FAILURE MAP
← Case archive

FA-77971 / Subtitle cue timing / Open access

Minimum gap and chaining between cues: trim floor · case 01

A short cue followed immediately by another ends before it starts.

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

ROOT CAUSE

The trimmed end is not bounded below by the cue start.

VERIFIED REPAIR

Keep the trimmed end at least one millisecond after the start.

Unsuccessful approach: Bounding the end by the start itself still produces zero-length cues.

Case contract

For sorted cues [start,end], compare each cue with the next start. If gap = next_start - end is below min_gap, the end is trimmed to next_start - min_gap but never below start+1. If min_gap <= gap < chain, the end is extended to next_start - min_gap. Larger gaps are untouched.

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_gap, chain):
    out=[list(c) for c in cues]
    for i in range(len(out)-1):
        cur=out[i]
        nxt_start=out[i+1][0]
        gap=nxt_start-cur[1]
        if gap<min_gap:
            cur[1]=nxt_start-min_gap
        elif gap<chain:
            cur[1]=nxt_start-min_gap
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: trim floor', [[[1000, 1400], [1499, 1899], [2398, 2498], [2399, 2799], [2900, 3900]], 100, 500], [[1000, 1399], [1499, 2298], [2398, 2399], [2399, 2800], [2900, 3900]]), ('regression variant: trim floor', [[[1000, 1100], [1001, 1401], [1351, 1451], [1456, 3456], [4456, 5456]], 80, 300], [[1000, 1001], [1001, 1271], [1351, 1376], [1456, 3456], [4456, 5456]]), ('partial repair probe: trim floor', [[[0, 400], [983, 1083], [1165, 1265], [1166, 2166], [2250, 2350]], 83, 500], [[0, 400], [983, 1082], [1165, 1166], [1166, 2167], [2250, 2350]]), ('partial repair variant: trim floor', [[[0, 100], [100, 500], [799, 1199]], 120, 300], [[0, 1], [100, 679], [799, 1199]]), ('boundary control', [[[0, 1000], [1050, 2000]], 100, 500], [[0, 950], [1050, 2000]]), ('boundary control', [[[0, 1000], [900, 2000]], 100, 500], [[0, 800], [900, 2000]]), ('normal control', [[[0, 1000], [1400, 2000]], 100, 500], [[0, 1300], [1400, 2000]]), ('normal control', [[[0, 400], [1400, 2400]], 80, 750], [[0, 400], [1400, 2400]]), ('normal control', [[[0, 100], [183, 2183], [3183, 3283], [3784, 5784]], 83, 500], [[0, 100], [183, 2183], [3183, 3283], [3784, 5784]])], [('regression: trim floor', [[[1000, 2000], [2501, 2901], [3901, 4001], [3902, 5902], [6902, 7002]], 83, 500], [[1000, 2000], [2501, 2901], [3901, 3902], [3902, 5902], [6902, 7002]]), ('regression variant: trim floor', [[[1000, 1400], [1480, 1580], [1481, 1881]], 80, 500], [[1000, 1400], [1480, 1481], [1481, 1881]]), ('partial repair probe: trim floor', [[[1000, 1100], [1001, 1101], [1402, 3402], [3484, 3584], [3589, 