localrepo: stop doing special dirstate backup at transaction open
Since the dirstate writes are already managed by the transaction, we already do
a backup of the dirstate when necessary (and even trigger one to keep `hg
rollback` happy).
We needs some special code to deal with the initial empty checkout, but it is
not too complicated.
Managing variable filename (as dirstate-v2 uses) at the "journalfile" level, is
complex and fragile (which is consistent with the fact these files are not
journal…). If we no longer do it, our life is significantly simpler.
In some sense, we apply the xkcd-1134¹ solution to our savebackup/restorebackup
problem.
[1] https://xkcd.com/1134/
(the change to test-hardlink are expect as decreasing the number of duplicated
backup drive the hardlink count down)
# Extension to write out fake unsupported records into the merge state
#
#
from mercurial import (
mergestate as mergestatemod,
registrar,
)
cmdtable = {}
command = registrar.command(cmdtable)
@command(
b'fakemergerecord',
[
(b'X', b'mandatory', None, b'add a fake mandatory record'),
(b'x', b'advisory', None, b'add a fake advisory record'),
],
'',
)
def fakemergerecord(ui, repo, *pats, **opts):
with repo.wlock():
ms = mergestatemod.mergestate.read(repo)
records = ms._makerecords()
if opts.get('mandatory'):
records.append((b'X', b'mandatory record'))
if opts.get('advisory'):
records.append((b'x', b'advisory record'))
ms._writerecords(records)