`slb_leading_segment_disc` was SIGKILLed by the OOM killer in `docker/ci/run`
at its 7 GB cap, so the documented 45/377 baseline did not reproduce on a 15 GB
box.
`PakArchive` holds the whole concatenated payload in memory and `sound.pak` is
1.01 GB (sound.p00-.p04). `bank()` and `bank_named()` opened it on every call --
inside loops -- and five tests opened their own besides, ~26 opens in all. With
cargo's default thread count that is ~6.1 GB of archive in flight against a
7 GB cap with `--memory-swap` equal to `--memory`, so there is no swap to
absorb it.
The archive is immutable once open and every accessor takes `&self`, so one
`OnceLock` instance is equivalent to N private ones at 1/N the memory.
⚠️ The failure mode is worth knowing: a SIGKILLed suite prints no
`test result:` line at all, so it disappears from a scraped tally instead of
failing visibly. The run still reported "0 failed" -- true, and useless. Check
cargo's exit code (101), not the tally.
Measured in the capped container, 7 GB, default threads:
* before: SIGKILL (signal 9), 0 of 10 tests reported
* after : 10 passed in 3.17s
* (single-threaded before the fix: 10 passed in 22.64s -- the fix is also
~7x faster, because it no longer re-reads 1 GB from disc 26 times)
* cargo fmt --check clean; cargo clippy --tests -D warnings clean
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
