{"abstract":"A reserve-qualified winner pays its own bid.","category":"Auction allocation rules","checks":7,"contract":"For nonnegative integer bids and reserve, sell one unit if maximum bid >= reserve; return payment max(reserve, second-highest bid), using zero when no runner-up. No sale returns None.","contract_signature":"bids, reserve","evaluation_group":"model-7f810a8c019b724d","failed_approach":"Charging the runner-up alone can charge below reserve.","family":"z-auction_matching-reserve-second-price","id":"FA-12691","implementations":{"attempt":{"sha256":"d52c0fb3a56fa5cae12301d18cb1c559481b4e2917584b7ea661421685b0f84d","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(bids, reserve):\n    return sorted(bids,reverse=True)[1] if len(bids)>1 and max(bids)>=reserve else (0 if bids and max(bids)>=reserve else None)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('reserve binds', solve([20+N,2], 10), 10)\ncheck('runner up binds', solve([20,15], 10), 15)\ncheck('single bidder', solve([20], 10), 10)\ncheck('empty', solve([], 10), None)\ncheck('no qualifying bid', solve([9,8], 10), None)\ncheck('equality qualifies', solve([10], 10), 10)\ncheck('zero reserve', solve([7,3], 0), 3)\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":"00373979a50873759b388651d3a825e01e35d765d5725805f74cc07f054b3e83","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(bids, reserve):\n    return max(bids) if bids and max(bids)>=reserve else None\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('reserve binds', solve([20+N,2], 10), 10)\ncheck('runner up binds', solve([20,15], 10), 15)\ncheck('single bidder', solve([20], 10), 10)\ncheck('empty', solve([], 10), None)\ncheck('no qualifying bid', solve([9,8], 10), None)\ncheck('equality qualifies', solve([10], 10), 10)\ncheck('zero reserve', solve([7,3], 0), 3)\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":"Offline toy model with explicit integer inputs; no strategic behavior or real market execution. 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":"z-auction_matching-reserve-second-price","generated_at":"2026-09-29T14:38:59.266601+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Deterministic teaching model for reviewing auction allocation software; not a representation of any venue or financial advice.","root_cause":"The winning value replaces the runner-up opportunity cost.","sha256":"78cbd7487bc4b7aaa2011a27fdb1bd9474e3e91683c69d3b16105e9eace4be4a","title":"A reserve-qualified winner pays its own bid · 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":38.232,"exit_code":1,"observations":[{"actual":2,"check":"reserve binds","expected":10,"passed":false},{"actual":15,"check":"runner up binds","expected":15,"passed":true},{"actual":0,"check":"single bidder","expected":10,"passed":false},{"actual":null,"check":"empty","expected":null,"passed":true},{"actual":null,"check":"no qualifying bid","expected":null,"passed":true},{"actual":0,"check":"equality qualifies","expected":10,"passed":false},{"actual":3,"check":"zero reserve","expected":3,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"reserve binds\", \"actual\": 2, \"expected\": 10, \"passed\": false}, {\"check\": \"runner up binds\", \"actual\": 15, \"expected\": 15, \"passed\": true}, {\"check\": \"single bidder\", \"actual\": 0, \"expected\": 10, \"passed\": false}, {\"check\": \"empty\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"no qualifying bid\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"equality qualifies\", \"actual\": 0, \"expected\": 10, \"passed\": false}, {\"check\": \"zero reserve\", \"actual\": 3, \"expected\": 3, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":41.931,"exit_code":1,"observations":[{"actual":21,"check":"reserve binds","expected":10,"passed":false},{"actual":20,"check":"runner up binds","expected":15,"passed":false},{"actual":20,"check":"single bidder","expected":10,"passed":false},{"actual":null,"check":"empty","expected":null,"passed":true},{"actual":null,"check":"no qualifying bid","expected":null,"passed":true},{"actual":10,"check":"equality qualifies","expected":10,"passed":true},{"actual":7,"check":"zero reserve","expected":3,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"reserve binds\", \"actual\": 21, \"expected\": 10, \"passed\": false}, {\"check\": \"runner up binds\", \"actual\": 20, \"expected\": 15, \"passed\": false}, {\"check\": \"single bidder\", \"actual\": 20, \"expected\": 10, \"passed\": false}, {\"check\": \"empty\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"no qualifying bid\", \"actual\": null, \"expected\": null, \"passed\": true}, {\"check\": \"equality qualifies\", \"actual\": 10, \"expected\": 10, \"passed\": true}, {\"check\": \"zero reserve\", \"actual\": 7, \"expected\": 3, \"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."}}