{"abstract":"Clicking a removed item clears a valid selection.","category":"Selection controls","checks":8,"contract":"Ranges include both endpoints in document order; plain clicks replace; additive selection unions; missing targets preserve selection.","contract_signature":"items, selected, anchor, target, extend, additive","evaluation_group":"xi-range-selection","failed_approach":"Adding a removed target introduces a nonexistent selection.","family":"xi-range-selection-missing-target","id":"FA-7956","implementations":{"attempt":{"sha256":"f290219bc4204b39e9216ae96d61ad77ce08255ec741e604209c645253705e35","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(items, selected, anchor, target, extend, additive):\n    if target not in items: return sorted(set(selected) | {target})\n    if not extend or anchor not in items: span = {target}\n    else:\n        a, b = sorted((items.index(anchor), items.index(target)))\n        span = set(items[a:b+1])\n    return sorted(set(selected) | span if additive else span)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('removed', solve(['a','b'], ['a'], 'a', 'x', False, False), ['a'])\ncheck('plain', solve(['a','b','c'], ['a'], 'a', 'c', False, False), ['c'])\ncheck('forward', solve(['a','b','c'], [], 'a', 'c', True, False), ['a', 'b', 'c'])\ncheck('backward', solve(['a','b','c'], [], 'c', 'a', True, False), ['a', 'b', 'c'])\ncheck('union', solve(['a','b','c'], ['a'], 'b', 'c', True, True), ['a', 'b', 'c'])\ncheck('replace', solve(['a','b','c'], ['a'], 'b', 'c', True, False), ['b', 'c'])\ncheck('parameterized inclusive range', solve(list(range(N+2)), [], 0, N, True, False), list(range(N+1)))\nfor repetition in range(N):\n    check('repeat replace', solve(['a','b','c'], ['a'], 'b', 'c', True, False), ['b', 'c'])\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":"a6af63f73a0d88dcbb4ec9112bcc112a509d5d1c82f78f7ba24d15bff409a10a","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(items, selected, anchor, target, extend, additive):\n    if target not in items: return []\n    if not extend or anchor not in items: span = {target}\n    else:\n        a, b = sorted((items.index(anchor), items.index(target)))\n        span = set(items[a:b+1])\n    return sorted(set(selected) | span if additive else span)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('removed', solve(['a','b'], ['a'], 'a', 'x', False, False), ['a'])\ncheck('plain', solve(['a','b','c'], ['a'], 'a', 'c', False, False), ['c'])\ncheck('forward', solve(['a','b','c'], [], 'a', 'c', True, False), ['a', 'b', 'c'])\ncheck('backward', solve(['a','b','c'], [], 'c', 'a', True, False), ['a', 'b', 'c'])\ncheck('union', solve(['a','b','c'], ['a'], 'b', 'c', True, True), ['a', 'b', 'c'])\ncheck('replace', solve(['a','b','c'], ['a'], 'b', 'c', True, False), ['b', 'c'])\ncheck('parameterized inclusive range', solve(list(range(N+2)), [], 0, N, True, False), list(range(N+1)))\nfor repetition in range(N):\n    check('repeat replace', solve(['a','b','c'], ['a'], 'b', 'c', True, False), ['b', 'c'])\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-range-selection-missing-target","generated_at":"2026-09-29T14:38:17.048216+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic model of anchored range selection; this isolates one interface invariant without requiring a browser.","root_cause":"The missing target operation uses `return []` where the contract requires `return sorted(selected)`.","sha256":"6f4e30105e40657666ee6903060695e4c26c761857982bbb3d8162de45ac6b6e","title":"Anchored range selection: Clicking a removed item clears a valid selection · 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":40.221,"exit_code":1,"observations":[{"actual":["a","x"],"check":"removed","expected":["a"],"passed":false},{"actual":["c"],"check":"plain","expected":["c"],"passed":true},{"actual":["a","b","c"],"check":"forward","expected":["a","b","c"],"passed":true},{"actual":["a","b","c"],"check":"backward","expected":["a","b","c"],"passed":true},{"actual":["a","b","c"],"check":"union","expected":["a","b","c"],"passed":true},{"actual":["b","c"],"check":"replace","expected":["b","c"],"passed":true},{"actual":[0,1],"check":"parameterized inclusive range","expected":[0,1],"passed":true},{"actual":["b","c"],"check":"repeat replace","expected":["b","c"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"removed\", \"actual\": [\"a\", \"x\"], \"expected\": [\"a\"], \"passed\": false}, {\"check\": \"plain\", \"actual\": [\"c\"], \"expected\": [\"c\"], \"passed\": true}, {\"check\": \"forward\", \"actual\": [\"a\", \"b\", \"c\"], \"expected\": [\"a\", \"b\", \"c\"], \"passed\": true}, {\"check\": \"backward\", \"actual\": [\"a\", \"b\", \"c\"], \"expected\": [\"a\", \"b\", \"c\"], \"passed\": true}, {\"check\": \"union\", \"actual\": [\"a\", \"b\", \"c\"], \"expected\": [\"a\", \"b\", \"c\"], \"passed\": true}, {\"check\": \"replace\", \"actual\": [\"b\", \"c\"], \"expected\": [\"b\", \"c\"], \"passed\": true}, {\"check\": \"parameterized inclusive range\", \"actual\": [0, 1], \"expected\": [0, 1], \"passed\": true}, {\"check\": \"repeat replace\", \"actual\": [\"b\", \"c\"], \"expected\": [\"b\", \"c\"], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":38.556,"exit_code":1,"observations":[{"actual":[],"check":"removed","expected":["a"],"passed":false},{"actual":["c"],"check":"plain","expected":["c"],"passed":true},{"actual":["a","b","c"],"check":"forward","expected":["a","b","c"],"passed":true},{"actual":["a","b","c"],"check":"backward","expected":["a","b","c"],"passed":true},{"actual":["a","b","c"],"check":"union","expected":["a","b","c"],"passed":true},{"actual":["b","c"],"check":"replace","expected":["b","c"],"passed":true},{"actual":[0,1],"check":"parameterized inclusive range","expected":[0,1],"passed":true},{"actual":["b","c"],"check":"repeat replace","expected":["b","c"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"removed\", \"actual\": [], \"expected\": [\"a\"], \"passed\": false}, {\"check\": \"plain\", \"actual\": [\"c\"], \"expected\": [\"c\"], \"passed\": true}, {\"check\": \"forward\", \"actual\": [\"a\", \"b\", \"c\"], \"expected\": [\"a\", \"b\", \"c\"], \"passed\": true}, {\"check\": \"backward\", \"actual\": [\"a\", \"b\", \"c\"], \"expected\": [\"a\", \"b\", \"c\"], \"passed\": true}, {\"check\": \"union\", \"actual\": [\"a\", \"b\", \"c\"], \"expected\": [\"a\", \"b\", \"c\"], \"passed\": true}, {\"check\": \"replace\", \"actual\": [\"b\", \"c\"], \"expected\": [\"b\", \"c\"], \"passed\": true}, {\"check\": \"parameterized inclusive range\", \"actual\": [0, 1], \"expected\": [0, 1], \"passed\": true}, {\"check\": \"repeat replace\", \"actual\": [\"b\", \"c\"], \"expected\": [\"b\", \"c\"], \"passed\": true}], \"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."}}