annotate mercurial/txnutil.py @ 41852:db3098d02a6d

setup: exclude some internal UCRT files

When attempting to build the Inno installer locally, I was getting
several file not found errors when py2exe was crawling DLL
dependencies. The missing DLLs appear to be "internal" DLLs
used by the Universal C Runtime (UCRT). In many cases, the
missing DLLs don't appear to exist on my system at all!
Some of the DLLs have version numbers that appear to be N+1
of what the existing version number is. Maybe the "public" UCRT
DLLs are probing for version N+1 at load time and py2exe is
picking these up? Who knows.

This commit adds the non-public UCRT DLLs as found by
py2exe on my system to the excluded DLLs set. After this
change, I'm able to produce an Inno installer with an
appropriate set of DLLs.

Differential Revision: https://phab.mercurial-scm.org/D6065

# 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)