FAILURE MAP
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FA-37526 / Table interactions / Open access

Table row height measurement cache: table total height · case 01

The table table total height result violates the stipulated table row height measurement cache contract.

Verified by executionVariant 1 · 7 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The table total height decision uses 'max(heights.values(),default=0)' instead of 'sum(heights.values())'.

THE FAILURE

The table total height decision uses 'max(heights.values(),default=0)' instead of 'sum(heights.values())'.

Unsuccessful approach: The attempted repair 'estimate*len(rows)' still loses a required part of the table contract.

Case contract

Measured row heights are keyed by stable row ID plus row-data generation and column-width fingerprint. Invalid measurements use an estimate, minimum applies before detail height, positions are ordered prefixes, and stale row measurements are pruned.

Why this case matters

An offline table UI model isolates table row height measurement cache, including adversarial row/column relationships.

1 / The failure

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

N = 1
observations = []
def solve(rows, measurements, generation, width_key, minimum, estimate, details):
    heights={}
    for r in rows:
        k=r['id']; m=measurements.get(k)
        valid=m is not None and m['generation']==generation and m['width_key']==width_key
        h=m['height'] if valid else estimate
        heights[k]=max(minimum,h)+details.get(k,0)
    ids=[r['id'] for r in rows]
    offsets={k:sum(heights[x] for x in ids[:i]) for i,k in enumerate(ids)}
    return {'heights':heights,'offsets':offsets,'total':max(heights.values(),default=0),'remeasure':[r['id'] for r in rows if r['id'] not in measurements or measurements[r['id']]['generation']!=generation or measurements[r['id']]['width_key']!=width_key],'retained':{k:v for k,v in measurements.items() if k in ids}}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
if N == 1:
    check('fresh variable rows', solve([{'id':'a'},{'id':'b'}], {'a':{'height':1+3,'generation':2,'width_key':'w'},'b':{'height':8,'generation':2,'width_key':'w'}}, 2, 'w', 2, 10, {'a':3}), {'heights': {'a': 7, 'b': 8}, 'offsets': {'a': 0, 'b': 7}, 'total': 15, 'remeasure': [], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 'w'}, 'b': {'height': 8, 'generation': 2, 'width_key': 'w'}}})
    check('stale generation', solve([{'id':'a'}], {'a':{'height':4,'generation':1,'width_key':'w'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 1, 'width_key': 'w'}}})
    check('changed widths', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':'old'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 'old'}}})
    check('typed width key', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':1}}, 2, '1', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 1}}})
    check('zero and stale id', solve([{'id':'a'}], {'a':{'height':0,'generation':2,'width_key':'w'},'gone':{'height':7,'generation':2,'width_key':'w'}}, 2, 'w', 0, 10, {}), {'heights': {'a': 0}, 'offsets': {'a': 0}, 'total': 0, 'remeasure': [], 'retained': {'a': {'height': 0, 'generation': 2, 'width_key': 'w'}}})
    check('minimum clamp', solve([{'id':'a'},{'id':'b'}], {'a':{'height':1,'generation':2,'width_key':'w'}}, 2, 'w', 3, 10, {'b':2}), {'heights': {'a': 3, 'b': 12}, 'offsets': {'a': 0, 'b': 3}, 'total': 15, 'remeasure': ['b'], 'retained': {'a': {'height': 1, 'generation': 2, 'width_key': 'w'}}})
    check('empty', solve([], {}, 2, 'w', 3, 10, {}), {'heights': {}, 'offsets': {}, 'total': 0, 'remeasure': [], 'retained': {}})

