FAILURE MAP
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FA-36971 / Table interactions / Open access

Grouped table header runs: span cardinality · case 01

The table span cardinality result violates the stipulated grouped table header runs contract.

Verified by executionVariant 1 · 6 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The span cardinality decision uses "'span':1" instead of "'span':len(r['leaves'])".

THE FAILURE

The span cardinality decision uses "'span':1" instead of "'span':len(r['leaves'])".

Unsuccessful approach: The attempted repair "'span':max(1,len(r['leaves'])-1)" still loses a required part of the table contract.

Case contract

Construct contiguous visible leaf runs keyed by exact group and pane, retaining leaf order and width sums. A missing group is a blank placeholder; an empty group string is an actual named group. Group resize handles require at least two visible leaves.

Why this case matters

An offline table UI model isolates grouped table header runs, 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(leaves, hidden, pins):
    v = [x for x in leaves if x['id'] not in hidden]
    runs=[]
    for x in v:
        pane=pins.get(x['id'], 'center')
        key=(x.get('group'),pane)
        if runs and runs[-1]['key']==key:
            runs[-1]['leaves'].append(x['id'])
            runs[-1]['width']+=x['width']
        else: runs.append({'key':key,'leaves':[x['id']],'width':x['width']})
    return [{'group':r['key'][0], 'pane':r['key'][1], 'span':1, 'width':r['width'], 'first':r['leaves'][0], 'last':r['leaves'][-1], 'leaf_ids':r['leaves'], 'blank':r['key'][0] is None, 'resizable':len(r['leaves'])>1} for r in runs]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
if N == 1:
    check('contiguous group', solve([{'id':'a','group':'G','width':2*1},{'id':'b','group':'G','width':3},{'id':'c','group':'H','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 2, 'width': 5, 'first': 'a', 'last': 'b', 'leaf_ids': ['a', 'b'], 'blank': False, 'resizable': True}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('pin splits group', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], [], {'a':'left'}), [{'group': 'G', 'pane': 'left', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 2, 'width': 7, 'first': 'b', 'last': 'c', 'leaf_ids': ['b', 'c'], 'blank': False, 'resizable': True}])
    check('hidden leaves', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], ['a','b'], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('blank versus empty', solve([{'id':'a','width':2},{'id':'b','group':'','width':3}], [], {}), [{'group': None, 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': True, 'resizable': False}, {'group': '', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}])
    check('separated groups', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'H','width':3},{'id':'c','group':'G','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('empty header', solve([], [], {}), [])

if N == 2:
    check('contiguous group', solve([{'id':'a','group':'G','width':2*2},{'id':'b','group':'G','width':3},{'id':'c','group':'H','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 2, 'width': 7, 'first': 'a', 'last': 'b', 'leaf_ids': ['a', 'b'], 'blank': False, 'resizable': True}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('pin splits group', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], [], {'a':'left'}), [{'group': 'G', 'pane': 'left', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 2, 'width': 7, 'first': 'b', 'last': 'c', 'leaf_ids': ['b', 'c'], 'blank': False, 'resizable': True}])
    check('hidden leaves', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], ['a','b'], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('blank versus empty', solve([{'id':'a','width':2},{'id':'b','group':'','width':3}], [], {}), [{'group': None, 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': True, 'resizable': False}, {'group': '', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}])
    check('separated groups', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'H','width':3},{'id':'c','group':'G','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('empty header', solve([], [], {}), [])

if N == 3:
    check('contiguous group', solve([{'id':'a','group':'G','width':2*3},{'id':'b','group':'G','width':3},{'id':'c','group':'H','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 2, 'width': 9, 'first': 'a', 'last': 'b', 'leaf_ids': ['a', 'b'], 'blank': False, 'resizable': True}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('pin splits group', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], [], {'a':'left'}), [{'group': 'G', 'pane': 'left', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 2, 'width': 7, 'first': 'b', 'last': 'c', 'leaf_ids': ['b', 'c'], 'blank': False, 'resizable': True}])
    check('hidden leaves', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], ['a','b'], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('blank versus empty', solve([{'id':'a','width':2},{'id':'b','group':'','width':3}], [], {}), [{'group': None, 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': True, 'resizable': False}, {'group': '', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}])
    check('separated groups', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'H','width':3},{'id':'c','group':'G','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('empty header', solve([], [], {}), [])

