view mercurial/txnutil.py @ 44907:bf5ed664f467 stable

flags: introduce explicit testing for merging change to exec flag

It turns out that we do not seems to test the simple case for merging exec flag
changes. More advanced case are test (merging exec flag without a common
ancestors, merging with a symlink, etc…) but not the basic.

We are about introduce various fixes to merging flag change across renames,
having  the most basic case tested first seems useful.

note: We are only testing "adding" an exec flag here, not removing it. We
introduce basic test on stable and will consolidate them on default.

Differential Revision: https://phab.mercurial-scm.org/D8529

# 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(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)