5589]], 83, 300], [[1000, 1001], [1001, 1101], [1402, 3401], [3484, 3506], [3589, 5589]]), ('partial repair variant: trim floor', [[[1000, 1100], [1001, 2001]], 80, 750], [[1000, 1001], [1001, 2001]]), ('boundary control', [[[0, 1000], [1400, 2000]], 100, 500], [[0, 1300], [1400, 2000]]), ('boundary control', [[[0, 1000], [1050, 2000]], 100, 500], [[0, 950], [1050, 2000]]), ('normal control', [[[0, 1000], [1005, 1105]], 100, 750], [[0, 905], [1005, 1105]]), ('normal control', [[[1000, 1400], [2151, 4151]], 80, 750], [[1000, 1400], [2151, 4151]]), ('normal control', [[[0, 400], [479, 879]], 80, 750], [[0, 399], [479, 879]])], [('regression: trim floor', [[[0, 400], [983, 1083], [1165, 1265], [1166, 2166], [2250, 2350]], 83, 500], [[0, 400], [983, 1082], [1165, 1166], [1166, 2167], [2250, 2350]]), ('regression variant: trim floor', [[[0, 2000], [2000, 2100], [2130, 2530], [2560, 2660], [2610, 3010]], 120, 750], [[0, 1880], [2000, 2010], [2130, 2440], [2560, 2561], [2610, 3010]]), ('partial repair probe: trim floor', [[[0, 100], [1100, 1500], [2080, 3080], [3579, 3679], [3629, 5629]], 80, 500], [[0, 100], [1100, 1500], [2080, 3499], [3579, 3580], [3629, 5629]]), ('partial repair variant: trim floor', [[[1000, 1100], [1219, 1319], [1269, 1369]], 120, 750], [[1000, 1099], [1219, 1220], [1269, 1369]]), ('boundary control', [[[0, 1000], [1500, 2000]], 100, 500], [[0, 1000], [1500, 2000]]), ('boundary control', [[[0, 1000], [1400, 2000]], 100, 500], [[0, 1300], [1400, 2000]]), ('normal control', [[[1000, 3000], [3030, 5030], [5113, 6113], [6864, 6964], [6964, 8964]], 83, 750], [[1000, 2947], [3030, 5030], [5113, 6113], [6864, 6881], [6964, 8964]]), ('normal control', [[[1000, 3000], [4000, 6000], [6030, 6430], [6230, 8230], [8030, 10030]], 80, 750], [[1000, 3000], [4000, 5950], [6030, 6150], [6230, 7950], [8030, 10030]]), ('normal control', [[[0, 2000], [1800, 2200]], 100, 300], [[0, 1700], [1800, 2200]])], [('regression: trim floor', [[[1000, 1100], [1001, 1101], [1402, 3402], [3484, 3584], [3589, 5589]], 83, 300], [[1000, 1001], [1001, 1101], [1402, 3401], [3484, 3506], [3589, 5589]]), ('regression variant: trim floor', [[[1000, 1100], [1105, 3105], [3204, 3304], [3254, 4254], [5005, 5105]], 100, 750], [[1000, 1005], [1105, 3104], [3204, 3205], [3254, 4254], [5005, 5105]]), ('partial repair probe: trim floor', [[[1000, 1100], [1001, 1401], [1351, 1451], [1456, 3456], [4456, 5456]], 80, 300], [[1000, 1001], [1001, 1271], [1351, 1376], [1456, 3456], [4456, 5456]]), ('partial repair variant: trim floor', [[[1000, 3000], [3080, 5080], [5580, 7580], [7380, 7480], [7430, 8430]], 80, 500], [[1000, 3000], [3080, 5080], [5580, 7300], [7380, 7381], [7430, 8430]]), ('boundary control', [[[0, 1000], [900, 2000]], 