{"abstract":"Selection API accepts a negative anchor.","category":"Accessibility interaction semantics","checks":9,"contract":"Input [text_length,multi,readonly,selections,operation] selections ordered [anchor,focus]; operation [kind,index,anchor,focus]. API supports add,replace,remove,clear; readonly concerns text edits and does not prevent selecting. Validate endpoints inclusive0..length and index for replace/remove. add only when multi or no selection; remove preserves other ranges; clear ignores index. Return [ranges,success,active] where active is last range's focus or None. Preserve anchor direction and collapsed selections. Failure leaves input unchanged.","evaluation_group":"s3-accessibility-text-selection-api","failed_approach":"The local repair substitutes -1 <= anchor <= length but still mishandles the regression fixtures.","family":"s3-accessibility-text-selection-api-anchor-bound","id":"FA-54111","implementations":{"attempt":{"sha256":"9e05a64d5b62fe8e6b97f9b0ec558e76c3d59c5016fb30f7e1837e59b2c2945e","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(data):\n    length,multi,readonly,selections,operation = data\n    ranges = [list(x) for x in selections]\n    kind,index,anchor,focus = operation\n    ok = False\n    if kind == 'clear': ranges,ok = [],True\n    elif kind in ('add','replace') and -1 <= anchor <= length and 0 <= focus <= length:\n        if kind == 'add' and (multi or not ranges): ranges.append([anchor,focus]); ok = True\n        elif kind == 'replace' and 0 <= index < len(ranges): ranges[index] = [anchor,focus]; ok = True\n    elif kind == 'remove' and 0 <= index < len(ranges): ranges.pop(index); ok = True\n    return [ranges,ok,ranges[-1][1] if ranges else None]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('contract fixture 1', solve([N+5,True,False,[[0,1]],['add',0,N+3,N]],), [[[0,1],[N+3,N]],True,N])\ncheck('contract fixture 2', solve([5,False,True,[],['add',0,5,5]],), [[[5,5]],True,5])\ncheck('contract fixture 3', solve([5,False,False,[[0,1]],['add',0,2,3]],), [[[0,1]],False,1])\ncheck('contract fixture 4', solve([5,True,False,[[0,1],[2,3]],['replace',0,4,2]],), [[[4,2],[2,3]],True,3])\ncheck('contract fixture 5', solve([5,True,False,[[0,1],[2,3]],['remove',0,0,0]],), [[[2,3]],True,3])\ncheck('contract fixture 6', solve([5,False,False,[[0,1]],['clear',99,-1,99]],), [[],True,None])\ncheck('contract fixture 7', solve([5,True,False,[[0,1]],['replace',-1,2,3]],), [[[0,1]],False,1])\ncheck('contract fixture 8', solve([5,True,False,[],['add',0,-1,3]],), [[],False,None])\ncheck('contract fixture 9', solve([5,True,False,[],['add',0,1,6]],), [[],False,None])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"37ceef9a9c582aa12815a6173e6040fae629dba259fc6286476396366f0748d5","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(data):\n    length,multi,readonly,selections,operation = data\n    ranges = [list(x) for x in selections]\n    kind,index,anchor,focus = operation\n    ok = False\n    if kind == 'clear': ranges,ok = [],True\n    elif kind in ('add','replace') and anchor <= length and 0 <= focus <= length:\n        if kind == 'add' and (multi or not ranges): ranges.append([anchor,focus]); ok = True\n        elif kind == 'replace' and 0 <= index < len(ranges): ranges[index] = [anchor,focus]; ok = True\n    elif kind == 'remove' and 0 <= index < len(ranges): ranges.pop(index); ok = True\n    return [ranges,ok,ranges[-1][1] if ranges else None]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('contract fixture 1', solve([N+5,True,False,[[0,1]],['add',0,N+3,N]],), [[[0,1],[N+3,N]],True,N])\ncheck('contract fixture 2', solve([5,False,True,[],['add',0,5,5]],), [[[5,5]],True,5])\ncheck('contract fixture 3', solve([5,False,False,[[0,1]],['add',0,2,3]],), [[[0,1]],False,1])\ncheck('contract fixture 4', solve([5,True,False,[[0,1],[2,3]],['replace',0,4,2]],), [[[4,2],[2,3]],True,3])\ncheck('contract fixture 5', solve([5,True,False,[[0,1],[2,3]],['remove',0,0,0]],), [[[2,3]],True,3])\ncheck('contract fixture 6', solve([5,False,False,[[0,1]],['clear',99,-1,99]],), [[],True,None])\ncheck('contract fixture 7', solve([5,True,False,[[0,1]],['replace',-1,2,3]],), [[[0,1]],False,1])\ncheck('contract fixture 8', solve([5,True,False,[],['add',0,-1,3]],), [[],False,None])\ncheck('contract fixture 9', solve([5,True,False,[],['add',0,1,6]],), [[],False,None])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"fixed":{"sha256":"725d4c725ca86d34b902a3c9b4d163c4933039170364ca138cf49147fdc9964a","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(data):\n    