{"abstract":"A 7-5 tiebreak is not closed and play continues to eight points.","category":"Sports scoring and tiebreakers","checks":9,"contract":"Tiebreak game. points is a string of A/B point winners; target is 7 (standard) or 10 (match tiebreak). The tiebreak ends at the first point where a player has at least target points and a two-point lead; later points are ignored. first_server serves point 0, then serve alternates every two points (point k is served by first_server when ((k + 1) // 2) is even). Return [a, b, winner or None, server of the next point or None when finished, ends_change] where ends_change is true when the tiebreak is unfinished and a positive multiple of 6 points has been played.","contract_signature":"points, first_server, target","evaluation_group":"w2-sports-scoring-tennis-tiebreak-service","failed_approach":"Comparing the combined point total with the target closes tiebreaks such as 5-2 early.","family":"w2-sports-scoring-tennis-tiebreak-service-target-threshold","id":"FA-83866","implementations":{"attempt":{"sha256":"810d5fde758c45ed5b2fa87a0ed2cfe9d525eac07cb8aa9079454dfc7fa1504b","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(points, first_server, target):\n    def finished(x, y):\n        return x + y >= target and abs(x - y) >= 2\n    a = b = 0\n    for p in points:\n        if p == 'A':\n            a += 1\n        else:\n            b += 1\n        if finished(a, b):\n            break\n    played = a + b\n    winner = None\n    if finished(a, b):\n        winner = 'A' if a > b else 'B'\n    other = 'B' if first_server == 'A' else 'A'\n    server = first_server if ((played + 1) // 2) % 2 == 0 else other\n    ends_change = played > 0 and played % 6 == 0 and winner is None\n    return [a, b, winner, None if winner else server, ends_change]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ndef run(args):\n    try:\n        return solve(*args)\n    except Exception as exc:\n        return 'raised ' + type(exc).__name__\ncases = [[('control opening point', ('', 'A', 7), [0, 0, None, 'A', False]),\n  ('boundary second server pair', ('A', 'A', 7), [1, 0, None, 'B', False]),\n  ('boundary third point back to first', ('AB', 'B', 7), [1, 1, None, 'A', False]),\n  ('control seven-five tiebreak', ('AAAAABBBBBAA', 'A', 7), [7, 5, 'A', None, False]),\n  ('boundary change of ends at six', ('ABABAB', 'A', 7), [3, 3, None, 'B', True]),\n  ('control match tiebreak not over at seven', ('AAAAAAA', 'B', 10), [7, 0, None, 'B', False]),\n  ('regression: target threshold', ('BBBBABBB', 'A', 7), [1, 7, 'B', None, False]),\n  ('variant scenario 1', ('B', 'A', 7), [0, 1, None, 'B', False]),\n  ('variant scenario 2', ('BAAA', 'A', 10), [3, 1, None, 'A', False])],\n [('control opening point', ('', 'A', 7), [0, 0, None, 'A', False]),\n  ('boundary second server pair', ('A', 'A', 7), [1, 0, None, 'B', False]),\n  ('boundary third point back to first', ('AB', 'B', 7), [1, 1, None, 'A', False]),\n  ('control seven-five tiebreak', ('AAAAABBBBBAA', 'A', 7), [7, 5, 'A', None, False]),\n  ('boundary change of ends at six', ('ABABAB', 'A', 7), [3, 3, None, 'B', True]),\n  ('control match tiebreak not over at seven', ('AAAAAAA', 'B', 10), [7, 0, None, 'B', False]),\n  ('regression: target threshold', ('BBAAAABBBABBB', 'B', 7), [5, 7, 'B', None, False]),\n  ('regression: