vfs: use checkambigatclosing in checkambig=True but atomictemp=False case
In Mercurial source tree, opening a file in "a"/"a+" mode like below
doesn't specify atomictemp=True for vfs, and this avoids file stat
ambiguity check by atomictempfile.
- writing changes out in revlog layer uses "a+" mode
- truncation in repair.strip() uses "a" mode
- truncation in transaction._playback() uses "a" mode
If steps below occurs at "the same time in sec", all of mtime, ctime
and size are same between (1) and (3).
1. append data to revlog-style file (and close transaction)
2. discard appended data by truncation (strip or rollback)
3. append same size but different data to revlog-style file again
Therefore, cache validation doesn't work after (3) as expected.
This patch uses checkambigatclosing in checkambig=True but
atomictemp=False case, to check (and get rid of) file stat ambiguity
at closing.
This is a part of ExactCacheValidationPlan.
https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan
# Extension to write out fake unsupported records into the merge state
#
#
from __future__ import absolute_import
from mercurial import (
cmdutil,
merge,
)
cmdtable = {}
command = cmdutil.command(cmdtable)
@command('fakemergerecord',
[('X', 'mandatory', None, 'add a fake mandatory record'),
('x', 'advisory', None, 'add a fake advisory record')], '')
def fakemergerecord(ui, repo, *pats, **opts):
with repo.wlock():
ms = merge.mergestate.read(repo)
records = ms._makerecords()
if opts.get('mandatory'):
records.append(('X', 'mandatory record'))
if opts.get('advisory'):
records.append(('x', 'advisory record'))
ms._writerecords(records)