{"abstract":"A car that plugged in before the tariff horizon is planned into slots at the end of the day.","category":"EV charging session scheduling","checks":7,"contract":"prices[i] is the tariff in cents/kWh of 15-minute slot i. The car is present for slots arrive..depart-1 (depart exclusive) clipped to the tariff horizon; arrive may be negative. Each slot delivers at most max_w//4 Wh. Fill the cheapest slots first (equal price: earlier slot first), the last slot partially. Return [[slot, wh] sorted by slot, cost in millicents (sum wh*price), unmet wh]. need_wh<=0 or max_w<=0 returns [[], 0, max(need_wh,0)].","contract_signature":"prices, arrive, depart, need_wh, max_w","evaluation_group":"w2-ev_charging_session_scheduling-tou-cheapest-slots","failed_approach":"Skipping slot 0 for early arrivals discards the first valid tariff slot.","family":"w2-ev_charging_session_scheduling-tou-cheapest-slots-pre-horizon-arrival-clipping","id":"FA-92866","implementations":{"attempt":{"sha256":"1df564d3bc161ac17dbb0b9553257384cb2cdcf8a56d20604a647487fd13113d","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(prices, arrive, depart, need_wh, max_w):\n    if need_wh <= 0 or max_w <= 0:\n        return [[], 0, max(need_wh, 0)]\n    slot_wh = max_w // 4\n    lo = max(arrive, 0) + 1 if arrive < 0 else arrive\n    hi = min(depart, len(prices))\n    window = list(range(lo, hi))\n    ranked = sorted(window, key=lambda s: (prices[s], s))\n    plan = []\n    left = need_wh\n    for s in ranked:\n        if left <= 0:\n            break\n        take = min(slot_wh, left)\n        plan.append([s, take])\n        left -= take\n    plan.sort()\n    cost = sum(wh * prices[s] for s, wh in plan)\n    return [plan, cost, left]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[['boundary: nothing needed', [[10, 20, 30], 0, 3, 0, 7400], [[], 0, 0]],\n  ['boundary: empty window', [[10, 20, 30], 2, 2, 5000, 7400], [[], 0, 5000]],\n  ['boundary: departure beyond tariff horizon', [[30, 10, 10, 20], 1, 9, 5000, 7400],\n   [[[1, 1850], [2, 1850], [3, 1300]], 63000, 0]],\n  ['regression: pre-horizon arrival clipping', [[30, 8, 15, 8, 20], -3, 4, 4000, 11000],\n   [[[1, 2750], [3, 1250]], 32000, 0]],\n  ['regression: pre-horizon arrival clipping (partial repair)',\n   [[12, 25, 12, 8, 30, 10], -1, 9, 7000, 11000], [[[0, 1500], [3, 2750], [5, 2750]], 67500, 0]],\n  ['control 1', [[25, 30, 20, 12, 12], 2, 2, 20000, 11000], [[], 0, 20000]],\n  ['control 2', [[8, 15, 12, 10, 8, 25, 12, 8, 8, 20, 20, 25, 12, 8], -3, 15, 7000, 3700],\n   [[[0, 925], [2, 925], [3, 925], [4, 925], [6, 525], [7, 925], [8, 925], [13, 925]], 63650, 0]]],\n [['boundary: nothing needed', [[10, 20, 30], 0, 3, 0, 7400], [[], 0, 0]],\n  ['boundary: empty window', [[10, 20, 30], 2, 2, 5000, 7400], [[], 0, 5000]],\n  ['boundary: departure beyond tariff horizon', [[30, 