mercurial/txnutil.py
author Martin von Zweigbergk <martinvonz@google.com>
Wed, 28 Apr 2021 08:48:10 -0700
changeset 47019 c4dbbaecaad3
parent 45942 89a2afe31e82
child 48875 6000f5b25c9b
permissions -rw-r--r--
rewriteutil: adapt "cannot %s while merging" to work with "change branch of" `rewriteutil.precheck()` creates error messages by inserting a given verb into a sentence. The `hg branch -r` command passes in "change branch of" as the verb. That doesn't work well with "cannot %s while merging" (making it "cannot change branch of while merging"). Let's insert a "changeset" there to make it work better. Building sentences like this seems obviously bad for i18n, but fixing that is out of scope for this series, IMO. Differential Revision: https://phab.mercurial-scm.org/D10530

# 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)