mercurial/txnutil.py
author Pulkit Goyal <7895pulkit@gmail.com>
Wed, 09 Sep 2020 16:49:19 +0530
changeset 45524 6877b0ee5f9d
parent 43077 687b865b95ad
child 45942 89a2afe31e82
permissions -rw-r--r--
mergestate: introduce a new ACTION_KEEP_NEW `ACTION_KEEP` is overloaded and it's hard to figure out how we end up with this KEEP, what was the state of things. In a previous patch, we introduced `ACTION_KEEP_ABSENT` which represents files which are kept absent in the working directory. There is another special case where we keep the file when it's not present on both ancestor and remote side. We introduce a dedicated action for that. The goal is to use these information to make bid merge smarter. Differential Revision: https://phab.mercurial-scm.org/D9002

# 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)