10, 10, 20], 1, 9, 5000, 7400],\n   [[[1, 1850], [2, 1850], [3, 1300]], 63000, 0]],\n  ['regression: pre-horizon arrival clipping',\n   [[25, 30, 20, 12, 30, 12, 30, 12, 30, 8, 12, 10], -1, 3, 20000, 7400],\n   [[[0, 1850], [1, 1850], [2, 1850]], 138750, 14450]],\n  ['regression: pre-horizon arrival clipping (partial repair)',\n   [[15, 12, 12, 15, 30, 25, 25, 10, 12, 15, 20, 12], -1, 14, 12500, 3700],\n   [[[0, 925], [1, 925], [2, 925], [3, 925], [4, 925], [5, 925], [6, 925], [7, 925], [8, 925],\n     [9, 925], [10, 925], [11, 925]],\n    187775, 1400]],\n  ['control 1', [[30, 12, 20, 30, 25, 30, 12, 30, 20, 10, 20, 8, 15], 7, 12, 4000, 11000],\n   [[[9, 1250], [11, 2750]], 34500, 0]],\n  ['control 2', [[12, 12, 25, 30, 8, 20, 12, 12], 3, 11, 9000, 3700],\n   [[[3, 925], [4, 925], [5, 925], [6, 925], [7, 925]], 75850, 4375]]],\n [['boundary: nothing needed', [[10, 20, 30], 0, 3, 0, 7400], [[], 0, 0]],\n  ['boundary: empty window', [[10, 20, 30], 2, 2, 5000, 7400], [[], 0, 5000]],\n  ['boundary: departure beyond tariff horizon', [[30, 10, 10, 20], 1, 9, 5000, 7400],\n   [[[1, 1850], [2, 1850], [3, 1300]], 63000, 0]],\n  ['regression: pre-horizon arrival clipping', [[15, 15, 25, 20], -1, 7, 7000, 7400],\n   [[[0, 1850], [1, 1850], [2, 1450], [3, 1850]], 128750, 0]],\n  ['regression: pre-horizon arrival clipping (partial repair)',\n   [[8, 10, 15, 10, 12, 8, 15, 20, 12, 8], -3, 7, 12500, 3700],\n   [[[0, 925], [1, 925], [2, 925], [3, 925], [4, 925], [5, 925], [6, 925]], 72150, 6025]],\n  ['control 1', [[12, 10, 15, 25, 30], 4, 4, 12500, 7400], [[], 0, 12500]],\n  ['control 2', [[30, 12, 15, 12, 30, 15, 12, 20, 20], -2, 1, 9000, 0], [[], 0, 9000]]],\n [['boundary: nothing needed', [[10, 20, 30], 0, 3, 0, 7400], [[], 0, 0]],\n  ['boundary: empty window', [[10, 20, 30], 2, 2, 5000, 7400], [[], 0, 5000]],\n  ['boundary: departure beyond tariff horizon', [[30, 10, 10, 20], 1, 9, 5000, 7400],\n   [[[1, 1850], [2, 1850], [3, 1300]], 63000, 0]],\n  ['regression: pre-horizon arrival clipping', [[10, 30, 12, 30, 30, 10], -1, 1, 12500, 11000],\n   [[[0, 2750]], 27500, 9750]],\n  ['regression: pre-horizon arrival clipping (partial repair)',\n   [[10, 12, 15, 25, 30], -1, 1, 12500, 3700], [[[0, 925]], 9250, 11575]],\n  ['control 1', [[12, 20, 8, 15, 10, 8, 25, 12, 30, 12], 2, 12, 20000, 11000],\n   [[[2, 2750], [3, 2750], [4, 2750], [5, 2750], [6, 2750], [7, 2750], [8, 750], [9, 2750]], 270000,\n    0]],\n  ['control 2', [[30, 30, 20, 12, 12, 15, 12, 10], -1, 8, 7000, 7400],\n   [[[3, 1850], [4, 1850], [6, 1450], [7, 1850]], 80300, 0]]],\n [['boundary: nothing needed', [[10, 20, 30], 0, 3, 0, 7400], [[], 0, 0]],\n  ['boundary: empty window', [[10, 20, 30], 2, 2, 5000, 7400], [[], 0, 5000]],\n  ['boundary: departure beyond tariff horizon', [[30, 10, 10, 20], 1, 9, 5000, 7400],\n   [[[1, 1850], [2, 1850], [3, 1300]], 