if N == 2:
    check('fresh variable rows', solve([{'id':'a'},{'id':'b'}], {'a':{'height':2+3,'generation':2,'width_key':'w'},'b':{'height':8,'generation':2,'width_key':'w'}}, 2, 'w', 2, 10, {'a':3}), {'heights': {'a': 8, 'b': 8}, 'offsets': {'a': 0, 'b': 8}, 'total': 16, 'remeasure': [], 'retained': {'a': {'height': 5, 'generation': 2, 'width_key': 'w'}, 'b': {'height': 8, 'generation': 2, 'width_key': 'w'}}})
    check('stale generation', solve([{'id':'a'}], {'a':{'height':4,'generation':1,'width_key':'w'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 1, 'width_key': 'w'}}})
    check('changed widths', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':'old'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 'old'}}})
    check('typed width key', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':1}}, 2, '1', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 1}}})
    check('zero and stale id', solve([{'id':'a'}], {'a':{'height':0,'generation':2,'width_key':'w'},'gone':{'height':7,'generation':2,'width_key':'w'}}, 2, 'w', 0, 10, {}), {'heights': {'a': 0}, 'offsets': {'a': 0}, 'total': 0, 'remeasure': [], 'retained': {'a': {'height': 0, 'generation': 2, 'width_key': 'w'}}})
    check('minimum clamp', solve([{'id':'a'},{'id':'b'}], {'a':{'height':1,'generation':2,'width_key':'w'}}, 2, 'w', 3, 10, {'b':2}), {'heights': {'a': 3, 'b': 12}, 'offsets': {'a': 0, 'b': 3}, 'total': 15, 'remeasure': ['b'], 'retained': {'a': {'height': 1, 'generation': 2, 'width_key': 'w'}}})
    check('empty', solve([], {}, 2, 'w', 3, 10, {}), {'heights': {}, 'offsets': {}, 'total': 0, 'remeasure': [], 'retained': {}})

if N == 3:
    check('fresh variable rows', solve([{'id':'a'},{'id':'b'}], {'a':{'height':3+3,'generation':2,'width_key':'w'},'b':{'height':8,'generation':2,'width_key':'w'}}, 2, 'w', 2, 10, {'a':3}), {'heights': {'a': 9, 'b': 8}, 'offsets': {'a': 0, 'b': 9}, 'total': 17, 'remeasure': [], 'retained': {'a': {'height': 6, 'generation': 2, 'width_key': 'w'}, 'b': {'height': 8, 'generation': 2, 'width_key': 'w'}}})
    check('stale generation', solve([{'id':'a'}], {'a':{'height':4,'generation':1,'width_key':'w'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 1, 'width_key': 'w'}}})
    check('changed widths', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':'old'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 'old'}}})
    check('typed width key', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':1}}, 2, '1', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 1}}})
    check('zero and stale id', solve([{'id':'a'}], {'a':{'height':0,'generation':2,'width_key':'w'},'gone':{'height':7,'generation':2,'width_key':'w'}}, 2, 'w', 0, 10, {}), {'heights': {'a': 0}, 'offsets': {'a': 0}, 'total': 0, 'remeasure': [], 'retained': {'a': {'height': 0, 'generation': 2, 'width_key': 'w'}}})
    check('minimum clamp', solve([{'id':'a'},{'id':'b'}], {'a':{'height':1,'generation':2,'width_key':'w'}}, 2, 'w', 3, 10, {'b':2}), {'heights': {'a': 3, 'b': 12}, 'offsets': {'a': 0, 'b': 3}, 'total': 15, 'remeasure': ['b'], 'retained': {'a': {'height': 1, 'generation': 2, 'width_key': 'w'}}})
    check('empty', solve([], {}, 2, 'w', 3, 10, {}), {'heights': {}, 'offsets': {}, 'total': 0, 'remeasure': [], 'retained': {}})

