{"abstract":"Drops instance binding for ordinary instance access and changes the required Python-language result.","category":"Descriptor lookup","checks":5,"contract":"Return [instance_is_None,owner_class_name] observed by an inherited descriptor for class, instance and super access. Owner is the accessing subclass, not necessarily the descriptor-defining class. Inputs use the finite Python types shown in the fixtures. An error string denotes the specified caught exception, not an unhandled process failure.","evaluation_group":"xl-descriptor-owner-argument","failed_approach":"The alternative still fails because it passes the metaclass rather than the owner class identity.","family":"xl-descriptor-owner-argument-all-access-class-only","id":"FA-5046","implementations":{"attempt":{"sha256":"031436d10fc505e9f13bc60a20599632517831e98db2a7985f9f505fbd13a315","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(mode):\n    class D:\n        def __get__(self,obj,owner): return [obj is None,type(owner).__name__]\n    class Base:\n        field=D()\n    class Child(Base): pass\n    obj=Child()\n    if mode=='base-class': return Base.field\n    if mode=='child-class': return Child.field\n    if mode=='instance': return obj.field\n    if mode=='super': return super(Child,obj).field\n    return Base().field\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('defining class access', solve('base-class'), [True, 'Base'])\ncheck('inherited class access', solve('child-class'), [True, 'Child'])\ncheck('subclass instance', solve('instance'), [False, 'Child'])\ncheck('super keeps dynamic owner', solve('super'), [False, 'Child'])\ncheck('base instance', solve('base-instance'), [False, 'Base'])\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":"33b89edaae709b1b4cf6bf04d626e58e65ab92fbfc089c3bc0c86f7511182ba3","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(mode):\n    class D:\n        def __get__(self,obj,owner): return [True,owner.__name__]\n    class Base:\n        field=D()\n    class Child(Base): pass\n    obj=Child()\n    if mode=='base-class': return Base.field\n    if mode=='child-class': return Child.field\n    if mode=='instance': return obj.field\n    if mode=='super': return super(Child,obj).field\n    return Base().field\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('defining class access', solve('base-class'), [True, 'Base'])\ncheck('inherited class access', solve('child-class'), [True, 'Child'])\ncheck('subclass instance', solve('instance'), [False, 'Child'])\ncheck('super keeps dynamic owner', solve('super'), [False, 'Child'])\ncheck('base instance', solve('base-instance'), [False, 'Base'])\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":"e13764a3905a1d701f986a8f8b660fd6ecaedf7105c7bc355bf253b524f5e66c","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(mode):\n    class D:\n        def __get__(self,obj,owner): return [obj is None,owner.__name__]\n    class Base:\n        field=D()\n    class Child(Base): pass\n    obj=Child()\n    if mode=='base-class': return Base.field\n    if mode=='child-class': return Child.field\n    if mode=='instance': return obj.field\n    if mode=='super': return super(Child,obj).field\n    return Base().field\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('defining class access', solve('base-class'), [True, 'Base'])\ncheck('inherited class access', solve('child-class'), [True, 'Child'])\ncheck('subclass instance', solve('instance'), [False, 'Child'])\ncheck('super keeps dynamic owner', solve('super'), [False, 'Child'])\ncheck('base instance', solve('base-instance'), [False, 'Base'])\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":"xl-descriptor-owner-argument-all-access-class-only","generated_at":"2026-09-29T14:37:45.664721+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Runs Python standard-library language operations in a deterministic local reproducer. Literal expected answers are authored independently. Related defects share an evaluation group to avoid benchmark split leakage.","repair":"Return [instance_is_None,owner_class_name] observed by an inherited descriptor for class, instance and super access. Owner