100, 500], [[0, 800], [900, 2000]]), ('boundary control', [[[0, 1000], [1500, 2000]], 100, 500], [[0, 1000], [1500, 2000]]), ('normal control', [[[0, 2000], [2830, 3830], [3911, 4911], [5741, 6141], [6891, 8891]], 80, 750], [[0, 2000], [2830, 3831], [3911, 4911], [5741, 6141], [6891, 8891]]), ('normal control', [[[0, 1000], [800, 1800], [2800, 3800]], 83, 750], [[0, 717], [800, 1800], [2800, 3800]]), ('normal control', [[[1000, 1400], [1899, 2299], [2099, 2499]], 80, 500], [[1000, 1819], [1899, 2019], [2099, 2499]])], [('regression: trim floor', [[[0, 100], [1100, 1500], [2080, 3080], [3579, 3679], [3629, 5629]], 80, 500], [[0, 100], [1100, 1500], [2080, 3499], [3579, 3580], [3629, 5629]]), ('regression variant: trim floor', [[[0, 100], [100, 500], [799, 1199]], 120, 300], [[0, 1], [100, 679], [799, 1199]]), ('partial repair probe: trim floor', [[[1000, 1400], [1480, 1580], [1481, 1881]], 80, 500], [[1000, 1400], [1480, 1481], [1481, 1881]]), ('partial repair variant: trim floor', [[[0, 1000], [1300, 1700], [1700, 2100], [2221, 2321], [2321, 2421]], 120, 300], [[0, 1000], [1300, 1580], [1700, 2101], [2221, 2222], [2321, 2421]]), ('boundary control', [[[0, 1000], [1050, 2000]], 100, 500], [[0, 950], [1050, 2000]]), ('boundary control', [[[0, 1000], [900, 2000]], 100, 500], [[0, 800], [900, 2000]]), ('normal control', [[[1000, 1400], [2151, 4151], [3951, 5951], [5751, 6751], [6870, 6970]], 120, 750], [[1000, 1400], [2151, 3831], [3951, 5631], [5751, 6750], [6870, 6970]]), ('normal control', [[[1000, 1100], [1180, 2180]], 80, 500], [[1000, 1100], [1180, 2180]]), ('normal control', [[[0, 1000], [1833, 2833]], 83, 750], [[0, 1000], [1833, 2833]])]]
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: trim floor[[1000, 1399], [1499, 2298], [2398, 2299], [2399, 2800], [2900, 3900]][[1000, 1399], [1499, 2298], [2398, 2399], [2399, 2800], [2900, 3900]]Failed
regression variant: trim floor[[1000, 921], [1001, 1271], [1351, 1376], [1456, 3456], [4456, 5456]][[1000, 1001], [1001, 1271], [1351, 1376], [1456, 3456], [4456, 5456]]Failed
partial repair probe: trim floor[[0, 400], [983, 1082], [1165, 1083], [1166, 2167], [2250, 2350]][[0, 400], [983, 1082], [1165, 1166], [1166, 2167], [2250, 2350]]Failed
partial repair variant: trim floor[[0, -20], [100, 679], [799, 1199]][[0, 1], [100, 679], [799, 1199]]Failed
boundary control[[0, 950], [1050, 2000]][[0, 950], [1050, 2000]]Passed
boundary control[[0, 800], [900, 2000]][[0, 800], [900, 2000]]Passed
normal control[[0, 1300], [1400, 2000]][[0, 1300], [1400, 2000]]Passed
normal control[[0, 400], [1400, 2400]][[0, 400], [1400, 2400]]Passed
normal control[[0, 100], [183, 2183], [3183, 3283], [3784, 5784]][[0, 100], [183, 2183], [3183, 3283], [3784, 5784]]Passed

