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FA-39426 / Tree accessibility / Open access

Tree indentation disclosure hit region: Embedded control hit uses wrong coordinate or boundary · case 01

Embedded control hit uses wrong coordinate or boundary produces the wrong hierarchical widget state in a regression fixture.

Verified by executionVariant 1 · 13 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The tree-hit-zone contract is violated at `left<=logical<right` by replacing it with `left<logical<=right`.

THE FAILURE

The tree-hit-zone contract is violated at `left<=logical<right` by replacing it with `left<logical<=right`.

Unsuccessful approach: The partial repair `left<=local<right` still violates a boundary or preservation case.

Case contract

Hit testing is in logical row coordinates after horizontal scrolling. Disclosure zone occupies one indent unit at the row depth; row text starts after it. Leaves have no disclosure action. RTL reflects the physical x coordinate. Drag handles and editable fields take priority over row selection.

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):
    local=d['width']-d['x'] if d['rtl'] else d['x']
    logical=local+d['scroll']
    start=d['depth']*d['indent']
    end=start+d['indent']
    inside=0<=d['x']<d['width'] and 0<=d['y']<d['height']
    disclosure=start<=logical<end and d['branch']
    text=logical>=end
    control=next((name for name,left,right in d['controls'] if left<logical<=right),None)
    action=('control:'+control) if control is not None else ('toggle' if disclosure else ('select' if text else 'none'))
    action=action if inside and not d['disabled'] else 'none'
    return [action,logical,start,end]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = {1: [('disclosure start', {'width': 130, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('text boundary', {'width': 130, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['select', 30, 20, 30]), ('leaf disclosure', {'width': 130, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 20, 20, 30]), ('leaf indent', {'width': 130, 'x': 25, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 25, 20, 30]), ('scrolled control', {'width': 130, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('RTL', {'width': 130, 'x': 110, 'y': 3, 'rtl': True, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('scrolled', {'width': 130, 'x': 10, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('control overlay', {'width': 130, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 20, 30]], 'disabled': False}, ['control:edit', 20, 20, 30]), ('control start', {'width': 130, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('right edge', {'width': 130, 'x': 130, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 130, 20, 30]), ('bottom edge', {'width': 130, 'x': 40, 'y': 20, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('above row', {'width': 130, 'x': 40, 'y': -1, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('disabled', {'width': 130, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': True}, ['none', 20, 20, 30])], 2: [('disclosure start', {'width': 140, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('text boundary', {'width': 140, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['select', 30, 20, 30]), ('leaf disclosure', {'width': 140, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 20, 20, 30]), ('leaf indent', {'width': 140, 'x': 25, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 25, 20, 30]), ('scrolled control', {'width': 140, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('RTL', {'width': 140, 'x': 120, 'y': 3, 'rtl': True, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('scrolled', {'width': 140, 'x': 10, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('control overlay', {'width': 140, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 20, 30]], 'disabled': False}, ['control:edit', 20, 20, 30]), ('control start', {'width': 140, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('right edge', {'width': 140, 'x': 140, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 140, 20, 30]), ('bottom edge', {'width': 140, 'x': 40, 'y': 20, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('above row', {'width': 140, 'x': 40, 'y': -1, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('disabled', {'width': 140, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': True}, ['none', 20, 20, 30])], 3: [('disclosure start', {'width': 150, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('text boundary', {'width': 150, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['select', 30, 20, 30]), ('leaf disclosure', {'width': 150, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 20, 20, 30]), ('leaf indent', {'width': 150, 'x': 25, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 25, 20, 30]), ('scrolled control', {'width': 150, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('RTL', {'width': 150, 'x': 130, 'y': 3, 'rtl': True, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('scrolled', {'width': 150, 'x': 10, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('control overlay', {'width': 150, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 20, 30]], 'disabled': False}, ['control:edit', 20, 20, 30]), ('control start', {'width': 150, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('right edge', {'width': 150, 'x': 150, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 150, 20, 30]), ('bottom edge', {'width': 150, 'x': 40, 'y': 20, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('above row', {'width': 150, 'x': 40, 'y': -1, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('disabled', {'width': 150, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': True}, ['none', 20, 20, 30])], 4: [('disclosure start', {'width': 160, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('text boundary', {'width': 160, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['select', 30, 20, 30]), ('leaf disclosure', {'width': 160, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 20, 20, 30]), ('leaf indent', {'width': 160, 'x': 25, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 25, 20, 30]), ('scrolled control', {'width': 160, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('RTL', {'width': 160, 'x': 140, 'y': 3, 'rtl': True, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('scrolled', {'width': 160, 'x': 10, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('control overlay', {'width': 160, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 20, 30]], 'disabled': False}, ['control:edit', 20, 20, 30]), ('control start', {'width': 160, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('right edge', {'width': 160, 'x': 160, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 160, 20, 30]), ('bottom edge', {'width': 160, 'x': 40, 'y': 20, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('above row', {'width': 160, 'x': 40, 'y': -1, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('disabled', {'width': 160, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': True}, ['none', 20, 20, 30])], 5: [('disclosure start', {'width': 170, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('text boundary', {'width': 170, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['select', 30, 20, 30]), ('leaf disclosure', {'width': 170, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 20, 20, 30]), ('leaf indent', {'width': 170, 'x': 25, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 25, 20, 30]), ('scrolled control', {'width': 170, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('RTL', {'width': 170, 'x': 150, 'y': 3, 'rtl': True, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('scrolled', {'width': 170, 'x': 10, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('control overlay', {'width': 170, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 20, 30]], 'disabled': False}, ['control:edit', 20, 20, 30]), ('control start', {'width': 170, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('right edge', {'width': 170, 'x': 170, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 170, 20, 30]), ('bottom edge', {'width': 170, 'x': 40, 'y': 20, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('above row', {'width': 170, 'x': 40, 'y': -1, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('disabled', {'width': 170, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': True}, ['none', 20, 20, 30])]}
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
disclosure start['toggle', 20, 20, 30]['toggle', 20, 20, 30]Passed
text boundary['select', 30, 20, 30]['select', 30, 20, 30]Passed
leaf disclosure['none', 20, 20, 30]['none', 20, 20, 30]Passed
leaf indent['none', 25, 20, 30]['none', 25, 20, 30]Passed
scrolled control['select', 30, 20, 30]['control:edit', 30, 20, 30]Failed
RTL['toggle', 20, 20, 30]['toggle', 20, 20, 30]Passed
scrolled['toggle', 20, 20, 30]['toggle', 20, 20, 30]Passed
control overlay['toggle', 20, 20, 30]['control:edit', 20, 20, 30]Failed
control start['select', 30, 20, 30]['control:edit', 30, 20, 30]Failed
right edge['none', 130, 20, 30]['none', 130, 20, 30]Passed
bottom edge['none', 40, 20, 30]['none', 40, 20, 30]Passed
above row['none', 40, 20, 30]['none', 40, 20, 30]Passed
disabled['none', 20, 20, 30]['none', 20, 20, 30]Passed