if N == 4:
    check('fresh variable rows', solve([{'id':'a'},{'id':'b'}], {'a':{'height':4+3,'generation':2,'width_key':'w'},'b':{'height':8,'generation':2,'width_key':'w'}}, 2, 'w', 2, 10, {'a':3}), {'heights': {'a': 10, 'b': 8}, 'offsets': {'a': 0, 'b': 10}, 'total': 18, 'remeasure': [], 'retained': {'a': {'height': 7, 'generation': 2, 'width_key': 'w'}, 'b': {'height': 8, 'generation': 2, 'width_key': 'w'}}})
    check('stale generation', solve([{'id':'a'}], {'a':{'height':4,'generation':1,'width_key':'w'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 1, 'width_key': 'w'}}})
    check('changed widths', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':'old'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 'old'}}})
    check('typed width key', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':1}}, 2, '1', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 1}}})
    check('zero and stale id', solve([{'id':'a'}], {'a':{'height':0,'generation':2,'width_key':'w'},'gone':{'height':7,'generation':2,'width_key':'w'}}, 2, 'w', 0, 10, {}), {'heights': {'a': 0}, 'offsets': {'a': 0}, 'total': 0, 'remeasure': [], 'retained': {'a': {'height': 0, 'generation': 2, 'width_key': 'w'}}})
    check('minimum clamp', solve([{'id':'a'},{'id':'b'}], {'a':{'height':1,'generation':2,'width_key':'w'}}, 2, 'w', 3, 10, {'b':2}), {'heights': {'a': 3, 'b': 12}, 'offsets': {'a': 0, 'b': 3}, 'total': 15, 'remeasure': ['b'], 'retained': {'a': {'height': 1, 'generation': 2, 'width_key': 'w'}}})
    check('empty', solve([], {}, 2, 'w', 3, 10, {}), {'heights': {}, 'offsets': {}, 'total': 0, 'remeasure': [], 'retained': {}})

if N == 5:
    check('fresh variable rows', solve([{'id':'a'},{'id':'b'}], {'a':{'height':5+3,'generation':2,'width_key':'w'},'b':{'height':8,'generation':2,'width_key':'w'}}, 2, 'w', 2, 10, {'a':3}), {'heights': {'a': 11, 'b': 8}, 'offsets': {'a': 0, 'b': 11}, 'total': 19, 'remeasure': [], 'retained': {'a': {'height': 8, 'generation': 2, 'width_key': 'w'}, 'b': {'height': 8, 'generation': 2, 'width_key': 'w'}}})
    check('stale generation', solve([{'id':'a'}], {'a':{'height':4,'generation':1,'width_key':'w'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 1, 'width_key': 'w'}}})
    check('changed widths', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':'old'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 'old'}}})
    check('typed width key', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':1}}, 2, '1', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 1}}})
    check('zero and stale id', solve([{'id':'a'}], {'a':{'height':0,'generation':2,'width_key':'w'},'gone':{'height':7,'generation':2,'width_key':'w'}}, 2, 'w', 0, 10, {}), {'heights': {'a': 0}, 'offsets': {'a': 0}, 'total': 0, 'remeasure': [], 'retained': {'a': {'height': 0, 'generation': 2, 'width_key': 'w'}}})
    check('minimum clamp', solve([{'id':'a'},{'id':'b'}], {'a':{'height':1,'generation':2,'width_key':'w'}}, 2, 'w', 3, 10, {'b':2}), {'heights': {'a': 3, 'b': 12}, 'offsets': {'a': 0, 'b': 3}, 'total': 15, 'remeasure': ['b'], 'retained': {'a': {'height': 1, 'generation': 2, 'width_key': 'w'}}})
    check('empty', solve([], {}, 2, 'w', 3, 10, {}), {'heights': {}, 'offsets': {}, 'total': 0, 'remeasure': [], 'retained': {}})

