rank: add a "rank" value to the revlog-entry tuple...
rank: add a "rank" value to the revlog-entry tuple
The rank of a revision is the size of sub-graph it defines as a head. In other
words, the rank of X is the size of `ancestors(X)` (X included).
This is a property that can help various algorithm and we intend to store it in
changelog-v2. We start with adding this new information to the "entry tuple",
with a default value. We will start to compute and persist the rank later.
Differential Revision:
https://phab.mercurial-scm.org/D11936
