{"abstract":"Customers who upgrade are later silently downgraded by an old scheduled change.","category":"Subscription proration billing","checks":8,"contract":"Input {cur, new, left, period, pending scheduled price|None}. Upgrade (new > cur): charge (new-cur)*left/period half-up now, switch immediately and clear any scheduled change. Downgrade: no charge, keep cur, schedule new (replacing any pending). Same price: no charge and clear the schedule. Return [charge, active_price, scheduled].","contract_signature":"x","evaluation_group":"w2-subscription-proration-upgrade-now-downgrade-later","failed_approach":"The attempt clears only schedules below the old price, keeping pending changes that are still below the new plan.","family":"w2-subscription-proration-upgrade-now-downgrade-later-upgrade-clears-schedule","id":"FA-59671","implementations":{"attempt":{"sha256":"493d2b1f2da0dfae997eaa9d2e8517f25022c3bf38656bb0b75a8d62cce60172","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    if x['new'] > x['cur']:\n        ch = ((x['new'] - x['cur']) * x['left'] * 2 + x['period']) // (2 * x['period'])\n        return [ch, x['new'], x['pending'] if x['pending'] and x['pending'] > x['cur'] else None]\n    if x['new'] < x['cur']:\n        return [0, x['cur'], x['new']]\n    return [0, x['cur'], None]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression', {'cur': 1000, 'new': 2000, 'left': 17, 'period': 30, 'pending': 2000}, [567, 2000, None]), ('regression', {'cur': 1000, 'new': 2000, 'left': 272, 'period': 365, 'pending': 500}, [745, 2000, None]), ('partial-repair probe', {'cur': 1000, 'new': 2000, 'left': 1, 'period': 30, 'pending': 2000}, [33, 2000, None]), ('partial-repair probe', {'cur': 1000, 'new': 2000, 'left': 39, 'period': 365, 'pending': 2000}, [107, 2000, None]), ('normal control', {'cur': 5000, 'new': 7500, 'left': 20, 'period': 30, 'pending': None}, [1667, 7500, None]), ('normal control', {'cur': 5000, 'new': 7500, 'left': 5, 'period': 30, 'pending': None}, [417, 7500, None]), ('normal control', {'cur': 2000, 'new': 5000, 'left': 21, 'period': 30, 'pending': None}, [2100, 5000, None]), ('normal control', {'cur': 5000, 'new': 1000, 'left': 28, 'period': 31, 'pending': 500}, [0, 5000, 1000])], [('regression', {'cur': 1000, 'new': 2000, 'left': 1, 'period': 30, 'pending': 2000}, [33, 2000, None]), ('regression', {'cur': 1000, 'new': 2000, 'left': 272, 'period': 365, 'pending': 500}, [745, 2000, None]), ('partial-repair probe', {'cur': 1000, 'new': 2000, 'left': 39, 'period': 365, 'pending': 2000}, [107, 2000, None]), ('partial-repair probe', {'cur': 1000, 'new': 5000, 'left': 16, 'period': 31, 'pending': 2000}, [2065, 5000, None]), ('normal control', {'cur': 1000, 'new': 1000, 'left': 21, 'period': 31, 'pending': None}, [0, 1000, None]), ('normal control', {'cur': 2000, 'new': 2000, 'left': 220, 'period': 365, 'pending': None}, [0, 2000, None]), ('normal control', {'cur': 5000, 'new': 5000, 'left': 26, 'period': 31, 'pending': 1000}, [0, 5000, None]), ('normal control', {'cur': 2000, 'new': 5000, 'left': 24, 'period': 30, 'pending': None}, [2400, 5000, None])], [('regression', {'cur': 1000, 'new': 2000, 'left': 39, 'period': 365, 'pending': 2000}, [107, 2000, None]), ('regression', {'cur': 1000, 'new': 2000, 'left': 1, 'period': 30, 'pending': 2000}, [33, 2000, None]), ('partial-repair probe', {'cur': 1000, 'new': 2000, 'left': 231, 'period': 365, 'pending': 2000}, [633, 2000, None]), ('partial-repair probe', {'cur': 1000, 'new': 7500, 'left': 41, 'period': 365, 'pending': 2000}, [730, 7500, None]), ('normal control', {'cur': 1000, 'new': 1000, 'left': 13, 'period': 30, 'pending': None}, [0, 1000, None]), ('normal control', {'cur': 5000, 'new': 1000, 'left': 14, 'period': 30, 'pending': 1000}, [0, 5000, 1000]), ('normal control', {'cur': 5000, 