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FA-38936 / Tree accessibility / Open access

Paged tree children accessibility merge: Page focus skips first newly loaded child · case 01

Page focus skips first newly loaded child produces the wrong hierarchical widget state in a regression fixture.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The sibling-page contract is violated at `new[0] if new else (d['parent'] if not more else d['focus'])` by replacing it with `new[-1] if new else d['focus']`.

THE FAILURE

The sibling-page contract is violated at `new[0] if new else (d['parent'] if not more else d['focus'])` by replacing it with `new[-1] if new else d['focus']`.

Unsuccessful approach: The partial repair `d['parent']` still violates a boundary or preservation case.

Case contract

Only the expected cursor and branch revision admit a page. Repeated child IDs preserve their first position but update their record. An empty string is a valid next cursor. Logical count is authoritative when supplied; otherwise unknown. Focus on the load-more row moves to first newly inserted child, or parent if no continuation.

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):
    accept=d['cursor']==d['expected_cursor'] and d['revision']==d['expected_revision']
    order=list(dict.fromkeys(d['order']+[r[0] for r in d['page']])) if accept else d['order']
    records=dict(d['records'])
    if accept: records.update(dict(d['page']))
    new=[r[0] for r in d['page'] if r[0] not in d['order']] if accept else []
    new=list(dict.fromkeys(new))
    nextcursor=d['next'] if accept else d['expected_cursor']
    more=nextcursor is not None
    size=d['total'] if accept and d['total'] is not None else d['size']
    focus=(new[-1] if new else d['focus']) if accept and d['focus']=='more' else d['focus']
    positions={x:i+1 for i,x in enumerate(order)}
    return [order,records,new,nextcursor,more,size,focus,positions]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = {1: [('overlap page', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 1, 'expected_revision': 1, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 1], ['b', 8], ['y', 2]], 'next': None, 'total': 9, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 2, 'b': 8}, ['y', 'b'], None, False, 9, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('stale cursor', {'cursor': 'old', 'expected_cursor': 'c', 'revision': 1, 'expected_revision': 1, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 1], ['b', 8], ['y', 2]], 'next': None, 'total': 9, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('stale revision', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 0, 'expected_revision': 1, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 1], ['b', 8], ['y', 2]], 'next': None, 'total': 9, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('empty cursor', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 1, 'expected_revision': 1, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 1], ['b', 8], ['y', 2]], 'next': '', 'total': 9, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 2, 'b': 8}, ['y', 'b'], '', True, 9, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('empty terminal', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 1, 'expected_revision': 1, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': None, 'total': 0, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], None, False, 0, 'p', {'z': 1, 'a': 2}]), ('empty continued', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 1, 'expected_revision': 1, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': 'x', 'total': 9, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'x', True, 9, 'more', {'z': 1, 'a': 2}]), ('unknown total', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 1, 'expected_revision': 1, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 1], ['b', 8], ['y', 2]], 'next': None, 'total': None, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 2, 'b': 8}, ['y', 'b'], None, False, -1, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('focus elsewhere', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 1, 'expected_revision': 1, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 1], ['b', 8], ['y', 2]], 'next': None, 'total': 9, 'size': -1, 'focus': 'z', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 2, 'b': 8}, ['y', 'b'], None, False, 9, 'z', {'z': 1, 'a': 2, 'y': 3, 'b': 4}])], 2: [('overlap page', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 2, 'expected_revision': 2, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 2], ['b', 8], ['y', 3]], 'next': None, 'total': 10, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 3, 'b': 8}, ['y', 'b'], None, False, 10, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('stale cursor', {'cursor': 'old', 'expected_cursor': 'c', 'revision': 2, 'expected_revision': 2, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 2], ['b', 8], ['y', 3]], 'next': None, 'total': 10, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('stale revision', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 1, 'expected_revision': 2, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 2], ['b', 8], ['y', 3]], 'next': None, 'total': 10, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('empty cursor', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 