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
fresh variable rows{'heights': {'a': 7, 'b': 8}, 'offsets': {'a': 0, 'b': 7}, 'remeasure': [], 'retained': {'a': {'generation': 2, 'height': 4, 'width_key': 'w'}, 'b': {'generation': 2, 'height': 8, 'width_key': 'w'}}, 'total': 8}{'heights': {'a': 7, 'b': 8}, 'offsets': {'a': 0, 'b': 7}, 'remeasure': [], 'retained': {'a': {'generation': 2, 'height': 4, 'width_key': 'w'}, 'b': {'generation': 2, 'height': 8, 'width_key': 'w'}}, 'total': 15}Failed
stale generation{'heights': {'a': 10}, 'offsets': {'a': 0}, 'remeasure': ['a'], 'retained': {'a': {'generation': 1, 'height': 4, 'width_key': 'w'}}, 'total': 10}{'heights': {'a': 10}, 'offsets': {'a': 0}, 'remeasure': ['a'], 'retained': {'a': {'generation': 1, 'height': 4, 'width_key': 'w'}}, 'total': 10}Passed
changed widths{'heights': {'a': 10}, 'offsets': {'a': 0}, 'remeasure': ['a'], 'retained': {'a': {'generation': 2, 'height': 4, 'width_key': 'old'}}, 'total': 10}{'heights': {'a': 10}, 'offsets': {'a': 0}, 'remeasure': ['a'], 'retained': {'a': {'generation': 2, 'height': 4, 'width_key': 'old'}}, 'total': 10}Passed
typed width key{'heights': {'a': 10}, 'offsets': {'a': 0}, 'remeasure': ['a'], 'retained': {'a': {'generation': 2, 'height': 4, 'width_key': 1}}, 'total': 10}{'heights': {'a': 10}, 'offsets': {'a': 0}, 'remeasure': ['a'], 'retained': {'a': {'generation': 2, 'height': 4, 'width_key': 1}}, 'total': 10}Passed
zero and stale id{'heights': {'a': 0}, 'offsets': {'a': 0}, 'remeasure': [], 'retained': {'a': {'generation': 2, 'height': 0, 'width_key': 'w'}}, 'total': 0}{'heights': {'a': 0}, 'offsets': {'a': 0}, 'remeasure': [], 'retained': {'a': {'generation': 2, 'height': 0, 'width_key': 'w'}}, 'total': 0}Passed
minimum clamp{'heights': {'a': 3, 'b': 12}, 'offsets': {'a': 0, 'b': 3}, 'remeasure': ['b'], 'retained': {'a': {'generation': 2, 'height': 1, 'width_key': 'w'}}, 'total': 12}{'heights': {'a': 3, 'b': 12}, 'offsets': {'a': 0, 'b': 3}, 'remeasure': ['b'], 'retained': {'a': {'generation': 2, 'height': 1, 'width_key': 'w'}}, 'total': 15}Failed
empty{'heights': {}, 'offsets': {}, 'remeasure': [], 'retained': {}, 'total': 0}{'heights': {}, 'offsets': {}, 'remeasure': [], 'retained': {}, 'total': 0}Passed

SHA-256 / a72c637f319ee72c8d93285d20546027c41a030b7f7dabe0f37d40537c03eebe

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(rows, measurements, generation, width_key, minimum, estimate, details):
    heights={}
    for r in rows:
        k=r['id']; m=measurements.get(k)
        valid=m is not None and m['generation']==generation and m['width_key']==width_key
        h=m['height'] if valid else estimate
        heights[k]=max(minimum,h)+details.get(k,0)
    ids=[r['id'] for r in rows]
    offsets={k:sum(heights[x] for x in ids[:i]) for i,k in enumerate(ids)}
    return {'heights':heights,'offsets':offsets,'total':estimate*len(rows),'remeasure':[r['id'] for r in rows if r['id'] not in measurements or measurements[r['id']]['generation']!=generation or measurements[r['id']]['width_key']!=width_key],'retained':{k:v for k,v in measurements.items() if k in ids}}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
if N == 1:
    check('fresh variable rows', solve([{'id':'a'},{'id':'b'}], {'a':{'height':1+3,'generation':2,'width_key':'w'},'b':{'height':8,'generation':2,'width_key':'w'}}, 2, 'w', 2, 10, {'a':3}), {'heights': {'a': 7, 'b': 8}, 'offsets': {'a': 0, 'b': 7}, 'total': 15, 'remeasure': [], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 'w'}, 'b': {'height': 8, 'generation': 2, 'width_key': 'w'}}})
    check('stale generation', solve([{'id':'a'}], {'a':{'height':4,'generation':1,'width_key':'w'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 1, 'width_key': 'w'}}})
    check('changed widths', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':'old'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 'old'}}})
    check('typed width key', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':1}}, 2, '1', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 1}}})
    check('zero and stale id', solve([{'id':'a'}], {'a':{'height':0,'generation':2,'width_key':'w'},'gone':{'height':7,'generation':2,'width_key':'w'}}, 2, 'w', 0, 10, {}), {'heights': {'a': 0}, 'offsets': {'a': 0}, 'total': 0, 'remeasure': [], 'retained': {'a': {'height': 0, 'generation': 2, 'width_key': 'w'}}})
    check('minimum clamp', solve([{'id':'a'},{'id':'b'}], {'a':{'height':1,'generation':2,'width_key':'w'}}, 2, 'w', 3, 10, {'b':2}), {'heights': {'a': 3, 'b': 12}, 'offsets': {'a': 0, 'b': 3}, 'total': 15, 'remeasure': ['b'], 'retained': {'a': {'height': 1, 'generation': 2, 'width_key': 'w'}}})
    check('empty', solve([], {}, 2, 'w', 3, 10, {}), {'heights': {}, 'offsets': {}, 'total': 0, 'remeasure': [], 'retained': {}})

