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FA-38606 / Tree accessibility / Open access

Subtree deletion state cleanup: Removed subtree requests are not cancelled selectively · case 01

Removed subtree requests are not cancelled selectively produces the wrong hierarchical widget state in a regression fixture.

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

ROOT CAUSE

The delete-subtree contract is violated at `pending={x:v for x,v in d['pending'].items() if x not in removed}` by replacing it with `pending=d['pending']`.

THE FAILURE

The delete-subtree contract is violated at `pending={x:v for x,v in d['pending'].items() if x not in removed}` by replacing it with `pending=d['pending']`.

Unsuccessful approach: The partial repair `pending={}` still violates a boundary or preservation case.

Case contract

Remove a supplied subtree closure atomically. Focus inside the deleted subtree recovers to surviving next sibling, previous sibling, then parent, then first root. Preserve unrelated state; clear only removed anchor, edits, expansion, selection and pending loads.

Why this case matters

Offline executable model of a hierarchical accessibility interaction; inputs are bounded and valid as stipulated. No browser, assistive technology, or normative ARIA conformance is claimed.

1 / The failure

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

N = 1
observations = []
def solve(d):
    removed=set(d['removed'])
    rows=[x for x in d['rows'] if x not in removed]
    selected=[x for x in d['selected'] if x not in removed]
    expanded=[x for x in d['expanded'] if x not in removed]
    pending=d['pending']
    nextrow=next((x for x in d['next'] if x in rows),None)
    prevrow=next((x for x in reversed(d['previous']) if x in rows),None)
    fallback=next((x for x in [nextrow,prevrow,d['parent']]+d['roots'] if x in rows),None)
    focus=fallback if d['focus'] in removed else d['focus']
    anchor=None if d['anchor'] in removed else d['anchor']
    edit=None if d['edit'] in removed else d['edit']
    return [rows,selected,expanded,pending,focus,anchor,edit]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = {1: [('next recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'z', None, None]), ('previous recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'x', None, None]), ('parent recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['a'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'r', None, None]), ('unrelated focus', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'a', 'anchor': 'a', 'edit': 'a'}, [['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'a', 'a', 'a']), ('last root', {'removed': ['b', 'c'], 'rows': ['b', 'c'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [[], ['a'], ['r'], {'a': 1}, None, None, None]), ('stale neighbors', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c'], 'previous': ['a', 'c', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'x', None, None])], 2: [('next recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0', 'q1'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1'], ['a'], ['r'], {'a': 1}, 'z', None, None]), ('previous recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1'], ['a'], ['r'], {'a': 1}, 'x', None, None]), ('parent recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['a'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1'], ['a'], ['r'], {'a': 1}, 'r', None, None]), ('unrelated focus', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0', 'q1'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'a', 'anchor': 'a', 'edit': 'a'}, [['r', 'a', 'x', 'z', 'q0', 'q1'], ['a'], ['r'], {'a': 1}, 'a', 'a', 'a']), ('last root', {'removed': ['b', 'c'], 'rows': ['b', 'c'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [[], ['a'], ['r'], {'a': 1}, None, None, None]), ('stale neighbors', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c'], 'previous': ['a', 'c', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1'], ['a'], ['r'], {'a': 1}, 'x', None, None])], 3: [('next recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0', 'q1', 