view mercurial/txnutil.py @ 42884:775224e26d74

discovery: replace "heads" by "changesets" in a output note (BC)

When using `hg push --rev X`, the subset considered by discovery is only `::X`.
In addition, `X` can be any local revisions not just local heads. As a result
the message "all local heads known locally" can be misleading. We replace it
with the more accurate "all local changesets known remotely".

The message appears when in verbose not, so this is stricly speaking a BC
breakage. I am not sure this would be a real issue in practice...

# 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)