Jonathan Brouwer 7b658037fd Rollup merge of #154865 - sunshowers:binary-search-test, r=Mark-Simulacrum ...

libtest: use binary search for --exact test filtering

When `--exact` is passed in, use binary search for O(f log n) lookups instead of an O(n) linear scan, under the assumption that f << n (which is true for the most relevant cases).

This is important for Miri, where the interpreted execution makes the linear scan very expensive.

I measured this against a repo with 1000 empty tests, running `cargo +stage1 miri nextest run test_00` (100 tests) under hyperfine:

* Before (linear scan): 49.7s ± 0.6s
* After (binary search): 41.9s ± 0.2s  (-15.7%)

I also tried a few other variations (particularly swapping matching tests to the front of the list + truncating the list), but the index + swap_remove approach proved to be the fastest.

Questions:

- [ ] To be conservative, I've assumed that test_main can potentially receive an unsorted list of tests. Is this assumption correct?

2026-04-19 16:04:32 +02:00

..

src

Rollup merge of #154865 - sunshowers:binary-search-test, r=Mark-Simulacrum

2026-04-19 16:04:32 +02:00

Cargo.toml

update thin-vec

2026-04-08 21:09:07 +02:00