if N == 2:
    check('fresh variable rows', solve([{'id':'a'},{'id':'b'}], {'a':{'height':2+3,'generation':2,'width_key':'w'},'b':{'height':8,'generation':2,'width_key':'w'}}, 2, 'w', 2, 10, {'a':3}), {'heights': {'a': 8, 'b': 8}, 'offsets': {'a': 0, 'b': 8}, 'total': 16, 'remeasure': [], 'retained': {'a': {'height': 5, 'generation': 2, 'width_key': 'w'}, 'b': {'height': 8, 'generation': 2, 'width_key': 'w'}}})
    check('stale generation', solve([{'id':'a'}], {'a':{'height':4,'generation':1,'width_key':'w'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 1, 'width_key': 'w'}}})
    check('changed widths', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':'old'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 'old'}}})
    check('typed width key', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':1}}, 2, '1', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 1}}})
    check('zero and stale id', solve([{'id':'a'}], {'a':{'height':0,'generation':2,'width_key':'w'},'gone':{'height':7,'generation':2,'width_key':'w'}}, 2, 'w', 0, 10, {}), {'heights': {'a': 0}, 'offsets': {'a': 0}, 'total': 0, 'remeasure': [], 'retained': {'a': {'height': 0, 'generation': 2, 'width_key': 'w'}}})
    check('minimum clamp', solve([{'id':'a'},{'id':'b'}], {'a':{'height':1,'generation':2,'width_key':'w'}}, 2, 'w', 3, 10, {'b':2}), {'heights': {'a': 3, 'b': 12}, 'offsets': {'a': 0, 'b': 3}, 'total': 15, 'remeasure': ['b'], 'retained': {'a': {'height': 1, 'generation': 2, 'width_key': 'w'}}})
    check('empty', solve([], {}, 2, 'w', 3, 10, {}), {'heights': {}, 'offsets': {}, 'total': 0, 'remeasure': [], 'retained': {}})

if N == 3:
    check('fresh variable rows', solve([{'id':'a'},{'id':'b'}], {'a':{'height':3+3,'generation':2,'width_key':'w'},'b':{'height':8,'generation':2,'width_key':'w'}}, 2, 'w', 2, 10, {'a':3}), {'heights': {'a': 9, 'b': 8}, 'offsets': {'a': 0, 'b': 9}, 'total': 17, 'remeasure': [], 'retained': {'a': {'height': 6, 'generation': 2, 'width_key': 'w'}, 'b': {'height': 8, 'generation': 2, 'width_key': 'w'}}})
    check('stale generation', solve([{'id':'a'}], {'a':{'height':4,'generation':1,'width_key':'w'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 1, 'width_key': 'w'}}})
    check('changed widths', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':'old'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 'old'}}})
    check('typed width key', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':1}}, 2, '1', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 1}}})
    check('zero and stale id', solve([{'id':'a'}], {'a':{'height':0,'generation':2,'width_key':'w'},'gone':{'height':7,'generation':2,'width_key':'w'}}, 2, 'w', 0, 10, {}), {'heights': {'a': 0}, 'offsets': {'a': 0}, 'total': 0, 'remeasure': [], 'retained': {'a': {'height': 0, 'generation': 2, 'width_key': 'w'}}})
    check('minimum clamp', solve([{'id':'a'},{'id':'b'}], {'a':{'height':1,'generation':2,'width_key':'w'}}, 2, 'w', 3, 10, {'b':2}), {'heights': {'a': 3, 'b': 12}, 'offsets': {'a': 0, 'b': 3}, 'total': 15, 'remeasure': ['b'], 'retained': {'a': {'height': 1, 'generation': 2, 'width_key': 'w'}}})
    check('empty', solve([], {}, 2, 'w', 3, 10, {}), {'heights': {}, 'offsets': {}, 'total': 0, 'remeasure': [], 'retained': {}})

