{"abstract":"Replayed or skewed requests reuse quotes that were not yet issued.","category":"Ride-hailing fare and surge pricing","checks":7,"contract":"A fare quote locks its surge for 300 seconds: requests with 0 <= elapsed < 300 seconds are locked (a request timestamped before the quote, from clock skew, is not). A locked request uses the lower of the quoted and current surge; otherwise the current surge. Price = core x surge / 10, half up. Return [price, locked|requoted].","evaluation_group":"w2-ride-hailing-fare-surge-quote-price-lock","failed_approach":"Accepting absolute skew still honors requests that predate the quote.","family":"w2-ride-hailing-fare-surge-quote-price-lock-clock-skew","id":"FA-85621","implementations":{"attempt":{"sha256":"011256d1d8361a7475007f115a9a7d75690f357e61eb0812f91ade748c079545","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(quote, request_t, current_surge):\n    elapsed = request_t - quote['t']\n    valid = abs(elapsed) < 300\n    used = min(quote['surge'], current_surge) if valid else current_surge\n    price = (quote['core'] * used * 2 + 10) // 20\n    return [price, 'locked' if valid else 'requoted']\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression: clock skew', [{'core': 999, 'surge': 15, 't': 5000}, 4995, 20], [1998, 'requoted']),\n  ('partial repair probe: clock skew', [{'core': 1111, 'surge': 10, 't': 5000}, 4995, 25],\n   [2778, 'requoted']),\n  ('second regression', [{'core': 2500, 'surge': 15, 't': 5000}, 4995, 25], [6250, 'requoted']),\n  ('normal control 1', [{'core': 999, 'surge': 10, 't': 5000}, 5000, 12], [999, 'locked']),\n  ('normal control 2', [{'core': 2500, 'surge': 20, 't': 5000}, 5900, 15], [3750, 'requoted']),\n  ('normal control 3', [{'core': 2500, 'surge': 10, 't': 5000}, 5000, 25], [2500, 'locked']),\n  ('normal control 4', [{'core': 999, 'surge': 15, 't': 5000}, 5300, 12], [1199, 'requoted'])],\n [('regression: clock skew', [{'core': 1111, 'surge': 10, 't': 5000}, 4995, 12], [1333, 'requoted']),\n  ('partial repair probe: clock skew', [{'core': 999, 'surge': 20, 't': 5000}, 4995, 20], [1998, 'requoted']),\n  ('second regression', [{'core': 2500, 'surge': 10, 't': 5000}, 4995, 10], [2500, 'requoted']),\n  ('normal control 1', [{'core': 999, 'surge': 10, 't': 5000}, 5300, 15], [1499, 'requoted']),\n  ('normal control 2', [{'core': 1111, 'surge': 10, 't': 5000}, 5299, 12], [1111, 'locked']),\n  ('normal control 3', [{'core': 2500, 'surge': 15, 't': 5000}, 5001, 10], [2500, 'locked']),\n  ('normal control 4', [{'core': 1111, 'surge': 20, 't': 5000}, 5120, 12], [1333, 'locked'])],\n [('regression: clock skew', [{'core': 1111, 'surge': 15, 't': 5000}, 4995, 15], [1667, 'requoted']),\n  ('partial repair probe: clock skew', [{'core': 999, 'surge': 15, 't': 5000}, 4995, 25], [2498, 'requoted']),\n  ('second regression', [{'core': 1111, 'surge': 10, 't': 5000}, 4995, 20], [2222, 'requoted']),\n  ('normal control 1', [{'core': 2500, 'surge': 10, 't': 5000}, 5299, 10], [2500, 'locked']),\n  ('normal control 2', [{'core': 999, 'surge': 10, 't': 5000}, 5300, 20], [1998, 'requoted']),\n  ('normal control 3', [{'core': 999, 'surge': 10, 't': 5000}, 5299, 20], [999, 'locked']),\n  ('normal control 4', [{'core': 1111, 'surge': 20, 't': 5000}, 5900, 10], [1111, 'requoted'])],\n [('regression: clock skew', [{'core': 999, 'surge': 20, 't': 5000}, 4995, 25], [2498, 'requoted']),\n  ('partial repair probe: clock skew', [{'core': 999, 'surge': 20, 't': 5000}, 4995, 10], [999, 'requoted']),\n  ('second regression', [{'core': 1111, 'surge': 20, 't': 5000}, 4995, 25], [2778, 'requoted']),\n  ('normal control 1', [{'core': 2500, 'surge': 15, 't': 5000}, 5001, 10], [2500, 'locked']),\n  ('normal control 2', [{'core': 