FA-38726 / Tree accessibility / Open access

Tree drop accessibility descriptor: Drop insertion position mixes child and sibling coordinates · case 01

Drop insertion position mixes child and sibling coordinates produces the wrong hierarchical widget state in a regression fixture.

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ROOT CAUSE

The drag-descriptor contract is violated at `d['child_count']+1 if inside else d['target_index']+1+(d['placement']=='after')` by replacing it with `d['target_index']+1`.

THE FAILURE

The drag-descriptor contract is violated at `d['child_count']+1 if inside else d['target_index']+1+(d['placement']=='after')` by replacing it with `d['target_index']+1`.

Unsuccessful approach: The partial repair `d['child_count'] if inside else d['target_index']+1` still violates a boundary or preservation case.

Case contract

A drag advertises one legal drop location at a time. Inside requires a writable branch; before/after require a parent and same sibling partition. Self and descendant targets are forbidden. Copy needs copy permission. Descriptor includes announced hierarchy level and one-based insertion position.

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):
    selfdrop=d['target'] in d['closure']
    inside=d['placement']=='inside'
    parent=d['target'] if inside else d['parent']
    structural=(d['branch'] if inside else parent is not None)
    partition=inside or d['source_partition']==d['target_partition']
    permission=d['writable'] and (d['copy_allowed'] if d['effect']=='copy' else d['move_allowed'])
    allowed=not selfdrop and structural and partition and permission
    position=d['target_index']+1
    level=d['target_level']+1 if inside else d['target_level']
    effect=d['effect'] if allowed else 'none'
    return [allowed,parent,position,level,effect]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = {1: [('copy inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [True, 't', 5, 3, 'copy']), ('after sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [True, 'p', 3, 2, 'copy']), ('before sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [True, 'p', 2, 2, 'copy']), ('descendant', {'target': 'c', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [False, 'c', 5, 3, 'none']), ('leaf inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [False, 't', 5, 3, 'none']), ('leaf sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [True, 'p', 3, 2, 'copy']), ('root sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': None, 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [False, None, 2, 2, 'none']), ('forbidden copy', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': False, 'move_allowed': True, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [False, 't', 5, 3, 'none']), ('move denied', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'move', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [False, 't', 5, 3, 'none']), ('partition mismatch', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [False, 'p', 3, 2, 'none'])], 2: [('copy inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [True, 't', 6, 4, 'copy']), ('after sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [True, 'p', 4, 3, 'copy']), ('before sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [True, 'p', 3, 3, 'copy']), ('descendant', {'target': 'c', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [False, 'c', 6, 4, 'none']), ('leaf inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [False, 't', 6, 4, 'none']), ('leaf sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [True, 'p', 4, 3, 'copy']), ('root sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': None, 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [False, None, 3, 3, 'none']), ('forbidden copy', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': False, 'move_allowed': True, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [False, 't', 6, 4, 'none']), ('move denied', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'move', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [False, 't', 6, 4, 'none']), ('partition mismatch', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [False, 'p', 4, 3, 'none'])], 3: [('copy inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [True, 't', 7, 5, 'copy']), ('after sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [True, 'p', 5, 4, 'copy']), ('before sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [True, 'p', 4, 4, 'copy']), ('descendant', {'target': 'c', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [False, 'c', 7, 5, 'none']), ('leaf inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [False, 't', 7, 5, 'none']), ('leaf sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [True, 'p', 5, 4, 'copy']), ('root sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': None, 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [False, None, 4, 4, 'none']), ('forbidden copy', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': False, 'move_allowed': True, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [False, 't', 7, 5, 'none']), ('move denied', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'move', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [False, 't', 7, 5, 'none']), ('partition mismatch', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [False, 'p', 5, 4, 'none'])], 4: [('copy inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [True, 't', 8, 6, 'copy']), ('after sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [True, 'p', 6, 5, 'copy']), ('before sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [True, 'p', 5, 5, 'copy']), ('descendant', {'target': 'c', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [False, 'c', 8, 6, 'none']), ('leaf inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [False, 't', 8, 6, 'none']), ('leaf sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [True, 'p', 6, 5, 'copy']), ('root sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': None, 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [False, None, 5, 5, 'none']), ('forbidden copy', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': False, 'move_allowed': True, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [False, 't', 8, 6, 'none']), ('move denied', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'move', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [False, 't', 8, 6, 'none']), ('partition mismatch', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [False, 'p', 6, 5, 'none'])], 5: [('copy inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [True, 't', 9, 7, 'copy']), ('after sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [True, 'p', 7, 6, 'copy']), ('before sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [True, 'p', 6, 6, 'copy']), ('descendant', {'target': 'c', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [False, 'c', 9, 7, 'none']), ('leaf inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [False, 't', 9, 7, 'none']), ('leaf sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [True, 'p', 7, 6, 'copy']), ('root sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': None, 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [False, None, 6, 6, 'none']), ('forbidden copy', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': False, 'move_allowed': True, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [False, 't', 9, 7, 'none']), ('move denied', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'move', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [False, 't', 9, 7, 'none']), ('partition mismatch', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [False, 'p', 7, 6, '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 fixture	Actual	Expected	Outcome
copy inside	`[True, 't', 2, 3, 'copy']`	`[True, 't', 5, 3, 'copy']`	Failed
after sibling	`[True, 'p', 2, 2, 'copy']`	`[True, 'p', 3, 2, 'copy']`	Failed
before sibling	`[True, 'p', 2, 2, 'copy']`	`[True, 'p', 2, 2, 'copy']`	Passed
descendant	`[False, 'c', 2, 3, 'none']`	`[False, 'c', 5, 3, 'none']`	Failed
leaf inside	`[False, 't', 2, 3, 'none']`	`[False, 't', 5, 3, 'none']`	Failed
leaf sibling	`[True, 'p', 2, 2, 'copy']`	`[True, 'p', 3, 2, 'copy']`	Failed
root sibling	`[False, None, 2, 2, 'none']`	`[False, None, 2, 2, 'none']`	Passed
forbidden copy	`[False, 't', 2, 3, 'none']`	`[False, 't', 5, 3, 'none']`	Failed
move denied	`[False, 't', 2, 3, 'none']`	`[False, 't', 5, 3, 'none']`	Failed
partition mismatch	`[False, 'p', 2, 2, 'none']`	`[False, 'p', 3, 2, 'none']`	Failed