'new': 1000, 'left': 16, 'period': 31, 'pending': 500}, [0, 5000, 1000]), ('normal control', {'cur': 2000, 'new': 1000, 'left': 1, 'period': 31, 'pending': 1000}, [0, 2000, 1000])], [('regression', {'cur': 1000, 'new': 5000, 'left': 16, 'period': 31, 'pending': 2000}, [2065, 5000, None]), ('regression', {'cur': 1000, 'new': 5000, 'left': 29, 'period': 30, 'pending': 1000}, [3867, 5000, None]), ('partial-repair probe', {'cur': 1000, 'new': 5000, 'left': 0, 'period': 30, 'pending': 2000}, [0, 5000, None]), ('partial-repair probe', {'cur': 1000, 'new': 7500, 'left': 282, 'period': 365, 'pending': 2000}, [5022, 7500, None]), ('normal control', {'cur': 5000, 'new': 2000, 'left': 30, 'period': 30, 'pending': 1000}, [0, 5000, 2000]), ('normal control', {'cur': 5000, 'new': 5000, 'left': 25, 'period': 31, 'pending': 2000}, [0, 5000, None]), ('normal control', {'cur': 2000, 'new': 5000, 'left': 139, 'period': 365, 'pending': None}, [1142, 5000, None]), ('normal control', {'cur': 2000, 'new': 1000, 'left': 15, 'period': 31, 'pending': 1000}, [0, 2000, 1000])], [('regression', {'cur': 1000, 'new': 2000, 'left': 231, 'period': 365, 'pending': 2000}, [633, 2000, None]), ('regression', {'cur': 1000, 'new': 2000, 'left': 39, 'period': 365, 'pending': 2000}, [107, 2000, None]), ('partial-repair probe', {'cur': 1000, 'new': 2000, 'left': 339, 'period': 365, 'pending': 2000}, [929, 2000, None]), ('partial-repair probe', {'cur': 1000, 'new': 7500, 'left': 181, 'period': 365, 'pending': 2000}, [3223, 7500, None]), ('normal control', {'cur': 2000, 'new': 1000, 'left': 252, 'period': 365, 'pending': 500}, [0, 2000, 1000]), ('normal control', {'cur': 5000, 'new': 1000, 'left': 25, 'period': 31, 'pending': 2000}, [0, 5000, 1000]), ('normal control', {'cur': 1000, 'new': 1000, 'left': 20, 'period': 31, 'pending': 2000}, [0, 1000, None]), ('normal control', {'cur': 5000, 'new': 5000, 'left': 24, 'period': 31, 'pending': None}, [0, 5000, None])]]\nfor i, (label, args, expected) in enumerate(fixtures[N-1]):\n    check(\"%s %d\" % (label, 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":"119cfb9c445fab085185ca56a22f457228387742f1eb1f5c8f38f43487c4776d","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    if x['new'] > x['cur']:\n        ch = ((x['new'] - x['cur']) * x['left'] * 2 + x['period']) // (2 * x['period'])\n        return [ch, x['new'], x['pending']]\n    if x['new'] < x['cur']:\n        return [0, x['cur'], x['new']]\n    return [0, x['cur'], None]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression', {'cur': 1000, 'new': 2000, 'left': 17, 'period': 30, 'pending': 2000}, [567, 2000, None]), ('regression', {'cur': 1000, 'new': 2000, 'left': 272, 'period': 365, 'pending': 500}, [745, 2000, None]), ('partial-repair probe', {'cur': 1000, 'new': 2000, 'left': 1, 'period': 30, 'pending': 2000}, [33, 2000, None]), ('partial-repair probe', {'cur': 1000, 'new': 2000, 'left': 39, 'period': 365, 'pending': 2000}, [107, 2000, None]), ('normal control', {'cur': 5000, 'new': 7500, 'left': 20, 'period': 30, 'pending': None}, [1667, 7500, None]), ('normal control', {'cur': 5000, 'new': 7500, 'left': 5, 'period': 30, 'pending': None}, [417, 7500, None]), ('normal control', {'cur': 2000, 'new': 5000, 'left': 21, 'period': 30, 'pending': None}, [2100, 5000, None]), ('normal control', {'cur': 5000, 'new': 1000, 'left': 28, 'period': 31, 'pending': 500}, [0, 5000, 1000])], [('regression', {'cur': 1000, 'new': 2000, 'left': 1, 'period': 30, 'pending': 2000}, [33, 2000, None]), ('regression', {'cur': 1000, 'new': 2000, 'left': 272, 'period': 365, 'pending': 500}, [745, 2000, None]), ('partial-repair probe', {'cur': 1000, 'new': 2000, 'left': 39, 'period': 365, 'pending': 2000}, [107, 2000, None]), ('partial-repair probe', {'cur': 1000, 'new': 5000, 'left': 16, 'period': 