63000, 0]],\n  ['regression: pre-horizon arrival clipping',\n   [[10, 12, 10, 20, 30, 15, 25, 12, 30, 10, 15, 12, 12], -1, 5, 9000, 7400],\n   [[[0, 1850], [1, 1850], [2, 1850], [3, 1850], [4, 1600]], 144200, 0]],\n  ['regression: pre-horizon arrival clipping (partial repair)',\n   [[12, 15, 12, 10, 12, 8, 15, 8], -1, 6, 9000, 11000],\n   [[[0, 2750], [2, 750], [3, 2750], [5, 2750]], 91500, 0]],\n  ['control 1', [[12, 12, 8, 15, 10, 12, 20, 15, 12, 10, 12, 12, 15, 15], 12, 13, 1500, 3700],\n   [[[12, 925]], 13875, 575]],\n  ['control 2', [[10, 12, 10, 8, 10, 12, 12], 2, 5, 4000, 11000],\n   [[[2, 1250], [3, 2750]], 34500, 0]]]]\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":"8da4ee6985d4cbdade5b56b3c753d98badd6c3eb7209d47d1b0639376bb8bd84","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(prices, arrive, depart, need_wh, max_w):\n    if need_wh <= 0 or max_w <= 0:\n        return [[], 0, max(need_wh, 0)]\n    slot_wh = max_w // 4\n    lo = arrive\n    hi = min(depart, len(prices))\n    window = list(range(lo, hi))\n    ranked = sorted(window, key=lambda s: (prices[s], s))\n    plan = []\n    left = need_wh\n    for s in ranked:\n        if left <= 0:\n            break\n        take = min(slot_wh, left)\n        plan.append([s, take])\n        left -= take\n    plan.sort()\n    cost = sum(wh * prices[s] for s, wh in plan)\n    return [plan, cost, left]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[['boundary: nothing needed', [[10, 20, 30], 0, 3, 0, 7400], [[], 0, 0]],\n  ['boundary: empty window', [[10, 20, 30], 2, 2, 5000, 7400], [[], 0, 5000]],\n  ['boundary: departure beyond tariff horizon', [[30, 10, 10, 20], 1, 9, 5000, 7400],\n   [[[1, 1850], [2, 1850], [3, 1300]], 63000, 0]],\n  ['regression: pre-horizon arrival clipping', [[30, 8, 15, 8, 20], -3, 4, 4000, 11000],\n   [[[1, 2750], [3, 1250]], 32000, 0]],\n  ['regression: pre-horizon arrival clipping (partial repair)',\n   [[12, 25, 12, 8, 30, 10], -1, 9, 7000, 11000], [[[0, 1500], [3, 2750], [5, 2750]], 67500, 0]],\n  ['control 1', [[25, 30, 20, 12, 12], 2, 2, 20000, 11000], [[], 0, 20000]],\n  ['control 2', [[8, 15, 12, 10, 8, 25, 12, 8, 8, 20, 20, 25, 12, 8], -3, 15, 7000, 3700],\n   [[[0, 925], [2, 925], [3, 925], [4, 925], [6, 525], [7, 925], [8, 925], [13, 925]], 63650, 0]]],\n [['boundary: nothing needed', [[10, 20, 30], 0, 3, 0, 7400], [[], 0, 0]],\n  ['boundary: empty window', [[10, 20, 30], 2, 2, 5000, 7400], [[], 0, 5000]],\n  ['boundary: departure beyond tariff horizon', [[30, 10, 10, 20], 1, 9, 5000, 7400],\n   [[[1, 1850], [2, 1850], [3, 1300]], 63000, 0]],\n  ['regression: pre-horizon arrival clipping',\n   [[25, 30, 20, 12, 30, 12, 30, 12, 30, 8, 12, 10], -1, 3, 20000, 7400],\n   [[[0, 1850], [1, 1850], [2, 1850]], 138750, 14450]],\n  ['regression: pre-horizon arrival clipping (partial repair)',\n   [[15, 12, 12, 