if N == 4:
    check('contiguous group', solve([{'id':'a','group':'G','width':2*4},{'id':'b','group':'G','width':3},{'id':'c','group':'H','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 2, 'width': 11, 'first': 'a', 'last': 'b', 'leaf_ids': ['a', 'b'], 'blank': False, 'resizable': True}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('pin splits group', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], [], {'a':'left'}), [{'group': 'G', 'pane': 'left', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 2, 'width': 7, 'first': 'b', 'last': 'c', 'leaf_ids': ['b', 'c'], 'blank': False, 'resizable': True}])
    check('hidden leaves', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], ['a','b'], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('blank versus empty', solve([{'id':'a','width':2},{'id':'b','group':'','width':3}], [], {}), [{'group': None, 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': True, 'resizable': False}, {'group': '', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}])
    check('separated groups', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'H','width':3},{'id':'c','group':'G','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('empty header', solve([], [], {}), [])

if N == 5:
    check('contiguous group', solve([{'id':'a','group':'G','width':2*5},{'id':'b','group':'G','width':3},{'id':'c','group':'H','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 2, 'width': 13, 'first': 'a', 'last': 'b', 'leaf_ids': ['a', 'b'], 'blank': False, 'resizable': True}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('pin splits group', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], [], {'a':'left'}), [{'group': 'G', 'pane': 'left', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 2, 'width': 7, 'first': 'b', 'last': 'c', 'leaf_ids': ['b', 'c'], 'blank': False, 'resizable': True}])
    check('hidden leaves', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], ['a','b'], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('blank versus empty', solve([{'id':'a','width':2},{'id':'b','group':'','width':3}], [], {}), [{'group': None, 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': True, 'resizable': False}, {'group': '', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}])
    check('separated groups', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'H','width':3},{'id':'c','group':'G','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('empty header', solve([], [], {}), [])

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
contiguous group[{'blank': False, 'first': 'a', 'group': 'G', 'last': 'b', 'leaf_ids': ['a', 'b'], 'pane': 'center', 'resizable': True, 'span': 1, 'width': 5}, {'blank': False, 'first': 'c', 'group': 'H', 'last': 'c', 'leaf_ids': ['c'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 4}][{'blank': False, 'first': 'a', 'group': 'G', 'last': 'b', 'leaf_ids': ['a', 'b'], 'pane': 'center', 'resizable': True, 'span': 2, 'width': 5}, {'blank': False, 'first': 'c', 'group': 'H', 'last': 'c', 'leaf_ids': ['c'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 4}]Failed
pin splits group[{'blank': False, 'first': 'a', 'group': 'G', 'last': 'a', 'leaf_ids': ['a'], 'pane': 'left', 'resizable': False, 'span': 1, 'width': 2}, {'blank': False, 'first': 'b', 'group': 'G', 'last': 'c', 'leaf_ids': ['b', 'c'], 'pane': 'center', 'resizable': True, 'span': 1, 'width': 7}][{'blank': False, 'first': 'a', 'group': 'G', 'last': 'a', 'leaf_ids': ['a'], 'pane': 'left', 'resizable': False, 'span': 1, 'width': 2}, {'blank': False, 'first': 'b', 'group': 'G', 'last': 'c', 'leaf_ids': ['b', 'c'], 'pane': 'center', 'resizable': True, 'span': 2, 'width': 7}]Failed
hidden leaves[{'blank': False, 'first': 'c', 'group': 'G', 'last': 'c', 'leaf_ids': ['c'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 4}][{'blank': False, 'first': 'c', 'group': 'G', 'last': 'c', 'leaf_ids': ['c'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 4}]Passed
blank versus empty[{'blank': True, 'first': 'a', 'group': None, 'last': 'a', 'leaf_ids': ['a'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 2}, {'blank': False, 'first': 'b', 'group': '', 'last': 'b', 'leaf_ids': ['b'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 3}][{'blank': True, 'first': 'a', 'group': None, 'last': 'a', 'leaf_ids': ['a'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 2}, {'blank': False, 'first': 'b', 'group': '', 'last': 'b', 'leaf_ids': ['b'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 3}]Passed
separated groups[{'blank': False, 'first': 'a', 'group': 'G', 'last': 'a', 'leaf_ids': ['a'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 2}, {'blank': False, 'first': 'b', 'group': 'H', 'last': 'b', 'leaf_ids': ['b'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 3}, {'blank': False, 'first': 'c', 'group': 'G', 'last': 'c', 'leaf_ids': ['c'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 4}][{'blank': False, 'first': 'a', 'group': 'G', 'last': 'a', 'leaf_ids': ['a'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 2}, {'blank': False, 'first': 'b', 'group': 'H', 'last': 'b', 'leaf_ids': ['b'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 3}, {'blank': False, 'first': 'c', 'group': 'G', 'last': 'c', 'leaf_ids': ['c'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 4}]Passed
empty header[][]Passed