31, 'pending': 2000}, [2065, 5000, None]), ('normal control', {'cur': 1000, 'new': 1000, 'left': 21, 'period': 31, 'pending': None}, [0, 1000, None]), ('normal control', {'cur': 2000, 'new': 2000, 'left': 220, 'period': 365, 'pending': None}, [0, 2000, None]), ('normal control', {'cur': 5000, 'new': 5000, 'left': 26, 'period': 31, 'pending': 1000}, [0, 5000, None]), ('normal control', {'cur': 2000, 'new': 5000, 'left': 24, 'period': 30, 'pending': None}, [2400, 5000, None])], [('regression', {'cur': 1000, 'new': 2000, 'left': 39, 'period': 365, 'pending': 2000}, [107, 2000, None]), ('regression', {'cur': 1000, 'new': 2000, 'left': 1, 'period': 30, 'pending': 2000}, [33, 2000, None]), ('partial-repair probe', {'cur': 1000, 'new': 2000, 'left': 231, 'period': 365, 'pending': 2000}, [633, 2000, None]), ('partial-repair probe', {'cur': 1000, 'new': 7500, 'left': 41, 'period': 365, 'pending': 2000}, [730, 7500, None]), ('normal control', {'cur': 1000, 'new': 1000, 'left': 13, 'period': 30, 'pending': None}, [0, 1000, None]), ('normal control', {'cur': 5000, 'new': 1000, 'left': 14, 'period': 30, 'pending': 1000}, [0, 5000, 1000]), ('normal control', {'cur': 5000, 'new': 1000, 'left': 16, 'period': 31, 'pending': 500}, [0, 5000, 1000]), ('normal control', {'cur': 2000, 'new': 1000, 'left': 1, 'period': 31, 'pending': 1000}, [0, 2000, 1000])], [('regression', {'cur': 1000, 'new': 5000, 'left': 16, 'period': 31, 'pending': 2000}, [2065, 5000, None]), ('regression', {'cur': 1000, 'new': 5000, 'left': 29, 'period': 30, 'pending': 1000}, [3867, 5000, None]), ('partial-repair probe', {'cur': 1000, 'new': 5000, 'left': 0, 'period': 30, 'pending': 2000}, [0, 5000, None]), ('partial-repair probe', {'cur': 1000, 'new': 7500, 'left': 282, 'period': 365, 'pending': 2000}, [5022, 7500, None]), ('normal control', {'cur': 5000, 'new': 2000, 'left': 30, 'period': 30, 'pending': 1000}, [0, 5000, 2000]), ('normal control', {'cur': 5000, 'new': 5000, 'left': 25, 'period': 31, 'pending': 2000}, [0, 5000, None]), ('normal control', {'cur': 2000, 'new': 5000, 'left': 139, 'period': 365, 'pending': None}, [1142, 5000, None]), ('normal control', {'cur': 2000, 'new': 1000, 'left': 15, 'period': 31, 'pending': 1000}, [0, 2000, 1000])], [('regression', {'cur': 1000, 'new': 2000, 'left': 231, 'period': 365, 'pending': 2000}, [633, 2000, None]), ('regression', {'cur': 1000, 'new': 2000, 'left': 39, 'period': 365, 'pending': 2000}, [107, 2000, None]), ('partial-repair probe', {'cur': 1000, 'new': 2000, 'left': 339, 'period': 365, 'pending': 2000}, [929, 2000, None]), ('partial-repair probe', {'cur': 1000, 'new': 7500, 'left': 181, 'period': 365, 'pending': 2000}, [3223, 7500, None]), ('normal control', {'cur': 2000, 'new': 1000, 'left': 252, 'period': 365, 'pending': 500}, [0, 2000, 1000]), ('normal control', {'cur': 5000, 'new': 1000, 'left': 25, 'period': 31, 'pending': 2000}, [0, 5000, 1000]), ('normal control', {'cur': 1000, 'new': 1000, 'left': 20, 'period': 31, 'pending': 2000}, [0, 1000, None]), ('normal control', {'cur': 5000, 'new': 5000, 'left': 24, 'period': 31, 'pending': None}, [0, 5000, None])]]\nfor i, (label, args, expected) in enumerate(fixtures[N-1]):\n    check(\"%s %d\" % (label, 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 teaching model of a stipulated billing rule. It makes no claim to reproduce any billing provider's exact behaviour and is not billing software. 