match: making visitdir() deal with non-recursive entries Primarily as an optimization to avoid recursing into directories that will never have a match inside, this classifies each matcher pattern's root as recursive or non-recursive (erring on the side of keeping it recursive, which may lead to wasteful directory or manifest walks that yield no matches). I measured the performance of "rootfilesin" in two repos: - The Firefox repo with tree manifests, with "hg files -r . -I rootfilesin:browser". The browser directory contains about 3K files across 249 subdirectories. - A specific Google-internal directory which contains 75K files across 19K subdirectories, with "hg files -r . -I rootfilesin:REDACTED". I tested with both cold and warm disk caches. Cold cache was produced by running "sync; echo 3 > /proc/sys/vm/drop_caches". Warm cache was produced by re-running the same command a few times. These were the results: Cold cache Warm cache Before After Before After firefox 0m5.1s 0m2.18s 0m0.22s 0m0.14s google3 dir 2m3.9s 0m1.57s 0m8.12s 0m0.16s Certain extensions, notably narrowhg, can depend on this for correctness (not trying to recurse into directories for which it has no information).