target threshold', ('BAAAABBAABAABBAB', 'B', 7), [7, 4, 'A', None, False]),\n  ('variant scenario 1', ('AAAAA', 'B', 7), [5, 0, None, 'A', False]),\n  ('variant scenario 2', ('ABBA', 'A', 7), [2, 2, None, 'A', False])],\n [('control opening point', ('', 'A', 7), [0, 0, None, 'A', False]),\n  ('boundary second server pair', ('A', 'A', 7), [1, 0, None, 'B', False]),\n  ('boundary third point back to first', ('AB', 'B', 7), [1, 1, None, 'A', False]),\n  ('control seven-five tiebreak', ('AAAAABBBBBAA', 'A', 7), [7, 5, 'A', None, False]),\n  ('boundary change of ends at six', ('ABABAB', 'A', 7), [3, 3, None, 'B', True]),\n  ('control match tiebreak not over at seven', ('AAAAAAA', 'B', 10), [7, 0, None, 'B', False]),\n  ('regression: target threshold', ('AAABABA', 'A', 7), [5, 2, None, 'A', False]),\n  ('regression: target threshold', ('ABABAABAAABA', 'B', 7), [7, 3, 'A', None, False]),\n  ('variant scenario 1', ('AA', 'A', 10), [2, 0, None, 'B', False]),\n  ('variant scenario 2', ('BABBBABBABBABA', 'B', 10), [5, 9, None, 'A', False])],\n [('control opening point', ('', 'A', 7), [0, 0, None, 'A', False]),\n  ('boundary second server pair', ('A', 'A', 7), [1, 0, None, 'B', False]),\n  ('boundary third point back to first', ('AB', 'B', 7), [1, 1, None, 'A', False]),\n  ('control seven-five tiebreak', ('AAAAABBBBBAA', 'A', 7), [7, 5, 'A', None, False]),\n  ('boundary change of ends at six', ('ABABAB', 'A', 7), [3, 3, None, 'B', True]),\n  ('control match tiebreak not over at seven', ('AAAAAAA', 'B', 10), [7, 0, None, 'B', False]),\n  ('regression: target threshold', ('BBBBABABABBBBABABB', 'B', 10), [3, 10, 'B', None, False]),\n  ('variant scenario 1', ('ABB', 'B', 7), [1, 2, None, 'B', False]),\n  ('variant scenario 2', ('AABAAABBBABABBBBABBBB', 'A', 10), [8, 10, 'B', None, False])],\n [('control opening point', ('', 'A', 7), [0, 0, None, 'A', False]),\n  ('boundary second server pair', ('A', 'A', 7), [1, 0, None, 'B', False]),\n  ('boundary third point back to first', ('AB', 'B', 7), [1, 1, None, 'A', False]),\n  ('control seven-five tiebreak', ('AAAAABBBBBAA', 'A', 7), [7, 5, 'A', None, False]),\n  ('boundary change of ends at six', ('ABABAB', 'A', 7), [3, 3, None, 'B', True]),\n  ('control match tiebreak not over at seven', ('AAAAAAA', 'B', 10), [7, 0, None, 'B', False]),\n  ('regression: target threshold', ('BBABBBBBBBABBBBABABBAA', 'A', 10), [2, 10, 'B', None, False]),\n  ('variant scenario 1', ('AB', 'B', 7), [1, 1, None, 'A', False]),\n  ('variant scenario 2', ('BBBBABBAABBBAABB', 'A', 7), [3, 7, 'B', None, False])]]\nfor label, args, expected in cases[N - 1]:\n    check(label, run(args), expected)\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":"de11715cf580a0b2429e0576b0eaa1322722c7cfe91a488676bc2c5b72c9678f","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(points, first_server, target):\n    def finished(x, y):\n        return max(x, y) > target and abs(x - y) >= 2\n    a = b = 0\n    for p in points:\n        if p == 'A':\n            a += 1\n        else:\n            b += 1\n        if finished(a, b):\n            break\n    played = a + b\n    winner = None\n    if finished(a, b):\n        winner = 'A' if a > b else 'B'\n    other = 'B' if first_server == 'A' else 'A'\n    server = first_server if ((played + 1) // 2) % 2 == 0 else other\n    ends_change = played > 0 and played % 6 == 0 and winner is None\n    return [a, b, winner, None if winner else server, ends_change]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ndef run(args):\n    try:\n        return solve(*args)\n    except Exception as exc:\n        return 'raised ' + type(exc).