view mercurial/txnutil.py @ 35473:02f54a1ec9eb

lfs: add note messages indicating what store holds the lfs blob

The following corruption related patches were written prior to adding the user
level cache, and it took awhile to track down why the tests changed.  (It
generally made things more resilient.)  But I think this will be useful to the
end user as well.  I didn't make it --debug level, because there can be a ton of
info coming out of clone/push/pull --debug.  The pointers are sorted for test
stability.

I opted for ui.note() instead of checking ui.verbose and then using ui.write()
for convenience, but I see most of this extension does the latter.  I have no
idea what the preferred form is.

# 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)