The tick_aggregator fuzz target found that TickAggregator::fill_between
allocates one placeholder Candle per skipped bucket without bounding the
gap size. An adversarial input (a clock-glitch tick years in the future)
produced an OOM on libFuzzer after malloc(~3 GB):
SUMMARY: libFuzzer: out-of-memory (malloc(3221225472))
A real-world failure mode too: a single bad timestamp from a flaky feed
could OOM the host process even though every individual tick passed
Tick::new validation.
Fix:
- Compute the gap size up-front via saturating arithmetic, before any
allocation, and refuse with Error::Malformed when it exceeds the new
MAX_GAP_FILL_CANDLES = 1_000_000 cap (≈ 1.9 years of contiguous
one-minute bars, well above any realistic missing-data window).
- Reserve the right Vec capacity in advance once we know the gap fits,
avoiding intermediate reallocations.
- Add two regression tests: gap_fill_rejects_runaway_timestamp_jump
(the fuzz scenario) and gap_fill_at_the_cap_succeeds (exact-cap input
still works).
The cap is exposed as pub const so callers can pre-validate their input
without relying on the error string.
kingchenc
df179fa579