{"abstract":"The operation returns a result or retained state that violates this contract: A local shared-ownership model executes [operation,handle,argument] commands. Only owners retain the resource. Output is one result per command; weak and borrowed handles do not retain it. An owner is unique when exactly one owner exists, regardless of weak and borrowed handles.","category":"Runtime and resources","checks":5,"contract":"A local shared-ownership model executes [operation,handle,argument] commands. Only owners retain the resource. Output is one result per command; weak and borrowed handles do not retain it. An owner is unique when exactly one owner exists, regardless of weak and borrowed handles. Inputs are the finite Python values shown by the executable fixtures; no concurrent execution is assumed.","contract_signature":"x, y=None","evaluation_group":"xr-suite-owner-clone-requires-live-owner","failed_approach":"The attempted transition changes the behavior but still violates the same invariant in at least one independent regression fixture.","family":"xr-uniqueness-counts-only-owners","id":"FA-4466","implementations":{"attempt":{"sha256":"72874aef850a34e67e19335544907d30751217728e0544889924884bfe75db88","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x, y=None):\n    h={'root':'owner'}; destroyed=False; out=[]\n    for op,k,arg in x:\n        owners=lambda: sum(v=='owner' for v in h.values())\n        if op=='clone':\n            ok=h.get(arg)=='owner' and k not in h and not destroyed\n            if ok: h[k]='owner'\n            out.append(ok)\n        elif op=='borrow':\n            ok=h.get(arg)=='owner' and k not in h and not destroyed\n            if ok: h[k]='borrow'\n            out.append(ok)\n        elif op=='weak':\n            ok=k not in h\n            if ok: h[k]='weak'\n            out.append(ok)\n        elif op=='upgrade':\n            ok=h.get(k)=='weak' and owners()>0 and arg not in h and not destroyed\n            if ok: h[arg]='owner'\n            out.append(ok)\n        elif op=='drop':\n            existed=k in h\n            kind=h.pop(k,None)\n            if kind=='owner' and owners()==0: destroyed=True\n            out.append(existed)\n        elif op=='move':\n            ok=k in h and arg not in h\n            if ok:\n                h[arg]=h[k]\n                del h[k]\n            out.append(ok)\n        elif op=='use':\n            out.append(h.get(k) in ('owner','borrow') and owners()>0 and not destroyed)\n        elif op=='unique':\n            out.append(owners()==1 and not destroyed)\n        elif op=='inspect':\n            out.append([owners(),destroyed,sorted(h)])\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('borrow cannot clone or outlive resource', solve([['borrow', 'b', 'root'], ['clone', 'c', 'b'], ['weak', 'w', None], ['use', 'w', None], ['unique', 'root', None], ['unique', 'b', None], ['drop', 'root', None], ['use', 'b', None], ['upgrade', 'w', 'c'], ['inspect', None, None]]), [True, False, True, False, True, False, True, False, False, [0, True, ['b', 'w']]])\ncheck('clones prevent premature destruction', solve([['clone', 'c', 'root'], ['drop', 'root', None], ['use', 'c', None], ['inspect', None, None], ['drop', 'c', None], ['inspect', None, None]]), [True, True, True, [1, False, ['c']], True, [0, True, []]])\ncheck('destination collisions preserve all handles', solve([['clone', 'c', 'root'], ['borrow', 'b', 'root'], ['clone', 'b', 'root'], ['borrow', 'c', 'root'], ['weak', 'w', None], ['upgrade', 'w', 'b'], ['move', 'root', 'c'], ['move', 'root', 'root'], ['inspect', None, None]]), [True, True, False, False, True, False, False, False, [2, False, ['b', 'c', 'root', 'w']]])\ncheck('move and borrower release preserve ownership', solve([['borrow', 'b', 'root'], ['drop', 'b', None], ['move', 'root', 'new'], ['use', 'root', None], ['borrow', 'b', 'new'], ['weak', 'w', None], ['upgrade', 'w', 'c'], ['borrow', 'z', 'b'], ['inspect', None, None]]), [True, True, True, False, True, True, True, False, [2, False, ['b', 'c', 'new', 'w']]])\ncheck('weak collision cannot discard owner', solve([['weak','root',None],['inspect',None,None]]), [False,[1,False,['root']]])\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":"eb6b94e1406550619fb7101faf73edfdb43895bc79630c38f8d9eaedaec51a8c","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x, y=None):\n    