reachableroots: use internal "revstates" array to test if rev is a root The main goal of this patch series is to reduce the use of PyXxx() function that is likely to require ugly error handling and inc/decref. Plus, this is faster than using PySet_Contains(). revset #0: 0::tip 0) 0.004168 1) 0.003678 88% This patch ignores out-of-range roots as they are in the pure implementation. Because reachable sets are calculated from heads, and out-of-range heads raise IndexError, we can just take out-of-range roots as unreachable. Otherwise, the test of "hg log -Gr '. + wdir()'" would fail. "heads" argument is changed to a list. Should we have to rename the C function as its signature is changed?