view mercurial/txnutil.py @ 37983:b9e6b71dc272

remotenames: enable the storage config option if extension is enabled

Before this patch, the config option to store remotenames was set to False by
default and remotenames extension does not set it True. So if you enable
remotenames extension without setting 'experimental.remotenames=True', you won't
get the remotenames.

This patch makes remotenames enable the config option if then extension is
enabled which makes sense.

Differential Revision: https://phab.mercurial-scm.org/D3520

# txnutil.py - transaction related utilities
#
#  Copyright FUJIWARA Katsunori <[e-mail]> 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('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('%s.pending' % filename, **kwargs), True)
        except IOError as inst:
            if inst.errno != errno.ENOENT:
                raise
    return (vfs(filename, **kwargs), False)