{"abstract":"The operation returns a result or retained state that violates this contract: Extending a bounded deque consumes the complete iterator even when capacity is zero; retain the newest capacity values.","category":"Bounded deques","checks":4,"contract":"Extending a bounded deque consumes the complete iterator even when capacity is zero; retain the newest capacity values. Inputs are the finite Python values shown by the executable fixtures; no concurrent execution is assumed.","contract_signature":"x, y=None","evaluation_group":"model-c9f3646aeafc1604","failed_approach":"Skipping zero-capacity extension leaves the source undrained.","family":"xr-deque-bounded-extend-consumes-complete-source","id":"FA-4776","implementations":{"attempt":{"sha256":"561d8ba8fb471addd5778995c7a16a7ba8c8bb39f7d4d7dadcfbfd25321506d9","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom collections import Counter, ChainMap, deque\nimport heapq\nN = 1\nobservations = []\ndef solve(x, y=None):\n    g=iter(y[1]); a=deque(x,maxlen=y[0]); a.extend(g if y[0] else []); return [list(a),list(g)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('full still consumes and replaces', solve(['a', 'b'], [2, ['c', 'd', 'e']]), [['d', 'e'], []])\ncheck('zero drains source', solve([], [0, ['a', 'b']]), [[], []])\ncheck('room accepts', solve([], [3, ['a']]), [['a'], []])\ncheck('empty source', solve(['a'], [2, []]), [['a'], []])\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":"7636405e6e7fa2e1d8891fefe87e8ea35326394ba0b990d5a39e87825766aad3","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nfrom collections import Counter, ChainMap, deque\nimport heapq\nN = 1\nobservations = []\ndef solve(x, y=None):\n    g=iter(y[1]); a=deque(x,maxlen=y[0]); a.extend(next(g) for _ in range(min(y[0]-len(a),len(y[1])))); return [list(a),list(g)]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('full still consumes and replaces', solve(['a', 'b'], [2, ['c', 'd', 'e']]), [['d', 'e'], []])\ncheck('zero drains source', solve([], [0, ['a', 'b']]), [[], []])\ncheck('room accepts', solve([], [3, ['a']]), [['a'], []])\ncheck('empty source', solve(['a'], [2, []]), [['a'], []])\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-deque-bounded-extend-consumes-complete-source","generated_at":"2026-09-29T14:37:42.729378+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":"Stopping at available space leaves later source elements unconsumed and prevents replacement.","sha256":"0392668303e4fc21447bae487ca0cfc5523de8b93a452767082c1e8d8d7db921","title":"Deque bounded extend consumes complete source · 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":109.31,"exit_code":1,"observations":[{"actual":[["d","e"],[]],"check":"full still consumes and replaces","expected":[["d","e"],[]],"passed":true},{"actual":[[],["a","b"]],"check":"zero drains source","expected":[[],[]],"passed":false},{"actual":[["a"],[]],"check":"room accepts","expected":[["a"],[]],"passed":true},{"actual":[["a"],[]],"check":"empty source","expected":[["a"],[]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"full still consumes and replaces\", \"actual\": [[\"d\", \"e\"], []], \"expected\": [[\"d\", \"e\"], []], \"passed\": true}, {\"check\": \"zero drains source\", \"actual\": [[], [\"a\", \"b\"]], \"expected\": [[], []], \"passed\": false}, {\"check\": \"room accepts\", \"actual\": [[\"a\"], []], \"expected\": [[\"a\"], []], \"passed\": true}, {\"check\": \"empty source\", \"actual\": [[\"a\"], []], \"expected\": [[\"a\"], []], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":36.185,"exit_code":1,"observations":[{"actual":[["a","b"],["c","d","e"]],"check":"full still consumes and replaces","expected":[["d","e"],[]],"passed":false},{"actual":[[],["a","b"]],"check":"zero drains source","expected":[[],[]],"passed":false},{"actual":[["a"],[]],"check":"room accepts","expected":[["a"],[]],"passed":true},{"actual":[["a"],[]],"check":"empty source","expected":[["a"],[]],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"full still consumes and replaces\", \"actual\": [[\"a\", \"b\"], [\"c\", \"d\", \"e\"]], \"expected\": [[\"d\", \"e\"], []], \"passed\": false}, {\"check\": \"zero drains source\", \"actual\": [[], [\"a\", \"b\"]], \"expected\": [[], []], \"passed\": false}, {\"check\": \"room accepts\", \"actual\": [[\"a\"], []], \"expected\": [[\"a\"], []], \"passed\": true}, {\"check\": \"empty source\", \"actual\": [[\"a\"], []], \"expected\": [[\"a\"], []], \"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."}}