FA-53871 / Accessibility interaction semantics / Open access

Hyperlink spans exceed document extent · case 01

Hyperlink spans exceed document extent.

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

ROOT CAUSE

The link end clamp decision in the hyperlink spans adapter violates its declared contract.

THE FAILURE

The link end clamp decision in the hyperlink spans adapter violates its declared contract.

Unsuccessful approach: The local repair substitutes min(length+1,end) 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),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: 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, 8, '/b']], 'b']`	`[[['a', 0, 2, '/a'], ['b', 2, 5, '/b']], 'b']`	Failed
contract fixture 3	`[[], None]`	`[[], None]`	Passed
contract fixture 4	`[[['a', 0, 2, 'early']], 'a']`	`[[['a', 0, 2, 'early']], 'a']`	Passed
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 / 88305f7515c2502b15389308e79c8f8984cad820b1d28f72c1d49e642c22dabe

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+1,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: 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, 6, '/b']], 'b']`	`[[['a', 0, 2, '/a'], ['b', 2, 5, '/b']], 'b']`	Failed
contract fixture 3	`[[], None]`	`[[], None]`	Passed
contract fixture 4	`[[['a', 0, 2, 'early']], 'a']`	`[[['a', 0, 2, 'early']], 'a']`	Passed
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 / 96e971c95fb2cb854879362fe951794ef59eb7d387c5c8eda9efb72f396cf7da

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 / 23bedd62fb90f231e652bbd38e8c358da46c853b3df96483caf08541022e99b3