mercurial/txnutil.py

narrow: only send the narrowspecs back if ACL in play

I am unable to think why we need to send narrowspecs back from the server. The
current state adds a 'narrow:spec' part to each changegroup which is generated
when narrow extension is enabled. So we are sending narrowspecs on pull also.

There is a problem with sending the narrowspecs the way we are doing it right
now. We add include and exclude as parameter of the 'narrow:spec' bundle2 part.
The the len of include or exclude string increase 255 which is obvious while
working on large repos, bundle2 generation code breaks. For more on that refer
issue5952 on bugzilla.

I was thinking why we need to send the narrowspecs back, and deleted the
'narrow:spec' bundle2 part generation code and found that only narrow-acl test
has some failure.

With this patch, we will only send the 'narrow:spec' bundle2 part if ACL is
enabled because the original narrowspecs in those cases can be a subset of
narrowspecs user requested.

There are phase related output change in couple of tests. The output change
shows that we are now dealing in public phases completely. So maybe sending the
narrow:spec bundle2 part was preventing phases being exchanged or phase bundle2
data being applied.

Differential Revision: https://phab.mercurial-scm.org/D4931

# 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)