15, 30, 25, 25, 10, 12, 15, 20, 12], -1, 14, 12500, 3700],\n   [[[0, 925], [1, 925], [2, 925], [3, 925], [4, 925], [5, 925], [6, 925], [7, 925], [8, 925],\n     [9, 925], [10, 925], [11, 925]],\n    187775, 1400]],\n  ['control 1', [[30, 12, 20, 30, 25, 30, 12, 30, 20, 10, 20, 8, 15], 7, 12, 4000, 11000],\n   [[[9, 1250], [11, 2750]], 34500, 0]],\n  ['control 2', [[12, 12, 25, 30, 8, 20, 12, 12], 3, 11, 9000, 3700],\n   [[[3, 925], [4, 925], [5, 925], [6, 925], [7, 925]], 75850, 4375]]],\n [['boundary: nothing needed', [[10, 20, 30], 0, 3, 0, 7400], [[], 0, 0]],\n  ['boundary: empty window', [[10, 20, 30], 2, 2, 5000, 7400], [[], 0, 5000]],\n  ['boundary: departure beyond tariff horizon', [[30, 10, 10, 20], 1, 9, 5000, 7400],\n   [[[1, 1850], [2, 1850], [3, 1300]], 63000, 0]],\n  ['regression: pre-horizon arrival clipping', [[15, 15, 25, 20], -1, 7, 7000, 7400],\n   [[[0, 1850], [1, 1850], [2, 1450], [3, 1850]], 128750, 0]],\n  ['regression: pre-horizon arrival clipping (partial repair)',\n   [[8, 10, 15, 10, 12, 8, 15, 20, 12, 8], -3, 7, 12500, 3700],\n   [[[0, 925], [1, 925], [2, 925], [3, 925], [4, 925], [5, 925], [6, 925]], 72150, 6025]],\n  ['control 1', [[12, 10, 15, 25, 30], 4, 4, 12500, 7400], [[], 0, 12500]],\n  ['control 2', [[30, 12, 15, 12, 30, 15, 12, 20, 20], -2, 1, 9000, 0], [[], 0, 9000]]],\n [['boundary: nothing needed', [[10, 20, 30], 0, 3, 0, 7400], [[], 0, 0]],\n  ['boundary: empty window', [[10, 20, 30], 2, 2, 5000, 7400], [[], 0, 5000]],\n  ['boundary: departure beyond tariff horizon', [[30, 10, 10, 20], 1, 9, 5000, 7400],\n   [[[1, 1850], [2, 1850], [3, 1300]], 63000, 0]],\n  ['regression: pre-horizon arrival clipping', [[10, 30, 12, 30, 30, 10], -1, 1, 12500, 11000],\n   [[[0, 2750]], 27500, 9750]],\n  ['regression: pre-horizon arrival clipping (partial repair)',\n   [[10, 12, 15, 25, 30], -1, 1, 12500, 3700], [[[0, 925]], 9250, 11575]],\n  ['control 1', [[12, 20, 8, 15, 10, 8, 25, 12, 30, 12], 2, 12, 20000, 11000],\n   [[[2, 2750], [3, 2750], [4, 2750], [5, 2750], [6, 2750], [7, 2750], [8, 750], [9, 2750]], 270000,\n    0]],\n  ['control 2', [[30, 30, 20, 12, 12, 15, 12, 10], -1, 8, 7000, 7400],\n   [[[3, 1850], [4, 1850], [6, 1450], [7, 1850]], 80300, 0]]],\n [['boundary: nothing needed', [[10, 20, 30], 0, 3, 0, 7400], [[], 0, 0]],\n  ['boundary: empty window', [[10, 20, 30], 2, 2, 5000, 7400], [[], 0, 5000]],\n  ['boundary: departure beyond tariff horizon', [[30, 10, 10, 20], 1, 9, 5000, 7400],\n   [[[1, 1850], [2, 1850], [3, 1300]], 63000, 0]],\n  ['regression: pre-horizon arrival clipping',\n   [[10, 12, 10, 20, 30, 15, 25, 12, 30, 10, 15, 12, 12], -1, 5, 9000, 7400],\n   [[[0, 1850], [1, 1850], [2, 1850], [3, 1850], [4, 1600]], 144200, 0]],\n  ['regression: pre-horizon arrival clipping (partial repair)',\n   [[12, 15, 12, 10, 12, 8, 15, 8], -1, 6, 9000, 11000],\n   [[[0, 