SHA-256 / 6c7d287ac7b0464cae64d4554c9daccce63ebd870413ad654bd5d68e6debaae3

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(d):
    selfdrop=d['target'] in d['closure']
    inside=d['placement']=='inside'
    parent=d['target'] if inside else d['parent']
    structural=(d['branch'] if inside else parent is not None)
    partition=inside or d['source_partition']==d['target_partition']
    permission=d['writable'] and (d['copy_allowed'] if d['effect']=='copy' else d['move_allowed'])
    allowed=not selfdrop and structural and partition and permission
    position=d['child_count'] if inside else d['target_index']+1
    level=d['target_level']+1 if inside else d['target_level']
    effect=d['effect'] if allowed else 'none'
    return [allowed,parent,position,level,effect]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = {1: [('copy inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [True, 't', 5, 3, 'copy']), ('after sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [True, 'p', 3, 2, 'copy']), ('before sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [True, 'p', 2, 2, 'copy']), ('descendant', {'target': 'c', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [False, 'c', 5, 3, 'none']), ('leaf inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [False, 't', 5, 3, 'none']), ('leaf sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [True, 'p', 3, 2, 'copy']), ('root sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': None, 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [False, None, 2, 2, 'none']), ('forbidden copy', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': False, 'move_allowed': True, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [False, 't', 5, 3, 'none']), ('move denied', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'move', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [False, 't', 5, 3, 'none']), ('partition mismatch', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 4, 'target_index': 1, 'target_level': 2}, [False, 'p', 3, 2, 'none'])], 2: [('copy inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [True, 't', 6, 4, 'copy']), ('after sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [True, 'p', 4, 3, 'copy']), ('before sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [True, 'p', 3, 3, 'copy']), ('descendant', {'target': 'c', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [False, 'c', 6, 4, 'none']), ('leaf inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [False, 't', 6, 4, 'none']), ('leaf sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [True, 'p', 4, 3, 'copy']), ('root sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': None, 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [False, None, 3, 3, 'none']), ('forbidden copy', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': False, 'move_allowed': True, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [False, 't', 6, 4, 'none']), ('move denied', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'move', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [False, 't', 6, 4, 'none']), ('partition mismatch', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 5, 'target_index': 2, 'target_level': 3}, [False, 'p', 4, 3, 'none'])], 3: [('copy inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [True, 't', 7, 5, 'copy']), ('after sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [True, 'p', 5, 4, 'copy']), ('before sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [True, 'p', 4, 4, 'copy']), ('descendant', {'target': 'c', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [False, 'c', 7, 5, 'none']), ('leaf inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [False, 't', 7, 5, 'none']), ('leaf sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [True, 'p', 5, 4, 'copy']), ('root sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': None, 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [False, None, 4, 4, 'none']), ('forbidden copy', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': False, 'move_allowed': True, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [False, 't', 7, 5, 'none']), ('move denied', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'move', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [False, 