mercurial/node.py

dirstate: make functions for backup aware of transaction activity

Some comments in this patch assume that subsequent patch changes
'dirstate.write()' like as below:

    def write(self, repo):
        if not self._dirty:
            return
        tr = repo.currenttransaction()
        if tr:
            tr.addfilegenerator('dirstate', (self._filename,),
                                self._writedirstate, location='plain')
            return # omit actual writing out
        st = self._opener('dirstate', "w", atomictemp=True)
        self._writedirstate(st)

This patch makes '_savebackup()' write in-memory changes out, and it
causes clearing 'self._dirty'. If dirstate isn't changed after
'_savebackup()', subsequent 'dirstate.write()' never invokes
'tr.addfilegenerator()' because 'not self._dirty' is true.

Then, 'tr.writepending()' unintentionally returns False, if there is
no other (e.g. changelog) changes pending, even though dirstate
changes are already written out at '_savebackup()'.

To avoid such situation, this patch makes '_savebackup()' explicitly
invoke 'tr.addfilegenerator()', if transaction is running.

'_savebackup()' should get awareness of transaction before 'write()',
because the former depends on the behavior of the latter before this
patch.

# node.py - basic nodeid manipulation for mercurial
#
# Copyright 2005, 2006 Matt Mackall <[e-mail]>
#
# 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 binascii

nullrev = -1
nullid = "\0" * 20

# pseudo identifiers for working directory
# (they are experimental, so don't add too many dependencies on them)
wdirrev = 0x7fffffff
wdirid = "\xff" * 20

# This ugly style has a noticeable effect in manifest parsing
hex = binascii.hexlify
bin = binascii.unhexlify

def short(node):
    return hex(node[:6])