{"abstract":"The final occurrence falling exactly on the end date is dropped.","category":"Calendar recurrence rules","checks":7,"contract":"A recurring task first due on first_due repeats every interval_days. Completions are processed in chronological order. mode \"regenerate\": the next due date is completion + interval. mode \"schedule\": completing advances to the next scheduled due date, skipping every scheduled date on or before the completion date. If the resulting due date passes until (inclusive bound, may be None), the task has no next due date (None).","contract_signature":"first_due, interval_days, mode, completions, until","evaluation_group":"w2-calendar-recurrence-rules-regenerating-task-due","failed_approach":"The partial repair `end is not None and cd > end` tests the completion date rather than the next due date.","family":"w2-calendar-recurrence-rules-regenerating-task-due-series-end","id":"FA-77336","implementations":{"attempt":{"sha256":"3fcf741d892cf91d6e3b763891be7354f4c5dd8fef350aef8e1ea1703dd1e3a3","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport datetime as dt\nimport calendar\nN = 1\nobservations = []\ndef solve(first_due, interval_days, mode, completions, until):\n    due = dt.date.fromisoformat(first_due)\n    end = dt.date.fromisoformat(until) if until else None\n    step = dt.timedelta(days=interval_days)\n    for c in sorted(completions):\n        cd = dt.date.fromisoformat(c)\n        if mode == 'regenerate':\n            due = cd + step\n        else:\n            due = due + step\n            while due <= cd:\n                due += step\n        if end is not None and cd > end:\n            return None\n    return due.isoformat()\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression: late completion on next due',\n   ['2024-01-01', 7, 'schedule', ['2024-01-08'], None],\n   '2024-01-15'),\n  ('early completion regenerate', ['2024-01-10', 7, 'regenerate', ['2024-01-05'], None], '2024-01-12'),\n  ('late completion regenerate', ['2024-01-10', 7, 'regenerate', ['2024-01-20'], None], '2024-01-27'),\n  ('out of order schedule', ['2024-01-01', 7, 'schedule', ['2024-01-20', '2024-01-02'], None], '2024-01-22'),\n  ('multiple missed schedule', ['2024-01-01', 3, 'schedule', ['2024-01-11'], None], '2024-01-13'),\n  ('until exact', ['2024-01-01', 7, 'schedule', ['2024-01-01'], '2024-01-08'], '2024-01-08'),\n  ('until passed', ['2024-01-01', 7, 'schedule', ['2024-01-01', '2024-01-08'], '2024-01-10'], None)],\n [('late completion regenerate', ['2024-01-10', 7, 'regenerate', ['2024-01-20'], None], '2024-01-27'),\n  ('out of order schedule', ['2024-01-01', 7, 'schedule', ['2024-01-20', '2024-01-02'], None], '2024-01-22'),\n  ('multiple missed schedule', ['2024-01-01', 3, 'schedule', ['2024-01-11'], None], '2024-01-13'),\n  ('until exact', ['2024-01-01', 7, 'schedule', ['2024-01-01'], '2024-01-08'], '2024-01-08'),\n  ('until passed', ['2024-01-01', 7, 'schedule', ['2024-01-01', '2024-01-08'], '2024-01-10'], None),\n  ('until regenerate', ['2024-02-01', 10, 'regenerate', ['2024-02-05'], '2024-02-15'], '2024-02-15'),\n  ('no completions', ['2024-02-01', 10, 'schedule', [], None], '2024-02-01')],\n [('multiple missed schedule', ['2024-01-01', 3, 'schedule', ['2024-01-11'], None], '2024-01-13'),\n  ('until exact', ['2024-01-01', 7, 'schedule', ['2024-01-01'], '2024-01-08'], '2024-01-08'),\n  ('until passed', ['2024-01-01', 7, 'schedule', ['2024-01-01', '2024-01-08'], '2024-01-10'], None),\n  ('until regenerate', ['2024-02-01', 10, 