length,multi,readonly,selections,operation = data\n    ranges = [list(x) for x in selections]\n    kind,index,anchor,focus = operation\n    ok = False\n    if kind == 'clear': ranges,ok = [],True\n    elif kind in ('add','replace') and 0 <= anchor <= length and 0 <= focus <= length:\n        if kind == 'add' and (multi or not ranges): ranges.append([anchor,focus]); ok = True\n        elif kind == 'replace' and 0 <= index < len(ranges): ranges[index] = [anchor,focus]; ok = True\n    elif kind == 'remove' and 0 <= index < len(ranges): ranges.pop(index); ok = True\n    return [ranges,ok,ranges[-1][1] if ranges else None]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('contract fixture 1', solve([N+5,True,False,[[0,1]],['add',0,N+3,N]],), [[[0,1],[N+3,N]],True,N])\ncheck('contract fixture 2', solve([5,False,True,[],['add',0,5,5]],), [[[5,5]],True,5])\ncheck('contract fixture 3', solve([5,False,False,[[0,1]],['add',0,2,3]],), [[[0,1]],False,1])\ncheck('contract fixture 4', solve([5,True,False,[[0,1],[2,3]],['replace',0,4,2]],), [[[4,2],[2,3]],True,3])\ncheck('contract fixture 5', solve([5,True,False,[[0,1],[2,3]],['remove',0,0,0]],), [[[2,3]],True,3])\ncheck('contract fixture 6', solve([5,False,False,[[0,1]],['clear',99,-1,99]],), [[],True,None])\ncheck('contract fixture 7', solve([5,True,False,[[0,1]],['replace',-1,2,3]],), [[[0,1]],False,1])\ncheck('contract fixture 8', solve([5,True,False,[],['add',0,-1,3]],), [[],False,None])\ncheck('contract fixture 9', solve([5,True,False,[],['add',0,1,6]],), [[],False,None])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"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.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"s3-accessibility-text-selection-api-anchor-bound","generated_at":"2026-09-29T14:45:45.240952+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Offline accessibility bridge model with explicit policy; useful for testing semantic API adapters independently of browser implementations.","repair":"Apply the exact contract at the anchor bound decision: 0 <= anchor <= length","root_cause":"The anchor bound decision in the text selection api adapter violates its declared contract.","sha256":"9b285e3d202157a18a057277d2c81e095af57b42aa6e073949fc4f2bbc5c2c75","title":"Selection API accepts a negative anchor · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":39.835,"exit_code":1,"observations":[{"actual":[[[0,1],[4,1]],true,1],"check":"contract fixture 1","expected":[[[0,1],[4,1]],true,1],"passed":true},{"actual":[[[5,5]],true,5],"check":"contract fixture 2","expected":[[[5,5]],true,5],"passed":true},{"actual":[[[0,1]],false,1],"check":"contract fixture 3","expected":[[[0,1]],false,1],"passed":true},{"actual":[[[4,2],[2,3]],true,3],"check":"contract fixture 4","expected":[[[4,2],[2,3]],true,3],"passed":true},{"actual":[[[2,3]],true,3],"check":"contract fixture 5","expected":[[[2,3]],true,3],"passed":true},{"actual":[[],true,null],"check":"contract fixture 6","expected":[[],true,null],"passed":true},{"actual":[[[0,1]],false,1],"check":"contract fixture 7","expected":[[[0,1]],false,1],"passed":true},{"actual":[[[-1,3]],true,3],"check":"contract fixture 8","expected":[[],false,null],"passed":false},{"actual":[[],false,null],"check":"contract fixture 9","expected":[[],false,null],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"contract fixture 1\", \"actual\": [[[0, 1], [4, 1]], true, 1], \"expected\": [[[0, 1], [4, 1]], true, 1], \"passed\": true}, {\"check\": \"contract fixture 2\", \"actual\": [[[5, 5]], true, 5], \"expected\": [[[5, 5]], true, 5], \"passed\": true}, {\"check\": \"contract fixture 3\", \"actual\": [[[0, 1]], false, 1], \"expected\": [[[0, 1]], false, 1], \"passed\": true}, {\"check\": \"contract fixture 4\", \"actual\": [[[4, 2], [2, 3]], true, 3], \"expected\": [[[4, 2], [2, 3]], true, 3], \"passed\": true}, {\"check\": \"contract fixture 5\", \"actual\": [[[2, 3]], true, 3], \"expected\": [[[2, 3]], true, 3], \"passed\": true}, {\"check\": \"contract fixture 6\", \"actual\": [[], true, null], \"expected\": [[], true, null], \"passed\": true}, {\"check\": \"contract fixture 7\", \"actual\": [[[0, 1]], false, 1], \"expected\": [[[0, 1]], false, 1], \"passed\": true}, {\"check\": \"contract fixture 8\", \"actual\": [[[-1, 3]], true, 