1111, 'surge': 15, 't': 5000}, 5120, 20], [1667, 'locked']),\n  ('normal control 3', [{'core': 999, 'surge': 10, 't': 5000}, 5301, 12], [1199, 'requoted']),\n  ('normal control 4', [{'core': 1111, 'surge': 15, 't': 5000}, 5000, 15], [1667, 'locked'])],\n [('regression: clock skew', [{'core': 1111, 'surge': 10, 't': 5000}, 4995, 20], [2222, 'requoted']),\n  ('partial repair probe: clock skew', [{'core': 2500, 'surge': 10, 't': 5000}, 4995, 20],\n   [5000, 'requoted']),\n  ('second regression', [{'core': 999, 'surge': 15, 't': 5000}, 4995, 25], [2498, 'requoted']),\n  ('normal control 1', [{'core': 999, 'surge': 15, 't': 5000}, 5299, 10], [999, 'locked']),\n  ('normal control 2', [{'core': 1111, 'surge': 15, 't': 5000}, 5120, 12], [1333, 'locked']),\n  ('normal control 3', [{'core': 1111, 'surge': 15, 't': 5000}, 5300, 20], [2222, 'requoted']),\n  ('normal control 4', [{'core': 2500, 'surge': 10, 't': 5000}, 5299, 15], [2500, 'locked'])]]\nfor label, args, expected in fixtures[N-1]:\n    check(label, 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":"fb57cd7be42d6646d9c7f56d9972e831d7e8f46e7b018b73b7de374ec1a3f748","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(quote, request_t, current_surge):\n    elapsed = request_t - quote['t']\n    valid = elapsed < 300\n    used = min(quote['surge'], current_surge) if valid else current_surge\n    price = (quote['core'] * used * 2 + 10) // 20\n    return [price, 'locked' if valid else 'requoted']\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression: clock skew', [{'core': 999, 'surge': 15, 't': 5000}, 4995, 20], [1998, 'requoted']),\n  ('partial repair probe: clock skew', [{'core': 1111, 'surge': 10, 't': 5000}, 4995, 25],\n   [2778, 'requoted']),\n  ('second regression', [{'core': 2500, 'surge': 15, 't': 5000}, 4995, 25], [6250, 'requoted']),\n  ('normal control 1', [{'core': 999, 'surge': 10, 't': 5000}, 5000, 12], [999, 'locked']),\n  ('normal control 2', [{'core': 2500, 'surge': 20, 't': 5000}, 5900, 15], [3750, 'requoted']),\n  ('normal control 3', [{'core': 2500, 'surge': 10, 't': 5000}, 5000, 25], [2500, 'locked']),\n  ('normal control 4', [{'core': 999, 'surge': 15, 't': 5000}, 5300, 12], [1199, 'requoted'])],\n [('regression: clock skew', [{'core': 1111, 'surge': 10, 't': 5000}, 4995, 12], [1333, 'requoted']),\n  ('partial repair probe: clock skew', [{'core': 999, 'surge': 20, 't': 5000}, 4995, 20], [1998, 'requoted']),\n  ('second regression', [{'core': 2500, 'surge': 10, 't': 5000}, 4995, 10], [2500, 'requoted']),\n  ('normal control 1', [{'core': 999, 'surge': 10, 't': 5000}, 5300, 15], [1499, 'requoted']),\n  ('normal control 2', [{'core': 1111, 'surge': 10, 't': 5000}, 5299, 12], [1111, 'locked']),\n  ('normal control 3', [{'core': 2500, 'surge': 15, 't': 5000}, 5001, 10], [2500, 'locked']),\n  ('normal control 4', [{'core': 1111, 'surge': 20, 't': 5000}, 5120, 12], [1333, 'locked'])],\n [('regression: clock skew', [{'core': 1111, 'surge': 15, 't': 5000}, 4995, 15], [1667, 'requoted']),\n  ('partial repair probe: clock skew', [{'core': 999, 'surge': 15, 't': 5000}, 4995, 25], [2498, 'requoted']),\n  ('second regression', [{'core': 1111, 'surge': 10, 't': 5000}, 4995, 20], [2222, 'requoted']),\n  ('normal control 1', [{'core': 2500, 'surge': 10, 't': 5000}, 5299, 10], [2500, 'locked']),\n  ('normal control 2', [{'core': 999, 'surge': 10, 't': 5000}, 5300, 20], [1998, 'requoted']),\n  ('normal control 3', [{'core': 999, 'surge': 10, 't': 5000}, 5299, 20], [999, 'locked']),\n  ('normal control 4', [{'core': 1111, 'surge': 20, 't': 5000}, 5900, 10], [1111, 'requoted'])],\n [('regression: clock skew', [{'core': 999, 'surge': 20, 't': 5000}, 4995, 25], [2498, 'requoted']),\n  ('partial repair