'regenerate', ['2024-02-05'], '2024-02-15'], '2024-02-15'),\n  ('no completions', ['2024-02-01', 10, 'schedule', [], None], '2024-02-01'),\n  ('completion after until but due inside',\n   ['2024-03-01', 30, 'schedule', ['2024-03-05'], '2024-03-31'],\n   '2024-03-31'),\n  ('two schedule completions',\n   ['2024-04-01', 14, 'schedule', ['2024-03-30', '2024-04-10'], None],\n   '2024-04-29')],\n [('until passed', ['2024-01-01', 7, 'schedule', ['2024-01-01', '2024-01-08'], '2024-01-10'], None),\n  ('until regenerate', ['2024-02-01', 10, 'regenerate', ['2024-02-05'], '2024-02-15'], '2024-02-15'),\n  ('no completions', ['2024-02-01', 10, 'schedule', [], None], '2024-02-01'),\n  ('completion after until but due inside',\n   ['2024-03-01', 30, 'schedule', ['2024-03-05'], '2024-03-31'],\n   '2024-03-31'),\n  ('two schedule completions',\n   ['2024-04-01', 14, 'schedule', ['2024-03-30', '2024-04-10'], None],\n   '2024-04-29'),\n  ('out of order regenerate',\n   ['2024-04-01', 5, 'regenerate', ['2024-04-09', '2024-04-02'], None],\n   '2024-04-14'),\n  ('regression: late completion on next due',\n   ['2024-01-01', 7, 'schedule', ['2024-01-08'], None],\n   '2024-01-15')],\n [('no completions', ['2024-02-01', 10, 'schedule', [], None], '2024-02-01'),\n  ('completion after until but due inside',\n   ['2024-03-01', 30, 'schedule', ['2024-03-05'], '2024-03-31'],\n   '2024-03-31'),\n  ('two schedule completions',\n   ['2024-04-01', 14, 'schedule', ['2024-03-30', '2024-04-10'], None],\n   '2024-04-29'),\n  ('out of order regenerate',\n   ['2024-04-01', 5, 'regenerate', ['2024-04-09', '2024-04-02'], None],\n   '2024-04-14'),\n  ('regression: late completion on next due',\n   ['2024-01-01', 7, 'schedule', ['2024-01-08'], None],\n   '2024-01-15'),\n  ('early completion regenerate', ['2024-01-10', 7, 'regenerate', ['2024-01-05'], None], '2024-01-12'),\n  ('late completion regenerate', ['2024-01-10', 7, 'regenerate', ['2024-01-20'], None], '2024-01-27'),\n  ('until passed', ['2024-01-01', 7, 'schedule', ['2024-01-01', '2024-01-08'], '2024-01-10'], None)]]\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":"dc376260c72867483427c95b9de795e1ff24441c0390708532f326c3c9860b40","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport datetime as dt\nimport calendar\nN = 1\nobservations = []\ndef solve(first_due, interval_days, mode, completions, until):\n    due = dt.date.fromisoformat(first_due)\n    end = dt.date.fromisoformat(until) if until else None\n    step = dt.timedelta(days=interval_days)\n    for c in sorted(completions):\n        cd = dt.date.fromisoformat(c)\n        if mode == 'regenerate':\n            due = cd + step\n        else:\n            due = due + step\n            while due <= cd:\n                due += step\n        if end is not None and due >= end:\n            return None\n    return due.isoformat()\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression: late completion on next due',\n   ['2024-01-01', 7, 'schedule', ['2024-01-08'], None],\n   '2024-01-15'),\n  ('early completion regenerate', ['2024-01-10', 7, 'regenerate', ['2024-01-05'], None], '2024-01-12'),\n  ('late completion regenerate', ['2024-01-10', 7, 'regenerate', ['2024-01-20'], None], '2024-01-27'),\n  ('out of order schedule', ['2024-01-01', 7, 'schedule', ['2024-01-20', '2024-01-02'], None], '2024-01-22'),\n  ('multiple missed schedule', ['2024-01-01', 3, 'schedule', ['2024-01-11'], None], '2024-01-13'),\n  ('until exact', ['2024-01-01', 7, 'schedule', ['2024-01-01'], '2024-01-08'], '2024-01-08'),\n  ('until passed', ['2024-01-01', 