2, 'expected_revision': 2, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 2], ['b', 8], ['y', 3]], 'next': '', 'total': 10, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 3, 'b': 8}, ['y', 'b'], '', True, 10, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('empty terminal', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 2, 'expected_revision': 2, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': None, 'total': 0, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], None, False, 0, 'p', {'z': 1, 'a': 2}]), ('empty continued', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 2, 'expected_revision': 2, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': 'x', 'total': 10, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'x', True, 10, 'more', {'z': 1, 'a': 2}]), ('unknown total', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 2, 'expected_revision': 2, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 2], ['b', 8], ['y', 3]], 'next': None, 'total': None, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 3, 'b': 8}, ['y', 'b'], None, False, -1, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('focus elsewhere', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 2, 'expected_revision': 2, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 2], ['b', 8], ['y', 3]], 'next': None, 'total': 10, 'size': -1, 'focus': 'z', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 3, 'b': 8}, ['y', 'b'], None, False, 10, 'z', {'z': 1, 'a': 2, 'y': 3, 'b': 4}])], 3: [('overlap page', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 3, 'expected_revision': 3, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 3], ['b', 8], ['y', 4]], 'next': None, 'total': 11, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 4, 'b': 8}, ['y', 'b'], None, False, 11, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('stale cursor', {'cursor': 'old', 'expected_cursor': 'c', 'revision': 3, 'expected_revision': 3, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 3], ['b', 8], ['y', 4]], 'next': None, 'total': 11, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('stale revision', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 2, 'expected_revision': 3, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 3], ['b', 8], ['y', 4]], 'next': None, 'total': 11, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('empty cursor', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 3, 'expected_revision': 3, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 3], ['b', 8], ['y', 4]], 'next': '', 'total': 11, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 4, 'b': 8}, ['y', 'b'], '', True, 11, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('empty terminal', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 3, 'expected_revision': 3, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': None, 'total': 0, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], None, False, 0, 'p', {'z': 1, 'a': 2}]), ('empty continued', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 3, 'expected_revision': 3, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': 'x', 'total': 11, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'x', True, 11, 'more', {'z': 1, 'a': 2}]), ('unknown total', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 3, 'expected_revision': 3, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 3], ['b', 8], ['y', 4]], 'next': None, 'total': None, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 4, 'b': 8}, ['y', 'b'], None, False, -1, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('focus elsewhere', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 3, 'expected_revision': 3, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 3], ['b', 8], ['y', 4]], 'next': None, 'total': 11, 'size': -1, 'focus': 'z', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 4, 'b': 8}, ['y', 'b'], None, False, 11, 'z', {'z': 1, 'a': 2, 'y': 3, 'b': 4}])], 4: [('overlap page', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 4, 'expected_revision': 4, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 4], ['b', 8], ['y', 5]], 'next': None, 'total': 12, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 5, 'b': 8}, ['y', 'b'], None, False, 12, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('stale cursor', {'cursor': 'old', 'expected_cursor': 'c', 'revision': 4, 'expected_revision': 4, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 4], ['b', 8], ['y', 5]], 'next': None, 'total': 12, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('stale revision', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 3, 'expected_revision': 4, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 4], ['b', 8], ['y', 5]], 'next': None, 'total': 12, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('empty cursor', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 4, 'expected_revision': 4, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 4], ['b', 8], ['y', 5]], 'next': '', 'total': 12, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 5, 'b': 8}, ['y', 'b'], '', True, 12, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('empty terminal', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 4, 'expected_revision': 4, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': None, 