'q2'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2'], ['a'], ['r'], {'a': 1}, 'z', None, None]), ('previous recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2'], ['a'], ['r'], {'a': 1}, 'x', None, None]), ('parent recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['a'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2'], ['a'], ['r'], {'a': 1}, 'r', None, None]), ('unrelated focus', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0', 'q1', 'q2'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'a', 'anchor': 'a', 'edit': 'a'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2'], ['a'], ['r'], {'a': 1}, 'a', 'a', 'a']), ('last root', {'removed': ['b', 'c'], 'rows': ['b', 'c'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [[], ['a'], ['r'], {'a': 1}, None, None, None]), ('stale neighbors', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c'], 'previous': ['a', 'c', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2'], ['a'], ['r'], {'a': 1}, 'x', None, None])], 4: [('next recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0', 'q1', 'q2', 'q3'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3'], ['a'], ['r'], {'a': 1}, 'z', None, None]), ('previous recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3'], ['a'], ['r'], {'a': 1}, 'x', None, None]), ('parent recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['a'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3'], ['a'], ['r'], {'a': 1}, 'r', None, None]), ('unrelated focus', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0', 'q1', 'q2', 'q3'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'a', 'anchor': 'a', 'edit': 'a'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3'], ['a'], ['r'], {'a': 1}, 'a', 'a', 'a']), ('last root', {'removed': ['b', 'c'], 'rows': ['b', 'c'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [[], ['a'], ['r'], {'a': 1}, None, None, None]), ('stale neighbors', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c'], 'previous': ['a', 'c', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3'], ['a'], ['r'], {'a': 1}, 'x', None, None])], 5: [('next recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], ['a'], ['r'], {'a': 1}, 'z', None, None]), ('previous recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], ['a'], ['r'], {'a': 1}, 'x', None, None]), ('parent recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['a'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], ['a'], ['r'], {'a': 1}, 'r', None, None]), ('unrelated focus', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'a', 'anchor': 'a', 'edit': 'a'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], ['a'], ['r'], {'a': 1}, 'a', 'a', 'a']), ('last root', {'removed': ['b', 'c'], 'rows': ['b', 'c'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [[], ['a'], ['r'], {'a': 1}, None, None, None]), ('stale neighbors', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c'], 'previous': ['a', 'c', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], ['a'], ['r'], {'a': 1}, 'x', None, None])]}
for label, data, expected in cases[N]:
    check(label, solve(data), 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
next recovery[['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1, 'c': 2}, 'z', None, None][['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'z', None, None]Failed
previous recovery[['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1, 'c': 2}, 'x', None, None][['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'x', None, None]Failed
parent recovery[['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1, 'c': 2}, 'r', None, None][['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'r', None, None]Failed
unrelated focus[['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1, 'c': 2}, 'a', 'a', 'a'][['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'a', 'a', 'a']Failed
last root[[], ['a'], ['r'], {'a': 1, 'c': 2}, None, None, None][[], ['a'], ['r'], {'a': 1}, None, None, None]Failed
stale neighbors[['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1, 'c': 2}, 'x', None, None][['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'x', None, None]Failed