if N == 4:
    check('fresh variable rows', solve([{'id':'a'},{'id':'b'}], {'a':{'height':4+3,'generation':2,'width_key':'w'},'b':{'height':8,'generation':2,'width_key':'w'}}, 2, 'w', 2, 10, {'a':3}), {'heights': {'a': 10, 'b': 8}, 'offsets': {'a': 0, 'b': 10}, 'total': 18, 'remeasure': [], 'retained': {'a': {'height': 7, 'generation': 2, 'width_key': 'w'}, 'b': {'height': 8, 'generation': 2, 'width_key': 'w'}}})
    check('stale generation', solve([{'id':'a'}], {'a':{'height':4,'generation':1,'width_key':'w'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 1, 'width_key': 'w'}}})
    check('changed widths', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':'old'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 'old'}}})
    check('typed width key', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':1}}, 2, '1', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 1}}})
    check('zero and stale id', solve([{'id':'a'}], {'a':{'height':0,'generation':2,'width_key':'w'},'gone':{'height':7,'generation':2,'width_key':'w'}}, 2, 'w', 0, 10, {}), {'heights': {'a': 0}, 'offsets': {'a': 0}, 'total': 0, 'remeasure': [], 'retained': {'a': {'height': 0, 'generation': 2, 'width_key': 'w'}}})
    check('minimum clamp', solve([{'id':'a'},{'id':'b'}], {'a':{'height':1,'generation':2,'width_key':'w'}}, 2, 'w', 3, 10, {'b':2}), {'heights': {'a': 3, 'b': 12}, 'offsets': {'a': 0, 'b': 3}, 'total': 15, 'remeasure': ['b'], 'retained': {'a': {'height': 1, 'generation': 2, 'width_key': 'w'}}})
    check('empty', solve([], {}, 2, 'w', 3, 10, {}), {'heights': {}, 'offsets': {}, 'total': 0, 'remeasure': [], 'retained': {}})

if N == 5:
    check('fresh variable rows', solve([{'id':'a'},{'id':'b'}], {'a':{'height':5+3,'generation':2,'width_key':'w'},'b':{'height':8,'generation':2,'width_key':'w'}}, 2, 'w', 2, 10, {'a':3}), {'heights': {'a': 11, 'b': 8}, 'offsets': {'a': 0, 'b': 11}, 'total': 19, 'remeasure': [], 'retained': {'a': {'height': 8, 'generation': 2, 'width_key': 'w'}, 'b': {'height': 8, 'generation': 2, 'width_key': 'w'}}})
    check('stale generation', solve([{'id':'a'}], {'a':{'height':4,'generation':1,'width_key':'w'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 1, 'width_key': 'w'}}})
    check('changed widths', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':'old'}}, 2, 'w', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 'old'}}})
    check('typed width key', solve([{'id':'a'}], {'a':{'height':4,'generation':2,'width_key':1}}, 2, '1', 2, 10, {}), {'heights': {'a': 10}, 'offsets': {'a': 0}, 'total': 10, 'remeasure': ['a'], 'retained': {'a': {'height': 4, 'generation': 2, 'width_key': 1}}})
    check('zero and stale id', solve([{'id':'a'}], {'a':{'height':0,'generation':2,'width_key':'w'},'gone':{'height':7,'generation':2,'width_key':'w'}}, 2, 'w', 0, 10, {}), {'heights': {'a': 0}, 'offsets': {'a': 0}, 'total': 0, 'remeasure': [], 'retained': {'a': {'height': 0, 'generation': 2, 'width_key': 'w'}}})
    check('minimum clamp', solve([{'id':'a'},{'id':'b'}], {'a':{'height':1,'generation':2,'width_key':'w'}}, 2, 'w', 3, 10, {'b':2}), {'heights': {'a': 3, 'b': 12}, 'offsets': {'a': 0, 'b': 3}, 'total': 15, 'remeasure': ['b'], 'retained': {'a': {'height': 1, 'generation': 2, 'width_key': 'w'}}})
    check('empty', solve([], {}, 2, 'w', 3, 10, {}), {'heights': {}, 'offsets': {}, 'total': 0, 'remeasure': [], 'retained': {}})