SHA-256 / 94472d7e52a218b11ab6d4e99b4dd73f5ec800e7d6ec668e7f4963e1204b1e3b

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(cues, min_gap, chain):
    out=[list(c) for c in cues]
    for i in range(len(out)-1):
        cur=out[i]
        nxt_start=out[i+1][0]
        gap=nxt_start-cur[1]
        if gap<min_gap:
            cur[1]=max(cur[0],nxt_start-min_gap)
        elif gap<chain:
            cur[1]=nxt_start-min_gap
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: trim floor', [[[1000, 1400], [1499, 1899], [2398, 2498], [2399, 2799], [2900, 3900]], 100, 500], [[1000, 1399], [1499, 2298], [2398, 2399], [2399, 2800], [2900, 3900]]), ('regression variant: trim floor', [[[1000, 1100], [1001, 1401], [1351, 1451], [1456, 3456], [4456, 5456]], 80, 300], [[1000, 1001], [1001, 1271], [1351, 1376], [1456, 3456], [4456, 5456]]), ('partial repair probe: trim floor', [[[0, 400], [983, 1083], [1165, 1265], [1166, 2166], [2250, 2350]], 83, 500], [[0, 400], [983, 1082], [1165, 1166], [1166, 2167], [2250, 2350]]), ('partial repair variant: trim floor', [[[0, 100], [100, 500], [799, 1199]], 120, 300], [[0, 1], [100, 679], [799, 1199]]), ('boundary control', [[[0, 1000], [1050, 2000]], 100, 500], [[0, 950], [1050, 2000]]), ('boundary control', [[[0, 1000], [900, 2000]], 100, 500], [[0, 800], [900, 2000]]), ('normal control', [[[0, 1000], [1400, 2000]], 100, 500], [[0, 1300], [1400, 2000]]), ('normal control', [[[0, 400], [1400, 2400]], 80, 750], [[0, 400], [1400, 2400]]), ('normal control', [[[0, 100], [183, 2183], [3183, 3283], [3784, 5784]], 83, 500], [[0, 100], [183, 2183], [3183, 3283], [3784, 5784]])], [('regression: trim floor', [[[1000, 2000], [2501, 2901], [3901, 4001], [3902, 5902], [6902, 7002]], 83, 500], [[1000, 2000], [2501, 2901], [3901, 3902], [3902, 5902], [6902, 7002]]), ('regression variant: trim floor', [[[1000, 1400], [1480, 1580], [1481, 1881]], 80, 500], [[1000, 1400], [1480, 1481], [1481, 1881]]), ('partial repair probe: trim floor', [[[1000, 1100], [1001, 1101], [1402, 3402], [3484, 3584], [3589, 5589]], 83, 300], [[1000, 1001], [1001, 1101], [1402, 3401], [3484, 3506], [3589, 5589]]), ('partial repair variant: trim floor', [[[1000, 1100], [1001, 2001]], 80, 750], [[1000, 1001], [1001, 2001]]), ('boundary control', [[[0, 1000], [1400, 2000]], 100, 500], [[0, 1300], [1400, 2000]]), ('boundary control', [[[0, 1000], [1050, 2000]], 100, 500], [[0, 950], [1050, 2000]]), ('normal control', [[[0, 1000], [1005, 1105]], 100, 750], [[0, 905], [1005, 1105]]), ('normal control', [[[1000, 1400], [2151, 4151]], 80, 750], [[1000, 1400], [2151, 4151]]), ('normal control', [[[0, 400], [479, 879]], 80, 750], [[0, 399], [479, 879]])], [('regression: trim floor', [[[0, 400], [983, 1083], [1165, 1265], [1166, 2166], [2250, 2350]], 83, 500], [[0, 400], [983, 1082], [1165, 1166], [1166, 2167], [2250, 2350]]), ('regression variant: trim floor', [[[0, 2000], [2000, 2100], [2130, 2530], [2560, 2660], [2610, 3010]], 120, 750], [[0, 1880], [2000, 2010], [2130, 2440], [2560, 2561], [2610, 3010]]), ('partial repair probe: trim floor', [[[0, 100], [1100, 1500], [2080, 3080], [3579, 3679], [3629, 5629]], 80, 500], [[0, 100], [1100, 1500], [2080, 3499], [3579, 3580], [3629, 5629]]), ('partial repair variant: trim floor', [[[1000, 1100], [1219, 1319], [1269, 1369]], 120, 750], [[1000, 1099], [1219, 1220], [1269, 1369]]), ('boundary control', [[[0, 1000], [1500, 2000]], 100, 500], [[0, 1000], [1500, 2000]]), ('boundary control', [[[0, 1000], [1400, 2000]], 100, 500], [[0, 1300], [1400, 2000]]), ('normal control', [[[1000, 3000], [3030, 5030], [5113, 6113], [6864, 6964], [6964, 8964]], 83, 750], [[1000, 2947], [3030, 5030], [5113, 6113], [6864, 6881], [6964, 8964]]), ('normal control', [[[1000, 3000], [4000, 