3], \"expected\": [[], false, null], \"passed\": false}, {\"check\": \"contract fixture 9\", \"actual\": [[], false, null], \"expected\": [[], false, null], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.121,"exit_code":1,"observations":[{"actual":[[[0,1],[4,1]],true,1],"check":"contract fixture 1","expected":[[[0,1],[4,1]],true,1],"passed":true},{"actual":[[[5,5]],true,5],"check":"contract fixture 2","expected":[[[5,5]],true,5],"passed":true},{"actual":[[[0,1]],false,1],"check":"contract fixture 3","expected":[[[0,1]],false,1],"passed":true},{"actual":[[[4,2],[2,3]],true,3],"check":"contract fixture 4","expected":[[[4,2],[2,3]],true,3],"passed":true},{"actual":[[[2,3]],true,3],"check":"contract fixture 5","expected":[[[2,3]],true,3],"passed":true},{"actual":[[],true,null],"check":"contract fixture 6","expected":[[],true,null],"passed":true},{"actual":[[[0,1]],false,1],"check":"contract fixture 7","expected":[[[0,1]],false,1],"passed":true},{"actual":[[[-1,3]],true,3],"check":"contract fixture 8","expected":[[],false,null],"passed":false},{"actual":[[],false,null],"check":"contract fixture 9","expected":[[],false,null],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"contract fixture 1\", \"actual\": [[[0, 1], [4, 1]], true, 1], \"expected\": [[[0, 1], [4, 1]], true, 1], \"passed\": true}, {\"check\": \"contract fixture 2\", \"actual\": [[[5, 5]], true, 5], \"expected\": [[[5, 5]], true, 5], \"passed\": true}, {\"check\": \"contract fixture 3\", \"actual\": [[[0, 1]], false, 1], \"expected\": [[[0, 1]], false, 1], \"passed\": true}, {\"check\": \"contract fixture 4\", \"actual\": [[[4, 2], [2, 3]], true, 3], \"expected\": [[[4, 2], [2, 3]], true, 3], \"passed\": true}, {\"check\": \"contract fixture 5\", \"actual\": [[[2, 3]], true, 3], \"expected\": [[[2, 3]], true, 3], \"passed\": true}, {\"check\": \"contract fixture 6\", \"actual\": [[], true, null], \"expected\": [[], true, null], \"passed\": true}, {\"check\": \"contract fixture 7\", \"actual\": [[[0, 1]], false, 1], \"expected\": [[[0, 1]], false, 1], \"passed\": true}, {\"check\": \"contract fixture 8\", \"actual\": [[[-1, 3]], true, 3], \"expected\": [[], false, null], \"passed\": false}, {\"check\": \"contract fixture 9\", \"actual\": [[], false, null], \"expected\": [[], false, null], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":38.995,"exit_code":0,"observations":[{"actual":[[[0,1],[4,1]],true,1],"check":"contract fixture 1","expected":[[[0,1],[4,1]],true,1],"passed":true},{"actual":[[[5,5]],true,5],"check":"contract fixture 2","expected":[[[5,5]],true,5],"passed":true},{"actual":[[[0,1]],false,1],"check":"contract fixture 3","expected":[[[0,1]],false,1],"passed":true},{"actual":[[[4,2],[2,3]],true,3],"check":"contract fixture 4","expected":[[[4,2],[2,3]],true,3],"passed":true},{"actual":[[[2,3]],true,3],"check":"contract fixture 5","expected":[[[2,3]],true,3],"passed":true},{"actual":[[],true,null],"check":"contract fixture 6","expected":[[],true,null],"passed":true},{"actual":[[[0,1]],false,1],"check":"contract fixture 7","expected":[[[0,1]],false,1],"passed":true},{"actual":[[],false,null],"check":"contract fixture 8","expected":[[],false,null],"passed":true},{"actual":[[],false,null],"check":"contract fixture 9","expected":[[],false,null],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"contract fixture 1\", \"actual\": [[[0, 1], [4, 1]], true, 1], \"expected\": [[[0, 1], [4, 1]], true, 1], \"passed\": true}, {\"check\": \"contract fixture 2\", \"actual\": [[[5, 5]], true, 5], \"expected\": [[[5, 5]], true, 5], \"passed\": true}, {\"check\": \"contract fixture 3\", \"actual\": [[[0, 1]], false, 1], \"expected\": [[[0, 1]], false, 1], \"passed\": true}, {\"check\": \"contract fixture 4\", \"actual\": [[[4, 2], [2, 3]], true, 3], \"expected\": [[[4, 2], [2, 3]], true, 3], \"passed\": true}, {\"check\": \"contract fixture 5\", \"actual\": [[[2, 3]], true, 3], \"expected\": [[[2, 3]], true, 3], \"passed\": true}, {\"check\": \"contract fixture 6\", \"actual\": [[], true, null], \"expected\": [[], true, null], \"passed\": true}, {\"check\": \"contract fixture 7\", \"actual\": [[[0, 1]], false, 1], \"expected\": [[[0, 1]], false, 1], \"passed\": true}, {\"check\": \"contract fixture 8\", \"actual\": [[], false, null], \"expected\": [[], false, null], \"passed\": true}, {\"check\": \"contract fixture 9\", \"actual\": [[], false, null], \"expected\": [[], false, null], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}