'total': 0, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], None, False, 0, 'p', {'z': 1, 'a': 2}]), ('empty continued', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 4, 'expected_revision': 4, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': 'x', 'total': 12, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'x', True, 12, 'more', {'z': 1, 'a': 2}]), ('unknown total', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 4, 'expected_revision': 4, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 4], ['b', 8], ['y', 5]], 'next': None, 'total': None, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 5, 'b': 8}, ['y', 'b'], None, False, -1, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('focus elsewhere', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 4, 'expected_revision': 4, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 4], ['b', 8], ['y', 5]], 'next': None, 'total': 12, 'size': -1, 'focus': 'z', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 5, 'b': 8}, ['y', 'b'], None, False, 12, 'z', {'z': 1, 'a': 2, 'y': 3, 'b': 4}])], 5: [('overlap page', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 5, 'expected_revision': 5, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 5], ['b', 8], ['y', 6]], 'next': None, 'total': 13, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 6, 'b': 8}, ['y', 'b'], None, False, 13, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('stale cursor', {'cursor': 'old', 'expected_cursor': 'c', 'revision': 5, 'expected_revision': 5, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 5], ['b', 8], ['y', 6]], 'next': None, 'total': 13, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('stale revision', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 4, 'expected_revision': 5, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 5], ['b', 8], ['y', 6]], 'next': None, 'total': 13, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('empty cursor', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 5, 'expected_revision': 5, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 5], ['b', 8], ['y', 6]], 'next': '', 'total': 13, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 6, 'b': 8}, ['y', 'b'], '', True, 13, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('empty terminal', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 5, 'expected_revision': 5, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': None, 'total': 0, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], None, False, 0, 'p', {'z': 1, 'a': 2}]), ('empty continued', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 5, 'expected_revision': 5, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': 'x', 'total': 13, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'x', True, 13, 'more', {'z': 1, 'a': 2}]), ('unknown total', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 5, 'expected_revision': 5, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 5], ['b', 8], ['y', 6]], 'next': None, 'total': None, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 6, 'b': 8}, ['y', 'b'], None, False, -1, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('focus elsewhere', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 5, 'expected_revision': 5, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 5], ['b', 8], ['y', 6]], 'next': None, 'total': 13, 'size': -1, 'focus': 'z', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 6, 'b': 8}, ['y', 'b'], None, False, 13, 'z', {'z': 1, 'a': 2, 'y': 3, 'b': 4}])]}
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
overlap page[['z', 'a', 'y', 'b'], {'a': 3, 'b': 8, 'y': 2, 'z': 1}, ['y', 'b'], None, False, 9, 'b', {'a': 2, 'b': 4, 'y': 3, 'z': 1}][['z', 'a', 'y', 'b'], {'a': 3, 'b': 8, 'y': 2, 'z': 1}, ['y', 'b'], None, False, 9, 'y', {'a': 2, 'b': 4, 'y': 3, 'z': 1}]Failed
stale cursor[['z', 'a'], {'a': 2, 'z': 1}, [], 'c', True, -1, 'more', {'a': 2, 'z': 1}][['z', 'a'], {'a': 2, 'z': 1}, [], 'c', True, -1, 'more', {'a': 2, 'z': 1}]Passed
stale revision[['z', 'a'], {'a': 2, 'z': 1}, [], 'c', True, -1, 'more', {'a': 2, 'z': 1}][['z', 'a'], {'a': 2, 'z': 1}, [], 'c', True, -1, 'more', {'a': 2, 'z': 1}]Passed
empty cursor[['z', 'a', 'y', 'b'], {'a': 3, 'b': 8, 'y': 2, 'z': 1}, ['y', 'b'], '', True, 9, 'b', {'a': 2, 'b': 4, 'y': 3, 'z': 1}][['z', 'a', 'y', 'b'], {'a': 3, 'b': 8, 'y': 2, 'z': 1}, ['y', 'b'], '', True, 9, 'y', {'a': 2, 'b': 4, 'y': 3, 'z': 1}]Failed
empty terminal[['z', 'a'], {'a': 2, 'z': 1}, [], None, False, 0, 'more', {'a': 2, 'z': 1}][['z', 'a'], {'a': 2, 'z': 1}, [], None, False, 0, 'p', {'a': 2, 'z': 1}]Failed
empty continued[['z', 'a'], {'a': 2, 'z': 1}, [], 'x', True, 9, 'more', {'a': 2, 'z': 1}][['z', 'a'], {'a': 2, 'z': 1}, [], 'x', True, 9, 'more', {'a': 2, 'z': 1}]Passed
unknown total[['z', 'a', 'y', 'b'], {'a': 3, 'b': 8, 'y': 2, 'z': 1}, ['y', 'b'], None, False, -1, 'b', {'a': 2, 'b': 4, 'y': 3, 'z': 1}][['z', 'a', 'y', 'b'], {'a': 3, 'b': 8, 'y': 2, 'z': 1}, ['y', 'b'], None, False, -1, 'y', {'a': 2, 'b': 4, 'y': 3, 'z': 1}]Failed
focus elsewhere[['z', 'a', 'y', 'b'], {'a': 3, 'b': 8, 'y': 2, 'z': 1}, ['y', 'b'], None, False, 9, 'z', {'a': 2, 'b': 4, 'y': 3, 'z': 1}][['z', 'a', 'y', 'b'], {'a': 3, 'b': 8, 'y': 2, 'z': 1}, ['y', 'b'], None, False, 9, 'z', {'a': 2, 'b': 4, 'y': 3, 'z': 1}]Passed

