{"abstract":"Current location appears before its ancestors.","category":"Client navigation","checks":7,"contract":"Append current after ancestors; optionally hide a distinct root; collapse long paths preserving root and recent tail within budget; only ancestors are links. Budget is at least two.","contract_signature":"ancestors, current, max_items, include_root","evaluation_group":"xi-breadcrumb","failed_approach":"Omitting the current location loses page context.","family":"xi-breadcrumb-current","id":"FA-8631","implementations":{"attempt":{"sha256":"8605646f8a8d81e6cb5a35c8bc33df38a8da9c6efa45cc4ae6fc78a76aaf0804","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(ancestors, current, max_items, include_root):\n    chain = list(ancestors)\n    if not include_root and len(chain) > 1: chain = chain[1:]\n    if len(chain) > max_items:\n        chain = [chain[0], '…'] + chain[-(max_items-2):] if max_items > 2 else chain[-max_items:]\n    return [(x, i != len(chain)-1) for i, x in enumerate(chain)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('normal', solve(['root','parent'], 'current', 5, True), [('root', True), ('parent', True), ('current', False)])\ncheck('only current', solve([], 'current', 5, False), [('current', False)])\ncheck('hide root', solve(['root','parent'], 'current', 5, False), [('parent', True), ('current', False)])\ncheck('collapsed', solve(['root','a','b','c'], 'current', 4, True), [('root', True), ('…', True), ('c', True), ('current', False)])\ncheck('small budget', solve(['root','a','b'], 'current', 2, True), [('b', True), ('current', False)])\ncheck('parameterized ancestor depth', solve(list(range(N)),N,N+2,True), [(i,i!=N) for i in range(N+1)])\nfor repetition in range(N):\n    check('repeat small budget', solve(['root','a','b'], 'current', 2, True), [('b', True), ('current', False)])\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":"b955e7b34b1d81b45ac5c0553193578d905871f5699746819f98e3cd1a190436","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(ancestors, current, max_items, include_root):\n    chain = [current] + list(ancestors)\n    if not include_root and len(chain) > 1: chain = chain[1:]\n    if len(chain) > max_items:\n        chain = [chain[0], '…'] + chain[-(max_items-2):] if max_items > 2 else chain[-max_items:]\n    return [(x, i != len(chain)-1) for i, x in enumerate(chain)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('normal', solve(['root','parent'], 'current', 5, True), [('root', True), ('parent', True), ('current', False)])\ncheck('only current', solve([], 'current', 5, False), [('current', False)])\ncheck('hide root', solve(['root','parent'], 'current', 5, False), [('parent', True), ('current', False)])\ncheck('collapsed', solve(['root','a','b','c'], 'current', 4, True), [('root', True), ('…', True), ('c', True), ('current', False)])\ncheck('small budget', solve(['root','a','b'], 'current', 2, True), [('b', True), ('current', False)])\ncheck('parameterized ancestor depth', solve(list(range(N)),N,N+2,True), [(i,i!=N) for i in range(N+1)])\nfor repetition in range(N):\n    check('repeat small budget', solve(['root','a','b'], 'current', 2, True), [('b', True), ('current', False)])\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":" 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":"xi-breadcrumb-current","generated_at":"2026-09-29T14:38:23.239034+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic model of breadcrumb ancestor rendering; this isolates one interface invariant without requiring a browser.","root_cause":"The current operation uses `[current] + list(ancestors)` where the contract requires `list(ancestors) + [current]`.","sha256":"862898af3f8f10ae2794c7c9b08f9ba3e32789e6cc15057c5cb0d368934d813a","title":"Breadcrumb ancestor rendering: Current location appears before its ancestors · 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":37.367,"exit_code":1,"observations":[{"actual":[["root",true],["parent",false]],"check":"normal","expected":[["root",true],["parent",true],["current",false]],"passed":false},{"actual":[],"check":"only