7, 'schedule', ['2024-01-01', '2024-01-08'], '2024-01-10'], None)],\n [('late completion regenerate', ['2024-01-10', 7, 'regenerate', ['2024-01-20'], None], '2024-01-27'),\n  ('out of order schedule', ['2024-01-01', 7, 'schedule', ['2024-01-20', '2024-01-02'], None], '2024-01-22'),\n  ('multiple missed schedule', ['2024-01-01', 3, 'schedule', ['2024-01-11'], None], '2024-01-13'),\n  ('until exact', ['2024-01-01', 7, 'schedule', ['2024-01-01'], '2024-01-08'], '2024-01-08'),\n  ('until passed', ['2024-01-01', 7, 'schedule', ['2024-01-01', '2024-01-08'], '2024-01-10'], None),\n  ('until regenerate', ['2024-02-01', 10, 'regenerate', ['2024-02-05'], '2024-02-15'], '2024-02-15'),\n  ('no completions', ['2024-02-01', 10, 'schedule', [], None], '2024-02-01')],\n [('multiple missed schedule', ['2024-01-01', 3, 'schedule', ['2024-01-11'], None], '2024-01-13'),\n  ('until exact', ['2024-01-01', 7, 'schedule', ['2024-01-01'], '2024-01-08'], '2024-01-08'),\n  ('until passed', ['2024-01-01', 7, 'schedule', ['2024-01-01', '2024-01-08'], '2024-01-10'], None),\n  ('until regenerate', ['2024-02-01', 10, 'regenerate', ['2024-02-05'], '2024-02-15'], '2024-02-15'),\n  ('no completions', ['2024-02-01', 10, 'schedule', [], None], '2024-02-01'),\n  ('completion after until but due inside',\n   ['2024-03-01', 30, 'schedule', ['2024-03-05'], '2024-03-31'],\n   '2024-03-31'),\n  ('two schedule completions',\n   ['2024-04-01', 14, 'schedule', ['2024-03-30', '2024-04-10'], None],\n   '2024-04-29')],\n [('until passed', ['2024-01-01', 7, 'schedule', ['2024-01-01', '2024-01-08'], '2024-01-10'], None),\n  ('until regenerate', ['2024-02-01', 10, 'regenerate', ['2024-02-05'], '2024-02-15'], '2024-02-15'),\n  ('no completions', ['2024-02-01', 10, 'schedule', [], None], '2024-02-01'),\n  ('completion after until but due inside',\n   ['2024-03-01', 30, 'schedule', ['2024-03-05'], '2024-03-31'],\n   '2024-03-31'),\n  ('two schedule completions',\n   ['2024-04-01', 14, 'schedule', ['2024-03-30', '2024-04-10'], None],\n   '2024-04-29'),\n  ('out of order regenerate',\n   ['2024-04-01', 5, 'regenerate', ['2024-04-09', '2024-04-02'], None],\n   '2024-04-14'),\n  ('regression: late completion on next due',\n   ['2024-01-01', 7, 'schedule', ['2024-01-08'], None],\n   '2024-01-15')],\n [('no completions', ['2024-02-01', 10, 'schedule', [], None], '2024-02-01'),\n  ('completion after until but due inside',\n   ['2024-03-01', 30, 'schedule', ['2024-03-05'], '2024-03-31'],\n   '2024-03-31'),\n  ('two schedule completions',\n   ['2024-04-01', 14, 'schedule', ['2024-03-30', '2024-04-10'], None],\n   '2024-04-29'),\n  ('out of order regenerate',\n   ['2024-04-01', 5, 'regenerate', ['2024-04-09', '2024-04-02'], None],\n   '2024-04-14'),\n  ('regression: late completion on next due',\n   ['2024-01-01', 7, 'schedule', ['2024-01-08'], None],\n   '2024-01-15'),\n  ('early completion regenerate', ['2024-01-10', 7, 'regenerate', ['2024-01-05'], None], '2024-01-12'),\n  ('late completion regenerate', ['2024-01-10', 7, 'regenerate', ['2024-01-20'], None], '2024-01-27'),\n  ('until passed', ['2024-01-01', 7, 'schedule', ['2024-01-01', '2024-01-08'], '2024-01-10'], None)]]\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":"Stipulated, bounded recurrence-expansion model evaluated offline on explicit fixtures; it is not a complete iCalendar implementation and makes no claim of standards conformance. 