SHA-256 / 9105c39f92d6232be56b6ac10a9ad6472c0ec33ea4be8b448fdc59d48c3a24ad

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(d):
    accept=d['cursor']==d['expected_cursor'] and d['revision']==d['expected_revision']
    order=list(dict.fromkeys(d['order']+[r[0] for r in d['page']])) if accept else d['order']
    records=dict(d['records'])
    if accept: records.update(dict(d['page']))
    new=[r[0] for r in d['page'] if r[0] not in d['order']] if accept else []
    new=list(dict.fromkeys(new))
    nextcursor=d['next'] if accept else d['expected_cursor']
    more=nextcursor is not None
    size=d['total'] if accept and d['total'] is not None else d['size']
    focus=(d['parent']) if accept and d['focus']=='more' else d['focus']
    positions={x:i+1 for i,x in enumerate(order)}
    return [order,records,new,nextcursor,more,size,focus,positions]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = {1: [('overlap page', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 1, 'expected_revision': 1, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 1], ['b', 8], ['y', 2]], 'next': None, 'total': 9, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 2, 'b': 8}, ['y', 'b'], None, False, 9, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('stale cursor', {'cursor': 'old', 'expected_cursor': 'c', 'revision': 1, 'expected_revision': 1, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 1], ['b', 8], ['y', 2]], 'next': None, 'total': 9, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('stale revision', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 0, 'expected_revision': 1, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 1], ['b', 8], ['y', 2]], 'next': None, 'total': 9, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('empty cursor', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 1, 'expected_revision': 1, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 1], ['b', 8], ['y', 2]], 'next': '', 'total': 9, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 2, 'b': 8}, ['y', 'b'], '', True, 9, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('empty terminal', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 1, 'expected_revision': 1, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': None, 'total': 0, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], None, False, 0, 'p', {'z': 1, 'a': 2}]), ('empty continued', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 1, 'expected_revision': 1, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': 'x', 'total': 9, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'x', True, 9, 'more', {'z': 1, 'a': 2}]), ('unknown total', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 1, 'expected_revision': 1, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 1], ['b', 8], ['y', 2]], 'next': None, 'total': None, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 2, 'b': 8}, ['y', 'b'], None, False, -1, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('focus elsewhere', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 1, 'expected_revision': 1, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 1], ['b', 8], ['y', 2]], 'next': None, 'total': 9, 'size': -1, 'focus': 'z', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 2, 'b': 8}, ['y', 'b'], None, False, 9, 'z', {'z': 1, 'a': 2, 'y': 3, 'b': 4}])], 2: [('overlap page', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 2, 'expected_revision': 2, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 2], ['b', 8], ['y', 3]], 'next': None, 'total': 10, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 3, 'b': 8}, ['y', 'b'], None, False, 10, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('stale cursor', {'cursor': 'old', 'expected_cursor': 'c', 'revision': 2, 'expected_revision': 2, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 2], ['b', 8], ['y', 3]], 'next': None, 'total': 10, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('stale revision', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 1, 'expected_revision': 2, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 2], ['b', 8], ['y', 3]], 'next': None, 'total': 10, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('empty cursor', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 2, 'expected_revision': 2, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 2], ['b', 8], ['y', 3]], 'next': '', 'total': 10, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 3, 'b': 8}, ['y', 'b'], '', True, 10, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('empty terminal', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 2, 'expected_revision': 2, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': None, 'total': 0, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], None, False, 0, 'p', {'z': 1, 'a': 2}]), ('empty continued', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 2, 'expected_revision': 2, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': 'x', 'total': 10, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'x', True, 10, 'more', {'z': 1, 'a': 2}]), ('unknown total', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 2, 'expected_revision': 2, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 2], ['b', 8], ['y', 3]], 'next': None, 'total': None, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 3, 'b': 8}, ['y', 'b'], None, False, -1, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('focus elsewhere', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 2, 'expected_revision': 2, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 2], ['b', 8], ['y', 3]], 'next': None, 'total': 10, 'size': -1, 'focus': 'z', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 3, 'b': 8}, ['y', 'b'], None, False, 10, 'z', {'z': 1, 'a': 2, 'y': 3, 'b': 4}])], 3: [('overlap page', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 3, 'expected_revision': 3, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 3], ['b', 8], ['y', 4]], 'next': None, 'total': 11, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 4, 'b': 8}, ['y', 'b'], None, False, 11, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('stale cursor', {'cursor': 'old', 'expected_cursor': 'c', 'revision': 3, 'expected_revision': 3, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 3], ['b', 8], ['y', 4]], 'next': None, 'total': 11, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('stale revision', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 2, 'expected_revision': 3, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 3], ['b', 8], ['y', 4]], 'next': None, 'total': 11, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('empty cursor', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 3, 'expected_revision': 3, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 3], ['b', 8], ['y', 4]], 'next': '', 'total': 11, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 4, 'b': 8}, ['y', 'b'], '', True, 11, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('empty terminal', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 3, 'expected_revision': 3, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': None, 'total': 0, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], None, False, 0, 'p', {'z': 1, 'a': 2}]), ('empty continued', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 3, 'expected_revision': 3, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': 'x', 'total': 11, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'x', True, 11, 'more', {'z': 1, 'a': 2}]), ('unknown total', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 3, 'expected_revision': 3, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 3], ['b', 8], ['y', 4]], 'next': None, 'total': None, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 4, 'b': 8}, ['y', 'b'], None, False, -1, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('focus elsewhere', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 3, 'expected_revision': 3, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 3], ['b', 8], ['y', 4]], 'next': None, 'total': 11, 'size': -1, 'focus': 'z', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 4, 'b': 8}, ['y', 'b'], None, False, 11, 'z', {'z': 1, 'a': 2, 'y': 3, 'b': 4}])], 4: [('overlap page', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 4, 'expected_revision': 4, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 4], ['b', 8], ['y', 5]], 'next': None, 'total': 12, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 5, 'b': 8}, ['y', 'b'], None, False, 12, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('stale cursor', {'cursor': 'old', 'expected_cursor': 'c', 'revision': 4, 'expected_revision': 4, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 4], ['b', 8], ['y', 5]], 'next': None, 'total': 12, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('stale revision', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 3, 'expected_revision': 4, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 4], ['b', 8], ['y', 5]], 'next': None, 'total': 12, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('empty cursor', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 4, 'expected_revision': 4, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 4], ['b', 8], ['y', 5]], 'next': '', 'total': 12, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 5, 'b': 8}, ['y', 'b'], '', True, 12, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('empty terminal', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 4, 'expected_revision': 4, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': None, 'total': 0, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], None, False, 0, 'p', {'z': 1, 'a': 2}]), ('empty continued', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 4, 'expected_revision': 4, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': 'x', 'total': 12, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'x', True, 12, 'more', {'z': 1, 'a': 2}]), ('unknown total', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 4, 'expected_revision': 4, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 4], ['b', 8], ['y', 5]], 'next': None, 'total': None, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 