{"abstract":"A timeout is reported when the late message finally arrives instead of 300 ms after the last activity.","category":"MIDI event timing","checks":8,"contract":"Input [messages, end_time] where messages are time-ordered [ms, kind]. Monitoring is armed by a \"sense\" message. While armed, if more than 300 ms pass between any two consecutive messages (of any kind), a timeout is reported at previous message time + 300 and monitoring disarms until the next sense message. At end_time the same check applies to the last message. Return the list of timeout times.","contract_signature":"x","evaluation_group":"w2-midi-event-timing-active-sensing","failed_approach":"Subtracting 300 from the arrival time is only correct when the gap is exactly 600 ms.","family":"w2-midi-event-timing-active-sensing-timeout-timestamp","id":"FA-81731","implementations":{"attempt":{"sha256":"b93fc9843a843849420176562be66bf8097f8756ec470b3e2c9900db8df9a8e8","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    if not isinstance(x, list) or len(x) != 2:\n        return None\n    msgs, end = x\n    armed = False\n    last = None\n    out = []\n    for t, m in msgs:\n        if armed and t - last > 300:\n            out.append(t - 300)\n            armed = False\n        if m == 'sense':\n            armed = True\n        last = t\n    if armed and end - last > 300:\n        out.append(last + 300)\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[([[[0, 'sense'], [200, 'sense'], [400, 'sense']], 500], []), ([[[0, 'sense'], [301, 'note']], 301], [300]), ([[[0, 'sense'], [300, 'note']], 300], []), ([[[0, 'note'], [1000, 'note']], 2000], []), ([[[0, 'sense'], [250, 'clock'], [500, 'clock'], [750, 'sense']], 800], []), ([[[0, 'sense'], [250, 'note'], [500, 'note']], 1000], [800]), ([[[0, 'sense'], [320, 'note'], [650, 'note']], 660], [300]), ([[[0, 'sense'], [200, 'clock'], [600, 'note']], 600], [500])], [([[[0, 'sense'], [250, 'clock'], [500, 'clock'], [750, 'sense']], 800], []), ([[[0, 'sense'], [250, 'note'], [500, 'note']], 1000], [800]), ([[[0, 'sense'], [800, 'note'], [900, 'note'], [1300, 'sense']], 1400], [300]), ([[[0, 'sense']], 301], [300]), ([[[0, 'sense']], 300], []), ([[], 100], []), ([[[0, 'sense'], [200, 'clock'], [600, 'note']], 600], [500]), ([[[100, 'sense'], [420, 'clock']], 430], [400])], [([[[0, 'sense'], [200, 'sense'], [400, 'sense']], 500], []), ([[[0, 'sense'], [301, 'note']], 301], [300]), ([[[0, 'sense'], [800, 'note'], [900, 'note'], [1300, 'sense']], 1400], [300]), ([[[0, 'sense']], 300], []), ([[[0, 'sense'], [320, 'note'], [650, 'note']], 660], [300]), ([[], 100], []), ([[[0, 'sense'], [200, 'clock'], [600, 'note']], 600], [500]), ([[[100, 'sense'], [420, 'clock']], 430], [400])], [([[[0, 'sense'], [200, 'sense'], [400, 'sense']], 500], []), ([[[0, 'sense'], [301, 'note']], 301], [300]), ([[[0, 'sense'], [300, 'note']], 300], []), ([[[0, 'note'], [1000, 'note']], 2000], []), ([[[0, 'sense'], [800, 'note'], [900, 'note'], [1300, 'sense']], 1400], [300]), ([[[0, 'sense'], [320, 'note'], [650, 'note']], 660], [300]), ([[[0, 'sense'], [200, 'clock'], [600, 'note']], 600], [500]), ([[[100, 'sense'], [420, 'clock']], 430], [400])], [([[[0, 'sense'], [200, 'sense'], [400, 'sense']], 500], []), ([[[0, 'sense'], [300, 'note']], 300], []), ([[[0, 'note'], [1000, 'note']], 2000], []), ([[[0, 'sense'], [250, 'clock'], [500, 'clock'], [750, 'sense']], 800], []), ([[[0, 'sense'], [250, 'note'], [500, 'note']], 1000], [800]), ([[[0, 'sense'], [800, 'note'], [900, 'note'], [1300, 'sense']], 1400], [300]), ([[[0, 'sense'], [320, 'note'], [650, 'note']], 660], [300]), ([[[100, 'sense'], [420, 'clock']], 430], [400])]]\nfor i, (args, expected) in enumerate(fixtures[N-1]):\n    check(\"oracle %d\" % i, solve(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":"c03be3723fce9221746780904da22c6ed3e6798344c7f3d391f233efd1514517","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    if not isinstance(x, list) or len(x) != 2:\n        return None\n    msgs, end = x\n    armed = False\n    last = None\n    out = []\n    for t, m in msgs:\n        if armed and t - last > 300:\n            out.append(t)\n            armed = False\n        if m == 'sense':\n            armed = True\n        last = t\n    if armed and end - last > 300:\n        out.append(last + 300)\n    return out\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[([[[0, 'sense'], [200, 'sense'], [400, 'sense']], 500], []), ([[[0, 'sense'], [301, 'note']], 301], [300]), ([[[0, 'sense'], [300, 'note']], 300], []), ([[[0, 'note'], [1000, 'note']], 2000], []), ([[[0, 'sense'], [250, 'clock'], [500, 'clock'], [750, 'sense']], 800], []), ([[[0, 'sense'], [250, 'note'], [500, 'note']], 1000], [800]), ([[[0, 'sense'], [320, 'note'], [650, 'note']], 660], [300]), ([[[0, 'sense'], [200, 'clock'], [600, 