annotate mercurial/txnutil.py @ 45796:e9555305c5c6

templates: include all non-branch namespaces in default one-line summary

I left out branches and custom namespaces on purpose from D9252
because I figured that people like us (Google) who have custom
namespaces can also have custom configs. However, I just realized that
this makes everyone with the topic extension lose the topic they've
had in rebase output for a long time (ever since someone was nice
enough to add it in D741). Sorry about the churn.

The more generic template couldn't easily keep the "log.bookmark"
label in the template because the namespace is called "bookmarks"
(plural). That means that we can't be compatible with users' existing
configs for "log.bookmark", so I decided to change the labels to be in
a brand-new "oneline-summary" namespace.

Differential Revision: https://phab.mercurial-scm.org/D9262

# 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)