h={'root':'owner'}; destroyed=False; out=[]\n    for op,k,arg in x:\n        owners=lambda: sum(v=='owner' for v in h.values())\n        if op=='clone':\n            ok=h.get(arg)=='owner' and k not in h and not destroyed\n            if ok: h[k]='owner'\n            out.append(ok)\n        elif op=='borrow':\n            ok=h.get(arg)=='owner' and k not in h and not destroyed\n            if ok: h[k]='borrow'\n            out.append(ok)\n        elif op=='weak':\n            ok=k not in h\n            if ok: h[k]='weak'\n            out.append(ok)\n        elif op=='upgrade':\n            ok=h.get(k)=='weak' and owners()>0 and arg not in h and not destroyed\n            if ok: h[arg]='owner'\n            out.append(ok)\n        elif op=='drop':\n            existed=k in h\n            kind=h.pop(k,None)\n            if kind=='owner' and owners()==0: destroyed=True\n            out.append(existed)\n        elif op=='move':\n            ok=k in h and arg not in h\n            if ok:\n                h[arg]=h[k]\n                del h[k]\n            out.append(ok)\n        elif op=='use':\n            out.append(h.get(k) in ('owner','borrow') and owners()>0 and not destroyed)\n        elif op=='unique':\n            out.append(h.get(k)=='owner' and len(h)==1)\n        elif op=='inspect':\n            out.append([owners(),destroyed,sorted(h)])\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('borrow cannot clone or outlive resource', solve([['borrow', 'b', 'root'], ['clone', 'c', 'b'], ['weak', 'w', None], ['use', 'w', None], ['unique', 'root', None], ['unique', 'b', None], ['drop', 'root', None], ['use', 'b', None], ['upgrade', 'w', 'c'], ['inspect', None, None]]), [True, False, True, False, True, False, True, False, False, [0, True, ['b', 'w']]])\ncheck('clones prevent premature destruction', solve([['clone', 'c', 'root'], ['drop', 'root', None], ['use', 'c', None], ['inspect', None, None], ['drop', 'c', None], ['inspect', None, None]]), [True, True, True, [1, False, ['c']], True, [0, True, []]])\ncheck('destination collisions preserve all handles', solve([['clone', 'c', 'root'], ['borrow', 'b', 'root'], ['clone', 'b', 'root'], ['borrow', 'c', 'root'], ['weak', 'w', None], ['upgrade', 'w', 'b'], ['move', 'root', 'c'], ['move', 'root', 'root'], ['inspect', None, None]]), [True, True, False, False, True, False, False, False, [2, False, ['b', 'c', 'root', 'w']]])\ncheck('move and borrower release preserve ownership', solve([['borrow', 'b', 'root'], ['drop', 'b', None], ['move', 'root', 'new'], ['use', 'root', None], ['borrow', 'b', 'new'], ['weak', 'w', None], ['upgrade', 'w', 'c'], ['borrow', 'z', 'b'], ['inspect', None, None]]), [True, True, True, False, True, True, True, False, [2, False, ['b', 'c', 'new', 'w']]])\ncheck('weak collision cannot discard owner', solve([['weak','root',None],['inspect',None,None]]), [False,[1,False,['root']]])\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":"xr-uniqueness-counts-only-owners","generated_at":"2026-09-29T14:37:39.327224+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A controlled local-runtime regression for collection APIs, language semantics, or ownership wrappers. Fixtures include boundary and interaction cases.","root_cause":"An owner is unique when exactly one owner exists, regardless of weak and borrowed handles. The broken transition violates that invariant.","sha256":"6ccc52c9eb8f5d717db32046c794a3a6e1fa41f2e6d080d8e6b496a5f008d154","title":"Uniqueness counts only owners · case 01","variant":1,"variant_policy":"Five execution reruns of a fixed adversarial fixture suite; variant number does not alter semantic inputs.