hgext/remotefilelog/shallowstore.py

rewrite: simplify the `retained_extras` extra logic

First, we move the definition of value outside of the rebase extensions, as this
apply to all rebase-like operation and some live in other place (like evolve).

Second we make it a simple set, so that it is easy for an extension to add a new
value in it.

Third, we move the associated logic in core too. That make it easily available
to other extensions.

Fourth we simplify it usage, as the verbose version of the filtering is just a
handful on line long, we are just going to test all the value for updates, so
the Projection overlay is not bringing much here.

Note that, we make it a module level set, is a key is worth preserving it is
probably worth preserving in all cases. This was already the behavior prior to
this change.

# shallowstore.py - shallow store for interacting with shallow repos
#
# Copyright 2013 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.


def wrapstore(store):
    class shallowstore(store.__class__):
        def __contains__(self, path):
            # Assume it exists
            return True

    store.__class__ = shallowstore

    return store