6000], [6030, 6430], [6230, 8230], [8030, 10030]], 80, 750], [[1000, 3000], [4000, 5950], [6030, 6150], [6230, 7950], [8030, 10030]]), ('normal control', [[[0, 2000], [1800, 2200]], 100, 300], [[0, 1700], [1800, 2200]])], [('regression: trim floor', [[[1000, 1100], [1001, 1101], [1402, 3402], [3484, 3584], [3589, 5589]], 83, 300], [[1000, 1001], [1001, 1101], [1402, 3401], [3484, 3506], [3589, 5589]]), ('regression variant: trim floor', [[[1000, 1100], [1105, 3105], [3204, 3304], [3254, 4254], [5005, 5105]], 100, 750], [[1000, 1005], [1105, 3104], [3204, 3205], [3254, 4254], [5005, 5105]]), ('partial repair probe: trim floor', [[[1000, 1100], [1001, 1401], [1351, 1451], [1456, 3456], [4456, 5456]], 80, 300], [[1000, 1001], [1001, 1271], [1351, 1376], [1456, 3456], [4456, 5456]]), ('partial repair variant: trim floor', [[[1000, 3000], [3080, 5080], [5580, 7580], [7380, 7480], [7430, 8430]], 80, 500], [[1000, 3000], [3080, 5080], [5580, 7300], [7380, 7381], [7430, 8430]]), ('boundary control', [[[0, 1000], [900, 2000]], 100, 500], [[0, 800], [900, 2000]]), ('boundary control', [[[0, 1000], [1500, 2000]], 100, 500], [[0, 1000], [1500, 2000]]), ('normal control', [[[0, 2000], [2830, 3830], [3911, 4911], [5741, 6141], [6891, 8891]], 80, 750], [[0, 2000], [2830, 3831], [3911, 4911], [5741, 6141], [6891, 8891]]), ('normal control', [[[0, 1000], [800, 1800], [2800, 3800]], 83, 750], [[0, 717], [800, 1800], [2800, 3800]]), ('normal control', [[[1000, 1400], [1899, 2299], [2099, 2499]], 80, 500], [[1000, 1819], [1899, 2019], [2099, 2499]])], [('regression: trim floor', [[[0, 100], [1100, 1500], [2080, 3080], [3579, 3679], [3629, 5629]], 80, 500], [[0, 100], [1100, 1500], [2080, 3499], [3579, 3580], [3629, 5629]]), ('regression variant: trim floor', [[[0, 100], [100, 500], [799, 1199]], 120, 300], [[0, 1], [100, 679], [799, 1199]]), ('partial repair probe: trim floor', [[[1000, 1400], [1480, 1580], [1481, 1881]], 80, 500], [[1000, 1400], [1480, 1481], [1481, 1881]]), ('partial repair variant: trim floor', [[[0, 1000], [1300, 1700], [1700, 2100], [2221, 2321], [2321, 2421]], 120, 300], [[0, 1000], [1300, 1580], [1700, 2101], [2221, 2222], [2321, 2421]]), ('boundary control', [[[0, 1000], [1050, 2000]], 100, 500], [[0, 950], [1050, 2000]]), ('boundary control', [[[0, 1000], [900, 2000]], 100, 500], [[0, 800], [900, 2000]]), ('normal control', [[[1000, 1400], [2151, 4151], [3951, 5951], [5751, 6751], [6870, 6970]], 120, 750], [[1000, 1400], [2151, 3831], [3951, 5631], [5751, 6750], [6870, 6970]]), ('normal control', [[[1000, 1100], [1180, 2180]], 80, 500], [[1000, 1100], [1180, 2180]]), ('normal control', [[[0, 1000], [1833, 2833]], 83, 750], [[0, 1000], [1833, 2833]])]]
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: trim floor[[1000, 1399], [1499, 2298], [2398, 2398], [2399, 2800], [2900, 3900]][[1000, 1399], [1499, 2298], [2398, 2399], [2399, 2800], [2900, 3900]]Failed
regression variant: trim floor[[1000, 1000], [1001, 1271], [1351, 1376], [1456, 3456], [4456, 5456]][[1000, 1001], [1001, 1271], [1351, 1376], [1456, 3456], [4456, 5456]]Failed
partial repair probe: trim floor[[0, 400], [983, 1082], [1165, 1165], [1166, 2167], [2250, 2350]][[0, 400], [983, 1082], [1165, 1166], [1166, 2167], [2250, 2350]]Failed
partial repair variant: trim floor[[0, 0], [100, 679], [799, 1199]][[0, 1], [100, 679], [799, 1199]]Failed
boundary control[[0, 950], [1050, 2000]][[0, 950], [1050, 2000]]Passed
boundary control[[0, 800], [900, 2000]][[0, 800], [900, 2000]]Passed
normal control[[0, 1300], [1400, 2000]][[0, 1300], [1400, 2000]]Passed
normal control[[0, 400], [1400, 2400]][[0, 400], [1400, 2400]]Passed
normal control[[0, 100], [183, 2183], [3183, 3283], [3784, 5784]][[0, 100], [183, 2183], [3183, 3283], [3784, 5784]]Passed

