exchange: support declaring pull depth...
exchange: support declaring pull depth
Upcoming commits will teach exchangev2 how to perform a shallow
clone. This commit teaches hg.clone(), exchange.pull(), and
exchange.pulloperation to recognize a request for a shallow clone
by having the caller specify a numeric depth of the maximum number of
ancestor changesets to fetch.
There are certainly other ways we could control shallow-ness. But this
one is simple to implement and is also how the narrow extension
controls things. So it seems to make sense to start here.
Differential Revision:
https://phab.mercurial-scm.org/D5136