__name__\ncases = [[('control opening point', ('', 'A', 7), [0, 0, None, 'A', False]),\n  ('boundary second server pair', ('A', 'A', 7), [1, 0, None, 'B', False]),\n  ('boundary third point back to first', ('AB', 'B', 7), [1, 1, None, 'A', False]),\n  ('control seven-five tiebreak', ('AAAAABBBBBAA', 'A', 7), [7, 5, 'A', None, False]),\n  ('boundary change of ends at six', ('ABABAB', 'A', 7), [3, 3, None, 'B', True]),\n  ('control match tiebreak not over at seven', ('AAAAAAA', 'B', 10), [7, 0, None, 'B', False]),\n  ('regression: target threshold', ('BBBBABBB', 'A', 7), [1, 7, 'B', None, False]),\n  ('variant scenario 1', ('B', 'A', 7), [0, 1, None, 'B', False]),\n  ('variant scenario 2', ('BAAA', 'A', 10), [3, 1, None, 'A', False])],\n [('control opening point', ('', 'A', 7), [0, 0, None, 'A', False]),\n  ('boundary second server pair', ('A', 'A', 7), [1, 0, None, 'B', False]),\n  ('boundary third point back to first', ('AB', 'B', 7), [1, 1, None, 'A', False]),\n  ('control seven-five tiebreak', ('AAAAABBBBBAA', 'A', 7), [7, 5, 'A', None, False]),\n  ('boundary change of ends at six', ('ABABAB', 'A', 7), [3, 3, None, 'B', True]),\n  ('control match tiebreak not over at seven', ('AAAAAAA', 'B', 10), [7, 0, None, 'B', False]),\n  ('regression: target threshold', ('BBAAAABBBABBB', 'B', 7), [5, 7, 'B', None, False]),\n  ('regression: target threshold', ('BAAAABBAABAABBAB', 'B', 7), [7, 4, 'A', None, False]),\n  ('variant scenario 1', ('AAAAA', 'B', 7), [5, 0, None, 'A', False]),\n  ('variant scenario 2', ('ABBA', 'A', 7), [2, 2, None, 'A', False])],\n [('control opening point', ('', 'A', 7), [0, 0, None, 'A', False]),\n  ('boundary second server pair', ('A', 'A', 7), [1, 0, None, 'B', False]),\n  ('boundary third point back to first', ('AB', 'B', 7), [1, 1, None, 'A', False]),\n  ('control seven-five tiebreak', ('AAAAABBBBBAA', 'A', 7), [7, 5, 'A', None, False]),\n  ('boundary change of ends at six', ('ABABAB', 'A', 7), [3, 3, None, 'B', True]),\n  ('control match tiebreak not over at seven', ('AAAAAAA', 'B', 10), [7, 0, None, 'B', False]),\n  ('regression: target threshold', ('AAABABA', 'A', 7), [5, 2, None, 'A', False]),\n  ('regression: target threshold', ('ABABAABAAABA', 'B', 7), [7, 3, 'A', None, False]),\n  ('variant scenario 1', ('AA', 'A', 10), [2, 0, None, 'B', False]),\n  ('variant scenario 2', ('BABBBABBABBABA', 'B', 10), [5, 9, None, 'A', False])],\n [('control opening point', ('', 'A', 7), [0, 0, None, 'A', False]),\n  ('boundary second server pair', ('A', 'A', 7), [1, 0, None, 'B', False]),\n  ('boundary third point back to first', ('AB', 'B', 7), [1, 1, None, 'A', False]),\n  ('control seven-five tiebreak', ('AAAAABBBBBAA', 'A', 7), [7, 5, 'A', None, False]),\n  ('boundary change of ends at six', ('ABABAB', 'A', 7), [3, 3, None, 'B', True]),\n  ('control match tiebreak not over at seven', ('AAAAAAA', 'B', 10), [7, 0, None, 'B', False]),\n  ('regression: target threshold', ('BBBBABABABBBBABABB', 'B', 10), [3, 10, 'B', None, False]),\n  ('variant scenario 1', ('ABB', 'B', 7), [1, 