view mercurial/txnutil.py @ 41234:4c0d4bbdc395

packaging: allow running packaging with custom uid+gid for CentOS

rpmbuild in CentOS 7 has a bug causing rpmbuild to fail
with "Bad owner/group" if spec or source files are owned
by a different user: https://github.com/rpm-software-management/rpm/issues/2

This makes it very annoying to try and build the CentOS RPMs
on CentOS with Docker.

As an alternative, this change makes it possible to do so,
using an environment variable.

Differential Revision: https://phab.mercurial-scm.org/D5571

# 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)