SHA-256 / 87e3181b369991c77d40831de88f803cc87800b8644a0fb3da49f2394a8059e5

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(leaves, hidden, pins):
    v = [x for x in leaves if x['id'] not in hidden]
    runs=[]
    for x in v:
        pane=pins.get(x['id'], 'center')
        key=(x.get('group'),pane)
        if runs and runs[-1]['key']==key:
            runs[-1]['leaves'].append(x['id'])
            runs[-1]['width']+=x['width']
        else: runs.append({'key':key,'leaves':[x['id']],'width':x['width']})
    return [{'group':r['key'][0], 'pane':r['key'][1], 'span':max(1,len(r['leaves'])-1), 'width':r['width'], 'first':r['leaves'][0], 'last':r['leaves'][-1], 'leaf_ids':r['leaves'], 'blank':r['key'][0] is None, 'resizable':len(r['leaves'])>1} for r in runs]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
if N == 1:
    check('contiguous group', solve([{'id':'a','group':'G','width':2*1},{'id':'b','group':'G','width':3},{'id':'c','group':'H','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 2, 'width': 5, 'first': 'a', 'last': 'b', 'leaf_ids': ['a', 'b'], 'blank': False, 'resizable': True}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('pin splits group', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], [], {'a':'left'}), [{'group': 'G', 'pane': 'left', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 2, 'width': 7, 'first': 'b', 'last': 'c', 'leaf_ids': ['b', 'c'], 'blank': False, 'resizable': True}])
    check('hidden leaves', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], ['a','b'], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('blank versus empty', solve([{'id':'a','width':2},{'id':'b','group':'','width':3}], [], {}), [{'group': None, 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': True, 'resizable': False}, {'group': '', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}])
    check('separated groups', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'H','width':3},{'id':'c','group':'G','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('empty header', solve([], [], {}), [])

if N == 2:
    check('contiguous group', solve([{'id':'a','group':'G','width':2*2},{'id':'b','group':'G','width':3},{'id':'c','group':'H','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 2, 'width': 7, 'first': 'a', 'last': 'b', 'leaf_ids': ['a', 'b'], 'blank': False, 'resizable': True}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('pin splits group', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], [], {'a':'left'}), [{'group': 'G', 'pane': 'left', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 2, 'width': 7, 'first': 'b', 'last': 'c', 'leaf_ids': ['b', 'c'], 'blank': False, 'resizable': True}])
    check('hidden leaves', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], ['a','b'], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('blank versus empty', solve([{'id':'a','width':2},{'id':'b','group':'','width':3}], [], {}), [{'group': None, 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': True, 'resizable': False}, {'group': '', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}])
    check('separated groups', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'H','width':3},{'id':'c','group':'G','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('empty header', solve([], [], {}), [])

if N == 3:
    check('contiguous group', solve([{'id':'a','group':'G','width':2*3},{'id':'b','group':'G','width':3},{'id':'c','group':'H','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 2, 'width': 9, 'first': 'a', 'last': 'b', 'leaf_ids': ['a', 'b'], 'blank': False, 'resizable': True}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('pin splits group', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], [], {'a':'left'}), [{'group': 'G', 'pane': 'left', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 2, 'width': 7, 'first': 'b', 'last': 'c', 'leaf_ids': ['b', 'c'], 'blank': False, 'resizable': True}])
    check('hidden leaves', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], ['a','b'], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('blank versus empty', solve([{'id':'a','width':2},{'id':'b','group':'','width':3}], [], {}), [{'group': None, 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': True, 'resizable': False}, {'group': '', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}])
    check('separated groups', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'H','width':3},{'id':'c','group':'G','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('empty header', solve([], [], {}), [])

if N == 4:
    check('contiguous group', solve([{'id':'a','group':'G','width':2*4},{'id':'b','group':'G','width':3},{'id':'c','group':'H','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 2, 'width': 11, 'first': 'a', 'last': 'b', 'leaf_ids': ['a', 'b'], 'blank': False, 'resizable': True}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('pin splits group', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], [], {'a':'left'}), [{'group': 'G', 'pane': 'left', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 2, 'width': 7, 'first': 'b', 'last': 'c', 'leaf_ids': ['b', 'c'], 'blank': False, 'resizable': True}])
    check('hidden leaves', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], ['a','b'], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('blank versus empty', solve([{'id':'a','width':2},{'id':'b','group':'','width':3}], [], {}), [{'group': None, 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': True, 'resizable': False}, {'group': '', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}])
    check('separated groups', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'H','width':3},{'id':'c','group':'G','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('empty header', solve([], [], {}), [])

