{"abstract":"A singleton semantic reading flow is dropped as already complete.","category":"Accessibility interaction semantics","checks":8,"contract":"Input [natural_ids,edges,excluded,start] where edges are directed reading-flow overrides. Keep unique natural IDs in original order excluding excluded IDs. Admit edges between eligible distinct IDs; first outgoing edge wins. Reading starts at specified eligible ID otherwise first eligible. Follow override if target unvisited; otherwise take earliest unvisited natural node. Include each eligible object exactly once, prevent cycles, and return list of IDs. Explicit start does not remove earlier unvisited nodes.","contract_signature":"data","evaluation_group":"s3-accessibility-reading-flow","failed_approach":"The local repair substitutes if len(items) == 1: return []\nif not items: return [] but still mishandles the regression fixtures.","family":"s3-accessibility-reading-flow-singleton-completion","id":"FA-53906","implementations":{"attempt":{"sha256":"e376c0bd17aaf45bdf742d7ee8f6b90098d9b6de74e095d3f89d32d3cef0e286","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(data):\n    natural,edges,excluded,start = data\n    items = list(dict.fromkeys(x for x in natural if x not in excluded))\n    if len(items) == 1: return []\n    if not items: return []\n    links = {}\n    for source,target in edges:\n        if source not in items or target not in items or source == target: continue\n        links.setdefault(source,target)\n    current = start if start in items else items[0]\n    seen = set()\n    result = []\n    while current is not None:\n        result.append(current)\n        seen.add(current)\n        nxt = links.get(current)\n        current = nxt if nxt is not None and nxt not in seen else next((x for x in items if x not in seen),None)\n    return result\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('contract fixture 1', solve([['a','b','c',str(N)],[['a','c'],['c','a']],[],'a'],), ['a','c','b',str(N)])\ncheck('contract fixture 2', solve([['a','b','c'],[['a','c'],['a','b']],[],'a'],), ['a','c','b'])\ncheck('contract fixture 3', solve([['a','b','c'],[['a','b'],['a','missing']],['b'],'a'],), ['a','c'])\ncheck('contract fixture 4', solve([['a','b','c'],[],[],'c'],), ['c','a','b'])\ncheck('contract fixture 5', solve([['b','a','b'],[['b','b']],[],'missing'],), ['b','a'])\ncheck('contract fixture 6', solve([['a'],[['a','missing']],['a'],'a'],), [])\ncheck('contract fixture 7', solve([['','a'],[['','a']],[],''],), ['','a'])\ncheck('contract fixture 8', solve([['only'],[],[],'only'],), ['only'])\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":"5815d6194627039e8d89b0903724a5108b273aa30744990488b7137002fa0286","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(data):\n    natural,edges,excluded,start = data\n    items = list(dict.fromkeys(x for x in natural if x not in excluded))\n    if len(items) < 2: return []\n    links = {}\n    for source,target in edges:\n        if source not in items or target not in items or source == target: continue\n        links.setdefault(source,target)\n    current = start if start in items else items[0]\n    seen = set()\n    result = []\n    while current is not None:\n        result.append(current)\n        seen.add(current)\n        nxt = links.get(current)\n        current = nxt if nxt is not None and nxt not in seen else next((x for x in items if x not in seen),None)\n    return result\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('contract fixture 1', solve([['a','b','c',str(N)],[['a','c'],['c','a']],[],'a'],), ['a','c','b',str(N)])\ncheck('contract fixture 2', solve([['a','b','c'],[['a','c'],['a','b']],[],'a'],), ['a','c','b'])\ncheck('contract fixture 3', solve([['a','b','c'],[['a','b'],['a','missing']],['b'],'a'],), ['a','c'])\ncheck('contract fixture 4', solve([['a','b','c'],[],[],'c'],), ['c','a','b'])\ncheck('contract fixture 5', solve([['b','a','b'],[['b','b']],[],'missing'],), ['b','a'])\ncheck('contract fixture 6', solve([['a'],[['a','missing']],['a'],'a'],), [])\ncheck('contract