SHA-256 / 1d40347eef7f48bf5c79c45a3920015412a555e8807bf695c651dbd882db6de4

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(cues, min_gap, chain):
    out=[list(c) for c in cues]
    for i in range(len(out)-1):
        cur=out[i]
        nxt_start=out[i+1][0]
        gap=nxt_start-cur[1]
        if gap<min_gap:
            cur[1]=max(cur[0]+1,nxt_start-min_gap)
        elif gap<chain:
            cur[1]=nxt_start-min_gap
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: trim floor', [[[1000, 1400], [1499, 1899], [2398, 2498], [2399, 2799], [2900, 3900]], 100, 500], [[1000, 1399], [1499, 2298], [2398, 2399], [2399, 2800], [2900, 3900]]), ('regression variant: trim floor', [[[1000, 1100], [1001, 1401], [1351, 1451], [1456, 3456], [4456, 5456]], 80, 300], [[1000, 1001], [1001, 1271], [1351, 1376], [1456, 3456], [4456, 5456]]), ('partial repair probe: trim floor', [[[0, 400], [983, 1083], [1165, 1265], [1166, 2166], [2250, 2350]], 83, 500], [[0, 400], [983, 1082], [1165, 1166], [1166, 2167], [2250, 2350]]), ('partial repair variant: trim floor', [[[0, 100], [100, 500], [799, 1199]], 120, 300], [[0, 1], [100, 679], [799, 1199]]), ('boundary control', [[[0, 1000], [1050, 2000]], 100, 500], [[0, 950], [1050, 2000]]), ('boundary control', [[[0, 1000], [900, 2000]], 100, 500], [[0, 800], [900, 2000]]), ('normal control', [[[0, 1000], [1400, 2000]], 100, 500], [[0, 1300], [1400, 2000]]), ('normal control', [[[0, 400], [1400, 2400]], 80, 750], [[0, 400], [1400, 2400]]), ('normal control', [[[0, 100], [183, 2183], [3183, 3283], [3784, 5784]], 83, 500], [[0, 100], [183, 2183], [3183, 3283], [3784, 5784]])], [('regression: trim floor', [[[1000, 2000], [2501, 2901], [3901, 4001], [3902, 5902], [6902, 7002]], 83, 500], [[1000, 2000], [2501, 2901], [3901, 3902], [3902, 5902], [6902, 7002]]), ('regression variant: trim floor', [[[1000, 1400], [1480, 1580], [1481, 1881]], 80, 500], [[1000, 1400], [1480, 1481], [1481, 1881]]), ('partial repair probe: trim floor', [[[1000, 1100], [1001, 1101], [1402, 3402], [3484, 3584], [3589, 5589]], 83, 300], [[1000, 1001], [1001, 1101], [1402, 3401], [3484, 3506], [3589, 5589]]), ('partial repair variant: trim floor', [[[1000, 1100], [1001, 2001]], 80, 750], [[1000, 1001], [1001, 2001]]), ('boundary control', [[[0, 1000], [1400, 2000]], 100, 500], [[0, 1300], [1400, 2000]]), ('boundary control', [[[0, 1000], [1050, 2000]], 100, 500], [[0, 950], [1050, 2000]]), ('normal control', [[[0, 1000], [1005, 1105]], 100, 750], [[0, 905], [1005, 1105]]), ('normal control', [[[1000, 1400], [2151, 4151]], 80, 750], [[1000, 1400], [2151, 