revlog: introduce an explicit NodeMap class for pure code This class make the "pure" nodemap raise the same exception than the C-extension one. This is a step toward unifying nodemap and index, the class is not meant to survive on the long run. This work is part of a refactoring to unify the revlog index and the nodemap. This unification prepare the use of a persistent nodemap. There is a new `isinstance` call, it will be cleaned up in coming changesets. Differential Revision: https://phab.mercurial-scm.org/D7312

# mercurial.revlogutils -- basic utilities for revlog
#
# Copyright 2019 Pierre-Yves David <pierre-yves.david@octobus.net>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import
from .. import error


class NodeMap(dict):
    def __missing__(self, x):
        raise error.RevlogError('unknown node: %s' % x)