if N == 5:
    check('contiguous group', solve([{'id':'a','group':'G','width':2*5},{'id':'b','group':'G','width':3},{'id':'c','group':'H','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 2, 'width': 13, 'first': 'a', 'last': 'b', 'leaf_ids': ['a', 'b'], 'blank': False, 'resizable': True}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('pin splits group', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], [], {'a':'left'}), [{'group': 'G', 'pane': 'left', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 2, 'width': 7, 'first': 'b', 'last': 'c', 'leaf_ids': ['b', 'c'], 'blank': False, 'resizable': True}])
    check('hidden leaves', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'G','width':3},{'id':'c','group':'G','width':4}], ['a','b'], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('blank versus empty', solve([{'id':'a','width':2},{'id':'b','group':'','width':3}], [], {}), [{'group': None, 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': True, 'resizable': False}, {'group': '', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}])
    check('separated groups', solve([{'id':'a','group':'G','width':2},{'id':'b','group':'H','width':3},{'id':'c','group':'G','width':4}], [], {}), [{'group': 'G', 'pane': 'center', 'span': 1, 'width': 2, 'first': 'a', 'last': 'a', 'leaf_ids': ['a'], 'blank': False, 'resizable': False}, {'group': 'H', 'pane': 'center', 'span': 1, 'width': 3, 'first': 'b', 'last': 'b', 'leaf_ids': ['b'], 'blank': False, 'resizable': False}, {'group': 'G', 'pane': 'center', 'span': 1, 'width': 4, 'first': 'c', 'last': 'c', 'leaf_ids': ['c'], 'blank': False, 'resizable': False}])
    check('empty header', solve([], [], {}), [])

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
contiguous group[{'blank': False, 'first': 'a', 'group': 'G', 'last': 'b', 'leaf_ids': ['a', 'b'], 'pane': 'center', 'resizable': True, 'span': 1, 'width': 5}, {'blank': False, 'first': 'c', 'group': 'H', 'last': 'c', 'leaf_ids': ['c'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 4}][{'blank': False, 'first': 'a', 'group': 'G', 'last': 'b', 'leaf_ids': ['a', 'b'], 'pane': 'center', 'resizable': True, 'span': 2, 'width': 5}, {'blank': False, 'first': 'c', 'group': 'H', 'last': 'c', 'leaf_ids': ['c'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 4}]Failed
pin splits group[{'blank': False, 'first': 'a', 'group': 'G', 'last': 'a', 'leaf_ids': ['a'], 'pane': 'left', 'resizable': False, 'span': 1, 'width': 2}, {'blank': False, 'first': 'b', 'group': 'G', 'last': 'c', 'leaf_ids': ['b', 'c'], 'pane': 'center', 'resizable': True, 'span': 1, 'width': 7}][{'blank': False, 'first': 'a', 'group': 'G', 'last': 'a', 'leaf_ids': ['a'], 'pane': 'left', 'resizable': False, 'span': 1, 'width': 2}, {'blank': False, 'first': 'b', 'group': 'G', 'last': 'c', 'leaf_ids': ['b', 'c'], 'pane': 'center', 'resizable': True, 'span': 2, 'width': 7}]Failed
hidden leaves[{'blank': False, 'first': 'c', 'group': 'G', 'last': 'c', 'leaf_ids': ['c'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 4}][{'blank': False, 'first': 'c', 'group': 'G', 'last': 'c', 'leaf_ids': ['c'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 4}]Passed
blank versus empty[{'blank': True, 'first': 'a', 'group': None, 'last': 'a', 'leaf_ids': ['a'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 2}, {'blank': False, 'first': 'b', 'group': '', 'last': 'b', 'leaf_ids': ['b'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 3}][{'blank': True, 'first': 'a', 'group': None, 'last': 'a', 'leaf_ids': ['a'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 2}, {'blank': False, 'first': 'b', 'group': '', 'last': 'b', 'leaf_ids': ['b'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 3}]Passed
separated groups[{'blank': False, 'first': 'a', 'group': 'G', 'last': 'a', 'leaf_ids': ['a'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 2}, {'blank': False, 'first': 'b', 'group': 'H', 'last': 'b', 'leaf_ids': ['b'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 3}, {'blank': False, 'first': 'c', 'group': 'G', 'last': 'c', 'leaf_ids': ['c'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 4}][{'blank': False, 'first': 'a', 'group': 'G', 'last': 'a', 'leaf_ids': ['a'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 2}, {'blank': False, 'first': 'b', 'group': 'H', 'last': 'b', 'leaf_ids': ['b'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 3}, {'blank': False, 'first': 'c', 'group': 'G', 'last': 'c', 'leaf_ids': ['c'], 'pane': 'center', 'resizable': False, 'span': 1, 'width': 4}]Passed
empty header[][]Passed

SHA-256 / e716a5b1c0f98fb4ee852ba53eeea2e04839aba6e995bf11582d143f00f36fdc

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 6 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

Leaf IDs are unique, group labels are scalar, and widths are nonnegative. 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 2026-09-29T14:42:56.744112+00:00.

Case digest / 307fb71d1f1dcb5d268f3b333404a7af5c5b55ccaa6c60d538fab9e732c06cef