4151]]), ('normal control', [[[0, 400], [479, 879]], 80, 750], [[0, 399], [479, 879]])], [('regression: trim floor', [[[0, 400], [983, 1083], [1165, 1265], [1166, 2166], [2250, 2350]], 83, 500], [[0, 400], [983, 1082], [1165, 1166], [1166, 2167], [2250, 2350]]), ('regression variant: trim floor', [[[0, 2000], [2000, 2100], [2130, 2530], [2560, 2660], [2610, 3010]], 120, 750], [[0, 1880], [2000, 2010], [2130, 2440], [2560, 2561], [2610, 3010]]), ('partial repair probe: trim floor', [[[0, 100], [1100, 1500], [2080, 3080], [3579, 3679], [3629, 5629]], 80, 500], [[0, 100], [1100, 1500], [2080, 3499], [3579, 3580], [3629, 5629]]), ('partial repair variant: trim floor', [[[1000, 1100], [1219, 1319], [1269, 1369]], 120, 750], [[1000, 1099], [1219, 1220], [1269, 1369]]), ('boundary control', [[[0, 1000], [1500, 2000]], 100, 500], [[0, 1000], [1500, 2000]]), ('boundary control', [[[0, 1000], [1400, 2000]], 100, 500], [[0, 1300], [1400, 2000]]), ('normal control', [[[1000, 3000], [3030, 5030], [5113, 6113], [6864, 6964], [6964, 8964]], 83, 750], [[1000, 2947], [3030, 5030], [5113, 6113], [6864, 6881], [6964, 8964]]), ('normal control', [[[1000, 3000], [4000, 6000], [6030, 6430], [6230, 8230], [8030, 10030]], 80, 750], [[1000, 3000], [4000, 5950], [6030, 6150], [6230, 7950], [8030, 10030]]), ('normal control', [[[0, 2000], [1800, 2200]], 100, 300], [[0, 1700], [1800, 2200]])], [('regression: trim floor', [[[1000, 1100], [1001, 1101], [1402, 3402], [3484, 3584], [3589, 5589]], 83, 300], [[1000, 1001], [1001, 1101], [1402, 3401], [3484, 3506], [3589, 5589]]), ('regression variant: trim floor', [[[1000, 1100], [1105, 3105], [3204, 3304], [3254, 4254], [5005, 5105]], 100, 750], [[1000, 1005], [1105, 3104], [3204, 3205], [3254, 4254], [5005, 5105]]), ('partial repair probe: trim floor', [[[1000, 1100], [1001, 1401], [1351, 1451], [1456, 3456], [4456, 5456]], 80, 300], [[1000, 1001], [1001, 1271], [1351, 1376], [1456, 3456], [4456, 5456]]), ('partial repair variant: trim floor', [[[1000, 3000], [3080, 5080], [5580, 7580], [7380, 7480], [7430, 8430]], 80, 500], [[1000, 3000], [3080, 5080], [5580, 7300], [7380, 7381], [7430, 8430]]), ('boundary control', [[[0, 1000], [900, 2000]], 100, 500], [[0, 800], [900, 2000]]), ('boundary control', [[[0, 1000], [1500, 2000]], 100, 500], [[0, 1000], [1500, 2000]]), ('normal control', [[[0, 2000], [2830, 3830], [3911, 4911], [5741, 6141], [6891, 8891]], 80, 750], [[0, 2000], [2830, 3831], [3911, 4911], [5741, 6141], [6891, 8891]]), ('normal control', [[[0, 1000], [800, 1800], [2800, 3800]], 83, 750], [[0, 717], [800, 1800], [2800, 