view mercurial/txnutil.py @ 46472:98e39f04d60e

upgrade: implement partial upgrade for upgrading persistent-nodemap Upgrading repositories to use persistent nodemap should be fast and easy as it requires only two things: 1) Updating the requirements 2) Writing a persistent-nodemap on disk For both of the steps above, we don't need to edit existing revlogs. This patch makes upgrade only do the above mentioned two steps if we are only upgarding to use persistent-nodemap feature. Since `nodemap.persist_nodemap()` assumes that there exists a nodemap file for the given revlog if we are trying to call it, this patch adds `force` argument to create a file if does not exist which is true in our upgrade case. The test changes demonstrate that we no longer write nodemap files for manifest after upgrade which I think is desirable. Differential Revision: https://phab.mercurial-scm.org/D9936
author Pulkit Goyal <7895pulkit@gmail.com>
date Mon, 01 Feb 2021 00:02:00 +0530
parents 89a2afe31e82
children 6000f5b25c9b
line wrap: on
line source

# txnutil.py - transaction related utilities
#
#  Copyright FUJIWARA Katsunori <foozy@lares.dti.ne.jp> and others
#
# 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

import errno

from . import encoding


def mayhavepending(root):
    """return whether 'root' may have pending changes, which are
    visible to this process.
    """
    return root == encoding.environ.get(b'HG_PENDING')


def trypending(root, vfs, filename, **kwargs):
    """Open  file to be read according to HG_PENDING environment variable

    This opens '.pending' of specified 'filename' only when HG_PENDING
    is equal to 'root'.

    This returns '(fp, is_pending_opened)' tuple.
    """
    if mayhavepending(root):
        try:
            return (vfs(b'%s.pending' % filename, **kwargs), True)
        except IOError as inst:
            if inst.errno != errno.ENOENT:
                raise
    return (vfs(filename, **kwargs), False)