mercurial/txnutil.py

rebase: clean up rebasestate from active transaction

Previously, rebase assumes the following pattern:

    rebase:
        with transaction as tr: # top-level
            ...
        tr.__close__ writes rebasestate
        unlink('rebasestate')

However it's possible that "rebase" was called inside a transaction:

    with transaction as tr1:
        rebase:
            with transaction as tr2: # not top-level
                ...
            tr2.__close__ does not write rebasestate
            unlink('rebasestate')
    tr1.__close__ writes rebasestate

That leaves a rebasestate on disk incorrectly.

This patch adds "removefilegenerator" to notify transaction code that the
state file is no longer needed therefore fixes the issue.

# 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)