{
  "python": "3.14.4 (main, Apr  7 2026, 13:13:20) [Clang 21.0.0 (clang-2100.0.123.102)]",
  "sqlite": "3.51.3",
  "platform": "macOS-27.0.1-arm64-arm-64bit-Mach-O",
  "source": "examples/system-design/labs/18/timeline.py",
  "sha256": "e08e696a70f01aa79cbe7d61e5519e67c4a4cf6b439598673544d481e9f7cc1c"
}
$ /opt/homebrew/opt/python@3.14/bin/python3.14 examples/system-design/labs/18/timeline.py
{"comparison": {"push": {"write_copies": 2020, "read_candidates": 14, "feeds": {"0": [[4, "s4"], [3, "n3"], [2, "n2"], [1, "s1"]], "1": [[4, "s4"], [3, "n3"], [2, "n2"], [1, "s1"]], "15": [[4, "s4"], [1, "s1"]], "30": [[4, "s4"], [1, "s1"]], "900": [[4, "s4"], [1, "s1"]]}}, "pull": {"write_copies": 0, "read_candidates": 14, "feeds": {"0": [[4, "s4"], [3, "n3"], [2, "n2"], [1, "s1"]], "1": [[4, "s4"], [3, "n3"], [2, "n2"], [1, "s1"]], "15": [[4, "s4"], [1, "s1"]], "30": [[4, "s4"], [1, "s1"]], "900": [[4, "s4"], [1, "s1"]]}}, "hybrid": {"write_copies": 20, "read_candidates": 14, "feeds": {"0": [[4, "s4"], [3, "n3"], [2, "n2"], [1, "s1"]], "1": [[4, "s4"], [3, "n3"], [2, "n2"], [1, "s1"]], "15": [[4, "s4"], [1, "s1"]], "30": [[4, "s4"], [1, "s1"]], "900": [[4, "s4"], [1, "s1"]]}}}, "first_page": [[4, "s4"], [3, "n3"]], "next_page": [[2, "n2"], [1, "s1"]]}
PASS: same workload yields equal feeds; fanout cost differs and cursor does not repeat

EXIT_CODE=0
$ /opt/homebrew/opt/python@3.14/bin/python3.14 examples/system-design/labs/18/timeline.py --unsafe
{"comparison": {"push": {"write_copies": 2020, "read_candidates": 14, "feeds": {"0": [[4, "s4"], [3, "n3"], [2, "n2"], [1, "s1"]], "1": [[4, "s4"], [3, "n3"], [2, "n2"], [1, "s1"]], "15": [[4, "s4"], [1, "s1"]], "30": [[4, "s4"], [1, "s1"]], "900": [[4, "s4"], [1, "s1"]]}}, "pull": {"write_copies": 0, "read_candidates": 14, "feeds": {"0": [[4, "s4"], [3, "n3"], [2, "n2"], [1, "s1"]], "1": [[4, "s4"], [3, "n3"], [2, "n2"], [1, "s1"]], "15": [[4, "s4"], [1, "s1"]], "30": [[4, "s4"], [1, "s1"]], "900": [[4, "s4"], [1, "s1"]]}}, "hybrid": {"write_copies": 20, "read_candidates": 14, "feeds": {"0": [[4, "s4"], [3, "n3"], [2, "n2"], [1, "s1"]], "1": [[4, "s4"], [3, "n3"], [2, "n2"], [1, "s1"]], "15": [[4, "s4"], [1, "s1"]], "30": [[4, "s4"], [1, "s1"]], "900": [[4, "s4"], [1, "s1"]]}}}, "first_page": [[4, "s4"], [3, "n3"]], "next_page": [[2, "n2"], [1, "s1"]]}
EXPECTED_REJECTION: universal push exceeds fixed write-copy budget 100

EXIT_CODE=2