SHA-256 / 30c806a1b38765d8ebe2e074dee244782c823e19cfee65a4d7279201bc41f7d8

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(d):
    removed=set(d['removed'])
    rows=[x for x in d['rows'] if x not in removed]
    selected=[x for x in d['selected'] if x not in removed]
    expanded=[x for x in d['expanded'] if x not in removed]
    pending={}
    nextrow=next((x for x in d['next'] if x in rows),None)
    prevrow=next((x for x in reversed(d['previous']) if x in rows),None)
    fallback=next((x for x in [nextrow,prevrow,d['parent']]+d['roots'] if x in rows),None)
    focus=fallback if d['focus'] in removed else d['focus']
    anchor=None if d['anchor'] in removed else d['anchor']
    edit=None if d['edit'] in removed else d['edit']
    return [rows,selected,expanded,pending,focus,anchor,edit]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = {1: [('next recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'z', None, None]), ('previous recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'x', None, None]), ('parent recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['a'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'r', None, None]), ('unrelated focus', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'a', 'anchor': 'a', 'edit': 'a'}, [['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'a', 'a', 'a']), ('last root', {'removed': ['b', 'c'], 'rows': ['b', 'c'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [[], ['a'], ['r'], {'a': 1}, None, None, None]), ('stale neighbors', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c'], 'previous': ['a', 'c', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'x', None, None])], 2: [('next recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0', 'q1'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1'], ['a'], ['r'], {'a': 1}, 'z', None, None]), ('previous recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1'], ['a'], ['r'], {'a': 1}, 'x', None, None]), ('parent recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['a'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1'], ['a'], ['r'], {'a': 1}, 'r', None, None]), ('unrelated focus', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0', 'q1'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'a', 'anchor': 'a', 'edit': 'a'}, [['r', 'a', 'x', 'z', 'q0', 'q1'], ['a'], ['r'], {'a': 1}, 'a', 'a', 'a']), ('last root', {'removed': ['b', 'c'], 'rows': ['b', 'c'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [[], ['a'], ['r'], {'a': 1}, None, None, None]), ('stale neighbors', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c'], 'previous': ['a', 'c', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1'], ['a'], ['r'], {'a': 1}, 'x', None, None])], 3: [('next recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0', 'q1', 'q2'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2'], ['a'], ['r'], {'a': 1}, 'z', None, None]), ('previous recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2'], ['a'], ['r'], {'a': 1}, 'x', None, None]), ('parent recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['a'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2'], ['a'], ['r'], {'a': 1}, 'r', None, None]), ('unrelated focus', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0', 'q1', 'q2'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'a', 'anchor': 'a', 'edit': 'a'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2'], ['a'], ['r'], {'a': 1}, 'a', 'a', 'a']), ('last root', {'removed': ['b', 'c'], 'rows': ['b', 'c'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [[], ['a'], ['r'], {'a': 1}, None, None, None]), ('stale neighbors', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c'], 'previous': ['a', 'c', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2'], ['a'], ['r'], {'a': 1}, 'x', None, None])], 4: [('next recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0', 'q1', 'q2', 'q3'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3'], ['a'], ['r'], {'a': 1}, 'z', None, None]), ('previous recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3'], ['a'], ['r'], {'a': 1}, 'x', None, None]), ('parent recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['a'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3'], ['a'], ['r'], {'a': 1}, 'r', None, None]), ('unrelated focus', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0', 'q1', 'q2', 'q3'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'a', 'anchor': 'a', 'edit': 'a'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3'], ['a'], ['r'], {'a': 1}, 'a', 'a', 'a']), ('last root', {'removed': ['b', 'c'], 'rows': ['b', 'c'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [[], ['a'], ['r'], {'a': 1}, None, None, None]), ('stale neighbors', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c'], 'previous': ['a', 'c', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3'], ['a'], ['r'], {'a': 1}, 'x', None, None])], 5: [('next recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], ['a'], ['r'], {'a': 1}, 'z', None, None]), ('previous recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], ['a'], ['r'], {'a': 1}, 'x', None, None]), ('parent recovery', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['a'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], ['a'], ['r'], {'a': 1}, 'r', None, None]), ('unrelated focus', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], 'previous': ['a', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'a', 'anchor': 'a', 'edit': 'a'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], ['a'], ['r'], {'a': 1}, 'a', 'a', 'a']), ('last root', {'removed': ['b', 'c'], 'rows': ['b', 'c'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': [], 'previous': [], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [[], ['a'], ['r'], {'a': 1}, None, None, None]), ('stale neighbors', {'removed': ['b', 'c'], 'rows': ['r', 'a', 'x', 'b', 'c', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], 'selected': ['a', 'c'], 'expanded': ['r', 'b'], 'pending': {'a': 1, 'c': 2}, 'next': ['c'], 'previous': ['a', 'c', 'x'], 'parent': 'r', 'roots': ['r'], 'focus': 'c', 'anchor': 'c', 'edit': 'c'}, [['r', 'a', 'x', 'z', 'q0', 'q1', 'q2', 'q3', 'q4'], ['a'], ['r'], {'a': 1}, 'x', None, None])]}
for label, data, expected in cases[N]:
    check(label, solve(data), 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
next recovery[['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {}, 'z', None, None][['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'z', None, None]Failed
previous recovery[['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {}, 'x', None, None][['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'x', None, None]Failed
parent recovery[['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {}, 'r', None, None][['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'r', None, None]Failed
unrelated focus[['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {}, 'a', 'a', 'a'][['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'a', 'a', 'a']Failed
last root[[], ['a'], ['r'], {}, None, None, None][[], ['a'], ['r'], {'a': 1}, None, None, None]Failed
stale neighbors[['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {}, 'x', None, None][['r', 'a', 'x', 'z', 'q0'], ['a'], ['r'], {'a': 1}, 'x', None, None]Failed

SHA-256 / 7a9bb0db25c4241526cb72d880a2993c3f25f732fa86bd835ae8a867f6844be3

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.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

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Verification & scope

Synthetic deterministic hierarchical-widget data contract; not an implementation of a browser accessibility tree. 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 2026-09-29T14:43:13.226036+00:00.

Case digest / 80d5b900f30873f53a2654698f0d2fa12c3b51735779263b495badabc4b271e5