2, None, 'B', False]),\n  ('variant scenario 2', ('AABAAABBBABABBBBABBBB', 'A', 10), [8, 10, 'B', None, False])],\n [('control opening point', ('', 'A', 7), [0, 0, None, 'A', False]),\n  ('boundary second server pair', ('A', 'A', 7), [1, 0, None, 'B', False]),\n  ('boundary third point back to first', ('AB', 'B', 7), [1, 1, None, 'A', False]),\n  ('control seven-five tiebreak', ('AAAAABBBBBAA', 'A', 7), [7, 5, 'A', None, False]),\n  ('boundary change of ends at six', ('ABABAB', 'A', 7), [3, 3, None, 'B', True]),\n  ('control match tiebreak not over at seven', ('AAAAAAA', 'B', 10), [7, 0, None, 'B', False]),\n  ('regression: target threshold', ('BBABBBBBBBABBBBABABBAA', 'A', 10), [2, 10, 'B', None, False]),\n  ('variant scenario 1', ('AB', 'B', 7), [1, 1, None, 'A', False]),\n  ('variant scenario 2', ('BBBBABBAABBBAABB', 'A', 7), [3, 7, 'B', None, False])]]\nfor label, args, expected in cases[N - 1]:\n    check(label, run(args), expected)\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":"Stipulated, bounded toy contract stated in the contract field; not a claim of conformance with any governing body rulebook or operator house rules. 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":"w2-sports-scoring-tennis-tiebreak-service-target-threshold","generated_at":"2026-09-29T14:50:25.556413+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Chair-umpire scoring software must drive the server indicator and change-of-ends prompt during tiebreaks.","root_cause":"The target check requires more than target points instead of at least target.","sha256":"bf100f2096ee8193370cbb62845037ea94cca34f9a88e45df29c5053f3f8482c","title":"Tiebreak target compared with a strict inequality · 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":41.453,"exit_code":1,"observations":[{"actual":[0,0,null,"A",false],"check":"control opening point","expected":[0,0,null,"A",false],"passed":true},{"actual":[1,0,null,"B",false],"check":"boundary second server pair","expected":[1,0,null,"B",false],"passed":true},{"actual":[1,1,null,"A",false],"check":"boundary third point back to first","expected":[1,1,null,"A",false],"passed":true},{"actual":[5,2,"A",null,false],"check":"control seven-five tiebreak","expected":[7,5,"A",null,false],"passed":false},{"actual":[3,3,null,"B",true],"check":"boundary change of ends at six","expected":[3,3,null,"B",true],"passed":true},{"actual":[7,0,null,"B",false],"check":"control match tiebreak not over at seven","expected":[7,0,null,"B",false],"passed":true},{"actual":[1,6,"B",null,false],"check":"regression: target threshold","expected":[1,7,"B",null,false],"passed":false},{"actual":[0,1,null,"B",false],"check":"variant scenario 1","expected":[0,1,null,"B",false],"passed":true},{"actual":[3,1,null,"A",false],"check":"variant scenario 2","expected":[3,1,null,"A",false],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"control opening point\", \"actual\": [0, 0, null, \"A\", false], \"expected\": [0, 0, null, \"A\", false], \"passed\": true}, {\"check\": \"boundary second server pair\", \"actual\": [1, 0, null, \"B\", false], \"expected\": [1, 0, null, \"B\", false], \"passed\": true}, {\"check\": \"boundary third point back to first\", \"actual\": [1, 1, null, \"A\", false], \"expected\": [1, 1, null, \"A\", false], \"passed\": true}, {\"check\": \"control seven-five