5, 'b': 8}, ['y', 'b'], None, False, -1, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('focus elsewhere', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 4, 'expected_revision': 4, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 4], ['b', 8], ['y', 5]], 'next': None, 'total': 12, 'size': -1, 'focus': 'z', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 5, 'b': 8}, ['y', 'b'], None, False, 12, 'z', {'z': 1, 'a': 2, 'y': 3, 'b': 4}])], 5: [('overlap page', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 5, 'expected_revision': 5, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 5], ['b', 8], ['y', 6]], 'next': None, 'total': 13, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 6, 'b': 8}, ['y', 'b'], None, False, 13, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('stale cursor', {'cursor': 'old', 'expected_cursor': 'c', 'revision': 5, 'expected_revision': 5, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 5], ['b', 8], ['y', 6]], 'next': None, 'total': 13, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('stale revision', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 4, 'expected_revision': 5, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 5], ['b', 8], ['y', 6]], 'next': None, 'total': 13, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'c', True, -1, 'more', {'z': 1, 'a': 2}]), ('empty cursor', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 5, 'expected_revision': 5, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 5], ['b', 8], ['y', 6]], 'next': '', 'total': 13, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 6, 'b': 8}, ['y', 'b'], '', True, 13, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('empty terminal', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 5, 'expected_revision': 5, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': None, 'total': 0, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], None, False, 0, 'p', {'z': 1, 'a': 2}]), ('empty continued', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 5, 'expected_revision': 5, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [], 'next': 'x', 'total': 13, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a'], {'z': 1, 'a': 2}, [], 'x', True, 13, 'more', {'z': 1, 'a': 2}]), ('unknown total', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 5, 'expected_revision': 5, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 5], ['b', 8], ['y', 6]], 'next': None, 'total': None, 'size': -1, 'focus': 'more', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 6, 'b': 8}, ['y', 'b'], None, False, -1, 'y', {'z': 1, 'a': 2, 'y': 3, 'b': 4}]), ('focus elsewhere', {'cursor': 'c', 'expected_cursor': 'c', 'revision': 5, 'expected_revision': 5, 'order': ['z', 'a'], 'records': {'z': 1, 'a': 2}, 'page': [['a', 3], ['y', 5], ['b', 8], ['y', 6]], 'next': None, 'total': 13, 'size': -1, 'focus': 'z', 'parent': 'p'}, [['z', 'a', 'y', 'b'], {'z': 1, 'a': 3, 'y': 6, 'b': 8}, ['y', 'b'], None, False, 13, 'z', {'z': 1, 'a': 2, 'y': 3, 'b': 4}])]}
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
overlap page[['z', 'a', 'y', 'b'], {'a': 3, 'b': 8, 'y': 2, 'z': 1}, ['y', 'b'], None, False, 9, 'p', {'a': 2, 'b': 4, 'y': 3, 'z': 1}][['z', 'a', 'y', 'b'], {'a': 3, 'b': 8, 'y': 2, 'z': 1}, ['y', 'b'], None, False, 9, 'y', {'a': 2, 'b': 4, 'y': 3, 'z': 1}]Failed
stale cursor[['z', 'a'], {'a': 2, 'z': 1}, [], 'c', True, -1, 'more', {'a': 2, 'z': 1}][['z', 'a'], {'a': 2, 'z': 1}, [], 'c', True, -1, 'more', {'a': 2, 'z': 1}]Passed
stale revision[['z', 'a'], {'a': 2, 'z': 1}, [], 'c', True, -1, 'more', {'a': 2, 'z': 1}][['z', 'a'], {'a': 2, 'z': 1}, [], 'c', True, -1, 'more', {'a': 2, 'z': 1}]Passed
empty cursor[['z', 'a', 'y', 'b'], {'a': 3, 'b': 8, 'y': 2, 'z': 1}, ['y', 'b'], '', True, 9, 'p', {'a': 2, 'b': 4, 'y': 3, 'z': 1}][['z', 'a', 'y', 'b'], {'a': 3, 'b': 8, 'y': 2, 'z': 1}, ['y', 'b'], '', True, 9, 'y', {'a': 2, 'b': 4, 'y': 3, 'z': 1}]Failed
empty terminal[['z', 'a'], {'a': 2, 'z': 1}, [], None, False, 0, 'p', {'a': 2, 'z': 1}][['z', 'a'], {'a': 2, 'z': 1}, [], None, False, 0, 'p', {'a': 2, 'z': 1}]Passed
empty continued[['z', 'a'], {'a': 2, 'z': 1}, [], 'x', True, 9, 'p', {'a': 2, 'z': 1}][['z', 'a'], {'a': 2, 'z': 1}, [], 'x', True, 9, 'more', {'a': 2, 'z': 1}]Failed
unknown total[['z', 'a', 'y', 'b'], {'a': 3, 'b': 8, 'y': 2, 'z': 1}, ['y', 'b'], None, False, -1, 'p', {'a': 2, 'b': 4, 'y': 3, 'z': 1}][['z', 'a', 'y', 'b'], {'a': 3, 'b': 8, 'y': 2, 'z': 1}, ['y', 'b'], None, False, -1, 'y', {'a': 2, 'b': 4, 'y': 3, 'z': 1}]Failed
focus elsewhere[['z', 'a', 'y', 'b'], {'a': 3, 'b': 8, 'y': 2, 'z': 1}, ['y', 'b'], None, False, 9, 'z', {'a': 2, 'b': 4, 'y': 3, 'z': 1}][['z', 'a', 'y', 'b'], {'a': 3, 'b': 8, 'y': 2, 'z': 1}, ['y', 'b'], None, False, 9, 'z', {'a': 2, 'b': 4, 'y': 3, 'z': 1}]Passed

SHA-256 / aa2a73221544e3300ffa9975bdffa837362ce9fce51946c0c27a72d3354f46d2

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 8 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 2026-09-29T14:43:16.280880+00:00.

Case digest / 5c47f3d82fe638551733a04f5f3939bc293d4553b772e29c00a880d550359b69