SHA-256 / fd2524830b97f96b4f249150af12e79ecdb6cde4535407a7c4855efe48a889df

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(d):
    local=d['width']-d['x'] if d['rtl'] else d['x']
    logical=local+d['scroll']
    start=d['depth']*d['indent']
    end=start+d['indent']
    inside=0<=d['x']<d['width'] and 0<=d['y']<d['height']
    disclosure=start<=logical<end and d['branch']
    text=logical>=end
    control=next((name for name,left,right in d['controls'] if left<=local<right),None)
    action=('control:'+control) if control is not None else ('toggle' if disclosure else ('select' if text else 'none'))
    action=action if inside and not d['disabled'] else 'none'
    return [action,logical,start,end]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = {1: [('disclosure start', {'width': 130, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('text boundary', {'width': 130, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['select', 30, 20, 30]), ('leaf disclosure', {'width': 130, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 20, 20, 30]), ('leaf indent', {'width': 130, 'x': 25, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 25, 20, 30]), ('scrolled control', {'width': 130, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('RTL', {'width': 130, 'x': 110, 'y': 3, 'rtl': True, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('scrolled', {'width': 130, 'x': 10, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('control overlay', {'width': 130, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 20, 30]], 'disabled': False}, ['control:edit', 20, 20, 30]), ('control start', {'width': 130, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('right edge', {'width': 130, 'x': 130, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 130, 20, 30]), ('bottom edge', {'width': 130, 'x': 40, 'y': 20, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('above row', {'width': 130, 'x': 40, 'y': -1, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('disabled', {'width': 130, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': True}, ['none', 20, 20, 30])], 2: [('disclosure start', {'width': 140, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('text boundary', {'width': 140, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['select', 30, 20, 30]), ('leaf disclosure', {'width': 140, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 20, 20, 30]), ('leaf indent', {'width': 140, 'x': 25, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 25, 20, 30]), ('scrolled control', {'width': 140, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('RTL', {'width': 140, 'x': 120, 'y': 3, 'rtl': True, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('scrolled', {'width': 140, 'x': 10, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('control overlay', {'width': 140, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 20, 30]], 'disabled': False}, ['control:edit', 20, 20, 30]), ('control start', {'width': 140, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('right edge', {'width': 140, 'x': 140, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 140, 20, 30]), ('bottom edge', {'width': 140, 'x': 40, 'y': 20, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('above row', {'width': 140, 'x': 40, 'y': -1, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('disabled', {'width': 140, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': True}, ['none', 20, 20, 30])], 3: [('disclosure start', {'width': 150, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('text boundary', {'width': 150, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['select', 30, 20, 30]), ('leaf disclosure', {'width': 150, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 20, 20, 30]), ('leaf indent', {'width': 150, 'x': 25, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 25, 20, 30]), ('scrolled control', {'width': 150, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('RTL', {'width': 150, 'x': 130, 'y': 3, 'rtl': True, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('scrolled', {'width': 150, 'x': 10, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('control overlay', {'width': 150, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 20, 30]], 'disabled': False}, ['control:edit', 20, 20, 30]), ('control start', {'width': 150, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('right edge', {'width': 150, 'x': 150, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 150, 20, 30]), ('bottom edge', {'width': 150, 'x': 40, 'y': 20, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('above row', {'width': 150, 'x': 40, 'y': -1, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('disabled', {'width': 150, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': True}, ['none', 20, 20, 30])], 4: [('disclosure start', {'width': 160, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('text boundary', {'width': 160, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['select', 30, 20, 30]), ('leaf disclosure', {'width': 160, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 20, 20, 30]), ('leaf indent', {'width': 160, 'x': 25, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 25, 20, 30]), ('scrolled control', {'width': 160, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('RTL', {'width': 160, 'x': 140, 'y': 3, 'rtl': True, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('scrolled', {'width': 160, 'x': 10, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('control overlay', {'width': 160, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 20, 30]], 'disabled': False}, ['control:edit', 20, 20, 30]), ('control start', {'width': 160, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('right edge', {'width': 160, 'x': 160, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 160, 20, 30]), ('bottom edge', {'width': 160, 'x': 40, 'y': 20, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('above row', {'width': 160, 'x': 40, 'y': -1, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('disabled', {'width': 160, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': True}, ['none', 20, 20, 30])], 5: [('disclosure start', {'width': 170, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('text boundary', {'width': 170, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['select', 30, 20, 30]), ('leaf disclosure', {'width': 170, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 20, 20, 30]), ('leaf indent', {'width': 170, 'x': 25, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': False, 'controls': [], 'disabled': False}, ['none', 25, 20, 30]), ('scrolled control', {'width': 170, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('RTL', {'width': 170, 'x': 150, 'y': 3, 'rtl': True, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('scrolled', {'width': 170, 'x': 10, 'y': 3, 'rtl': False, 'scroll': 10, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['toggle', 20, 20, 30]), ('control overlay', {'width': 170, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 20, 30]], 'disabled': False}, ['control:edit', 20, 20, 30]), ('control start', {'width': 170, 'x': 30, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [['edit', 30, 40]], 'disabled': False}, ['control:edit', 30, 20, 30]), ('right edge', {'width': 170, 'x': 170, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 170, 20, 30]), ('bottom edge', {'width': 170, 'x': 40, 'y': 20, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('above row', {'width': 170, 'x': 40, 'y': -1, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': False}, ['none', 40, 20, 30]), ('disabled', {'width': 170, 'x': 20, 'y': 3, 'rtl': False, 'scroll': 0, 'depth': 2, 'indent': 10, 'height': 20, 'branch': True, 'controls': [], 'disabled': True}, ['none', 20, 20, 30])]}
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
disclosure start['toggle', 20, 20, 30]['toggle', 20, 20, 30]Passed
text boundary['select', 30, 20, 30]['select', 30, 20, 30]Passed
leaf disclosure['none', 20, 20, 30]['none', 20, 20, 30]Passed
leaf indent['none', 25, 20, 30]['none', 25, 20, 30]Passed
scrolled control['select', 30, 20, 30]['control:edit', 30, 20, 30]Failed
RTL['toggle', 20, 20, 30]['toggle', 20, 20, 30]Passed
scrolled['toggle', 20, 20, 30]['toggle', 20, 20, 30]Passed
control overlay['control:edit', 20, 20, 30]['control:edit', 20, 20, 30]Passed
control start['control:edit', 30, 20, 30]['control:edit', 30, 20, 30]Passed
right edge['none', 130, 20, 30]['none', 130, 20, 30]Passed
bottom edge['none', 40, 20, 30]['none', 40, 20, 30]Passed
above row['none', 40, 20, 30]['none', 40, 20, 30]Passed
disabled['none', 20, 20, 30]['none', 20, 20, 30]Passed

SHA-256 / e56c6ad3af5df492b91dd22770d51e02b1d76d1260da187fd424a5b357a7fbc1

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

This mechanism has 13 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.

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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 2026-09-29T14:43:21.183934+00:00.

Case digest / 6b10bc442848602181324fda1d1adb6952dcbd0435f41bd30435203574e64f76