hgext/purge.py

upgrade: speed up when we have only nodemap to downgrade

Similar to what we do on upgrade, if we have only persistent-nodemap to
downgrade we will just delete the nodemap files and update repository
requirements instead of processing all the revlogs.

After downgrade, we are left with unrequired docket and transaction files which
seems fine but can work on deleting them if someone feels we should.

Differential Revision: https://phab.mercurial-scm.org/D9992

# Copyright (C) 2006 - Marco Barisione <[e-mail]>
#
# This is a small extension for Mercurial (https://mercurial-scm.org/)
# that removes files not known to mercurial
#
# This program was inspired by the "cvspurge" script contained in CVS
# utilities (http://www.red-bean.com/cvsutils/).
#
# For help on the usage of "hg purge" use:
#  hg help purge
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, see <http://www.gnu.org/licenses/>.

'''command to delete untracked files from the working directory (DEPRECATED)

The functionality of this extension has been included in core Mercurial since
version 5.7. Please use :hg:`purge ...` instead. :hg:`purge --confirm` is now the default, unless the extension is enabled for backward compatibility.
'''

# This empty extension looks pointless, but core mercurial checks if it's loaded
# to implement the slightly different behavior documented above.