is the accessing subclass, not necessarily the descriptor-defining class.","root_cause":"Drops instance binding for ordinary instance access. The executable reproducer isolates this operation from the rest of the contract.","sha256":"ece60f24b742c98ec5c4d4aaa3068250b5a17b585b181bac573b3e640572cb42","title":"Descriptor owner argument: Drops instance binding for ordinary instance access · case 01","variant":1,"variant_policy":"The five numbered cases rerun the same authored boundary fixtures; they are reproducibility runs, not independent input variants.","verification":{"attempt":{"elapsed_ms":35.201,"exit_code":1,"observations":[{"actual":[true,"type"],"check":"defining class access","expected":[true,"Base"],"passed":false},{"actual":[true,"type"],"check":"inherited class access","expected":[true,"Child"],"passed":false},{"actual":[false,"type"],"check":"subclass instance","expected":[false,"Child"],"passed":false},{"actual":[false,"type"],"check":"super keeps dynamic owner","expected":[false,"Child"],"passed":false},{"actual":[false,"type"],"check":"base instance","expected":[false,"Base"],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"defining class access\", \"actual\": [true, \"type\"], \"expected\": [true, \"Base\"], \"passed\": false}, {\"check\": \"inherited class access\", \"actual\": [true, \"type\"], \"expected\": [true, \"Child\"], \"passed\": false}, {\"check\": \"subclass instance\", \"actual\": [false, \"type\"], \"expected\": [false, \"Child\"], \"passed\": false}, {\"check\": \"super keeps dynamic owner\", \"actual\": [false, \"type\"], \"expected\": [false, \"Child\"], \"passed\": false}, {\"check\": \"base instance\", \"actual\": [false, \"type\"], \"expected\": [false, \"Base\"], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":41.469,"exit_code":1,"observations":[{"actual":[true,"Base"],"check":"defining class access","expected":[true,"Base"],"passed":true},{"actual":[true,"Child"],"check":"inherited class access","expected":[true,"Child"],"passed":true},{"actual":[true,"Child"],"check":"subclass instance","expected":[false,"Child"],"passed":false},{"actual":[true,"Child"],"check":"super keeps dynamic owner","expected":[false,"Child"],"passed":false},{"actual":[true,"Base"],"check":"base instance","expected":[false,"Base"],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"defining class access\", \"actual\": [true, \"Base\"], \"expected\": [true, \"Base\"], \"passed\": true}, {\"check\": \"inherited class access\", \"actual\": [true, \"Child\"], \"expected\": [true, \"Child\"], \"passed\": true}, {\"check\": \"subclass instance\", \"actual\": [true, \"Child\"], \"expected\": [false, \"Child\"], \"passed\": false}, {\"check\": \"super keeps dynamic owner\", \"actual\": [true, \"Child\"], \"expected\": [false, \"Child\"], \"passed\": false}, {\"check\": \"base instance\", \"actual\": [true, \"Base\"], \"expected\": [false, \"Base\"], \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":35.79,"exit_code":0,"observations":[{"actual":[true,"Base"],"check":"defining class access","expected":[true,"Base"],"passed":true},{"actual":[true,"Child"],"check":"inherited class access","expected":[true,"Child"],"passed":true},{"actual":[false,"Child"],"check":"subclass instance","expected":[false,"Child"],"passed":true},{"actual":[false,"Child"],"check":"super keeps dynamic owner","expected":[false,"Child"],"passed":true},{"actual":[false,"Base"],"check":"base instance","expected":[false,"Base"],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"defining class access\", \"actual\": [true, \"Base\"], \"expected\": [true, \"Base\"], \"passed\": true}, {\"check\": \"inherited class access\", \"actual\": [true, \"Child\"], \"expected\": [true, \"Child\"], \"passed\": true}, {\"check\": \"subclass instance\", \"actual\": [false, \"Child\"], \"expected\": [false, \"Child\"], \"passed\": true}, {\"check\": \"super keeps dynamic owner\", \"actual\": [false, \"Child\"], \"expected\": [false, \"Child\"], \"passed\": true}, {\"check\": \"base instance\", \"actual\": [false, \"Base\"], \"expected\": [false, \"Base\"], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}