Matt Mackall <mpm@selenic.com> [Fri, 27 Mar 2015 23:52:23 -0500] rev 24490
import-checker: make search algorithm non-recursive breadth-first
Breadth-first allows finding the shortest cycle including the starting
module. This lets us terminate our search early when we've discovered
shorter paths already. This gives a tremendous speed-up to the
cycle-finding portion of the test, dropping total runtime from 39s to
3s.