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-calendar-recurrence-rules-regenerating-task-due-series-end","generated_at":"2026-09-29T14:49:24.536755+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Recurring calendar series are expanded into concrete instances for display, reminders and conflict checks.","root_cause":"The end bound is treated as exclusive.","sha256":"9a0a28c3b28903a547a863ee36e5692f7847929df3e19e7042391e3a6a940f00","title":"Next due date for a recurring task after completions: series end · 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":43.229,"exit_code":1,"observations":[{"actual":"2024-01-15","check":"regression: late completion on next due","expected":"2024-01-15","passed":true},{"actual":"2024-01-12","check":"early completion regenerate","expected":"2024-01-12","passed":true},{"actual":"2024-01-27","check":"late completion regenerate","expected":"2024-01-27","passed":true},{"actual":"2024-01-22","check":"out of order schedule","expected":"2024-01-22","passed":true},{"actual":"2024-01-13","check":"multiple missed schedule","expected":"2024-01-13","passed":true},{"actual":"2024-01-08","check":"until exact","expected":"2024-01-08","passed":true},{"actual":"2024-01-15","check":"until passed","expected":null,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: late completion on next due\", \"actual\": \"2024-01-15\", \"expected\": \"2024-01-15\", \"passed\": true}, {\"check\": \"early completion regenerate\", \"actual\": \"2024-01-12\", \"expected\": \"2024-01-12\", \"passed\": true}, {\"check\": \"late completion regenerate\", \"actual\": \"2024-01-27\", \"expected\": \"2024-01-27\", \"passed\": true}, {\"check\": \"out of order schedule\", \"actual\": \"2024-01-22\", \"expected\": \"2024-01-22\", \"passed\": true}, {\"check\": \"multiple missed schedule\", \"actual\": \"2024-01-13\", \"expected\": \"2024-01-13\", \"passed\": true}, {\"check\": \"until exact\", \"actual\": \"2024-01-08\", \"expected\": \"2024-01-08\", \"passed\": true}, {\"check\": \"until passed\", \"actual\": \"2024-01-15\", \"expected\": null, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":41.485,"exit_code":1,"observations":[{"actual":"2024-01-15","check":"regression: late completion on next due","expected":"2024-01-15","passed":true},{"actual":"2024-01-12","check":"early completion regenerate","expected":"2024-01-12","passed":true},{"actual":"2024-01-27","check":"late completion regenerate","expected":"2024-01-27","passed":true},{"actual":"2024-01-22","check":"out of order schedule","expected":"2024-01-22","passed":true},{"actual":"2024-01-13","check":"multiple missed schedule","expected":"2024-01-13","passed":true},{"actual":null,"check":"until exact","expected":"2024-01-08","passed":false},{"actual":null,"check":"until passed","expected":null,"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: late completion on next due\", \"actual\": \"2024-01-15\", \"expected\": \"2024-01-15\", \"passed\": true}, {\"check\": \"early completion regenerate\", \"actual\": \"2024-01-12\", \"expected\": \"2024-01-12\", \"passed\": true}, {\"check\": \"late completion regenerate\", \"actual\": \"2024-01-27\", \"expected\": \"2024-01-27\", \"passed\": true}, {\"check\": \"out of order schedule\", \"actual\": \"2024-01-22\", \"expected\": \"2024-01-22\", \"passed\": true}, {\"check\": \"multiple missed schedule\", \"actual\": \"2024-01-13\", \"expected\": \"2024-01-13\", \"passed\": true}, {\"check\": \"until exact\", \"actual\": null, \"expected\": \"2024-01-08\", \"passed\": false}, {\"check\": \"until passed\", \"actual\": null, \"expected\": null, \"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."}}