'note']], 600], [500])], [([[[0, 'sense'], [250, 'clock'], [500, 'clock'], [750, 'sense']], 800], []), ([[[0, 'sense'], [250, 'note'], [500, 'note']], 1000], [800]), ([[[0, 'sense'], [800, 'note'], [900, 'note'], [1300, 'sense']], 1400], [300]), ([[[0, 'sense']], 301], [300]), ([[[0, 'sense']], 300], []), ([[], 100], []), ([[[0, 'sense'], [200, 'clock'], [600, 'note']], 600], [500]), ([[[100, 'sense'], [420, 'clock']], 430], [400])], [([[[0, 'sense'], [200, 'sense'], [400, 'sense']], 500], []), ([[[0, 'sense'], [301, 'note']], 301], [300]), ([[[0, 'sense'], [800, 'note'], [900, 'note'], [1300, 'sense']], 1400], [300]), ([[[0, 'sense']], 300], []), ([[[0, 'sense'], [320, 'note'], [650, 'note']], 660], [300]), ([[], 100], []), ([[[0, 'sense'], [200, 'clock'], [600, 'note']], 600], [500]), ([[[100, 'sense'], [420, 'clock']], 430], [400])], [([[[0, 'sense'], [200, 'sense'], [400, 'sense']], 500], []), ([[[0, 'sense'], [301, 'note']], 301], [300]), ([[[0, 'sense'], [300, 'note']], 300], []), ([[[0, 'note'], [1000, 'note']], 2000], []), ([[[0, 'sense'], [800, 'note'], [900, 'note'], [1300, 'sense']], 1400], [300]), ([[[0, 'sense'], [320, 'note'], [650, 'note']], 660], [300]), ([[[0, 'sense'], [200, 'clock'], [600, 'note']], 600], [500]), ([[[100, 'sense'], [420, 'clock']], 430], [400])], [([[[0, 'sense'], [200, 'sense'], [400, 'sense']], 500], []), ([[[0, 'sense'], [300, 'note']], 300], []), ([[[0, 'note'], [1000, 'note']], 2000], []), ([[[0, 'sense'], [250, 'clock'], [500, 'clock'], [750, 'sense']], 800], []), ([[[0, 'sense'], [250, 'note'], [500, 'note']], 1000], [800]), ([[[0, 'sense'], [800, 'note'], [900, 'note'], [1300, 'sense']], 1400], [300]), ([[[0, 'sense'], [320, 'note'], [650, 'note']], 660], [300]), ([[[100, 'sense'], [420, 'clock']], 430], [400])]]\nfor i, (args, expected) in enumerate(fixtures[N-1]):\n    check(\"oracle %d\" % i, solve(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":"A deterministic bounded teaching model with a stipulated toy contract; it is not a complete Standard MIDI File or MIDI 1.0/2.0 implementation. 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-midi-event-timing-active-sensing-timeout-timestamp","generated_at":"2026-09-29T14:50:05.714291+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"MIDI sequencers, file readers and synth drivers depend on exact event ordering and tick/time arithmetic.","root_cause":"The timeout is timestamped with the arrival time of the message that revealed the gap.","sha256":"1b4867300d6010dfdeeda93f83bec3d063d01982f6f1c70bc31a0626caeaf434","title":"Active sensing timeout detection: timeout stamped at the next message arrival · 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":39.522,"exit_code":1,"observations":[{"actual":[],"check":"oracle 0","expected":[],"passed":true},{"actual":[1],"check":"oracle 1","expected":[300],"passed":false},{"actual":[],"check":"oracle 2","expected":[],"passed":true},{"actual":[],"check":"oracle 3","expected":[],"passed":true},{"actual":[],"check":"oracle 4","expected":[],"passed":true},{"actual":[800],"check":"oracle 5","expected":[800],"passed":true},{"actual":[20],"check":"oracle 6","expected":[300],"passed":false},{"actual":[300],"check":"oracle 7","expected":[500],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 0\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 1\", \"actual\": [1], \"expected\": [300], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [800], \"expected\": [800], \"passed\": true}, {\"check\": \"oracle 6\", \"actual\": [20], \"expected\": [300], \"passed\": false}, {\"check\": \"oracle 7\", \"actual\": [300], \"expected\": [500], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.552,"exit_code":1,"observations":[{"actual":[],"check":"oracle 0","expected":[],"passed":true},{"actual":[301],"check":"oracle 1","expected":[300],"passed":false},{"actual":[],"check":"oracle 2","expected":[],"passed":true},{"actual":[],"check":"oracle 3","expected":[],"passed":true},{"actual":[],"check":"oracle 4","expected":[],"passed":true},{"actual":[800],"check":"oracle 5","expected":[800],"passed":true},{"actual":[320],"check":"oracle 6","expected":[300],"passed":false},{"actual":[600],"check":"oracle 7","expected":[500],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"oracle 0\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 1\", \"actual\": [301], \"expected\": [300], \"passed\": false}, {\"check\": \"oracle 2\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 4\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"oracle 5\", \"actual\": [800], \"expected\": [800], \"passed\": true}, {\"check\": \"oracle 6\", \"actual\": [320], \"expected\": [300], \"passed\": false}, {\"check\": \"oracle 7\", \"actual\": [600], \"expected\": [500], \"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."}}