hgext/narrow/narrowdirstate.py

exthelper: reintroduce the ability to register templates

Same mechanism as revsets earlier in this series.  The LFS extension is updated
to provide test coverage.

This also seems to make the test failure around issue6033 mentioned in
0a7f582f6f1f much less regular on Windows.

# narrowdirstate.py - extensions to mercurial dirstate to support narrow clones
#
# Copyright 2017 Google, Inc.
#
# 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 mercurial.i18n import _
from mercurial import (
    error,
)

def wrapdirstate(repo, dirstate):
    """Add narrow spec dirstate ignore, block changes outside narrow spec."""

    def _editfunc(fn):
        def _wrapper(self, *args):
            narrowmatch = repo.narrowmatch()
            for f in args:
                if f is not None and not narrowmatch(f) and f not in self:
                    raise error.Abort(_("cannot track '%s' - it is outside " +
                        "the narrow clone") % f)
            return fn(self, *args)
        return _wrapper

    class narrowdirstate(dirstate.__class__):
        # Prevent adding/editing/copying/deleting files that are outside the
        # sparse checkout
        @_editfunc
        def normal(self, *args):
            return super(narrowdirstate, self).normal(*args)

        @_editfunc
        def add(self, *args):
            return super(narrowdirstate, self).add(*args)

        @_editfunc
        def normallookup(self, *args):
            return super(narrowdirstate, self).normallookup(*args)

        @_editfunc
        def copy(self, *args):
            return super(narrowdirstate, self).copy(*args)

        @_editfunc
        def remove(self, *args):
            return super(narrowdirstate, self).remove(*args)

        @_editfunc
        def merge(self, *args):
            return super(narrowdirstate, self).merge(*args)

        def rebuild(self, parent, allfiles, changedfiles=None):
            if changedfiles is None:
                # Rebuilding entire dirstate, let's filter allfiles to match the
                # narrowspec.
                allfiles = [f for f in allfiles if repo.narrowmatch()(f)]
            super(narrowdirstate, self).rebuild(parent, allfiles, changedfiles)

    dirstate.__class__ = narrowdirstate
    return dirstate