current","expected":[["current",false]],"passed":false},{"actual":[["parent",false]],"check":"hide root","expected":[["parent",true],["current",false]],"passed":false},{"actual":[["root",true],["a",true],["b",true],["c",false]],"check":"collapsed","expected":[["root",true],["…",true],["c",true],["current",false]],"passed":false},{"actual":[["a",true],["b",false]],"check":"small budget","expected":[["b",true],["current",false]],"passed":false},{"actual":[[0,false]],"check":"parameterized ancestor depth","expected":[[0,true],[1,false]],"passed":false},{"actual":[["a",true],["b",false]],"check":"repeat small budget","expected":[["b",true],["current",false]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"normal\", \"actual\": [[\"root\", true], [\"parent\", false]], \"expected\": [[\"root\", true], [\"parent\", true], [\"current\", false]], \"passed\": false}, {\"check\": \"only current\", \"actual\": [], \"expected\": [[\"current\", false]], \"passed\": false}, {\"check\": \"hide root\", \"actual\": [[\"parent\", false]], \"expected\": [[\"parent\", true], [\"current\", false]], \"passed\": false}, {\"check\": \"collapsed\", \"actual\": [[\"root\", true], [\"a\", true], [\"b\", true], [\"c\", false]], \"expected\": [[\"root\", true], [\"…\", true], [\"c\", true], [\"current\", false]], \"passed\": false}, {\"check\": \"small budget\", \"actual\": [[\"a\", true], [\"b\", false]], \"expected\": [[\"b\", true], [\"current\", false]], \"passed\": false}, {\"check\": \"parameterized ancestor depth\", \"actual\": [[0, false]], \"expected\": [[0, true], [1, false]], \"passed\": false}, {\"check\": \"repeat small budget\", \"actual\": [[\"a\", true], [\"b\", false]], \"expected\": [[\"b\", true], [\"current\", false]], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.213,"exit_code":1,"observations":[{"actual":[["current",true],["root",true],["parent",false]],"check":"normal","expected":[["root",true],["parent",true],["current",false]],"passed":false},{"actual":[["current",false]],"check":"only current","expected":[["current",false]],"passed":true},{"actual":[["root",true],["parent",false]],"check":"hide root","expected":[["parent",true],["current",false]],"passed":false},{"actual":[["current",true],["…",true],["b",true],["c",false]],"check":"collapsed","expected":[["root",true],["…",true],["c",true],["current",false]],"passed":false},{"actual":[["a",true],["b",false]],"check":"small budget","expected":[["b",true],["current",false]],"passed":false},{"actual":[[1,true],[0,false]],"check":"parameterized ancestor depth","expected":[[0,true],[1,false]],"passed":false},{"actual":[["a",true],["b",false]],"check":"repeat small budget","expected":[["b",true],["current",false]],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"normal\", \"actual\": [[\"current\", true], [\"root\", true], [\"parent\", false]], \"expected\": [[\"root\", true], [\"parent\", true], [\"current\", false]], \"passed\": false}, {\"check\": \"only current\", \"actual\": [[\"current\", false]], \"expected\": [[\"current\", false]], \"passed\": true}, {\"check\": \"hide root\", \"actual\": [[\"root\", true], [\"parent\", false]], \"expected\": [[\"parent\", true], [\"current\", false]], \"passed\": false}, {\"check\": \"collapsed\", \"actual\": [[\"current\", true], [\"…\", true], [\"b\", true], [\"c\", false]], \"expected\": [[\"root\", true], [\"…\", true], [\"c\", true], [\"current\", false]], \"passed\": false}, {\"check\": \"small budget\", \"actual\": [[\"a\", true], [\"b\", false]], \"expected\": [[\"b\", true], [\"current\", false]], \"passed\": false}, {\"check\": \"parameterized ancestor depth\", \"actual\": [[1, true], [0, false]], \"expected\": [[0, true], [1, false]], \"passed\": false}, {\"check\": \"repeat small budget\", \"actual\": [[\"a\", true], [\"b\", false]], \"expected\": [[\"b\", true], [\"current\", false]], \"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."}}