2750], [2, 750], [3, 2750], [5, 2750]], 91500, 0]],\n  ['control 1', [[12, 12, 8, 15, 10, 12, 20, 15, 12, 10, 12, 12, 15, 15], 12, 13, 1500, 3700],\n   [[[12, 925]], 13875, 575]],\n  ['control 2', [[10, 12, 10, 8, 10, 12, 12], 2, 5, 4000, 11000],\n   [[[2, 1250], [3, 2750]], 34500, 0]]]]\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":"Deterministic stipulated toy contract for teaching; no claim of conformance with any standard, vendor protocol or production controller. 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-ev_charging_session_scheduling-tou-cheapest-slots-pre-horizon-arrival-clipping","generated_at":"2026-09-29T14:51:49.843662+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Depot, workplace and public EV chargers schedule sessions against prices, circuit limits and departure deadlines; a wrong decision silently strands a driver or overloads a feeder.","root_cause":"A negative arrival index is used directly, so Python negative indexing wraps into late slots.","sha256":"8fc197e4d633672db0631fbd8bfdb5fa84a0858da4cf7062eded19a9d67cce22","title":"Time-of-use cheapest slot plan: pre-horizon arrival clipping · 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":43.004,"exit_code":1,"observations":[{"actual":[[],0,0],"check":"boundary: nothing needed","expected":[[],0,0],"passed":true},{"actual":[[],0,5000],"check":"boundary: empty window","expected":[[],0,5000],"passed":true},{"actual":[[[1,1850],[2,1850],[3,1300]],63000,0],"check":"boundary: departure beyond tariff horizon","expected":[[[1,1850],[2,1850],[3,1300]],63000,0],"passed":true},{"actual":[[[1,2750],[3,1250]],32000,0],"check":"regression: pre-horizon arrival clipping","expected":[[[1,2750],[3,1250]],32000,0],"passed":true},{"actual":[[[2,1500],[3,2750],[5,2750]],67500,0],"check":"regression: pre-horizon arrival clipping (partial repair)","expected":[[[0,1500],[3,2750],[5,2750]],67500,0],"passed":false},{"actual":[[],0,20000],"check":"control 1","expected":[[],0,20000],"passed":true},{"actual":[[[2,925],[3,925],[4,925],[6,925],[7,925],[8,925],[12,525],[13,925]],67350,0],"check":"control 2","expected":[[[0,925],[2,925],[3,925],[4,925],[6,525],[7,925],[8,925],[13,925]],63650,0],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary: nothing needed\", \"actual\": [[], 0, 0], \"expected\": [[], 0, 0], \"passed\": true}, {\"check\": \"boundary: empty window\", \"actual\": [[], 0, 5000], \"expected\": [[], 0, 5000], \"passed\": true}, {\"check\": \"boundary: departure beyond tariff horizon\", \"actual\": [[[1, 1850], [2, 1850], [3, 1300]], 63000, 0], \"expected\": [[[1, 1850], [2, 1850], [3, 1300]], 63000, 0], \"passed\": true}, {\"check\": \"regression: pre-horizon arrival clipping\", \"actual\": [[[1, 2750], [3, 1250]], 32000, 0], \"expected\": [[[1, 2750], [3, 1250]], 32000, 0], \"passed\": true}, {\"check\": \"regression: pre-horizon arrival clipping (partial repair)\", \"actual\": [[[2, 1500], [3, 2750], [5, 2750]], 67500, 0], \"expected\": [[[0, 1500], [3, 2750], [5, 2750]], 67500, 0], \"passed\": false}, {\"check\": \"control 1\", \"actual\": [[], 0, 20000], \"expected\": [[], 0, 20000], \"passed\": true}, {\"check\": \"control 2\", \"actual\": [[[2, 925], [3, 925], [4, 925], [6, 925], [7, 925], [8, 925], [12, 525], [13, 925]], 67350, 0], \"expected\": [[[0, 925], [2, 925], [3, 925], [4, 925], [6, 525], [7, 925], [8, 925], [13, 925]], 63650, 0], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":39.821,"exit_code":1,"observations":[{"actual":[[],0,0],"check":"boundary: nothing needed","expected":[[],0,0],"passed":true},{"actual":[[],0,5000],"check":"boundary: empty window","expected":[[],0,5000],"passed":true},{"actual":[[[1,1850],[2,1850],[3,1300]],63000,0],"check":"boundary: departure beyond tariff horizon","expected":[[[1,1850],[2,1850],[3,1300]],63000,0],"passed":true},{"actual":[[[-2,2750],[1,1250]],32000,0],"check":"regression: pre-horizon arrival clipping","expected":[[[1,2750],[3,1250]],32000,0],"passed":false},{"actual":[[[-1,2750],[3,2750],[5,1500]],64500,0],"check":"regression: pre-horizon arrival clipping (partial repair)","expected":[[[0,1500],[3,2750],[5,2750]],67500,0],"passed":false},{"actual":[[],0,20000],"check":"control 1","expected":[[],0,20000],"passed":true},{"actual":[[[-2,525],[-1,925],[0,925],[3,925],[4,925],[7,925],[8,925],[13,925]],59950,0],"check":"control 2","expected":[[[0,925],[2,925],[3,925],[4,925],[6,525],[7,925],[8,925],[13,925]],63650,0],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"boundary: nothing needed\", \"actual\": [[], 0, 0], \"expected\": [[], 0, 0], \"passed\": true}, {\"check\": \"boundary: empty window\", \"actual\": [[], 0, 5000], \"expected\": [[], 0, 5000], \"passed\": true}, {\"check\": \"boundary: departure beyond tariff horizon\", \"actual\": [[[1, 1850], [2, 1850], [3, 1300]], 63000, 0], \"expected\": [[[1, 1850], [2, 1850], [3, 1300]], 63000, 0], \"passed\": true}, {\"check\": \"regression: pre-horizon arrival clipping\", \"actual\": [[[-2, 2750], [1, 1250]], 32000, 0], \"expected\": [[[1, 2750], [3, 1250]], 32000, 0], \"passed\": false}, {\"check\": \"regression: pre-horizon arrival clipping (partial repair)\", \"actual\": [[[-1, 2750], [3, 2750], [5, 1500]], 64500, 0], \"expected\": [[[0, 1500], [3, 2750], [5, 2750]], 67500, 0], \"passed\": false}, {\"check\": \"control 1\", \"actual\": [[], 0, 20000], \"expected\": [[], 0, 20000], \"passed\": true}, {\"check\": \"control 2\", \"actual\": [[[-2, 525], [-1, 925], [0, 925], [3, 925], [4, 925], [7, 925], [8, 925], [13, 925]], 59950, 0], \"expected\": [[[0, 925], [2, 925], [3, 925], [4, 925], [6, 525], [7, 925], [8, 925], [13, 925]], 63650, 0], \"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."}}