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":109.759,"exit_code":1,"observations":[{"actual":[true,false,true,false,true,true,true,false,false,[0,true,["b","w"]]],"check":"borrow cannot clone or outlive resource","expected":[true,false,true,false,true,false,true,false,false,[0,true,["b","w"]]],"passed":false},{"actual":[true,true,true,[1,false,["c"]],true,[0,true,[]]],"check":"clones prevent premature destruction","expected":[true,true,true,[1,false,["c"]],true,[0,true,[]]],"passed":true},{"actual":[true,true,false,false,true,false,false,false,[2,false,["b","c","root","w"]]],"check":"destination collisions preserve all handles","expected":[true,true,false,false,true,false,false,false,[2,false,["b","c","root","w"]]],"passed":true},{"actual":[true,true,true,false,true,true,true,false,[2,false,["b","c","new","w"]]],"check":"move and borrower release preserve ownership","expected":[true,true,true,false,true,true,true,false,[2,false,["b","c","new","w"]]],"passed":true},{"actual":[false,[1,false,["root"]]],"check":"weak collision cannot discard owner","expected":[false,[1,false,["root"]]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"borrow cannot clone or outlive resource\", \"actual\": [true, false, true, false, true, true, true, false, false, [0, true, [\"b\", \"w\"]]], \"expected\": [true, false, true, false, true, false, true, false, false, [0, true, [\"b\", \"w\"]]], \"passed\": false}, {\"check\": \"clones prevent premature destruction\", \"actual\": [true, true, true, [1, false, [\"c\"]], true, [0, true, []]], \"expected\": [true, true, true, [1, false, [\"c\"]], true, [0, true, []]], \"passed\": true}, {\"check\": \"destination collisions preserve all handles\", \"actual\": [true, true, false, false, true, false, false, false, [2, false, [\"b\", \"c\", \"root\", \"w\"]]], \"expected\": [true, true, false, false, true, false, false, false, [2, false, [\"b\", \"c\", \"root\", \"w\"]]], \"passed\": true}, {\"check\": \"move and borrower release preserve ownership\", \"actual\": [true, true, true, false, true, true, true, false, [2, false, [\"b\", \"c\", \"new\", \"w\"]]], \"expected\": [true, true, true, false, true, true, true, false, [2, false, [\"b\", \"c\", \"new\", \"w\"]]], \"passed\": true}, {\"check\": \"weak collision cannot discard owner\", \"actual\": [false, [1, false, [\"root\"]]], \"expected\": [false, [1, false, [\"root\"]]], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":44.204,"exit_code":1,"observations":[{"actual":[true,false,true,false,false,false,true,false,false,[0,true,["b","w"]]],"check":"borrow cannot clone or outlive resource","expected":[true,false,true,false,true,false,true,false,false,[0,true,["b","w"]]],"passed":false},{"actual":[true,true,true,[1,false,["c"]],true,[0,true,[]]],"check":"clones prevent premature destruction","expected":[true,true,true,[1,false,["c"]],true,[0,true,[]]],"passed":true},{"actual":[true,true,false,false,true,false,false,false,[2,false,["b","c","root","w"]]],"check":"destination collisions preserve all handles","expected":[true,true,false,false,true,false,false,false,[2,false,["b","c","root","w"]]],"passed":true},{"actual":[true,true,true,false,true,true,true,false,[2,false,["b","c","new","w"]]],"check":"move and borrower release preserve ownership","expected":[true,true,true,false,true,true,true,false,[2,false,["b","c","new","w"]]],"passed":true},{"actual":[false,[1,false,["root"]]],"check":"weak collision cannot discard owner","expected":[false,[1,false,["root"]]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"borrow cannot clone or outlive resource\", \"actual\": [true, false, true, false, false, false, true, false, false, [0, true, [\"b\", \"w\"]]], \"expected\": [true, false, true, false, true, false, true, false, false, [0, true, [\"b\", \"w\"]]], \"passed\": false}, {\"check\": \"clones prevent premature destruction\", \"actual\": [true, true, true, [1, false, [\"c\"]], true, [0, true, []]], \"expected\": [true, true, true, [1, false, [\"c\"]], true, [0, true, []]], \"passed\": true}, {\"check\": \"destination collisions preserve all handles\", \"actual\": [true, true, false, false, true, false, false, false, [2, false, [\"b\", \"c\", \"root\", \"w\"]]], \"expected\": [true, true, false, false, true, false, false, false, [2, false, [\"b\", \"c\", \"root\", \"w\"]]], \"passed\": true}, {\"check\": \"move and borrower release preserve ownership\", \"actual\": [true, true, true, false, true, true, true, false, [2, false, [\"b\", \"c\", \"new\", \"w\"]]], \"expected\": [true, true, true, false, true, true, true, false, [2, false, [\"b\", \"c\", \"new\", \"w\"]]], \"passed\": true}, {\"check\": \"weak collision cannot discard owner\", \"actual\": [false, [1, false, [\"root\"]]], \"expected\": [false, [1, false, [\"root\"]]], \"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."}}