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-subscription-proration-upgrade-now-downgrade-later-upgrade-clears-schedule","generated_at":"2026-09-29T14:46:38.489777+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Asymmetric upgrade/downgrade policies must not let a stale scheduled downgrade override an upgrade.","root_cause":"The pending scheduled change survives an immediate upgrade.","sha256":"d03ff5ac4d2193f4878f82567ad752e9120f2058f51904d55d72bad267677888","title":"Immediate upgrades and scheduled downgrades: upgrade clears schedule · 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":40.767,"exit_code":1,"observations":[{"actual":[567,2000,2000],"check":"regression 0","expected":[567,2000,null],"passed":false},{"actual":[745,2000,null],"check":"regression 1","expected":[745,2000,null],"passed":true},{"actual":[33,2000,2000],"check":"partial-repair probe 2","expected":[33,2000,null],"passed":false},{"actual":[107,2000,2000],"check":"partial-repair probe 3","expected":[107,2000,null],"passed":false},{"actual":[1667,7500,null],"check":"normal control 4","expected":[1667,7500,null],"passed":true},{"actual":[417,7500,null],"check":"normal control 5","expected":[417,7500,null],"passed":true},{"actual":[2100,5000,null],"check":"normal control 6","expected":[2100,5000,null],"passed":true},{"actual":[0,5000,1000],"check":"normal control 7","expected":[0,5000,1000],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression 0\", \"actual\": [567, 2000, 2000], \"expected\": [567, 2000, null], \"passed\": false}, {\"check\": \"regression 1\", \"actual\": [745, 2000, null], \"expected\": [745, 2000, null], \"passed\": true}, {\"check\": \"partial-repair probe 2\", \"actual\": [33, 2000, 2000], \"expected\": [33, 2000, null], \"passed\": false}, {\"check\": \"partial-repair probe 3\", \"actual\": [107, 2000, 2000], \"expected\": [107, 2000, null], \"passed\": false}, {\"check\": \"normal control 4\", \"actual\": [1667, 7500, null], \"expected\": [1667, 7500, null], \"passed\": true}, {\"check\": \"normal control 5\", \"actual\": [417, 7500, null], \"expected\": [417, 7500, null], \"passed\": true}, {\"check\": \"normal control 6\", \"actual\": [2100, 5000, null], \"expected\": [2100, 5000, null], \"passed\": true}, {\"check\": \"normal control 7\", \"actual\": [0, 5000, 1000], \"expected\": [0, 5000, 1000], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":44.238,"exit_code":1,"observations":[{"actual":[567,2000,2000],"check":"regression 0","expected":[567,2000,null],"passed":false},{"actual":[745,2000,500],"check":"regression 1","expected":[745,2000,null],"passed":false},{"actual":[33,2000,2000],"check":"partial-repair probe 2","expected":[33,2000,null],"passed":false},{"actual":[107,2000,2000],"check":"partial-repair probe 3","expected":[107,2000,null],"passed":false},{"actual":[1667,7500,null],"check":"normal control 4","expected":[1667,7500,null],"passed":true},{"actual":[417,7500,null],"check":"normal control 5","expected":[417,7500,null],"passed":true},{"actual":[2100,5000,null],"check":"normal control 6","expected":[2100,5000,null],"passed":true},{"actual":[0,5000,1000],"check":"normal control 7","expected":[0,5000,1000],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression 0\", \"actual\": [567, 2000, 2000], \"expected\": [567, 2000, null], \"passed\": false}, {\"check\": \"regression 1\", \"actual\": [745, 2000, 500], \"expected\": [745, 2000, null], \"passed\": false}, {\"check\": \"partial-repair probe 2\", \"actual\": [33, 2000, 2000], \"expected\": [33, 2000, null], \"passed\": false}, {\"check\": \"partial-repair probe 3\", \"actual\": [107, 2000, 2000], \"expected\": [107, 2000, null], \"passed\": false}, {\"check\": \"normal control 4\", \"actual\": [1667, 7500, null], \"expected\": [1667, 7500, null], \"passed\": true}, {\"check\": \"normal control 5\", \"actual\": [417, 7500, null], \"expected\": [417, 7500, null], \"passed\": true}, {\"check\": \"normal control 6\", \"actual\": [2100, 5000, null], \"expected\": [2100, 5000, null], \"passed\": true}, {\"check\": \"normal control 7\", \"actual\": [0, 5000, 1000], \"expected\": [0, 5000, 1000], \"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."}}