Pierre-Yves David <pierre-yves.david@octobus.net> [Mon, 23 Oct 2017 15:11:48 +0200] rev 3123
topic: instroduce a fast path when computing stack
We do some stack related computation during transaction now. The current
inefficiency of the revset is hurting us too much. We pre-compute a subset using
native set operation to speed things up.