FAILURE MAP
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FA-54296 / Accessibility interaction semantics / Open access

Removed objects are mistaken for newly added objects · case 01

Removed objects are mistaken for newly added objects.

Verified by executionVariant 1 · 7 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The removed direction decision in the snapshot delta adapter violates its declared contract.

THE FAILURE

The removed direction decision in the snapshot delta adapter violates its declared contract.

Unsuccessful approach: The local repair substitutes set(before)&set(after) but still mishandles the regression fixtures.

Case contract

Input [before,after] maps stable object ID to {role,name,parent,order}. Return delta operations in phases: removed IDs sorted lexical; added IDs sorted by after order then ID; common IDs sorted lexical get role-replace if role differs, otherwise name-set if name differs; parent/order changes append move even after role-replace. Removed values use old role, added records preserve complete new record, name-set preserves empty names. Same ID is never remove+add just for role changes. Return operations lists.

Why this case matters

Offline accessibility bridge model with explicit policy; useful for testing semantic API adapters independently of browser implementations.

1 / The failure

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

N = 1
observations = []
def solve(data):
    before,after = data
    result = []
    for ident in sorted(set()): result.append(['remove',ident,before[ident]['role']])
    for ident in sorted(set(after)-set(before),key=lambda x:(after[x]['order'],x)): result.append(['add',ident,after[ident]])
    for ident in sorted(set(before)&set(after)):
        old,new = before[ident],after[ident]
        if old['role'] != new['role']: result.append(['replace-role',ident,new['role']])
        elif old['name'] != new['name']: result.append(['set-name',ident,new['name']])
        if old['parent'] != new['parent'] or old['order'] != new['order']: result.append(['move',ident,new['parent'],new['order']])
    return result
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('contract fixture 1', solve([{'x':{'role':'image','name':'old','parent':'a','order':N}},{'x':{'role':'button','name':'new','parent':'b','order':N+1}}],), [['replace-role','x','button'],['move','x','b',N+1]])
check('contract fixture 2', solve([{'x':{'role':'image','name':'old','parent':None,'order':0}},{'x':{'role':'image','name':'','parent':None,'order':0}}],), [['set-name','x','']])
check('contract fixture 3', solve([{'z':{'role':'image','name':'Z','parent':None,'order':0},'a':{'role':'group','name':'A','parent':None,'order':1}},{}],), [['remove','a','group'],['remove','z','image']])
check('contract fixture 4', solve([{}, {'z':{'role':'image','name':'Z','parent':None,'order':0},'a':{'role':'group','name':'A','parent':None,'order':1}}],), [['add','z',{'role':'image','name':'Z','parent':None,'order':0}],['add','a',{'role':'group','name':'A','parent':None,'order':1}]])
check('contract fixture 5', solve([{'x':{'role':'image','name':'X','parent':'a','order':0}},{'x':{'role':'image','name':'X','parent':'a','order':N}}],), [['move','x','a',N]])
check('contract fixture 6', solve([{'x':{'role':'image','name':'X','parent':'a','order':0}},{'x':{'role':'image','name':'X','parent':'b','order':0}}],), [['move','x','b',0]])
check('contract fixture 7', solve([{},{}],), [])
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
contract fixture 1[['replace-role', 'x', 'button'], ['move', 'x', 'b', 2]][['replace-role', 'x', 'button'], ['move', 'x', 'b', 2]]Passed
contract fixture 2[['set-name', 'x', '']][['set-name', 'x', '']]Passed
contract fixture 3[][['remove', 'a', 'group'], ['remove', 'z', 'image']]Failed
contract fixture 4[['add', 'z', {'name': 'Z', 'order': 0, 'parent': None, 'role': 'image'}], ['add', 'a', {'name': 'A', 'order': 1, 'parent': None, 'role': 'group'}]][['add', 'z', {'name': 'Z', 'order': 0, 'parent': None, 'role': 'image'}], ['add', 'a', {'name': 'A', 'order': 1, 'parent': None, 'role': 'group'}]]Passed
contract fixture 5[['move', 'x', 'a', 1]][['move', 'x', 'a', 1]]Passed
contract fixture 6[['move', 'x', 'b', 0]][['move', 'x', 'b', 0]]Passed
contract fixture 7[][]Passed

