How does RegexSet cache programs?

[adamchalmers]

Hi! I'm trying to find the source of some memory leaks in a gRPC server my team is building. One of the endpoints runs some RegexSets over some inputs.

I'm using dhat to measure memory usage, and I notice running RegexSet::matches(field).into_iter().next() adds around 2.4kb of memory leak per run. I know the RegexSets have an internal cache where they store programs. I was wondering if this cache grows unboundedly? Is it possible to put a limit on the cache size, or to describe the cache behaviour in the crate's docs?

[BurntSushi]

I think it would be better to treat this as a bug report. So I've created an issue from this discussion and responded there: #875