mercurial/txnutil.py

transaction: remember original len(repo) instead of tracking added revs (API)

It's silly to keep updating xrange(len(changelog), len(changelog) + 1) for
each added revision. Instead, let's simply remember the first revision to
be added.

The test output slightly changed as the branch cache is also warmed up by
stream clone, which seems more consistent.

.. api::

   ``tr.changes['revs']`` is replaced by ``tr.changes['origrepolen']`` which
   is the first revision number to be added.

# 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)