probe: clock skew', [{'core': 999, 'surge': 20, 't': 5000}, 4995, 10], [999, 'requoted']),\n  ('second regression', [{'core': 1111, 'surge': 20, 't': 5000}, 4995, 25], [2778, 'requoted']),\n  ('normal control 1', [{'core': 2500, 'surge': 15, 't': 5000}, 5001, 10], [2500, 'locked']),\n  ('normal control 2', [{'core': 1111, 'surge': 15, 't': 5000}, 5120, 20], [1667, 'locked']),\n  ('normal control 3', [{'core': 999, 'surge': 10, 't': 5000}, 5301, 12], [1199, 'requoted']),\n  ('normal control 4', [{'core': 1111, 'surge': 15, 't': 5000}, 5000, 15], [1667, 'locked'])],\n [('regression: clock skew', [{'core': 1111, 'surge': 10, 't': 5000}, 4995, 20], [2222, 'requoted']),\n  ('partial repair probe: clock skew', [{'core': 2500, 'surge': 10, 't': 5000}, 4995, 20],\n   [5000, 'requoted']),\n  ('second regression', [{'core': 999, 'surge': 15, 't': 5000}, 4995, 25], [2498, 'requoted']),\n  ('normal control 1', [{'core': 999, 'surge': 15, 't': 5000}, 5299, 10], [999, 'locked']),\n  ('normal control 2', [{'core': 1111, 'surge': 15, 't': 5000}, 5120, 12], [1333, 'locked']),\n  ('normal control 3', [{'core': 1111, 'surge': 15, 't': 5000}, 5300, 20], [2222, 'requoted']),\n  ('normal control 4', [{'core': 2500, 'surge': 10, 't': 5000}, 5299, 15], [2500, 'locked'])]]\nfor label, args, expected in fixtures[N-1]:\n    check(label, 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"},"fixed":{"sha256":"497ff1a3ccf8fd55caff22a2bb24bb09d320dc73157e5d8b41bb8975f246c653","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(quote, request_t, current_surge):\n    elapsed = request_t - quote['t']\n    valid = 0 <= elapsed < 300\n    used = min(quote['surge'], current_surge) if valid else current_surge\n    price = (quote['core'] * used * 2 + 10) // 20\n    return [price, 'locked' if valid else 'requoted']\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression: clock skew', [{'core': 999, 'surge': 15, 't': 5000}, 4995, 20], [1998, 'requoted']),\n  ('partial repair probe: clock skew', [{'core': 1111, 'surge': 10, 't': 5000}, 4995, 25],\n   [2778, 'requoted']),\n  ('second regression', [{'core': 2500, 'surge': 15, 't': 5000}, 4995, 25], [6250, 'requoted']),\n  ('normal control 1', [{'core': 999, 'surge': 10, 't': 5000}, 5000, 12], [999, 'locked']),\n  ('normal control 2', [{'core': 2500, 'surge': 20, 't': 5000}, 5900, 15], [3750, 'requoted']),\n  ('normal control 3', [{'core': 2500, 'surge': 10, 't': 5000}, 5000, 25], [2500, 'locked']),\n  ('normal control 4', [{'core': 999, 'surge': 15, 't': 5000}, 5300, 12], [1199, 'requoted'])],\n [('regression: clock skew', [{'core': 1111, 'surge': 10, 't': 5000}, 4995, 12], [1333, 'requoted']),\n  ('partial repair probe: clock skew', [{'core': 999, 'surge': 20, 't': 5000}, 4995, 20], [1998, 'requoted']),\n  ('second regression', [{'core': 2500, 'surge': 10, 't': 5000}, 4995, 10], [2500, 'requoted']),\n  ('normal control 1', [{'core': 999, 'surge': 10, 't': 5000}, 5300, 15], [1499, 'requoted']),\n  ('normal control 2', [{'core': 1111, 'surge': 10, 't': 5000}, 5299, 12], [1111, 'locked']),\n  ('normal control 3', [{'core': 2500, 'surge': 15, 't': 5000}, 5001, 10], [2500, 'locked']),\n  ('normal control 4', [{'core': 1111, 'surge': 20, 't': 5000}, 5120, 12], [1333, 'locked'])],\n [('regression: clock skew', [{'core': 1111, 'surge': 15, 't': 5000}, 4995, 15], [1667, 'requoted']),\n  ('partial repair probe: clock skew', [{'core': 999, 'surge': 15, 't': 5000}, 4995, 25], [2498, 'requoted']),\n  ('second regression', [{'core': 1111, 'surge': 10, 't': 5000}, 4995, 20], [2222, 'requoted']),\n  ('normal control 1', [{'core': 2500, 'surge': 10, 't': 5000}, 5299, 10], [2500, 'locked']),\n  ('normal control 2', [{'core': 999, 'surge': 10, 't': 5000}, 5300, 