view mercurial/txnutil.py @ 44139:2ad4e8aefcf4

lfs: explicitly close the file handle for the blob being uploaded

The previous code relied on reading the blob fully to close it.  The obvious
problem is if an error occurs before that point.  But there is also a problem
when using workers where the data may need to be re-read, which can't happen
once it is closed.  This eliminates the surprising behavior before attempting to
fix the worker problem.

Differential Revision: https://phab.mercurial-scm.org/D7957

# 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)