mercurial/txnutil.py
author Gregory Szorc <gregory.szorc@gmail.com>
Sat, 28 Mar 2020 13:12:43 -0700
changeset 44641 e74af49aa3c9
parent 43077 687b865b95ad
child 45942 89a2afe31e82
permissions -rw-r--r--
url: pass str to pathname2url This is needed to appease Python 3. This fixes test-extdata.t and test-url-download.t on Python 3 on Windows. Differential Revision: https://phab.mercurial-scm.org/D8335

# 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)