20], [1998, 'requoted']),\n  ('normal control 3', [{'core': 999, 'surge': 10, 't': 5000}, 5299, 20], [999, 'locked']),\n  ('normal control 4', [{'core': 1111, 'surge': 20, 't': 5000}, 5900, 10], [1111, 'requoted'])],\n [('regression: clock skew', [{'core': 999, 'surge': 20, 't': 5000}, 4995, 25], [2498, 'requoted']),\n  ('partial repair probe: clock skew', [{'core': 999, 'surge': 20, 't': 5000}, 4995, 10], [999, 'requoted']),\n  ('second regression', [{'core': 1111, 'surge': 20, 't': 5000}, 4995, 25], [2778, 'requoted']),\n  ('normal control 1', [{'core': 2500, 'surge': 15, 't': 5000}, 5001, 10], [2500, 'locked']),\n  ('normal control 2', [{'core': 1111, 'surge': 15, 't': 5000}, 5120, 20], [1667, 'locked']),\n  ('normal control 3', [{'core': 999, 'surge': 10, 't': 5000}, 5301, 12], [1199, 'requoted']),\n  ('normal control 4', [{'core': 1111, 'surge': 15, 't': 5000}, 5000, 15], [1667, 'locked'])],\n [('regression: clock skew', [{'core': 1111, 'surge': 10, 't': 5000}, 4995, 20], [2222, 'requoted']),\n  ('partial repair probe: clock skew', [{'core': 2500, 'surge': 10, 't': 5000}, 4995, 20],\n   [5000, 'requoted']),\n  ('second regression', [{'core': 999, 'surge': 15, 't': 5000}, 4995, 25], [2498, 'requoted']),\n  ('normal control 1', [{'core': 999, 'surge': 15, 't': 5000}, 5299, 10], [999, 'locked']),\n  ('normal control 2', [{'core': 1111, 'surge': 15, 't': 5000}, 5120, 12], [1333, 'locked']),\n  ('normal control 3', [{'core': 1111, 'surge': 15, 't': 5000}, 5300, 20], [2222, 'requoted']),\n  ('normal control 4', [{'core': 2500, 'surge': 10, 't': 5000}, 5299, 15], [2500, 'locked'])]]\nfor label, args, expected in fixtures[N-1]:\n    check(label, 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 toy pricing contract stipulated for this example; it does not reproduce the pricing of any real ride-hailing operator or regulator. 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-ride-hailing-fare-surge-quote-price-lock-clock-skew","generated_at":"2026-09-29T14:50:42.179376+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Ride-hailing prices are computed per trip at scale; ordering, unit and boundary slips become systematic over- or under-charging.","repair":"Require elapsed to be non-negative.","root_cause":"Negative elapsed times pass the validity test.","sha256":"79552d2374ab3ae6e5cc2289842a9547b3b76f549f8d8defce5c990fed3b1068","title":"Request stamped before its quote treated as locked · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":43.91,"exit_code":1,"observations":[{"actual":[1499,"locked"],"check":"regression: clock skew","expected":[1998,"requoted"],"passed":false},{"actual":[1111,"locked"],"check":"partial repair probe: clock skew","expected":[2778,"requoted"],"passed":false},{"actual":[3750,"locked"],"check":"second regression","expected":[6250,"requoted"],"passed":false},{"actual":[999,"locked"],"check":"normal control 1","expected":[999,"locked"],"passed":true},{"actual":[3750,"requoted"],"check":"normal control 2","expected":[3750,"requoted"],"passed":true},{"actual":[2500,"locked"],"check":"normal control 3","expected":[2500,"locked"],"passed":true},{"actual":[1199,"requoted"],"check":"normal control 4","expected":[1199,"requoted"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: clock skew\", \"actual\": [1499, \"locked\"], \"expected\": [1998, \"requoted\"], \"passed\": false}, {\"check\": \"partial repair probe: clock skew\", \"actual\": [1111, \"locked\"], \"expected\": [2778, \"requoted\"], \"passed\": false}, {\"check\": \"second regression\", \"actual\": [3750, \"locked\"], \"expected\": [6250, \"requoted\"], \"passed\": false}, {\"check\": \"normal control 1\", \"actual\": [999, \"locked\"], \"expected\": [999, \"locked\"], \"passed\": true}, {\"check\": \"normal