fixture 7', solve([['','a'],[['','a']],[],''],), ['','a'])\ncheck('contract fixture 8', solve([['only'],[],[],'only'],), ['only'])\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-reading-flow-singleton-completion","generated_at":"2026-09-29T14:45:43.846653+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.","root_cause":"The singleton completion decision in the reading flow adapter violates its declared contract.","sha256":"29b8be75ad8bc22dc4cc6ec88ef0f371db105ee5a407f810ad1ca8fd5043ebba","title":"A singleton semantic reading flow is dropped as already complete · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":39.855,"exit_code":1,"observations":[{"actual":["a","c","b","1"],"check":"contract fixture 1","expected":["a","c","b","1"],"passed":true},{"actual":["a","c","b"],"check":"contract fixture 2","expected":["a","c","b"],"passed":true},{"actual":["a","c"],"check":"contract fixture 3","expected":["a","c"],"passed":true},{"actual":["c","a","b"],"check":"contract fixture 4","expected":["c","a","b"],"passed":true},{"actual":["b","a"],"check":"contract fixture 5","expected":["b","a"],"passed":true},{"actual":[],"check":"contract fixture 6","expected":[],"passed":true},{"actual":["","a"],"check":"contract fixture 7","expected":["","a"],"passed":true},{"actual":[],"check":"contract fixture 8","expected":["only"],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"contract fixture 1\", \"actual\": [\"a\", \"c\", \"b\", \"1\"], \"expected\": [\"a\", \"c\", \"b\", \"1\"], \"passed\": true}, {\"check\": \"contract fixture 2\", \"actual\": [\"a\", \"c\", \"b\"], \"expected\": [\"a\", \"c\", \"b\"], \"passed\": true}, {\"check\": \"contract fixture 3\", \"actual\": [\"a\", \"c\"], \"expected\": [\"a\", \"c\"], \"passed\": true}, {\"check\": \"contract fixture 4\", \"actual\": [\"c\", \"a\", \"b\"], \"expected\": [\"c\", \"a\", \"b\"], \"passed\": true}, {\"check\": \"contract fixture 5\", \"actual\": [\"b\", \"a\"], \"expected\": [\"b\", \"a\"], \"passed\": true}, {\"check\": \"contract fixture 6\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"contract fixture 7\", \"actual\": [\"\", \"a\"], \"expected\": [\"\", \"a\"], \"passed\": true}, {\"check\": \"contract fixture 8\", \"actual\": [], \"expected\": [\"only\"], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.934,"exit_code":1,"observations":[{"actual":["a","c","b","1"],"check":"contract fixture 1","expected":["a","c","b","1"],"passed":true},{"actual":["a","c","b"],"check":"contract fixture 2","expected":["a","c","b"],"passed":true},{"actual":["a","c"],"check":"contract fixture 3","expected":["a","c"],"passed":true},{"actual":["c","a","b"],"check":"contract fixture 4","expected":["c","a","b"],"passed":true},{"actual":["b","a"],"check":"contract fixture 5","expected":["b","a"],"passed":true},{"actual":[],"check":"contract fixture 6","expected":[],"passed":true},{"actual":["","a"],"check":"contract fixture 7","expected":["","a"],"passed":true},{"actual":[],"check":"contract fixture 8","expected":["only"],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"contract fixture 1\", \"actual\": [\"a\", \"c\", \"b\", \"1\"], \"expected\": [\"a\", \"c\", \"b\", \"1\"], \"passed\": true}, {\"check\": \"contract fixture 2\", \"actual\": [\"a\", \"c\", \"b\"], \"expected\": [\"a\", \"c\", \"b\"], \"passed\": true}, {\"check\": \"contract fixture 3\", \"actual\": [\"a\", \"c\"], \"expected\": [\"a\", \"c\"], \"passed\": true}, {\"check\": \"contract fixture 4\", \"actual\": [\"c\", \"a\", \"b\"], \"expected\": [\"c\", \"a\", \"b\"], \"passed\": true}, {\"check\": \"contract fixture 5\", \"actual\": [\"b\", \"a\"], \"expected\": [\"b\", \"a\"], \"passed\": true}, {\"check\": \"contract fixture 6\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"contract fixture 7\", \"actual\": [\"\", \"a\"], \"expected\": [\"\", \"a\"], \"passed\": true}, {\"check\": \"contract fixture 8\", \"actual\": [], \"expected\": [\"only\"], \"passed\": false}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}