FA-53891 / Accessibility interaction semantics / Open access

Repeated hyperlink IDs yield multiple indexed descriptors · case 01

Repeated hyperlink IDs yield multiple indexed descriptors.

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

ROOT CAUSE

The duplicate id decision in the hyperlink spans adapter violates its declared contract.

THE FAILURE

The duplicate id decision in the hyperlink spans adapter violates its declared contract.

Unsuccessful approach: The local repair substitutes if ident in seen and not url: continue but still mishandles the regression fixtures.

Case contract

Input [text_length,links,offset] where links [id,start,end,url,enabled]. Admit only nonempty URL, enabled and nonempty interval after clamping. Sort by start then shorter interval then input order; dedupe IDs after sorting. Query offset resolves the first matching half-open span, or None. Return [ordered descriptors,hit_id]. URLs remain exact including fragments; IDs are retained even when URL is shared.

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):
    length,links,offset = data
    valid = []
    for i,(ident,start,end,url,enabled) in enumerate(links):
        if not enabled or not url: continue
        start,end = max(0,start),min(length,end)
        if start >= end: continue
        valid.append((start,end-start,i,ident,end,url))
    valid.sort(key=lambda x:(x[0],x[1],x[2]))
    seen = set()
    rows = []
    for start,width,i,ident,end,url in valid:
        if False: continue
        seen.add(ident)
        rows.append([ident,start,end,url])
    hit = next((ident for ident,start,end,url in rows if start <= offset < end),None)
    return [rows,hit]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('contract fixture 1', solve([N+5,[['wide',N,N+4,'/a#x',True],['small',N,N+2,'/a#y',True]],N+1],), [[['small',N,N+2,'/a#y'],['wide',N,N+4,'/a#x']],'small'])
check('contract fixture 2', solve([5,[['a',-3,2,'/a',True],['b',2,8,'/b',True]],2],), [[['a',0,2,'/a'],['b',2,5,'/b']],'b'])
check('contract fixture 3', solve([5,[['a',1,1,'/a',True],['b',4,2,'/b',True],['c',0,3,'',True],['d',0,3,'/d',False]],0],), [[],None])
check('contract fixture 4', solve([6,[['a',3,6,'later',True],['a',0,2,'early',True]],1],), [[['a',0,2,'early']],'a'])
check('contract fixture 5', solve([3,[['a',0,3,'/same',True],['b',0,3,'/same',True]],3],), [[['a',0,3,'/same'],['b',0,3,'/same']],None])
check('contract fixture 6', solve([0,[],0],), [[],None])
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
contract fixture 1	`[[['small', 1, 3, '/a#y'], ['wide', 1, 5, '/a#x']], 'small']`	`[[['small', 1, 3, '/a#y'], ['wide', 1, 5, '/a#x']], 'small']`	Passed
contract fixture 2	`[[['a', 0, 2, '/a'], ['b', 2, 5, '/b']], 'b']`	`[[['a', 0, 2, '/a'], ['b', 2, 5, '/b']], 'b']`	Passed
contract fixture 3	`[[], None]`	`[[], None]`	Passed
contract fixture 4	`[[['a', 0, 2, 'early'], ['a', 3, 6, 'later']], 'a']`	`[[['a', 0, 2, 'early']], 'a']`	Failed
contract fixture 5	`[[['a', 0, 3, '/same'], ['b', 0, 3, '/same']], None]`	`[[['a', 0, 3, '/same'], ['b', 0, 3, '/same']], None]`	Passed
contract fixture 6	`[[], None]`	`[[], None]`	Passed

SHA-256 / e0f0e3dbaf8ae854270fc7e42e02b7e802f94cc9318b3a14ccb7a875c4449d5e

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(data):
    length,links,offset = data
    valid = []
    for i,(ident,start,end,url,enabled) in enumerate(links):
        if not enabled or not url: continue
        start,end = max(0,start),min(length,end)
        if start >= end: continue
        valid.append((start,end-start,i,ident,end,url))
    valid.sort(key=lambda x:(x[0],x[1],x[2]))
    seen = set()
    rows = []
    for start,width,i,ident,end,url in valid:
        if ident in seen and not url: continue
        seen.add(ident)
        rows.append([ident,start,end,url])
    hit = next((ident for ident,start,end,url in rows if start <= offset < end),None)
    return [rows,hit]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('contract fixture 1', solve([N+5,[['wide',N,N+4,'/a#x',True],['small',N,N+2,'/a#y',True]],N+1],), [[['small',N,N+2,'/a#y'],['wide',N,N+4,'/a#x']],'small'])
check('contract fixture 2', solve([5,[['a',-3,2,'/a',True],['b',2,8,'/b',True]],2],), [[['a',0,2,'/a'],['b',2,5,'/b']],'b'])
check('contract fixture 3', solve([5,[['a',1,1,'/a',True],['b',4,2,'/b',True],['c',0,3,'',True],['d',0,3,'/d',False]],0],), [[],None])
check('contract fixture 4', solve([6,[['a',3,6,'later',True],['a',0,2,'early',True]],1],), [[['a',0,2,'early']],'a'])
check('contract fixture 5', solve([3,[['a',0,3,'/same',True],['b',0,3,'/same',True]],3],), [[['a',0,3,'/same'],['b',0,3,'/same']],None])
check('contract fixture 6', solve([0,[],0],), [[],None])
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
contract fixture 1	`[[['small', 1, 3, '/a#y'], ['wide', 1, 5, '/a#x']], 'small']`	`[[['small', 1, 3, '/a#y'], ['wide', 1, 5, '/a#x']], 'small']`	Passed
contract fixture 2	`[[['a', 0, 2, '/a'], ['b', 2, 5, '/b']], 'b']`	`[[['a', 0, 2, '/a'], ['b', 2, 5, '/b']], 'b']`	Passed
contract fixture 3	`[[], None]`	`[[], None]`	Passed
contract fixture 4	`[[['a', 0, 2, 'early'], ['a', 3, 6, 'later']], 'a']`	`[[['a', 0, 2, 'early']], 'a']`	Failed
contract fixture 5	`[[['a', 0, 3, '/same'], ['b', 0, 3, '/same']], None]`	`[[['a', 0, 3, '/same'], ['b', 0, 3, '/same']], None]`	Passed
contract fixture 6	`[[], None]`	`[[], None]`	Passed

SHA-256 / 567d67773f884b255f785c5154717d9caa294f1339b4bbf3a18ad228be5ca2a1

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 6 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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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 2026-09-29T14:45:43.286063+00:00.

Case digest / 385d0b8d6ace01feca4b958e8446994c7451833f36e91488b957a9d0391b6f68