control 2\", \"actual\": [3750, \"requoted\"], \"expected\": [3750, \"requoted\"], \"passed\": true}, {\"check\": \"normal control 3\", \"actual\": [2500, \"locked\"], \"expected\": [2500, \"locked\"], \"passed\": true}, {\"check\": \"normal control 4\", \"actual\": [1199, \"requoted\"], \"expected\": [1199, \"requoted\"], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.993,"exit_code":1,"observations":[{"actual":[1499,"locked"],"check":"regression: clock skew","expected":[1998,"requoted"],"passed":false},{"actual":[1111,"locked"],"check":"partial repair probe: clock skew","expected":[2778,"requoted"],"passed":false},{"actual":[3750,"locked"],"check":"second regression","expected":[6250,"requoted"],"passed":false},{"actual":[999,"locked"],"check":"normal control 1","expected":[999,"locked"],"passed":true},{"actual":[3750,"requoted"],"check":"normal control 2","expected":[3750,"requoted"],"passed":true},{"actual":[2500,"locked"],"check":"normal control 3","expected":[2500,"locked"],"passed":true},{"actual":[1199,"requoted"],"check":"normal control 4","expected":[1199,"requoted"],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: clock skew\", \"actual\": [1499, \"locked\"], \"expected\": [1998, \"requoted\"], \"passed\": false}, {\"check\": \"partial repair probe: clock skew\", \"actual\": [1111, \"locked\"], \"expected\": [2778, \"requoted\"], \"passed\": false}, {\"check\": \"second regression\", \"actual\": [3750, \"locked\"], \"expected\": [6250, \"requoted\"], \"passed\": false}, {\"check\": \"normal control 1\", \"actual\": [999, \"locked\"], \"expected\": [999, \"locked\"], \"passed\": true}, {\"check\": \"normal control 2\", \"actual\": [3750, \"requoted\"], \"expected\": [3750, \"requoted\"], \"passed\": true}, {\"check\": \"normal control 3\", \"actual\": [2500, \"locked\"], \"expected\": [2500, \"locked\"], \"passed\": true}, {\"check\": \"normal control 4\", \"actual\": [1199, \"requoted\"], \"expected\": [1199, \"requoted\"], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":41.965,"exit_code":0,"observations":[{"actual":[1998,"requoted"],"check":"regression: clock skew","expected":[1998,"requoted"],"passed":true},{"actual":[2778,"requoted"],"check":"partial repair probe: clock skew","expected":[2778,"requoted"],"passed":true},{"actual":[6250,"requoted"],"check":"second regression","expected":[6250,"requoted"],"passed":true},{"actual":[999,"locked"],"check":"normal control 1","expected":[999,"locked"],"passed":true},{"actual":[3750,"requoted"],"check":"normal control 2","expected":[3750,"requoted"],"passed":true},{"actual":[2500,"locked"],"check":"normal control 3","expected":[2500,"locked"],"passed":true},{"actual":[1199,"requoted"],"check":"normal control 4","expected":[1199,"requoted"],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: clock skew\", \"actual\": [1998, \"requoted\"], \"expected\": [1998, \"requoted\"], \"passed\": true}, {\"check\": \"partial repair probe: clock skew\", \"actual\": [2778, \"requoted\"], \"expected\": [2778, \"requoted\"], \"passed\": true}, {\"check\": \"second regression\", \"actual\": [6250, \"requoted\"], \"expected\": [6250, \"requoted\"], \"passed\": true}, {\"check\": \"normal control 1\", \"actual\": [999, \"locked\"], \"expected\": [999, \"locked\"], \"passed\": true}, {\"check\": \"normal control 2\", \"actual\": [3750, \"requoted\"], \"expected\": [3750, \"requoted\"], \"passed\": true}, {\"check\": \"normal control 3\", \"actual\": [2500, \"locked\"], \"expected\": [2500, \"locked\"], \"passed\": true}, {\"check\": \"normal control 4\", \"actual\": [1199, \"requoted\"], \"expected\": [1199, \"requoted\"], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}