't', 7, 5, 'none']), ('partition mismatch', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 6, 'target_index': 3, 'target_level': 4}, [False, 'p', 5, 4, 'none'])], 4: [('copy inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [True, 't', 8, 6, 'copy']), ('after sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [True, 'p', 6, 5, 'copy']), ('before sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [True, 'p', 5, 5, 'copy']), ('descendant', {'target': 'c', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [False, 'c', 8, 6, 'none']), ('leaf inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [False, 't', 8, 6, 'none']), ('leaf sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [True, 'p', 6, 5, 'copy']), ('root sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': None, 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [False, None, 5, 5, 'none']), ('forbidden copy', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': False, 'move_allowed': True, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [False, 't', 8, 6, 'none']), ('move denied', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'move', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [False, 't', 8, 6, 'none']), ('partition mismatch', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 7, 'target_index': 4, 'target_level': 5}, [False, 'p', 6, 5, 'none'])], 5: [('copy inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [True, 't', 9, 7, 'copy']), ('after sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [True, 'p', 7, 6, 'copy']), ('before sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [True, 'p', 6, 6, 'copy']), ('descendant', {'target': 'c', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [False, 'c', 9, 7, 'none']), ('leaf inside', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [False, 't', 9, 7, 'none']), ('leaf sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': False, 'source_partition': 'A', 'target_partition': 'A', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [True, 'p', 7, 6, 'copy']), ('root sibling', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'before', 'parent': None, 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [False, None, 6, 6, 'none']), ('forbidden copy', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': False, 'move_allowed': True, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [False, 't', 9, 7, 'none']), ('move denied', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'inside', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'move', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [False, 't', 9, 7, 'none']), ('partition mismatch', {'target': 't', 'source': 's', 'closure': ['s', 'c'], 'placement': 'after', 'parent': 'p', 'branch': True, 'source_partition': 'A', 'target_partition': 'B', 'writable': True, 'copy_allowed': True, 'move_allowed': False, 'effect': 'copy', 'child_count': 8, 'target_index': 5, 'target_level': 6}, [False, 'p', 7, 6, '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 fixture	Actual	Expected	Outcome
copy inside	`[True, 't', 4, 3, 'copy']`	`[True, 't', 5, 3, 'copy']`	Failed
after sibling	`[True, 'p', 2, 2, 'copy']`	`[True, 'p', 3, 2, 'copy']`	Failed
before sibling	`[True, 'p', 2, 2, 'copy']`	`[True, 'p', 2, 2, 'copy']`	Passed
descendant	`[False, 'c', 4, 3, 'none']`	`[False, 'c', 5, 3, 'none']`	Failed
leaf inside	`[False, 't', 4, 3, 'none']`	`[False, 't', 5, 3, 'none']`	Failed
leaf sibling	`[True, 'p', 2, 2, 'copy']`	`[True, 'p', 3, 2, 'copy']`	Failed
root sibling	`[False, None, 2, 2, 'none']`	`[False, None, 2, 2, 'none']`	Passed
forbidden copy	`[False, 't', 4, 3, 'none']`	`[False, 't', 5, 3, 'none']`	Failed
move denied	`[False, 't', 4, 3, 'none']`	`[False, 't', 5, 3, 'none']`	Failed
partition mismatch	`[False, 'p', 2, 2, 'none']`	`[False, 'p', 3, 2, 'none']`	Failed

SHA-256 / 7a47fe4c0ddb83ce5fddf20a58271134b35d225bfdab6e949f653ab8196565b7

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 10 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

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 2026-09-29T14:43:14.233332+00:00.

Case digest / 9764e2541bb511dbd9f327f89692804e2865395f30b53d43ad204e3c08c6359e