SHA-256 / 35c82d7eb7566d445e2424d18b34e6c4d5584092ecd0e6a6ff31ba8c28ab03c7

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(data):
    before,after = data
    result = []
    for ident in sorted(set(before)&set(after)): result.append(['remove',ident,before[ident]['role']])
    for ident in sorted(set(after)-set(before),key=lambda x:(after[x]['order'],x)): result.append(['add',ident,after[ident]])
    for ident in sorted(set(before)&set(after)):
        old,new = before[ident],after[ident]
        if old['role'] != new['role']: result.append(['replace-role',ident,new['role']])
        elif old['name'] != new['name']: result.append(['set-name',ident,new['name']])
        if old['parent'] != new['parent'] or old['order'] != new['order']: result.append(['move',ident,new['parent'],new['order']])
    return result
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('contract fixture 1', solve([{'x':{'role':'image','name':'old','parent':'a','order':N}},{'x':{'role':'button','name':'new','parent':'b','order':N+1}}],), [['replace-role','x','button'],['move','x','b',N+1]])
check('contract fixture 2', solve([{'x':{'role':'image','name':'old','parent':None,'order':0}},{'x':{'role':'image','name':'','parent':None,'order':0}}],), [['set-name','x','']])
check('contract fixture 3', solve([{'z':{'role':'image','name':'Z','parent':None,'order':0},'a':{'role':'group','name':'A','parent':None,'order':1}},{}],), [['remove','a','group'],['remove','z','image']])
check('contract fixture 4', solve([{}, {'z':{'role':'image','name':'Z','parent':None,'order':0},'a':{'role':'group','name':'A','parent':None,'order':1}}],), [['add','z',{'role':'image','name':'Z','parent':None,'order':0}],['add','a',{'role':'group','name':'A','parent':None,'order':1}]])
check('contract fixture 5', solve([{'x':{'role':'image','name':'X','parent':'a','order':0}},{'x':{'role':'image','name':'X','parent':'a','order':N}}],), [['move','x','a',N]])
check('contract fixture 6', solve([{'x':{'role':'image','name':'X','parent':'a','order':0}},{'x':{'role':'image','name':'X','parent':'b','order':0}}],), [['move','x','b',0]])
check('contract fixture 7', solve([{},{}],), [])
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
contract fixture 1[['remove', 'x', 'image'], ['replace-role', 'x', 'button'], ['move', 'x', 'b', 2]][['replace-role', 'x', 'button'], ['move', 'x', 'b', 2]]Failed
contract fixture 2[['remove', 'x', 'image'], ['set-name', 'x', '']][['set-name', 'x', '']]Failed
contract fixture 3[][['remove', 'a', 'group'], ['remove', 'z', 'image']]Failed
contract fixture 4[['add', 'z', {'name': 'Z', 'order': 0, 'parent': None, 'role': 'image'}], ['add', 'a', {'name': 'A', 'order': 1, 'parent': None, 'role': 'group'}]][['add', 'z', {'name': 'Z', 'order': 0, 'parent': None, 'role': 'image'}], ['add', 'a', {'name': 'A', 'order': 1, 'parent': None, 'role': 'group'}]]Passed
contract fixture 5[['remove', 'x', 'image'], ['move', 'x', 'a', 1]][['move', 'x', 'a', 1]]Failed
contract fixture 6[['remove', 'x', 'image'], ['move', 'x', 'b', 0]][['move', 'x', 'b', 0]]Failed
contract fixture 7[][]Passed

SHA-256 / adc5c489728d384e6b252b0a5e0d5af0c0545cce4c10080f0ae4592f3cd3d525

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 7 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

Stipulated finite adapter contract, not a claim of platform accessibility or ARIA conformance. 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 2026-09-29T14:45:47.427179+00:00.

Case digest / a736586e9b2f334f5122c2fa1a867146b937e105b80108c527723f3d98daf8e5