view mercurial/txnutil.py @ 45761:341e014fe0fb stable

repoview: only pin obsolete wdir parents while there are unresolved conflicts

I noticed after doing an update from an obsolete revision with a dirty wdir that
the obsolete commit stayed visible for no obvious reason.  It was decided in
85b03b1e4715 not to clear mergestate once all of the conflicts were resolved, in
order to allow re-resolving.  Since the point of pinning the obsolete parents
was to allow resolving in the first place (aaeccdb6e654), it makes sense to also
gate it on whether or not there are any remaining files to resolve.  This might
result in pinning again if files are marked unresolved again, but that seems
reasonable, given that it still solves the original issue.

Note that this isn't purely cosmetic- pushing with a pinned obsolete revision is
likely to cause complaints about pushing multiple heads or other unexpected
errors.  So the faster it comes out of that state, the better.

Differential Revision: https://phab.mercurial-scm.org/D9248

# 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)