3800]]), ('normal control', [[[1000, 1400], [1899, 2299], [2099, 2499]], 80, 500], [[1000, 1819], [1899, 2019], [2099, 2499]])], [('regression: trim floor', [[[0, 100], [1100, 1500], [2080, 3080], [3579, 3679], [3629, 5629]], 80, 500], [[0, 100], [1100, 1500], [2080, 3499], [3579, 3580], [3629, 5629]]), ('regression variant: trim floor', [[[0, 100], [100, 500], [799, 1199]], 120, 300], [[0, 1], [100, 679], [799, 1199]]), ('partial repair probe: trim floor', [[[1000, 1400], [1480, 1580], [1481, 1881]], 80, 500], [[1000, 1400], [1480, 1481], [1481, 1881]]), ('partial repair variant: trim floor', [[[0, 1000], [1300, 1700], [1700, 2100], [2221, 2321], [2321, 2421]], 120, 300], [[0, 1000], [1300, 1580], [1700, 2101], [2221, 2222], [2321, 2421]]), ('boundary control', [[[0, 1000], [1050, 2000]], 100, 500], [[0, 950], [1050, 2000]]), ('boundary control', [[[0, 1000], [900, 2000]], 100, 500], [[0, 800], [900, 2000]]), ('normal control', [[[1000, 1400], [2151, 4151], [3951, 5951], [5751, 6751], [6870, 6970]], 120, 750], [[1000, 1400], [2151, 3831], [3951, 5631], [5751, 6750], [6870, 6970]]), ('normal control', [[[1000, 1100], [1180, 2180]], 80, 500], [[1000, 1100], [1180, 2180]]), ('normal control', [[[0, 1000], [1833, 2833]], 83, 750], [[0, 1000], [1833, 2833]])]]
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: trim floor[[1000, 1399], [1499, 2298], [2398, 2399], [2399, 2800], [2900, 3900]][[1000, 1399], [1499, 2298], [2398, 2399], [2399, 2800], [2900, 3900]]Passed
regression variant: trim floor[[1000, 1001], [1001, 1271], [1351, 1376], [1456, 3456], [4456, 5456]][[1000, 1001], [1001, 1271], [1351, 1376], [1456, 3456], [4456, 5456]]Passed
partial repair probe: trim floor[[0, 400], [983, 1082], [1165, 1166], [1166, 2167], [2250, 2350]][[0, 400], [983, 1082], [1165, 1166], [1166, 2167], [2250, 2350]]Passed
partial repair variant: trim floor[[0, 1], [100, 679], [799, 1199]][[0, 1], [100, 679], [799, 1199]]Passed
boundary control[[0, 950], [1050, 2000]][[0, 950], [1050, 2000]]Passed
boundary control[[0, 800], [900, 2000]][[0, 800], [900, 2000]]Passed
normal control[[0, 1300], [1400, 2000]][[0, 1300], [1400, 2000]]Passed
normal control[[0, 400], [1400, 2400]][[0, 400], [1400, 2400]]Passed
normal control[[0, 100], [183, 2183], [3183, 3283], [3784, 5784]][[0, 100], [183, 2183], [3183, 3283], [3784, 5784]]Passed

SHA-256 / bdf8ab534fa68f62462b08bc53f02bb710fe9f5fb2ed9495dac581a44e85c860

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 2026-09-29T14:49:30.759737+00:00.

Case digest / ffddac3cdbd116b2369797b07773733c9576618f7300d916a00a05728f82e21b