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
fresh variable rows{'heights': {'a': 7, 'b': 8}, 'offsets': {'a': 0, 'b': 7}, 'remeasure': [], 'retained': {'a': {'generation': 2, 'height': 4, 'width_key': 'w'}, 'b': {'generation': 2, 'height': 8, 'width_key': 'w'}}, 'total': 20}{'heights': {'a': 7, 'b': 8}, 'offsets': {'a': 0, 'b': 7}, 'remeasure': [], 'retained': {'a': {'generation': 2, 'height': 4, 'width_key': 'w'}, 'b': {'generation': 2, 'height': 8, 'width_key': 'w'}}, 'total': 15}Failed
stale generation{'heights': {'a': 10}, 'offsets': {'a': 0}, 'remeasure': ['a'], 'retained': {'a': {'generation': 1, 'height': 4, 'width_key': 'w'}}, 'total': 10}{'heights': {'a': 10}, 'offsets': {'a': 0}, 'remeasure': ['a'], 'retained': {'a': {'generation': 1, 'height': 4, 'width_key': 'w'}}, 'total': 10}Passed
changed widths{'heights': {'a': 10}, 'offsets': {'a': 0}, 'remeasure': ['a'], 'retained': {'a': {'generation': 2, 'height': 4, 'width_key': 'old'}}, 'total': 10}{'heights': {'a': 10}, 'offsets': {'a': 0}, 'remeasure': ['a'], 'retained': {'a': {'generation': 2, 'height': 4, 'width_key': 'old'}}, 'total': 10}Passed
typed width key{'heights': {'a': 10}, 'offsets': {'a': 0}, 'remeasure': ['a'], 'retained': {'a': {'generation': 2, 'height': 4, 'width_key': 1}}, 'total': 10}{'heights': {'a': 10}, 'offsets': {'a': 0}, 'remeasure': ['a'], 'retained': {'a': {'generation': 2, 'height': 4, 'width_key': 1}}, 'total': 10}Passed
zero and stale id{'heights': {'a': 0}, 'offsets': {'a': 0}, 'remeasure': [], 'retained': {'a': {'generation': 2, 'height': 0, 'width_key': 'w'}}, 'total': 10}{'heights': {'a': 0}, 'offsets': {'a': 0}, 'remeasure': [], 'retained': {'a': {'generation': 2, 'height': 0, 'width_key': 'w'}}, 'total': 0}Failed
minimum clamp{'heights': {'a': 3, 'b': 12}, 'offsets': {'a': 0, 'b': 3}, 'remeasure': ['b'], 'retained': {'a': {'generation': 2, 'height': 1, 'width_key': 'w'}}, 'total': 20}{'heights': {'a': 3, 'b': 12}, 'offsets': {'a': 0, 'b': 3}, 'remeasure': ['b'], 'retained': {'a': {'generation': 2, 'height': 1, 'width_key': 'w'}}, 'total': 15}Failed
empty{'heights': {}, 'offsets': {}, 'remeasure': [], 'retained': {}, 'total': 0}{'heights': {}, 'offsets': {}, 'remeasure': [], 'retained': {}, 'total': 0}Passed

SHA-256 / 41fcf4ec66bca5bbc90627303e088fa3cdbef836c7af432cb82d365335ba6f6c

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.

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Verification & scope

Row IDs are unique; estimates and minimum/detail heights are nonnegative; width fingerprints are scalar. Deterministic offline table UI model; no browser, DOM, framework, or standards conformance is claimed. 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 2026-09-29T14:43:02.155506+00:00.

Case digest / 8f4a8ad2f12da705f8a8117407c613e0717254f930ce7b5b1ac942b48af2ac7e