tiebreak\", \"actual\": [5, 2, \"A\", null, false], \"expected\": [7, 5, \"A\", null, false], \"passed\": false}, {\"check\": \"boundary change of ends at six\", \"actual\": [3, 3, null, \"B\", true], \"expected\": [3, 3, null, \"B\", true], \"passed\": true}, {\"check\": \"control match tiebreak not over at seven\", \"actual\": [7, 0, null, \"B\", false], \"expected\": [7, 0, null, \"B\", false], \"passed\": true}, {\"check\": \"regression: target threshold\", \"actual\": [1, 6, \"B\", null, false], \"expected\": [1, 7, \"B\", null, false], \"passed\": false}, {\"check\": \"variant scenario 1\", \"actual\": [0, 1, null, \"B\", false], \"expected\": [0, 1, null, \"B\", false], \"passed\": true}, {\"check\": \"variant scenario 2\", \"actual\": [3, 1, null, \"A\", false], \"expected\": [3, 1, null, \"A\", false], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.751,"exit_code":1,"observations":[{"actual":[0,0,null,"A",false],"check":"control opening point","expected":[0,0,null,"A",false],"passed":true},{"actual":[1,0,null,"B",false],"check":"boundary second server pair","expected":[1,0,null,"B",false],"passed":true},{"actual":[1,1,null,"A",false],"check":"boundary third point back to first","expected":[1,1,null,"A",false],"passed":true},{"actual":[7,5,null,"A",true],"check":"control seven-five tiebreak","expected":[7,5,"A",null,false],"passed":false},{"actual":[3,3,null,"B",true],"check":"boundary change of ends at six","expected":[3,3,null,"B",true],"passed":true},{"actual":[7,0,null,"B",false],"check":"control match tiebreak not over at seven","expected":[7,0,null,"B",false],"passed":true},{"actual":[1,7,null,"A",false],"check":"regression: target threshold","expected":[1,7,"B",null,false],"passed":false},{"actual":[0,1,null,"B",false],"check":"variant scenario 1","expected":[0,1,null,"B",false],"passed":true},{"actual":[3,1,null,"A",false],"check":"variant scenario 2","expected":[3,1,null,"A",false],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"control opening point\", \"actual\": [0, 0, null, \"A\", false], \"expected\": [0, 0, null, \"A\", false], \"passed\": true}, {\"check\": \"boundary second server pair\", \"actual\": [1, 0, null, \"B\", false], \"expected\": [1, 0, null, \"B\", false], \"passed\": true}, {\"check\": \"boundary third point back to first\", \"actual\": [1, 1, null, \"A\", false], \"expected\": [1, 1, null, \"A\", false], \"passed\": true}, {\"check\": \"control seven-five tiebreak\", \"actual\": [7, 5, null, \"A\", true], \"expected\": [7, 5, \"A\", null, false], \"passed\": false}, {\"check\": \"boundary change of ends at six\", \"actual\": [3, 3, null, \"B\", true], \"expected\": [3, 3, null, \"B\", true], \"passed\": true}, {\"check\": \"control match tiebreak not over at seven\", \"actual\": [7, 0, null, \"B\", false], \"expected\": [7, 0, null, \"B\", false], \"passed\": true}, {\"check\": \"regression: target threshold\", \"actual\": [1, 7, null, \"A\", false], \"expected\": [1, 7, \"B\", null, false], \"passed\": false}, {\"check\": \"variant scenario 1\", \"actual\": [0, 1, null, \"B\", false], \"expected\": [0, 1, null, \"B\", false], \"passed\": true}, {\"check\": \"variant scenario 2\", \"actual\": [3, 1, null, \"A\", false], \"expected\": [3, 1, null, \"A\", false], \"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."}}