Pierre-Yves David <pierre-yves.david@fb.com> [Mon, 06 Oct 2014 11:46:53 -0700] rev 22808
smartset: add first and last methods
In multiple places in the code, we use `someset[0]` or `someset[-1]`. This
works only because the `someset` is usually a baseset. For the same reason we
introduce a `first` and `last` methods to be implemented for all smartset
classes.
Pierre-Yves David <pierre-yves.david@fb.com> [Tue, 07 Oct 2014 00:20:00 -0700] rev 22807
getgraphlogrevs: remove user of baseset.append
A `baseset` has multiple cached results and will get even more in the future.
Making it an object "populated once" like the other smartsets makes it both safer
and simpler. The append method will be removed at some point.