, 2001]], 1200, 40], [[200, 500], [500, 1460], [1500, 3500], [1500, 2699], [2000, 3200]]), ('partial repair probe: extension base', [[[1000, 2120], [200, 1400]], 1200, 80], [[1000, 2200], [200, 1400]]), ('partial repair variant: extension base', [[[0, 700], [1000, 1001], [2000, 2699]], 700, 80], [[0, 700], [1000, 1700], [2000, 2700]]), ('boundary control', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[0, 1], [200, 900], [2000, 4000]], 700, 0], [[0, 200], [200, 900], [2000, 4000]]), ('normal control', [[[1000, 3000]], 1200, 0], [[1000, 3000]]), ('normal control', [[[500, 800], [500, 2500], [800, 1799], [1000, 1001], [1000, 3000]], 1000, 40], [[500, 800], [500, 2500], [800, 1799], [1000, 1001], [1000, 3000]])], [('regression: extension base', [[[500, 600], [0, 100]], 700, 40], [[500, 1200], [0, 460]]), ('regression variant: extension base', [[[0, 1001], [1500, 2500], [3000, 3999], [800, 2800], [0, 1]], 1000, 0], [[0, 1001], [1500, 2500], [3000, 4000], [800, 2800], [0, 800]]), ('partial repair probe: extension base', [[[2000, 2001], [800, 1100]], 1000, 80], [[2000, 3000], [800, 1800]]), ('partial repair variant: extension base', [[[200, 500], [496, 1497], [800, 1799], [3000, 3999]], 1000, 40], [[200, 500], [496, 1497], [800, 1800], [3000, 4000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('boundary control', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('normal control', [[[2000, 4000], [1500, 1600], [1500, 2699]], 1200, 80], [[2000, 4000], [1500, 1600], [1500, 2699]]), ('normal control', [[[1500, 3500]], 700, 0], [[1500, 3500]]), ('normal control', [[[1500, 1600], [1500, 1600], [2000, 3200], [3000, 5000]], 1200, 0], [[1500, 1600], [1500, 2000], [2000, 3200], [3000, 5000]])], [('regression: extension base', [[[1000, 2120], [200, 1400]], 1200, 80], [[1000, 2200], [200, 1400]]), ('regression variant: extension base', [[[479, 2479], [2000, 2300], [1000, 2120], [800, 2001]], 1200, 80], [[479, 2479], [2000, 3200], [1000, 2120], [800, 2001]]), ('partial repair probe: extension base', [[[1000, 1960], [2000, 2300], [3000, 3999], [3000, 3001]], 1000, 40], [[1000, 1960], [2000, 2960], [3000, 3999], [3000, 4000]]), ('partial repair variant: extension base', [[[0, 1]], 1200, 40], [[0, 1200]]), ('boundary control', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[1000, 1999], [1000, 3000]], 1000, 80], [[1000, 1999], [1000, 3000]]), ('normal control', [[[2000, 3000], [2000, 3000], [1000, 1100], [4355, 6355]], 1000, 0], [[2000, 3000], [2000, 3000], [1000, 2000], [4355, 6355]]), ('normal control', [[[500, 1500]], 1000, 0], [[500, 1500]])], [('regression: extension base', [[[2000, 2001], [800, 1100]], 1000, 80], [[2000, 3000], [800, 1800]]), ('regression variant: extension base', [[[0, 2000], [200, 500]], 700, 80], [[0, 2000], [200, 900]]), ('partial repair probe: extension base', [[[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: extension base', [[[0, 2000], [200, 1160], [500, 1499], [1186, 1187], [2429, 3430]], 1000, 40], [[0, 2000], [200, 1160], [500, 1499], [1186, 2186], [2429, 3430]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('boundary control', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('normal control', [[[200, 901], [1000, 1100], [1000, 1701], [1000, 1701]], 700, 40], [[200, 901], [1000, 1100], [1000, 1701], [1000, 1701]]), ('normal control', [[[0, 300], [1000, 3000]], 1200, 0], [[0, 1000], [1000, 3000]]), ('normal control', [[[200, 2200], [1000, 2199], [2000, 2300], [3000, 3300], [3000, 4200]], 1200, 40], [[200, 2200], [1000, 2199], [2000, 2960], [3000, 3300], [3000, 4200]])], [('regression: extension base', [[[1000, 1960], [2000, 2300], [3000, 3999], [3000, 3001]], 1000, 40], [[1000, 1960], [2000, 2960], [3000, 3999], [3000, 4000]]), ('regression variant: extension base', [[[3000, 3700], [500, 501]], 700, 0], [[3000, 3700], [500, 1200]]), ('partial repair probe: extension base', [[[479, 2479], [2000, 2300], [1000, 2120], [800, 2001]], 1200, 80], [[479, 2479], [2000, 3200], [1000, 2120], [800, 2001]]), ('partial repair variant: extension base', [[[800, 1999]], 1200, 40], [[800, 2000]]), ('boundary control', [[[0, 300], [500, 3000]], 1000, 80], [[0, 420], [500, 3000]]), ('boundary control', [[[0, 1000]], 1000, 0], [[0, 1000]]), ('normal control', [[[200, 2200], [500, 1701], [500, 2500]], 1200, 80], [[200, 2200], [500, 1701], [500, 2500]]), ('normal control', [[[800, 2800], [1500, 2700], [3000, 4201]], 1200, 0], [[800, 2800], [1500, 2700], [3000, 4201]]), ('normal control', [[[500, 1700], [1422, 3422], [1500, 1800], [2000, 3160], [3000, 4200]], 1200, 40], [[500, 1700], [1422, 3422], [1500, 1960], [2000, 3160], [3000, 4200]])]]
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: extension base[[0, 1000], [2000, 3000]][[0, 1000], [2000, 3000]]Passed
regression variant: extension base[[200, 500], [500, 1460], [1500, 3500], [1500, 2699], [2000, 3200]][[200, 500], [500, 1460], [1500, 3500], [1500, 2699], [2000, 3200]]Passed
partial repair probe: extension base[[1000, 2200], [200, 1400]][[1000, 2200], [200, 1400]]Passed
partial repair variant: extension base[[0, 700], [1000, 1700], [2000, 2700]][[0, 700], [1000, 1700], [2000, 2700]]Passed
boundary control[[0, 420], [500, 3000]][[0, 420], [500, 3000]]Passed
boundary control[[0, 1000]][[0, 1000]]Passed
normal control[[0, 200], [200, 900], [2000, 4000]][[0, 200], [200, 900], [2000, 4000]]Passed
normal control[[1000, 3000]][[1000, 3000]]Passed
normal control[[500, 800], [500, 2500], [800, 1799], [1000, 1001], [1000, 3000]][[500, 800], [500, 2500], [800, 1799], [1000, 1001], [1000, 3000]]Passed

SHA-256 / 14db632990ae82b04030b869040a19073fd423ecc87588a20997affbea81520e

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 2026-09-29T14:49:31.130612+00:00.

Case digest / c7bec95525ea25ce5a4d5734d679b3ace95ff306213356b3788cc862500af0fa